LCOV - code coverage report
Current view: top level - src/backend/optimizer/path - indxpath.c (source / functions) Hit Total Coverage
Test: PostgreSQL 18devel Lines: 1154 1228 94.0 %
Date: 2025-04-24 12:15:10 Functions: 47 48 97.9 %
Legend: Lines: hit not hit

          Line data    Source code
       1             : /*-------------------------------------------------------------------------
       2             :  *
       3             :  * indxpath.c
       4             :  *    Routines to determine which indexes are usable for scanning a
       5             :  *    given relation, and create Paths accordingly.
       6             :  *
       7             :  * Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group
       8             :  * Portions Copyright (c) 1994, Regents of the University of California
       9             :  *
      10             :  *
      11             :  * IDENTIFICATION
      12             :  *    src/backend/optimizer/path/indxpath.c
      13             :  *
      14             :  *-------------------------------------------------------------------------
      15             :  */
      16             : #include "postgres.h"
      17             : 
      18             : #include <math.h>
      19             : 
      20             : #include "access/stratnum.h"
      21             : #include "access/sysattr.h"
      22             : #include "catalog/pg_am.h"
      23             : #include "catalog/pg_amop.h"
      24             : #include "catalog/pg_operator.h"
      25             : #include "catalog/pg_opfamily.h"
      26             : #include "catalog/pg_type.h"
      27             : #include "nodes/makefuncs.h"
      28             : #include "nodes/nodeFuncs.h"
      29             : #include "nodes/supportnodes.h"
      30             : #include "optimizer/cost.h"
      31             : #include "optimizer/optimizer.h"
      32             : #include "optimizer/pathnode.h"
      33             : #include "optimizer/paths.h"
      34             : #include "optimizer/prep.h"
      35             : #include "optimizer/restrictinfo.h"
      36             : #include "utils/lsyscache.h"
      37             : #include "utils/selfuncs.h"
      38             : 
      39             : 
      40             : /* XXX see PartCollMatchesExprColl */
      41             : #define IndexCollMatchesExprColl(idxcollation, exprcollation) \
      42             :     ((idxcollation) == InvalidOid || (idxcollation) == (exprcollation))
      43             : 
      44             : /* Whether we are looking for plain indexscan, bitmap scan, or either */
      45             : typedef enum
      46             : {
      47             :     ST_INDEXSCAN,               /* must support amgettuple */
      48             :     ST_BITMAPSCAN,              /* must support amgetbitmap */
      49             :     ST_ANYSCAN,                 /* either is okay */
      50             : } ScanTypeControl;
      51             : 
      52             : /* Data structure for collecting qual clauses that match an index */
      53             : typedef struct
      54             : {
      55             :     bool        nonempty;       /* True if lists are not all empty */
      56             :     /* Lists of IndexClause nodes, one list per index column */
      57             :     List       *indexclauses[INDEX_MAX_KEYS];
      58             : } IndexClauseSet;
      59             : 
      60             : /* Per-path data used within choose_bitmap_and() */
      61             : typedef struct
      62             : {
      63             :     Path       *path;           /* IndexPath, BitmapAndPath, or BitmapOrPath */
      64             :     List       *quals;          /* the WHERE clauses it uses */
      65             :     List       *preds;          /* predicates of its partial index(es) */
      66             :     Bitmapset  *clauseids;      /* quals+preds represented as a bitmapset */
      67             :     bool        unclassifiable; /* has too many quals+preds to process? */
      68             : } PathClauseUsage;
      69             : 
      70             : /* Callback argument for ec_member_matches_indexcol */
      71             : typedef struct
      72             : {
      73             :     IndexOptInfo *index;        /* index we're considering */
      74             :     int         indexcol;       /* index column we want to match to */
      75             : } ec_member_matches_arg;
      76             : 
      77             : 
      78             : static void consider_index_join_clauses(PlannerInfo *root, RelOptInfo *rel,
      79             :                                         IndexOptInfo *index,
      80             :                                         IndexClauseSet *rclauseset,
      81             :                                         IndexClauseSet *jclauseset,
      82             :                                         IndexClauseSet *eclauseset,
      83             :                                         List **bitindexpaths);
      84             : static void consider_index_join_outer_rels(PlannerInfo *root, RelOptInfo *rel,
      85             :                                            IndexOptInfo *index,
      86             :                                            IndexClauseSet *rclauseset,
      87             :                                            IndexClauseSet *jclauseset,
      88             :                                            IndexClauseSet *eclauseset,
      89             :                                            List **bitindexpaths,
      90             :                                            List *indexjoinclauses,
      91             :                                            int considered_clauses,
      92             :                                            List **considered_relids);
      93             : static void get_join_index_paths(PlannerInfo *root, RelOptInfo *rel,
      94             :                                  IndexOptInfo *index,
      95             :                                  IndexClauseSet *rclauseset,
      96             :                                  IndexClauseSet *jclauseset,
      97             :                                  IndexClauseSet *eclauseset,
      98             :                                  List **bitindexpaths,
      99             :                                  Relids relids,
     100             :                                  List **considered_relids);
     101             : static bool eclass_already_used(EquivalenceClass *parent_ec, Relids oldrelids,
     102             :                                 List *indexjoinclauses);
     103             : static void get_index_paths(PlannerInfo *root, RelOptInfo *rel,
     104             :                             IndexOptInfo *index, IndexClauseSet *clauses,
     105             :                             List **bitindexpaths);
     106             : static List *build_index_paths(PlannerInfo *root, RelOptInfo *rel,
     107             :                                IndexOptInfo *index, IndexClauseSet *clauses,
     108             :                                bool useful_predicate,
     109             :                                ScanTypeControl scantype,
     110             :                                bool *skip_nonnative_saop);
     111             : static List *build_paths_for_OR(PlannerInfo *root, RelOptInfo *rel,
     112             :                                 List *clauses, List *other_clauses);
     113             : static List *generate_bitmap_or_paths(PlannerInfo *root, RelOptInfo *rel,
     114             :                                       List *clauses, List *other_clauses);
     115             : static Path *choose_bitmap_and(PlannerInfo *root, RelOptInfo *rel,
     116             :                                List *paths);
     117             : static int  path_usage_comparator(const void *a, const void *b);
     118             : static Cost bitmap_scan_cost_est(PlannerInfo *root, RelOptInfo *rel,
     119             :                                  Path *ipath);
     120             : static Cost bitmap_and_cost_est(PlannerInfo *root, RelOptInfo *rel,
     121             :                                 List *paths);
     122             : static PathClauseUsage *classify_index_clause_usage(Path *path,
     123             :                                                     List **clauselist);
     124             : static void find_indexpath_quals(Path *bitmapqual, List **quals, List **preds);
     125             : static int  find_list_position(Node *node, List **nodelist);
     126             : static bool check_index_only(RelOptInfo *rel, IndexOptInfo *index);
     127             : static double get_loop_count(PlannerInfo *root, Index cur_relid, Relids outer_relids);
     128             : static double adjust_rowcount_for_semijoins(PlannerInfo *root,
     129             :                                             Index cur_relid,
     130             :                                             Index outer_relid,
     131             :                                             double rowcount);
     132             : static double approximate_joinrel_size(PlannerInfo *root, Relids relids);
     133             : static void match_restriction_clauses_to_index(PlannerInfo *root,
     134             :                                                IndexOptInfo *index,
     135             :                                                IndexClauseSet *clauseset);
     136             : static void match_join_clauses_to_index(PlannerInfo *root,
     137             :                                         RelOptInfo *rel, IndexOptInfo *index,
     138             :                                         IndexClauseSet *clauseset,
     139             :                                         List **joinorclauses);
     140             : static void match_eclass_clauses_to_index(PlannerInfo *root,
     141             :                                           IndexOptInfo *index,
     142             :                                           IndexClauseSet *clauseset);
     143             : static void match_clauses_to_index(PlannerInfo *root,
     144             :                                    List *clauses,
     145             :                                    IndexOptInfo *index,
     146             :                                    IndexClauseSet *clauseset);
     147             : static void match_clause_to_index(PlannerInfo *root,
     148             :                                   RestrictInfo *rinfo,
     149             :                                   IndexOptInfo *index,
     150             :                                   IndexClauseSet *clauseset);
     151             : static IndexClause *match_clause_to_indexcol(PlannerInfo *root,
     152             :                                              RestrictInfo *rinfo,
     153             :                                              int indexcol,
     154             :                                              IndexOptInfo *index);
     155             : static bool IsBooleanOpfamily(Oid opfamily);
     156             : static IndexClause *match_boolean_index_clause(PlannerInfo *root,
     157             :                                                RestrictInfo *rinfo,
     158             :                                                int indexcol, IndexOptInfo *index);
     159             : static IndexClause *match_opclause_to_indexcol(PlannerInfo *root,
     160             :                                                RestrictInfo *rinfo,
     161             :                                                int indexcol,
     162             :                                                IndexOptInfo *index);
     163             : static IndexClause *match_funcclause_to_indexcol(PlannerInfo *root,
     164             :                                                  RestrictInfo *rinfo,
     165             :                                                  int indexcol,
     166             :                                                  IndexOptInfo *index);
     167             : static IndexClause *get_index_clause_from_support(PlannerInfo *root,
     168             :                                                   RestrictInfo *rinfo,
     169             :                                                   Oid funcid,
     170             :                                                   int indexarg,
     171             :                                                   int indexcol,
     172             :                                                   IndexOptInfo *index);
     173             : static IndexClause *match_saopclause_to_indexcol(PlannerInfo *root,
     174             :                                                  RestrictInfo *rinfo,
     175             :                                                  int indexcol,
     176             :                                                  IndexOptInfo *index);
     177             : static IndexClause *match_rowcompare_to_indexcol(PlannerInfo *root,
     178             :                                                  RestrictInfo *rinfo,
     179             :                                                  int indexcol,
     180             :                                                  IndexOptInfo *index);
     181             : static IndexClause *match_orclause_to_indexcol(PlannerInfo *root,
     182             :                                                RestrictInfo *rinfo,
     183             :                                                int indexcol,
     184             :                                                IndexOptInfo *index);
     185             : static IndexClause *expand_indexqual_rowcompare(PlannerInfo *root,
     186             :                                                 RestrictInfo *rinfo,
     187             :                                                 int indexcol,
     188             :                                                 IndexOptInfo *index,
     189             :                                                 Oid expr_op,
     190             :                                                 bool var_on_left);
     191             : static void match_pathkeys_to_index(IndexOptInfo *index, List *pathkeys,
     192             :                                     List **orderby_clauses_p,
     193             :                                     List **clause_columns_p);
     194             : static Expr *match_clause_to_ordering_op(IndexOptInfo *index,
     195             :                                          int indexcol, Expr *clause, Oid pk_opfamily);
     196             : static bool ec_member_matches_indexcol(PlannerInfo *root, RelOptInfo *rel,
     197             :                                        EquivalenceClass *ec, EquivalenceMember *em,
     198             :                                        void *arg);
     199             : 
     200             : 
     201             : /*
     202             :  * create_index_paths()
     203             :  *    Generate all interesting index paths for the given relation.
     204             :  *    Candidate paths are added to the rel's pathlist (using add_path).
     205             :  *
     206             :  * To be considered for an index scan, an index must match one or more
     207             :  * restriction clauses or join clauses from the query's qual condition,
     208             :  * or match the query's ORDER BY condition, or have a predicate that
     209             :  * matches the query's qual condition.
     210             :  *
     211             :  * There are two basic kinds of index scans.  A "plain" index scan uses
     212             :  * only restriction clauses (possibly none at all) in its indexqual,
     213             :  * so it can be applied in any context.  A "parameterized" index scan uses
     214             :  * join clauses (plus restriction clauses, if available) in its indexqual.
     215             :  * When joining such a scan to one of the relations supplying the other
     216             :  * variables used in its indexqual, the parameterized scan must appear as
     217             :  * the inner relation of a nestloop join; it can't be used on the outer side,
     218             :  * nor in a merge or hash join.  In that context, values for the other rels'
     219             :  * attributes are available and fixed during any one scan of the indexpath.
     220             :  *
     221             :  * An IndexPath is generated and submitted to add_path() for each plain or
     222             :  * parameterized index scan this routine deems potentially interesting for
     223             :  * the current query.
     224             :  *
     225             :  * 'rel' is the relation for which we want to generate index paths
     226             :  *
     227             :  * Note: check_index_predicates() must have been run previously for this rel.
     228             :  *
     229             :  * Note: in cases involving LATERAL references in the relation's tlist, it's
     230             :  * possible that rel->lateral_relids is nonempty.  Currently, we include
     231             :  * lateral_relids into the parameterization reported for each path, but don't
     232             :  * take it into account otherwise.  The fact that any such rels *must* be
     233             :  * available as parameter sources perhaps should influence our choices of
     234             :  * index quals ... but for now, it doesn't seem worth troubling over.
     235             :  * In particular, comments below about "unparameterized" paths should be read
     236             :  * as meaning "unparameterized so far as the indexquals are concerned".
     237             :  */
     238             : void
     239      399858 : create_index_paths(PlannerInfo *root, RelOptInfo *rel)
     240             : {
     241             :     List       *indexpaths;
     242             :     List       *bitindexpaths;
     243             :     List       *bitjoinpaths;
     244             :     List       *joinorclauses;
     245             :     IndexClauseSet rclauseset;
     246             :     IndexClauseSet jclauseset;
     247             :     IndexClauseSet eclauseset;
     248             :     ListCell   *lc;
     249             : 
     250             :     /* Skip the whole mess if no indexes */
     251      399858 :     if (rel->indexlist == NIL)
     252       68670 :         return;
     253             : 
     254             :     /* Bitmap paths are collected and then dealt with at the end */
     255      331188 :     bitindexpaths = bitjoinpaths = joinorclauses = NIL;
     256             : 
     257             :     /* Examine each index in turn */
     258     1049284 :     foreach(lc, rel->indexlist)
     259             :     {
     260      718096 :         IndexOptInfo *index = (IndexOptInfo *) lfirst(lc);
     261             : 
     262             :         /* Protect limited-size array in IndexClauseSets */
     263             :         Assert(index->nkeycolumns <= INDEX_MAX_KEYS);
     264             : 
     265             :         /*
     266             :          * Ignore partial indexes that do not match the query.
     267             :          * (generate_bitmap_or_paths() might be able to do something with
     268             :          * them, but that's of no concern here.)
     269             :          */
     270      718096 :         if (index->indpred != NIL && !index->predOK)
     271         496 :             continue;
     272             : 
     273             :         /*
     274             :          * Identify the restriction clauses that can match the index.
     275             :          */
     276    24398400 :         MemSet(&rclauseset, 0, sizeof(rclauseset));
     277      717600 :         match_restriction_clauses_to_index(root, index, &rclauseset);
     278             : 
     279             :         /*
     280             :          * Build index paths from the restriction clauses.  These will be
     281             :          * non-parameterized paths.  Plain paths go directly to add_path(),
     282             :          * bitmap paths are added to bitindexpaths to be handled below.
     283             :          */
     284      717600 :         get_index_paths(root, rel, index, &rclauseset,
     285             :                         &bitindexpaths);
     286             : 
     287             :         /*
     288             :          * Identify the join clauses that can match the index.  For the moment
     289             :          * we keep them separate from the restriction clauses.  Note that this
     290             :          * step finds only "loose" join clauses that have not been merged into
     291             :          * EquivalenceClasses.  Also, collect join OR clauses for later.
     292             :          */
     293    24398400 :         MemSet(&jclauseset, 0, sizeof(jclauseset));
     294      717600 :         match_join_clauses_to_index(root, rel, index,
     295             :                                     &jclauseset, &joinorclauses);
     296             : 
     297             :         /*
     298             :          * Look for EquivalenceClasses that can generate joinclauses matching
     299             :          * the index.
     300             :          */
     301    24398400 :         MemSet(&eclauseset, 0, sizeof(eclauseset));
     302      717600 :         match_eclass_clauses_to_index(root, index,
     303             :                                       &eclauseset);
     304             : 
     305             :         /*
     306             :          * If we found any plain or eclass join clauses, build parameterized
     307             :          * index paths using them.
     308             :          */
     309      717600 :         if (jclauseset.nonempty || eclauseset.nonempty)
     310      131040 :             consider_index_join_clauses(root, rel, index,
     311             :                                         &rclauseset,
     312             :                                         &jclauseset,
     313             :                                         &eclauseset,
     314             :                                         &bitjoinpaths);
     315             :     }
     316             : 
     317             :     /*
     318             :      * Generate BitmapOrPaths for any suitable OR-clauses present in the
     319             :      * restriction list.  Add these to bitindexpaths.
     320             :      */
     321      331188 :     indexpaths = generate_bitmap_or_paths(root, rel,
     322             :                                           rel->baserestrictinfo, NIL);
     323      331188 :     bitindexpaths = list_concat(bitindexpaths, indexpaths);
     324             : 
     325             :     /*
     326             :      * Likewise, generate BitmapOrPaths for any suitable OR-clauses present in
     327             :      * the joinclause list.  Add these to bitjoinpaths.
     328             :      */
     329      331188 :     indexpaths = generate_bitmap_or_paths(root, rel,
     330             :                                           joinorclauses, rel->baserestrictinfo);
     331      331188 :     bitjoinpaths = list_concat(bitjoinpaths, indexpaths);
     332             : 
     333             :     /*
     334             :      * If we found anything usable, generate a BitmapHeapPath for the most
     335             :      * promising combination of restriction bitmap index paths.  Note there
     336             :      * will be only one such path no matter how many indexes exist.  This
     337             :      * should be sufficient since there's basically only one figure of merit
     338             :      * (total cost) for such a path.
     339             :      */
     340      331188 :     if (bitindexpaths != NIL)
     341             :     {
     342             :         Path       *bitmapqual;
     343             :         BitmapHeapPath *bpath;
     344             : 
     345      200732 :         bitmapqual = choose_bitmap_and(root, rel, bitindexpaths);
     346      200732 :         bpath = create_bitmap_heap_path(root, rel, bitmapqual,
     347             :                                         rel->lateral_relids, 1.0, 0);
     348      200732 :         add_path(rel, (Path *) bpath);
     349             : 
     350             :         /* create a partial bitmap heap path */
     351      200732 :         if (rel->consider_parallel && rel->lateral_relids == NULL)
     352      144632 :             create_partial_bitmap_paths(root, rel, bitmapqual);
     353             :     }
     354             : 
     355             :     /*
     356             :      * Likewise, if we found anything usable, generate BitmapHeapPaths for the
     357             :      * most promising combinations of join bitmap index paths.  Our strategy
     358             :      * is to generate one such path for each distinct parameterization seen
     359             :      * among the available bitmap index paths.  This may look pretty
     360             :      * expensive, but usually there won't be very many distinct
     361             :      * parameterizations.  (This logic is quite similar to that in
     362             :      * consider_index_join_clauses, but we're working with whole paths not
     363             :      * individual clauses.)
     364             :      */
     365      331188 :     if (bitjoinpaths != NIL)
     366             :     {
     367             :         List       *all_path_outers;
     368             : 
     369             :         /* Identify each distinct parameterization seen in bitjoinpaths */
     370      119848 :         all_path_outers = NIL;
     371      264346 :         foreach(lc, bitjoinpaths)
     372             :         {
     373      144498 :             Path       *path = (Path *) lfirst(lc);
     374      144498 :             Relids      required_outer = PATH_REQ_OUTER(path);
     375             : 
     376      144498 :             all_path_outers = list_append_unique(all_path_outers,
     377             :                                                  required_outer);
     378             :         }
     379             : 
     380             :         /* Now, for each distinct parameterization set ... */
     381      257354 :         foreach(lc, all_path_outers)
     382             :         {
     383      137506 :             Relids      max_outers = (Relids) lfirst(lc);
     384             :             List       *this_path_set;
     385             :             Path       *bitmapqual;
     386             :             Relids      required_outer;
     387             :             double      loop_count;
     388             :             BitmapHeapPath *bpath;
     389             :             ListCell   *lcp;
     390             : 
     391             :             /* Identify all the bitmap join paths needing no more than that */
     392      137506 :             this_path_set = NIL;
     393      329814 :             foreach(lcp, bitjoinpaths)
     394             :             {
     395      192308 :                 Path       *path = (Path *) lfirst(lcp);
     396             : 
     397      192308 :                 if (bms_is_subset(PATH_REQ_OUTER(path), max_outers))
     398      151480 :                     this_path_set = lappend(this_path_set, path);
     399             :             }
     400             : 
     401             :             /*
     402             :              * Add in restriction bitmap paths, since they can be used
     403             :              * together with any join paths.
     404             :              */
     405      137506 :             this_path_set = list_concat(this_path_set, bitindexpaths);
     406             : 
     407             :             /* Select best AND combination for this parameterization */
     408      137506 :             bitmapqual = choose_bitmap_and(root, rel, this_path_set);
     409             : 
     410             :             /* And push that path into the mix */
     411      137506 :             required_outer = PATH_REQ_OUTER(bitmapqual);
     412      137506 :             loop_count = get_loop_count(root, rel->relid, required_outer);
     413      137506 :             bpath = create_bitmap_heap_path(root, rel, bitmapqual,
     414             :                                             required_outer, loop_count, 0);
     415      137506 :             add_path(rel, (Path *) bpath);
     416             :         }
     417             :     }
     418             : }
     419             : 
     420             : /*
     421             :  * consider_index_join_clauses
     422             :  *    Given sets of join clauses for an index, decide which parameterized
     423             :  *    index paths to build.
     424             :  *
     425             :  * Plain indexpaths are sent directly to add_path, while potential
     426             :  * bitmap indexpaths are added to *bitindexpaths for later processing.
     427             :  *
     428             :  * 'rel' is the index's heap relation
     429             :  * 'index' is the index for which we want to generate paths
     430             :  * 'rclauseset' is the collection of indexable restriction clauses
     431             :  * 'jclauseset' is the collection of indexable simple join clauses
     432             :  * 'eclauseset' is the collection of indexable clauses from EquivalenceClasses
     433             :  * '*bitindexpaths' is the list to add bitmap paths to
     434             :  */
     435             : static void
     436      131040 : consider_index_join_clauses(PlannerInfo *root, RelOptInfo *rel,
     437             :                             IndexOptInfo *index,
     438             :                             IndexClauseSet *rclauseset,
     439             :                             IndexClauseSet *jclauseset,
     440             :                             IndexClauseSet *eclauseset,
     441             :                             List **bitindexpaths)
     442             : {
     443      131040 :     int         considered_clauses = 0;
     444      131040 :     List       *considered_relids = NIL;
     445             :     int         indexcol;
     446             : 
     447             :     /*
     448             :      * The strategy here is to identify every potentially useful set of outer
     449             :      * rels that can provide indexable join clauses.  For each such set,
     450             :      * select all the join clauses available from those outer rels, add on all
     451             :      * the indexable restriction clauses, and generate plain and/or bitmap
     452             :      * index paths for that set of clauses.  This is based on the assumption
     453             :      * that it's always better to apply a clause as an indexqual than as a
     454             :      * filter (qpqual); which is where an available clause would end up being
     455             :      * applied if we omit it from the indexquals.
     456             :      *
     457             :      * This looks expensive, but in most practical cases there won't be very
     458             :      * many distinct sets of outer rels to consider.  As a safety valve when
     459             :      * that's not true, we use a heuristic: limit the number of outer rel sets
     460             :      * considered to a multiple of the number of clauses considered.  (We'll
     461             :      * always consider using each individual join clause, though.)
     462             :      *
     463             :      * For simplicity in selecting relevant clauses, we represent each set of
     464             :      * outer rels as a maximum set of clause_relids --- that is, the indexed
     465             :      * relation itself is also included in the relids set.  considered_relids
     466             :      * lists all relids sets we've already tried.
     467             :      */
     468      327342 :     for (indexcol = 0; indexcol < index->nkeycolumns; indexcol++)
     469             :     {
     470             :         /* Consider each applicable simple join clause */
     471      196302 :         considered_clauses += list_length(jclauseset->indexclauses[indexcol]);
     472      196302 :         consider_index_join_outer_rels(root, rel, index,
     473             :                                        rclauseset, jclauseset, eclauseset,
     474             :                                        bitindexpaths,
     475             :                                        jclauseset->indexclauses[indexcol],
     476             :                                        considered_clauses,
     477             :                                        &considered_relids);
     478             :         /* Consider each applicable eclass join clause */
     479      196302 :         considered_clauses += list_length(eclauseset->indexclauses[indexcol]);
     480      196302 :         consider_index_join_outer_rels(root, rel, index,
     481             :                                        rclauseset, jclauseset, eclauseset,
     482             :                                        bitindexpaths,
     483             :                                        eclauseset->indexclauses[indexcol],
     484             :                                        considered_clauses,
     485             :                                        &considered_relids);
     486             :     }
     487      131040 : }
     488             : 
     489             : /*
     490             :  * consider_index_join_outer_rels
     491             :  *    Generate parameterized paths based on clause relids in the clause list.
     492             :  *
     493             :  * Workhorse for consider_index_join_clauses; see notes therein for rationale.
     494             :  *
     495             :  * 'rel', 'index', 'rclauseset', 'jclauseset', 'eclauseset', and
     496             :  *      'bitindexpaths' as above
     497             :  * 'indexjoinclauses' is a list of IndexClauses for join clauses
     498             :  * 'considered_clauses' is the total number of clauses considered (so far)
     499             :  * '*considered_relids' is a list of all relids sets already considered
     500             :  */
     501             : static void
     502      392604 : consider_index_join_outer_rels(PlannerInfo *root, RelOptInfo *rel,
     503             :                                IndexOptInfo *index,
     504             :                                IndexClauseSet *rclauseset,
     505             :                                IndexClauseSet *jclauseset,
     506             :                                IndexClauseSet *eclauseset,
     507             :                                List **bitindexpaths,
     508             :                                List *indexjoinclauses,
     509             :                                int considered_clauses,
     510             :                                List **considered_relids)
     511             : {
     512             :     ListCell   *lc;
     513             : 
     514             :     /* Examine relids of each joinclause in the given list */
     515      536458 :     foreach(lc, indexjoinclauses)
     516             :     {
     517      143854 :         IndexClause *iclause = (IndexClause *) lfirst(lc);
     518      143854 :         Relids      clause_relids = iclause->rinfo->clause_relids;
     519      143854 :         EquivalenceClass *parent_ec = iclause->rinfo->parent_ec;
     520             :         int         num_considered_relids;
     521             : 
     522             :         /* If we already tried its relids set, no need to do so again */
     523      143854 :         if (list_member(*considered_relids, clause_relids))
     524        2758 :             continue;
     525             : 
     526             :         /*
     527             :          * Generate the union of this clause's relids set with each
     528             :          * previously-tried set.  This ensures we try this clause along with
     529             :          * every interesting subset of previous clauses.  However, to avoid
     530             :          * exponential growth of planning time when there are many clauses,
     531             :          * limit the number of relid sets accepted to 10 * considered_clauses.
     532             :          *
     533             :          * Note: get_join_index_paths appends entries to *considered_relids,
     534             :          * but we do not need to visit such newly-added entries within this
     535             :          * loop, so we don't use foreach() here.  No real harm would be done
     536             :          * if we did visit them, since the subset check would reject them; but
     537             :          * it would waste some cycles.
     538             :          */
     539      141096 :         num_considered_relids = list_length(*considered_relids);
     540      151518 :         for (int pos = 0; pos < num_considered_relids; pos++)
     541             :         {
     542       10422 :             Relids      oldrelids = (Relids) list_nth(*considered_relids, pos);
     543             : 
     544             :             /*
     545             :              * If either is a subset of the other, no new set is possible.
     546             :              * This isn't a complete test for redundancy, but it's easy and
     547             :              * cheap.  get_join_index_paths will check more carefully if we
     548             :              * already generated the same relids set.
     549             :              */
     550       10422 :             if (bms_subset_compare(clause_relids, oldrelids) != BMS_DIFFERENT)
     551          24 :                 continue;
     552             : 
     553             :             /*
     554             :              * If this clause was derived from an equivalence class, the
     555             :              * clause list may contain other clauses derived from the same
     556             :              * eclass.  We should not consider that combining this clause with
     557             :              * one of those clauses generates a usefully different
     558             :              * parameterization; so skip if any clause derived from the same
     559             :              * eclass would already have been included when using oldrelids.
     560             :              */
     561       20634 :             if (parent_ec &&
     562       10236 :                 eclass_already_used(parent_ec, oldrelids,
     563             :                                     indexjoinclauses))
     564        6978 :                 continue;
     565             : 
     566             :             /*
     567             :              * If the number of relid sets considered exceeds our heuristic
     568             :              * limit, stop considering combinations of clauses.  We'll still
     569             :              * consider the current clause alone, though (below this loop).
     570             :              */
     571        3420 :             if (list_length(*considered_relids) >= 10 * considered_clauses)
     572           0 :                 break;
     573             : 
     574             :             /* OK, try the union set */
     575        3420 :             get_join_index_paths(root, rel, index,
     576             :                                  rclauseset, jclauseset, eclauseset,
     577             :                                  bitindexpaths,
     578             :                                  bms_union(clause_relids, oldrelids),
     579             :                                  considered_relids);
     580             :         }
     581             : 
     582             :         /* Also try this set of relids by itself */
     583      141096 :         get_join_index_paths(root, rel, index,
     584             :                              rclauseset, jclauseset, eclauseset,
     585             :                              bitindexpaths,
     586             :                              clause_relids,
     587             :                              considered_relids);
     588             :     }
     589      392604 : }
     590             : 
     591             : /*
     592             :  * get_join_index_paths
     593             :  *    Generate index paths using clauses from the specified outer relations.
     594             :  *    In addition to generating paths, relids is added to *considered_relids
     595             :  *    if not already present.
     596             :  *
     597             :  * Workhorse for consider_index_join_clauses; see notes therein for rationale.
     598             :  *
     599             :  * 'rel', 'index', 'rclauseset', 'jclauseset', 'eclauseset',
     600             :  *      'bitindexpaths', 'considered_relids' as above
     601             :  * 'relids' is the current set of relids to consider (the target rel plus
     602             :  *      one or more outer rels)
     603             :  */
     604             : static void
     605      144516 : get_join_index_paths(PlannerInfo *root, RelOptInfo *rel,
     606             :                      IndexOptInfo *index,
     607             :                      IndexClauseSet *rclauseset,
     608             :                      IndexClauseSet *jclauseset,
     609             :                      IndexClauseSet *eclauseset,
     610             :                      List **bitindexpaths,
     611             :                      Relids relids,
     612             :                      List **considered_relids)
     613             : {
     614             :     IndexClauseSet clauseset;
     615             :     int         indexcol;
     616             : 
     617             :     /* If we already considered this relids set, don't repeat the work */
     618      144516 :     if (list_member(*considered_relids, relids))
     619           0 :         return;
     620             : 
     621             :     /* Identify indexclauses usable with this relids set */
     622     4913544 :     MemSet(&clauseset, 0, sizeof(clauseset));
     623             : 
     624      366070 :     for (indexcol = 0; indexcol < index->nkeycolumns; indexcol++)
     625             :     {
     626             :         ListCell   *lc;
     627             : 
     628             :         /* First find applicable simple join clauses */
     629      257822 :         foreach(lc, jclauseset->indexclauses[indexcol])
     630             :         {
     631       36268 :             IndexClause *iclause = (IndexClause *) lfirst(lc);
     632             : 
     633       36268 :             if (bms_is_subset(iclause->rinfo->clause_relids, relids))
     634       35842 :                 clauseset.indexclauses[indexcol] =
     635       35842 :                     lappend(clauseset.indexclauses[indexcol], iclause);
     636             :         }
     637             : 
     638             :         /*
     639             :          * Add applicable eclass join clauses.  The clauses generated for each
     640             :          * column are redundant (cf generate_implied_equalities_for_column),
     641             :          * so we need at most one.  This is the only exception to the general
     642             :          * rule of using all available index clauses.
     643             :          */
     644      236706 :         foreach(lc, eclauseset->indexclauses[indexcol])
     645             :         {
     646      129932 :             IndexClause *iclause = (IndexClause *) lfirst(lc);
     647             : 
     648      129932 :             if (bms_is_subset(iclause->rinfo->clause_relids, relids))
     649             :             {
     650      114780 :                 clauseset.indexclauses[indexcol] =
     651      114780 :                     lappend(clauseset.indexclauses[indexcol], iclause);
     652      114780 :                 break;
     653             :             }
     654             :         }
     655             : 
     656             :         /* Add restriction clauses */
     657      221554 :         clauseset.indexclauses[indexcol] =
     658      221554 :             list_concat(clauseset.indexclauses[indexcol],
     659      221554 :                         rclauseset->indexclauses[indexcol]);
     660             : 
     661      221554 :         if (clauseset.indexclauses[indexcol] != NIL)
     662      177772 :             clauseset.nonempty = true;
     663             :     }
     664             : 
     665             :     /* We should have found something, else caller passed silly relids */
     666             :     Assert(clauseset.nonempty);
     667             : 
     668             :     /* Build index path(s) using the collected set of clauses */
     669      144516 :     get_index_paths(root, rel, index, &clauseset, bitindexpaths);
     670             : 
     671             :     /*
     672             :      * Remember we considered paths for this set of relids.
     673             :      */
     674      144516 :     *considered_relids = lappend(*considered_relids, relids);
     675             : }
     676             : 
     677             : /*
     678             :  * eclass_already_used
     679             :  *      True if any join clause usable with oldrelids was generated from
     680             :  *      the specified equivalence class.
     681             :  */
     682             : static bool
     683       10236 : eclass_already_used(EquivalenceClass *parent_ec, Relids oldrelids,
     684             :                     List *indexjoinclauses)
     685             : {
     686             :     ListCell   *lc;
     687             : 
     688       13956 :     foreach(lc, indexjoinclauses)
     689             :     {
     690       10698 :         IndexClause *iclause = (IndexClause *) lfirst(lc);
     691       10698 :         RestrictInfo *rinfo = iclause->rinfo;
     692             : 
     693       21396 :         if (rinfo->parent_ec == parent_ec &&
     694       10698 :             bms_is_subset(rinfo->clause_relids, oldrelids))
     695        6978 :             return true;
     696             :     }
     697        3258 :     return false;
     698             : }
     699             : 
     700             : 
     701             : /*
     702             :  * get_index_paths
     703             :  *    Given an index and a set of index clauses for it, construct IndexPaths.
     704             :  *
     705             :  * Plain indexpaths are sent directly to add_path, while potential
     706             :  * bitmap indexpaths are added to *bitindexpaths for later processing.
     707             :  *
     708             :  * This is a fairly simple frontend to build_index_paths().  Its reason for
     709             :  * existence is mainly to handle ScalarArrayOpExpr quals properly.  If the
     710             :  * index AM supports them natively, we should just include them in simple
     711             :  * index paths.  If not, we should exclude them while building simple index
     712             :  * paths, and then make a separate attempt to include them in bitmap paths.
     713             :  */
     714             : static void
     715      862116 : get_index_paths(PlannerInfo *root, RelOptInfo *rel,
     716             :                 IndexOptInfo *index, IndexClauseSet *clauses,
     717             :                 List **bitindexpaths)
     718             : {
     719             :     List       *indexpaths;
     720      862116 :     bool        skip_nonnative_saop = false;
     721             :     ListCell   *lc;
     722             : 
     723             :     /*
     724             :      * Build simple index paths using the clauses.  Allow ScalarArrayOpExpr
     725             :      * clauses only if the index AM supports them natively.
     726             :      */
     727      862116 :     indexpaths = build_index_paths(root, rel,
     728             :                                    index, clauses,
     729      862116 :                                    index->predOK,
     730             :                                    ST_ANYSCAN,
     731             :                                    &skip_nonnative_saop);
     732             : 
     733             :     /*
     734             :      * Submit all the ones that can form plain IndexScan plans to add_path. (A
     735             :      * plain IndexPath can represent either a plain IndexScan or an
     736             :      * IndexOnlyScan, but for our purposes here that distinction does not
     737             :      * matter.  However, some of the indexes might support only bitmap scans,
     738             :      * and those we mustn't submit to add_path here.)
     739             :      *
     740             :      * Also, pick out the ones that are usable as bitmap scans.  For that, we
     741             :      * must discard indexes that don't support bitmap scans, and we also are
     742             :      * only interested in paths that have some selectivity; we should discard
     743             :      * anything that was generated solely for ordering purposes.
     744             :      */
     745     1370726 :     foreach(lc, indexpaths)
     746             :     {
     747      508610 :         IndexPath  *ipath = (IndexPath *) lfirst(lc);
     748             : 
     749      508610 :         if (index->amhasgettuple)
     750      495208 :             add_path(rel, (Path *) ipath);
     751             : 
     752      508610 :         if (index->amhasgetbitmap &&
     753      508610 :             (ipath->path.pathkeys == NIL ||
     754      312658 :              ipath->indexselectivity < 1.0))
     755      372308 :             *bitindexpaths = lappend(*bitindexpaths, ipath);
     756             :     }
     757             : 
     758             :     /*
     759             :      * If there were ScalarArrayOpExpr clauses that the index can't handle
     760             :      * natively, generate bitmap scan paths relying on executor-managed
     761             :      * ScalarArrayOpExpr.
     762             :      */
     763      862116 :     if (skip_nonnative_saop)
     764             :     {
     765          32 :         indexpaths = build_index_paths(root, rel,
     766             :                                        index, clauses,
     767             :                                        false,
     768             :                                        ST_BITMAPSCAN,
     769             :                                        NULL);
     770          32 :         *bitindexpaths = list_concat(*bitindexpaths, indexpaths);
     771             :     }
     772      862116 : }
     773             : 
     774             : /*
     775             :  * build_index_paths
     776             :  *    Given an index and a set of index clauses for it, construct zero
     777             :  *    or more IndexPaths. It also constructs zero or more partial IndexPaths.
     778             :  *
     779             :  * We return a list of paths because (1) this routine checks some cases
     780             :  * that should cause us to not generate any IndexPath, and (2) in some
     781             :  * cases we want to consider both a forward and a backward scan, so as
     782             :  * to obtain both sort orders.  Note that the paths are just returned
     783             :  * to the caller and not immediately fed to add_path().
     784             :  *
     785             :  * At top level, useful_predicate should be exactly the index's predOK flag
     786             :  * (ie, true if it has a predicate that was proven from the restriction
     787             :  * clauses).  When working on an arm of an OR clause, useful_predicate
     788             :  * should be true if the predicate required the current OR list to be proven.
     789             :  * Note that this routine should never be called at all if the index has an
     790             :  * unprovable predicate.
     791             :  *
     792             :  * scantype indicates whether we want to create plain indexscans, bitmap
     793             :  * indexscans, or both.  When it's ST_BITMAPSCAN, we will not consider
     794             :  * index ordering while deciding if a Path is worth generating.
     795             :  *
     796             :  * If skip_nonnative_saop is non-NULL, we ignore ScalarArrayOpExpr clauses
     797             :  * unless the index AM supports them directly, and we set *skip_nonnative_saop
     798             :  * to true if we found any such clauses (caller must initialize the variable
     799             :  * to false).  If it's NULL, we do not ignore ScalarArrayOpExpr clauses.
     800             :  *
     801             :  * 'rel' is the index's heap relation
     802             :  * 'index' is the index for which we want to generate paths
     803             :  * 'clauses' is the collection of indexable clauses (IndexClause nodes)
     804             :  * 'useful_predicate' indicates whether the index has a useful predicate
     805             :  * 'scantype' indicates whether we need plain or bitmap scan support
     806             :  * 'skip_nonnative_saop' indicates whether to accept SAOP if index AM doesn't
     807             :  */
     808             : static List *
     809      865144 : build_index_paths(PlannerInfo *root, RelOptInfo *rel,
     810             :                   IndexOptInfo *index, IndexClauseSet *clauses,
     811             :                   bool useful_predicate,
     812             :                   ScanTypeControl scantype,
     813             :                   bool *skip_nonnative_saop)
     814             : {
     815      865144 :     List       *result = NIL;
     816             :     IndexPath  *ipath;
     817             :     List       *index_clauses;
     818             :     Relids      outer_relids;
     819             :     double      loop_count;
     820             :     List       *orderbyclauses;
     821             :     List       *orderbyclausecols;
     822             :     List       *index_pathkeys;
     823             :     List       *useful_pathkeys;
     824             :     bool        pathkeys_possibly_useful;
     825             :     bool        index_is_ordered;
     826             :     bool        index_only_scan;
     827             :     int         indexcol;
     828             : 
     829             :     Assert(skip_nonnative_saop != NULL || scantype == ST_BITMAPSCAN);
     830             : 
     831             :     /*
     832             :      * Check that index supports the desired scan type(s)
     833             :      */
     834      865144 :     switch (scantype)
     835             :     {
     836           0 :         case ST_INDEXSCAN:
     837           0 :             if (!index->amhasgettuple)
     838           0 :                 return NIL;
     839           0 :             break;
     840        3028 :         case ST_BITMAPSCAN:
     841        3028 :             if (!index->amhasgetbitmap)
     842           0 :                 return NIL;
     843        3028 :             break;
     844      862116 :         case ST_ANYSCAN:
     845             :             /* either or both are OK */
     846      862116 :             break;
     847             :     }
     848             : 
     849             :     /*
     850             :      * 1. Combine the per-column IndexClause lists into an overall list.
     851             :      *
     852             :      * In the resulting list, clauses are ordered by index key, so that the
     853             :      * column numbers form a nondecreasing sequence.  (This order is depended
     854             :      * on by btree and possibly other places.)  The list can be empty, if the
     855             :      * index AM allows that.
     856             :      *
     857             :      * We also build a Relids set showing which outer rels are required by the
     858             :      * selected clauses.  Any lateral_relids are included in that, but not
     859             :      * otherwise accounted for.
     860             :      */
     861      865144 :     index_clauses = NIL;
     862      865144 :     outer_relids = bms_copy(rel->lateral_relids);
     863     2458292 :     for (indexcol = 0; indexcol < index->nkeycolumns; indexcol++)
     864             :     {
     865             :         ListCell   *lc;
     866             : 
     867     2027266 :         foreach(lc, clauses->indexclauses[indexcol])
     868             :         {
     869      433788 :             IndexClause *iclause = (IndexClause *) lfirst(lc);
     870      433788 :             RestrictInfo *rinfo = iclause->rinfo;
     871             : 
     872      433788 :             if (skip_nonnative_saop && !index->amsearcharray &&
     873       21236 :                 IsA(rinfo->clause, ScalarArrayOpExpr))
     874             :             {
     875             :                 /*
     876             :                  * Caller asked us to generate IndexPaths that omit any
     877             :                  * ScalarArrayOpExpr clauses when the underlying index AM
     878             :                  * lacks native support.
     879             :                  *
     880             :                  * We must omit this clause (and tell caller about it).
     881             :                  */
     882          32 :                 *skip_nonnative_saop = true;
     883          32 :                 continue;
     884             :             }
     885             : 
     886             :             /* OK to include this clause */
     887      433756 :             index_clauses = lappend(index_clauses, iclause);
     888      433756 :             outer_relids = bms_add_members(outer_relids,
     889      433756 :                                            rinfo->clause_relids);
     890             :         }
     891             : 
     892             :         /*
     893             :          * If no clauses match the first index column, check for amoptionalkey
     894             :          * restriction.  We can't generate a scan over an index with
     895             :          * amoptionalkey = false unless there's at least one index clause.
     896             :          * (When working on columns after the first, this test cannot fail. It
     897             :          * is always okay for columns after the first to not have any
     898             :          * clauses.)
     899             :          */
     900     1593478 :         if (index_clauses == NIL && !index->amoptionalkey)
     901         330 :             return NIL;
     902             :     }
     903             : 
     904             :     /* We do not want the index's rel itself listed in outer_relids */
     905      864814 :     outer_relids = bms_del_member(outer_relids, rel->relid);
     906             : 
     907             :     /* Compute loop_count for cost estimation purposes */
     908      864814 :     loop_count = get_loop_count(root, rel->relid, outer_relids);
     909             : 
     910             :     /*
     911             :      * 2. Compute pathkeys describing index's ordering, if any, then see how
     912             :      * many of them are actually useful for this query.  This is not relevant
     913             :      * if we are only trying to build bitmap indexscans.
     914             :      */
     915     1726600 :     pathkeys_possibly_useful = (scantype != ST_BITMAPSCAN &&
     916      861786 :                                 has_useful_pathkeys(root, rel));
     917      864814 :     index_is_ordered = (index->sortopfamily != NULL);
     918      864814 :     if (index_is_ordered && pathkeys_possibly_useful)
     919             :     {
     920      644104 :         index_pathkeys = build_index_pathkeys(root, index,
     921             :                                               ForwardScanDirection);
     922      644104 :         useful_pathkeys = truncate_useless_pathkeys(root, rel,
     923             :                                                     index_pathkeys);
     924      644104 :         orderbyclauses = NIL;
     925      644104 :         orderbyclausecols = NIL;
     926             :     }
     927      220710 :     else if (index->amcanorderbyop && pathkeys_possibly_useful)
     928             :     {
     929             :         /*
     930             :          * See if we can generate ordering operators for query_pathkeys or at
     931             :          * least some prefix thereof.  Matching to just a prefix of the
     932             :          * query_pathkeys will allow an incremental sort to be considered on
     933             :          * the index's partially sorted results.
     934             :          */
     935        1076 :         match_pathkeys_to_index(index, root->query_pathkeys,
     936             :                                 &orderbyclauses,
     937             :                                 &orderbyclausecols);
     938        1076 :         if (list_length(root->query_pathkeys) == list_length(orderbyclauses))
     939         470 :             useful_pathkeys = root->query_pathkeys;
     940             :         else
     941         606 :             useful_pathkeys = list_copy_head(root->query_pathkeys,
     942             :                                              list_length(orderbyclauses));
     943             :     }
     944             :     else
     945             :     {
     946      219634 :         useful_pathkeys = NIL;
     947      219634 :         orderbyclauses = NIL;
     948      219634 :         orderbyclausecols = NIL;
     949             :     }
     950             : 
     951             :     /*
     952             :      * 3. Check if an index-only scan is possible.  If we're not building
     953             :      * plain indexscans, this isn't relevant since bitmap scans don't support
     954             :      * index data retrieval anyway.
     955             :      */
     956     1726600 :     index_only_scan = (scantype != ST_BITMAPSCAN &&
     957      861786 :                        check_index_only(rel, index));
     958             : 
     959             :     /*
     960             :      * 4. Generate an indexscan path if there are relevant restriction clauses
     961             :      * in the current clauses, OR the index ordering is potentially useful for
     962             :      * later merging or final output ordering, OR the index has a useful
     963             :      * predicate, OR an index-only scan is possible.
     964             :      */
     965      864814 :     if (index_clauses != NIL || useful_pathkeys != NIL || useful_predicate ||
     966             :         index_only_scan)
     967             :     {
     968      511048 :         ipath = create_index_path(root, index,
     969             :                                   index_clauses,
     970             :                                   orderbyclauses,
     971             :                                   orderbyclausecols,
     972             :                                   useful_pathkeys,
     973             :                                   ForwardScanDirection,
     974             :                                   index_only_scan,
     975             :                                   outer_relids,
     976             :                                   loop_count,
     977             :                                   false);
     978      511048 :         result = lappend(result, ipath);
     979             : 
     980             :         /*
     981             :          * If appropriate, consider parallel index scan.  We don't allow
     982             :          * parallel index scan for bitmap index scans.
     983             :          */
     984      511048 :         if (index->amcanparallel &&
     985      490686 :             rel->consider_parallel && outer_relids == NULL &&
     986             :             scantype != ST_BITMAPSCAN)
     987             :         {
     988      271996 :             ipath = create_index_path(root, index,
     989             :                                       index_clauses,
     990             :                                       orderbyclauses,
     991             :                                       orderbyclausecols,
     992             :                                       useful_pathkeys,
     993             :                                       ForwardScanDirection,
     994             :                                       index_only_scan,
     995             :                                       outer_relids,
     996             :                                       loop_count,
     997             :                                       true);
     998             : 
     999             :             /*
    1000             :              * if, after costing the path, we find that it's not worth using
    1001             :              * parallel workers, just free it.
    1002             :              */
    1003      271996 :             if (ipath->path.parallel_workers > 0)
    1004        9864 :                 add_partial_path(rel, (Path *) ipath);
    1005             :             else
    1006      262132 :                 pfree(ipath);
    1007             :         }
    1008             :     }
    1009             : 
    1010             :     /*
    1011             :      * 5. If the index is ordered, a backwards scan might be interesting.
    1012             :      */
    1013      864814 :     if (index_is_ordered && pathkeys_possibly_useful)
    1014             :     {
    1015      644104 :         index_pathkeys = build_index_pathkeys(root, index,
    1016             :                                               BackwardScanDirection);
    1017      644104 :         useful_pathkeys = truncate_useless_pathkeys(root, rel,
    1018             :                                                     index_pathkeys);
    1019      644104 :         if (useful_pathkeys != NIL)
    1020             :         {
    1021         590 :             ipath = create_index_path(root, index,
    1022             :                                       index_clauses,
    1023             :                                       NIL,
    1024             :                                       NIL,
    1025             :                                       useful_pathkeys,
    1026             :                                       BackwardScanDirection,
    1027             :                                       index_only_scan,
    1028             :                                       outer_relids,
    1029             :                                       loop_count,
    1030             :                                       false);
    1031         590 :             result = lappend(result, ipath);
    1032             : 
    1033             :             /* If appropriate, consider parallel index scan */
    1034         590 :             if (index->amcanparallel &&
    1035         590 :                 rel->consider_parallel && outer_relids == NULL &&
    1036             :                 scantype != ST_BITMAPSCAN)
    1037             :             {
    1038         500 :                 ipath = create_index_path(root, index,
    1039             :                                           index_clauses,
    1040             :                                           NIL,
    1041             :                                           NIL,
    1042             :                                           useful_pathkeys,
    1043             :                                           BackwardScanDirection,
    1044             :                                           index_only_scan,
    1045             :                                           outer_relids,
    1046             :                                           loop_count,
    1047             :                                           true);
    1048             : 
    1049             :                 /*
    1050             :                  * if, after costing the path, we find that it's not worth
    1051             :                  * using parallel workers, just free it.
    1052             :                  */
    1053         500 :                 if (ipath->path.parallel_workers > 0)
    1054         168 :                     add_partial_path(rel, (Path *) ipath);
    1055             :                 else
    1056         332 :                     pfree(ipath);
    1057             :             }
    1058             :         }
    1059             :     }
    1060             : 
    1061      864814 :     return result;
    1062             : }
    1063             : 
    1064             : /*
    1065             :  * build_paths_for_OR
    1066             :  *    Given a list of restriction clauses from one arm of an OR clause,
    1067             :  *    construct all matching IndexPaths for the relation.
    1068             :  *
    1069             :  * Here we must scan all indexes of the relation, since a bitmap OR tree
    1070             :  * can use multiple indexes.
    1071             :  *
    1072             :  * The caller actually supplies two lists of restriction clauses: some
    1073             :  * "current" ones and some "other" ones.  Both lists can be used freely
    1074             :  * to match keys of the index, but an index must use at least one of the
    1075             :  * "current" clauses to be considered usable.  The motivation for this is
    1076             :  * examples like
    1077             :  *      WHERE (x = 42) AND (... OR (y = 52 AND z = 77) OR ....)
    1078             :  * While we are considering the y/z subclause of the OR, we can use "x = 42"
    1079             :  * as one of the available index conditions; but we shouldn't match the
    1080             :  * subclause to any index on x alone, because such a Path would already have
    1081             :  * been generated at the upper level.  So we could use an index on x,y,z
    1082             :  * or an index on x,y for the OR subclause, but not an index on just x.
    1083             :  * When dealing with a partial index, a match of the index predicate to
    1084             :  * one of the "current" clauses also makes the index usable.
    1085             :  *
    1086             :  * 'rel' is the relation for which we want to generate index paths
    1087             :  * 'clauses' is the current list of clauses (RestrictInfo nodes)
    1088             :  * 'other_clauses' is the list of additional upper-level clauses
    1089             :  */
    1090             : static List *
    1091       11824 : build_paths_for_OR(PlannerInfo *root, RelOptInfo *rel,
    1092             :                    List *clauses, List *other_clauses)
    1093             : {
    1094       11824 :     List       *result = NIL;
    1095       11824 :     List       *all_clauses = NIL;  /* not computed till needed */
    1096             :     ListCell   *lc;
    1097             : 
    1098       40998 :     foreach(lc, rel->indexlist)
    1099             :     {
    1100       29174 :         IndexOptInfo *index = (IndexOptInfo *) lfirst(lc);
    1101             :         IndexClauseSet clauseset;
    1102             :         List       *indexpaths;
    1103             :         bool        useful_predicate;
    1104             : 
    1105             :         /* Ignore index if it doesn't support bitmap scans */
    1106       29174 :         if (!index->amhasgetbitmap)
    1107       26178 :             continue;
    1108             : 
    1109             :         /*
    1110             :          * Ignore partial indexes that do not match the query.  If a partial
    1111             :          * index is marked predOK then we know it's OK.  Otherwise, we have to
    1112             :          * test whether the added clauses are sufficient to imply the
    1113             :          * predicate. If so, we can use the index in the current context.
    1114             :          *
    1115             :          * We set useful_predicate to true iff the predicate was proven using
    1116             :          * the current set of clauses.  This is needed to prevent matching a
    1117             :          * predOK index to an arm of an OR, which would be a legal but
    1118             :          * pointlessly inefficient plan.  (A better plan will be generated by
    1119             :          * just scanning the predOK index alone, no OR.)
    1120             :          */
    1121       29174 :         useful_predicate = false;
    1122       29174 :         if (index->indpred != NIL)
    1123             :         {
    1124         168 :             if (index->predOK)
    1125             :             {
    1126             :                 /* Usable, but don't set useful_predicate */
    1127             :             }
    1128             :             else
    1129             :             {
    1130             :                 /* Form all_clauses if not done already */
    1131         144 :                 if (all_clauses == NIL)
    1132          60 :                     all_clauses = list_concat_copy(clauses, other_clauses);
    1133             : 
    1134         144 :                 if (!predicate_implied_by(index->indpred, all_clauses, false))
    1135          96 :                     continue;   /* can't use it at all */
    1136             : 
    1137          48 :                 if (!predicate_implied_by(index->indpred, other_clauses, false))
    1138          48 :                     useful_predicate = true;
    1139             :             }
    1140             :         }
    1141             : 
    1142             :         /*
    1143             :          * Identify the restriction clauses that can match the index.
    1144             :          */
    1145      988652 :         MemSet(&clauseset, 0, sizeof(clauseset));
    1146       29078 :         match_clauses_to_index(root, clauses, index, &clauseset);
    1147             : 
    1148             :         /*
    1149             :          * If no matches so far, and the index predicate isn't useful, we
    1150             :          * don't want it.
    1151             :          */
    1152       29078 :         if (!clauseset.nonempty && !useful_predicate)
    1153       26082 :             continue;
    1154             : 
    1155             :         /*
    1156             :          * Add "other" restriction clauses to the clauseset.
    1157             :          */
    1158        2996 :         match_clauses_to_index(root, other_clauses, index, &clauseset);
    1159             : 
    1160             :         /*
    1161             :          * Construct paths if possible.
    1162             :          */
    1163        2996 :         indexpaths = build_index_paths(root, rel,
    1164             :                                        index, &clauseset,
    1165             :                                        useful_predicate,
    1166             :                                        ST_BITMAPSCAN,
    1167             :                                        NULL);
    1168        2996 :         result = list_concat(result, indexpaths);
    1169             :     }
    1170             : 
    1171       11824 :     return result;
    1172             : }
    1173             : 
    1174             : /*
    1175             :  * Utility structure used to group similar OR-clause arguments in
    1176             :  * group_similar_or_args().  It represents information about the OR-clause
    1177             :  * argument and its matching index key.
    1178             :  */
    1179             : typedef struct
    1180             : {
    1181             :     int         indexnum;       /* index of the matching index, or -1 if no
    1182             :                                  * matching index */
    1183             :     int         colnum;         /* index of the matching column, or -1 if no
    1184             :                                  * matching index */
    1185             :     Oid         opno;           /* OID of the OpClause operator, or InvalidOid
    1186             :                                  * if not an OpExpr */
    1187             :     Oid         inputcollid;    /* OID of the OpClause input collation */
    1188             :     int         argindex;       /* index of the clause in the list of
    1189             :                                  * arguments */
    1190             :     int         groupindex;     /* value of argindex for the fist clause in
    1191             :                                  * the group of similar clauses */
    1192             : } OrArgIndexMatch;
    1193             : 
    1194             : /*
    1195             :  * Comparison function for OrArgIndexMatch which provides sort order placing
    1196             :  * similar OR-clause arguments together.
    1197             :  */
    1198             : static int
    1199        7964 : or_arg_index_match_cmp(const void *a, const void *b)
    1200             : {
    1201        7964 :     const OrArgIndexMatch *match_a = (const OrArgIndexMatch *) a;
    1202        7964 :     const OrArgIndexMatch *match_b = (const OrArgIndexMatch *) b;
    1203             : 
    1204        7964 :     if (match_a->indexnum < match_b->indexnum)
    1205        1514 :         return -1;
    1206        6450 :     else if (match_a->indexnum > match_b->indexnum)
    1207        3376 :         return 1;
    1208             : 
    1209        3074 :     if (match_a->colnum < match_b->colnum)
    1210        1058 :         return -1;
    1211        2016 :     else if (match_a->colnum > match_b->colnum)
    1212          24 :         return 1;
    1213             : 
    1214        1992 :     if (match_a->opno < match_b->opno)
    1215          18 :         return -1;
    1216        1974 :     else if (match_a->opno > match_b->opno)
    1217          42 :         return 1;
    1218             : 
    1219        1932 :     if (match_a->inputcollid < match_b->inputcollid)
    1220           0 :         return -1;
    1221        1932 :     else if (match_a->inputcollid > match_b->inputcollid)
    1222           0 :         return 1;
    1223             : 
    1224        1932 :     if (match_a->argindex < match_b->argindex)
    1225        1854 :         return -1;
    1226          78 :     else if (match_a->argindex > match_b->argindex)
    1227          78 :         return 1;
    1228             : 
    1229           0 :     return 0;
    1230             : }
    1231             : 
    1232             : /*
    1233             :  * Another comparison function for OrArgIndexMatch.  It sorts groups together
    1234             :  * using groupindex.  The group items are then sorted by argindex.
    1235             :  */
    1236             : static int
    1237        8066 : or_arg_index_match_cmp_group(const void *a, const void *b)
    1238             : {
    1239        8066 :     const OrArgIndexMatch *match_a = (const OrArgIndexMatch *) a;
    1240        8066 :     const OrArgIndexMatch *match_b = (const OrArgIndexMatch *) b;
    1241             : 
    1242        8066 :     if (match_a->groupindex < match_b->groupindex)
    1243        4048 :         return -1;
    1244        4018 :     else if (match_a->groupindex > match_b->groupindex)
    1245        3574 :         return 1;
    1246             : 
    1247         444 :     if (match_a->argindex < match_b->argindex)
    1248         444 :         return -1;
    1249           0 :     else if (match_a->argindex > match_b->argindex)
    1250           0 :         return 1;
    1251             : 
    1252           0 :     return 0;
    1253             : }
    1254             : 
    1255             : /*
    1256             :  * group_similar_or_args
    1257             :  *      Transform incoming OR-restrictinfo into a list of sub-restrictinfos,
    1258             :  *      each of them containing a subset of similar OR-clause arguments from
    1259             :  *      the source rinfo.
    1260             :  *
    1261             :  * Similar OR-clause arguments are of the form "indexkey op constant" having
    1262             :  * the same indexkey, operator, and collation.  Constant may comprise either
    1263             :  * Const or Param.  It may be employed later, during the
    1264             :  * match_clause_to_indexcol() to transform the whole OR-sub-rinfo to an SAOP
    1265             :  * clause.
    1266             :  *
    1267             :  * Returns the processed list of OR-clause arguments.
    1268             :  */
    1269             : static List *
    1270       10128 : group_similar_or_args(PlannerInfo *root, RelOptInfo *rel, RestrictInfo *rinfo)
    1271             : {
    1272             :     int         n;
    1273             :     int         i;
    1274             :     int         group_start;
    1275             :     OrArgIndexMatch *matches;
    1276       10128 :     bool        matched = false;
    1277             :     ListCell   *lc;
    1278             :     ListCell   *lc2;
    1279             :     List       *orargs;
    1280       10128 :     List       *result = NIL;
    1281       10128 :     Index       relid = rel->relid;
    1282             : 
    1283             :     Assert(IsA(rinfo->orclause, BoolExpr));
    1284       10128 :     orargs = ((BoolExpr *) rinfo->orclause)->args;
    1285       10128 :     n = list_length(orargs);
    1286             : 
    1287             :     /*
    1288             :      * To avoid N^2 behavior, take utility pass along the list of OR-clause
    1289             :      * arguments.  For each argument, fill the OrArgIndexMatch structure,
    1290             :      * which will be used to sort these arguments at the next step.
    1291             :      */
    1292       10128 :     i = -1;
    1293       10128 :     matches = (OrArgIndexMatch *) palloc(sizeof(OrArgIndexMatch) * n);
    1294       33886 :     foreach(lc, orargs)
    1295             :     {
    1296       23758 :         Node       *arg = lfirst(lc);
    1297             :         RestrictInfo *argrinfo;
    1298             :         OpExpr     *clause;
    1299             :         Oid         opno;
    1300             :         Node       *leftop,
    1301             :                    *rightop;
    1302             :         Node       *nonConstExpr;
    1303             :         int         indexnum;
    1304             :         int         colnum;
    1305             : 
    1306       23758 :         i++;
    1307       23758 :         matches[i].argindex = i;
    1308       23758 :         matches[i].groupindex = i;
    1309       23758 :         matches[i].indexnum = -1;
    1310       23758 :         matches[i].colnum = -1;
    1311       23758 :         matches[i].opno = InvalidOid;
    1312       23758 :         matches[i].inputcollid = InvalidOid;
    1313             : 
    1314       23758 :         if (!IsA(arg, RestrictInfo))
    1315        2336 :             continue;
    1316             : 
    1317       21422 :         argrinfo = castNode(RestrictInfo, arg);
    1318             : 
    1319             :         /* Only operator clauses can match  */
    1320       21422 :         if (!IsA(argrinfo->clause, OpExpr))
    1321        8702 :             continue;
    1322             : 
    1323       12720 :         clause = (OpExpr *) argrinfo->clause;
    1324       12720 :         opno = clause->opno;
    1325             : 
    1326             :         /* Only binary operators can match  */
    1327       12720 :         if (list_length(clause->args) != 2)
    1328           0 :             continue;
    1329             : 
    1330             :         /*
    1331             :          * Ignore any RelabelType node above the operands.  This is needed to
    1332             :          * be able to apply indexscanning in binary-compatible-operator cases.
    1333             :          * Note: we can assume there is at most one RelabelType node;
    1334             :          * eval_const_expressions() will have simplified if more than one.
    1335             :          */
    1336       12720 :         leftop = get_leftop(clause);
    1337       12720 :         if (IsA(leftop, RelabelType))
    1338         204 :             leftop = (Node *) ((RelabelType *) leftop)->arg;
    1339             : 
    1340       12720 :         rightop = get_rightop(clause);
    1341       12720 :         if (IsA(rightop, RelabelType))
    1342         992 :             rightop = (Node *) ((RelabelType *) rightop)->arg;
    1343             : 
    1344             :         /*
    1345             :          * Check for clauses of the form: (indexkey operator constant) or
    1346             :          * (constant operator indexkey).  But we don't know a particular index
    1347             :          * yet.  Therefore, we try to distinguish the potential index key and
    1348             :          * constant first, then search for a matching index key among all
    1349             :          * indexes.
    1350             :          */
    1351       12720 :         if (bms_is_member(relid, argrinfo->right_relids) &&
    1352        2336 :             !bms_is_member(relid, argrinfo->left_relids) &&
    1353        2264 :             !contain_volatile_functions(leftop))
    1354             :         {
    1355        2264 :             opno = get_commutator(opno);
    1356             : 
    1357        2264 :             if (!OidIsValid(opno))
    1358             :             {
    1359             :                 /* commutator doesn't exist, we can't reverse the order */
    1360           0 :                 continue;
    1361             :             }
    1362        2264 :             nonConstExpr = rightop;
    1363             :         }
    1364       10456 :         else if (bms_is_member(relid, argrinfo->left_relids) &&
    1365        8264 :                  !bms_is_member(relid, argrinfo->right_relids) &&
    1366        8192 :                  !contain_volatile_functions(rightop))
    1367             :         {
    1368        8192 :             nonConstExpr = leftop;
    1369             :         }
    1370             :         else
    1371             :         {
    1372        2264 :             continue;
    1373             :         }
    1374             : 
    1375             :         /*
    1376             :          * Match non-constant part to the index key.  It's possible that a
    1377             :          * single non-constant part matches multiple index keys.  It's OK, we
    1378             :          * just stop with first matching index key.  Given that this choice is
    1379             :          * determined the same for every clause, we will group similar clauses
    1380             :          * together anyway.
    1381             :          */
    1382       10456 :         indexnum = 0;
    1383       22520 :         foreach(lc2, rel->indexlist)
    1384             :         {
    1385       18466 :             IndexOptInfo *index = (IndexOptInfo *) lfirst(lc2);
    1386             : 
    1387             :             /*
    1388             :              * Ignore index if it doesn't support bitmap scans or SAOP
    1389             :              * clauses.
    1390             :              */
    1391       18466 :             if (!index->amhasgetbitmap || !index->amsearcharray)
    1392          54 :                 continue;
    1393             : 
    1394       41728 :             for (colnum = 0; colnum < index->nkeycolumns; colnum++)
    1395             :             {
    1396       29718 :                 if (match_index_to_operand(nonConstExpr, colnum, index))
    1397             :                 {
    1398        6402 :                     matches[i].indexnum = indexnum;
    1399        6402 :                     matches[i].colnum = colnum;
    1400        6402 :                     matches[i].opno = opno;
    1401        6402 :                     matches[i].inputcollid = clause->inputcollid;
    1402        6402 :                     matched = true;
    1403        6402 :                     break;
    1404             :                 }
    1405             :             }
    1406             : 
    1407             :             /*
    1408             :              * Stop looping through the indexes, if we managed to match
    1409             :              * nonConstExpr to any index column.
    1410             :              */
    1411       18412 :             if (matches[i].indexnum >= 0)
    1412        6402 :                 break;
    1413       12010 :             indexnum++;
    1414             :         }
    1415             :     }
    1416             : 
    1417             :     /*
    1418             :      * Fast-path check: if no clause is matching to the index column, we can
    1419             :      * just give up at this stage and return the clause list as-is.
    1420             :      */
    1421       10128 :     if (!matched)
    1422             :     {
    1423        5656 :         pfree(matches);
    1424        5656 :         return orargs;
    1425             :     }
    1426             : 
    1427             :     /*
    1428             :      * Sort clauses to make similar clauses go together.  But at the same
    1429             :      * time, we would like to change the order of clauses as little as
    1430             :      * possible.  To do so, we reorder each group of similar clauses so that
    1431             :      * the first item of the group stays in place, and all the other items are
    1432             :      * moved after it.  So, if there are no similar clauses, the order of
    1433             :      * clauses stays the same.  When there are some groups, required
    1434             :      * reordering happens while the rest of the clauses remain in their
    1435             :      * places.  That is achieved by assigning a 'groupindex' to each clause:
    1436             :      * the number of the first item in the group in the original clause list.
    1437             :      */
    1438        4472 :     qsort(matches, n, sizeof(OrArgIndexMatch), or_arg_index_match_cmp);
    1439             : 
    1440             :     /* Assign groupindex to the sorted clauses */
    1441       10690 :     for (i = 1; i < n; i++)
    1442             :     {
    1443             :         /*
    1444             :          * When two clauses are similar and should belong to the same group,
    1445             :          * copy the 'groupindex' from the previous clause.  Given we are
    1446             :          * considering clauses in direct order, all the clauses would have a
    1447             :          * 'groupindex' equal to the 'groupindex' of the first clause in the
    1448             :          * group.
    1449             :          */
    1450        6218 :         if (matches[i].indexnum == matches[i - 1].indexnum &&
    1451        2912 :             matches[i].colnum == matches[i - 1].colnum &&
    1452        1842 :             matches[i].opno == matches[i - 1].opno &&
    1453        1794 :             matches[i].inputcollid == matches[i - 1].inputcollid &&
    1454        1794 :             matches[i].indexnum != -1)
    1455         444 :             matches[i].groupindex = matches[i - 1].groupindex;
    1456             :     }
    1457             : 
    1458             :     /* Re-sort clauses first by groupindex then by argindex */
    1459        4472 :     qsort(matches, n, sizeof(OrArgIndexMatch), or_arg_index_match_cmp_group);
    1460             : 
    1461             :     /*
    1462             :      * Group similar clauses into single sub-restrictinfo. Side effect: the
    1463             :      * resulting list of restrictions will be sorted by indexnum and colnum.
    1464             :      */
    1465        4472 :     group_start = 0;
    1466       15162 :     for (i = 1; i <= n; i++)
    1467             :     {
    1468             :         /* Check if it's a group boundary */
    1469       10690 :         if (group_start >= 0 &&
    1470        6218 :             (i == n ||
    1471        6218 :              matches[i].indexnum != matches[group_start].indexnum ||
    1472        2840 :              matches[i].colnum != matches[group_start].colnum ||
    1473        1788 :              matches[i].opno != matches[group_start].opno ||
    1474        1746 :              matches[i].inputcollid != matches[group_start].inputcollid ||
    1475        1746 :              matches[i].indexnum == -1))
    1476             :         {
    1477             :             /*
    1478             :              * One clause in group: add it "as is" to the upper-level OR.
    1479             :              */
    1480       10246 :             if (i - group_start == 1)
    1481             :             {
    1482        9934 :                 result = lappend(result,
    1483             :                                  list_nth(orargs,
    1484        9934 :                                           matches[group_start].argindex));
    1485             :             }
    1486             :             else
    1487             :             {
    1488             :                 /*
    1489             :                  * Two or more clauses in a group: create a nested OR.
    1490             :                  */
    1491         312 :                 List       *args = NIL;
    1492         312 :                 List       *rargs = NIL;
    1493             :                 RestrictInfo *subrinfo;
    1494             :                 int         j;
    1495             : 
    1496             :                 Assert(i - group_start >= 2);
    1497             : 
    1498             :                 /* Construct the list of nested OR arguments */
    1499        1068 :                 for (j = group_start; j < i; j++)
    1500             :                 {
    1501         756 :                     Node       *arg = list_nth(orargs, matches[j].argindex);
    1502             : 
    1503         756 :                     rargs = lappend(rargs, arg);
    1504         756 :                     if (IsA(arg, RestrictInfo))
    1505         756 :                         args = lappend(args, ((RestrictInfo *) arg)->clause);
    1506             :                     else
    1507           0 :                         args = lappend(args, arg);
    1508             :                 }
    1509             : 
    1510             :                 /* Construct the nested OR and wrap it with RestrictInfo */
    1511         312 :                 subrinfo = make_plain_restrictinfo(root,
    1512             :                                                    make_orclause(args),
    1513             :                                                    make_orclause(rargs),
    1514         312 :                                                    rinfo->is_pushed_down,
    1515         312 :                                                    rinfo->has_clone,
    1516         312 :                                                    rinfo->is_clone,
    1517         312 :                                                    rinfo->pseudoconstant,
    1518             :                                                    rinfo->security_level,
    1519             :                                                    rinfo->required_relids,
    1520             :                                                    rinfo->incompatible_relids,
    1521             :                                                    rinfo->outer_relids);
    1522         312 :                 result = lappend(result, subrinfo);
    1523             :             }
    1524             : 
    1525       10246 :             group_start = i;
    1526             :         }
    1527             :     }
    1528        4472 :     pfree(matches);
    1529        4472 :     return result;
    1530             : }
    1531             : 
    1532             : /*
    1533             :  * make_bitmap_paths_for_or_group
    1534             :  *      Generate bitmap paths for a group of similar OR-clause arguments
    1535             :  *      produced by group_similar_or_args().
    1536             :  *
    1537             :  * This function considers two cases: (1) matching a group of clauses to
    1538             :  * the index as a whole, and (2) matching the individual clauses one-by-one.
    1539             :  * (1) typically comprises an optimal solution.  If not, (2) typically
    1540             :  * comprises fair alternative.
    1541             :  *
    1542             :  * Ideally, we could consider all arbitrary splits of arguments into
    1543             :  * subgroups, but that could lead to unacceptable computational complexity.
    1544             :  * This is why we only consider two cases of above.
    1545             :  */
    1546             : static List *
    1547         306 : make_bitmap_paths_for_or_group(PlannerInfo *root, RelOptInfo *rel,
    1548             :                                RestrictInfo *ri, List *other_clauses)
    1549             : {
    1550         306 :     List       *jointlist = NIL;
    1551         306 :     List       *splitlist = NIL;
    1552             :     ListCell   *lc;
    1553             :     List       *orargs;
    1554         306 :     List       *args = ((BoolExpr *) ri->orclause)->args;
    1555         306 :     Cost        jointcost = 0.0,
    1556         306 :                 splitcost = 0.0;
    1557             :     Path       *bitmapqual;
    1558             :     List       *indlist;
    1559             : 
    1560             :     /*
    1561             :      * First, try to match the whole group to the one index.
    1562             :      */
    1563         306 :     orargs = list_make1(ri);
    1564         306 :     indlist = build_paths_for_OR(root, rel,
    1565             :                                  orargs,
    1566             :                                  other_clauses);
    1567         306 :     if (indlist != NIL)
    1568             :     {
    1569         300 :         bitmapqual = choose_bitmap_and(root, rel, indlist);
    1570         300 :         jointcost = bitmapqual->total_cost;
    1571         300 :         jointlist = list_make1(bitmapqual);
    1572             :     }
    1573             : 
    1574             :     /*
    1575             :      * If we manage to find a bitmap scan, which uses the group of OR-clause
    1576             :      * arguments as a whole, we can skip matching OR-clause arguments
    1577             :      * one-by-one as long as there are no other clauses, which can bring more
    1578             :      * efficiency to one-by-one case.
    1579             :      */
    1580         306 :     if (jointlist != NIL && other_clauses == NIL)
    1581          84 :         return jointlist;
    1582             : 
    1583             :     /*
    1584             :      * Also try to match all containing clauses one-by-one.
    1585             :      */
    1586         768 :     foreach(lc, args)
    1587             :     {
    1588         552 :         orargs = list_make1(lfirst(lc));
    1589             : 
    1590         552 :         indlist = build_paths_for_OR(root, rel,
    1591             :                                      orargs,
    1592             :                                      other_clauses);
    1593             : 
    1594         552 :         if (indlist == NIL)
    1595             :         {
    1596           6 :             splitlist = NIL;
    1597           6 :             break;
    1598             :         }
    1599             : 
    1600         546 :         bitmapqual = choose_bitmap_and(root, rel, indlist);
    1601         546 :         splitcost += bitmapqual->total_cost;
    1602         546 :         splitlist = lappend(splitlist, bitmapqual);
    1603             :     }
    1604             : 
    1605             :     /*
    1606             :      * Pick the best option.
    1607             :      */
    1608         222 :     if (splitlist == NIL)
    1609           6 :         return jointlist;
    1610         216 :     else if (jointlist == NIL)
    1611           0 :         return splitlist;
    1612             :     else
    1613         216 :         return (jointcost < splitcost) ? jointlist : splitlist;
    1614             : }
    1615             : 
    1616             : 
    1617             : /*
    1618             :  * generate_bitmap_or_paths
    1619             :  *      Look through the list of clauses to find OR clauses, and generate
    1620             :  *      a BitmapOrPath for each one we can handle that way.  Return a list
    1621             :  *      of the generated BitmapOrPaths.
    1622             :  *
    1623             :  * other_clauses is a list of additional clauses that can be assumed true
    1624             :  * for the purpose of generating indexquals, but are not to be searched for
    1625             :  * ORs.  (See build_paths_for_OR() for motivation.)
    1626             :  */
    1627             : static List *
    1628      663806 : generate_bitmap_or_paths(PlannerInfo *root, RelOptInfo *rel,
    1629             :                          List *clauses, List *other_clauses)
    1630             : {
    1631      663806 :     List       *result = NIL;
    1632             :     List       *all_clauses;
    1633             :     ListCell   *lc;
    1634             : 
    1635             :     /*
    1636             :      * We can use both the current and other clauses as context for
    1637             :      * build_paths_for_OR; no need to remove ORs from the lists.
    1638             :      */
    1639      663806 :     all_clauses = list_concat_copy(clauses, other_clauses);
    1640             : 
    1641     1037134 :     foreach(lc, clauses)
    1642             :     {
    1643      373328 :         RestrictInfo *rinfo = lfirst_node(RestrictInfo, lc);
    1644             :         List       *pathlist;
    1645             :         Path       *bitmapqual;
    1646             :         ListCell   *j;
    1647             :         List       *groupedArgs;
    1648      373328 :         List       *inner_other_clauses = NIL;
    1649             : 
    1650             :         /* Ignore RestrictInfos that aren't ORs */
    1651      373328 :         if (!restriction_is_or_clause(rinfo))
    1652      363200 :             continue;
    1653             : 
    1654             :         /*
    1655             :          * We must be able to match at least one index to each of the arms of
    1656             :          * the OR, else we can't use it.
    1657             :          */
    1658       10128 :         pathlist = NIL;
    1659             : 
    1660             :         /*
    1661             :          * Group the similar OR-clause arguments into dedicated RestrictInfos,
    1662             :          * because each of those RestrictInfos has a chance to match the index
    1663             :          * as a whole.
    1664             :          */
    1665       10128 :         groupedArgs = group_similar_or_args(root, rel, rinfo);
    1666             : 
    1667       10128 :         if (groupedArgs != ((BoolExpr *) rinfo->orclause)->args)
    1668             :         {
    1669             :             /*
    1670             :              * Some parts of the rinfo were probably grouped.  In this case,
    1671             :              * we have a set of sub-rinfos that together are an exact
    1672             :              * duplicate of rinfo.  Thus, we need to remove the rinfo from
    1673             :              * other clauses. match_clauses_to_index detects duplicated
    1674             :              * iclauses by comparing pointers to original rinfos that would be
    1675             :              * different.  So, we must delete rinfo to avoid de-facto
    1676             :              * duplicated clauses in the index clauses list.
    1677             :              */
    1678        4472 :             inner_other_clauses = list_delete(list_copy(all_clauses), rinfo);
    1679             :         }
    1680             : 
    1681       12248 :         foreach(j, groupedArgs)
    1682             :         {
    1683       11272 :             Node       *orarg = (Node *) lfirst(j);
    1684             :             List       *indlist;
    1685             : 
    1686             :             /* OR arguments should be ANDs or sub-RestrictInfos */
    1687       11272 :             if (is_andclause(orarg))
    1688             :             {
    1689        1430 :                 List       *andargs = ((BoolExpr *) orarg)->args;
    1690             : 
    1691        1430 :                 indlist = build_paths_for_OR(root, rel,
    1692             :                                              andargs,
    1693             :                                              all_clauses);
    1694             : 
    1695             :                 /* Recurse in case there are sub-ORs */
    1696        1430 :                 indlist = list_concat(indlist,
    1697        1430 :                                       generate_bitmap_or_paths(root, rel,
    1698             :                                                                andargs,
    1699             :                                                                all_clauses));
    1700             :             }
    1701        9842 :             else if (restriction_is_or_clause(castNode(RestrictInfo, orarg)))
    1702             :             {
    1703         306 :                 RestrictInfo *ri = castNode(RestrictInfo, orarg);
    1704             : 
    1705             :                 /*
    1706             :                  * Generate bitmap paths for the group of similar OR-clause
    1707             :                  * arguments.
    1708             :                  */
    1709         306 :                 indlist = make_bitmap_paths_for_or_group(root,
    1710             :                                                          rel, ri,
    1711             :                                                          inner_other_clauses);
    1712             : 
    1713         306 :                 if (indlist == NIL)
    1714             :                 {
    1715           6 :                     pathlist = NIL;
    1716           6 :                     break;
    1717             :                 }
    1718             :                 else
    1719             :                 {
    1720         300 :                     pathlist = list_concat(pathlist, indlist);
    1721         300 :                     continue;
    1722             :                 }
    1723             :             }
    1724             :             else
    1725             :             {
    1726        9536 :                 RestrictInfo *ri = castNode(RestrictInfo, orarg);
    1727             :                 List       *orargs;
    1728             : 
    1729        9536 :                 orargs = list_make1(ri);
    1730             : 
    1731        9536 :                 indlist = build_paths_for_OR(root, rel,
    1732             :                                              orargs,
    1733             :                                              all_clauses);
    1734             :             }
    1735             : 
    1736             :             /*
    1737             :              * If nothing matched this arm, we can't do anything with this OR
    1738             :              * clause.
    1739             :              */
    1740       10966 :             if (indlist == NIL)
    1741             :             {
    1742        9146 :                 pathlist = NIL;
    1743        9146 :                 break;
    1744             :             }
    1745             : 
    1746             :             /*
    1747             :              * OK, pick the most promising AND combination, and add it to
    1748             :              * pathlist.
    1749             :              */
    1750        1820 :             bitmapqual = choose_bitmap_and(root, rel, indlist);
    1751        1820 :             pathlist = lappend(pathlist, bitmapqual);
    1752             :         }
    1753             : 
    1754       10128 :         if (inner_other_clauses != NIL)
    1755        2554 :             list_free(inner_other_clauses);
    1756             : 
    1757             :         /*
    1758             :          * If we have a match for every arm, then turn them into a
    1759             :          * BitmapOrPath, and add to result list.
    1760             :          */
    1761       10128 :         if (pathlist != NIL)
    1762             :         {
    1763         976 :             bitmapqual = (Path *) create_bitmap_or_path(root, rel, pathlist);
    1764         976 :             result = lappend(result, bitmapqual);
    1765             :         }
    1766             :     }
    1767             : 
    1768      663806 :     return result;
    1769             : }
    1770             : 
    1771             : 
    1772             : /*
    1773             :  * choose_bitmap_and
    1774             :  *      Given a nonempty list of bitmap paths, AND them into one path.
    1775             :  *
    1776             :  * This is a nontrivial decision since we can legally use any subset of the
    1777             :  * given path set.  We want to choose a good tradeoff between selectivity
    1778             :  * and cost of computing the bitmap.
    1779             :  *
    1780             :  * The result is either a single one of the inputs, or a BitmapAndPath
    1781             :  * combining multiple inputs.
    1782             :  */
    1783             : static Path *
    1784      340904 : choose_bitmap_and(PlannerInfo *root, RelOptInfo *rel, List *paths)
    1785             : {
    1786      340904 :     int         npaths = list_length(paths);
    1787             :     PathClauseUsage **pathinfoarray;
    1788             :     PathClauseUsage *pathinfo;
    1789             :     List       *clauselist;
    1790      340904 :     List       *bestpaths = NIL;
    1791      340904 :     Cost        bestcost = 0;
    1792             :     int         i,
    1793             :                 j;
    1794             :     ListCell   *l;
    1795             : 
    1796             :     Assert(npaths > 0);          /* else caller error */
    1797      340904 :     if (npaths == 1)
    1798      261718 :         return (Path *) linitial(paths);    /* easy case */
    1799             : 
    1800             :     /*
    1801             :      * In theory we should consider every nonempty subset of the given paths.
    1802             :      * In practice that seems like overkill, given the crude nature of the
    1803             :      * estimates, not to mention the possible effects of higher-level AND and
    1804             :      * OR clauses.  Moreover, it's completely impractical if there are a large
    1805             :      * number of paths, since the work would grow as O(2^N).
    1806             :      *
    1807             :      * As a heuristic, we first check for paths using exactly the same sets of
    1808             :      * WHERE clauses + index predicate conditions, and reject all but the
    1809             :      * cheapest-to-scan in any such group.  This primarily gets rid of indexes
    1810             :      * that include the interesting columns but also irrelevant columns.  (In
    1811             :      * situations where the DBA has gone overboard on creating variant
    1812             :      * indexes, this can make for a very large reduction in the number of
    1813             :      * paths considered further.)
    1814             :      *
    1815             :      * We then sort the surviving paths with the cheapest-to-scan first, and
    1816             :      * for each path, consider using that path alone as the basis for a bitmap
    1817             :      * scan.  Then we consider bitmap AND scans formed from that path plus
    1818             :      * each subsequent (higher-cost) path, adding on a subsequent path if it
    1819             :      * results in a reduction in the estimated total scan cost. This means we
    1820             :      * consider about O(N^2) rather than O(2^N) path combinations, which is
    1821             :      * quite tolerable, especially given than N is usually reasonably small
    1822             :      * because of the prefiltering step.  The cheapest of these is returned.
    1823             :      *
    1824             :      * We will only consider AND combinations in which no two indexes use the
    1825             :      * same WHERE clause.  This is a bit of a kluge: it's needed because
    1826             :      * costsize.c and clausesel.c aren't very smart about redundant clauses.
    1827             :      * They will usually double-count the redundant clauses, producing a
    1828             :      * too-small selectivity that makes a redundant AND step look like it
    1829             :      * reduces the total cost.  Perhaps someday that code will be smarter and
    1830             :      * we can remove this limitation.  (But note that this also defends
    1831             :      * against flat-out duplicate input paths, which can happen because
    1832             :      * match_join_clauses_to_index will find the same OR join clauses that
    1833             :      * extract_restriction_or_clauses has pulled OR restriction clauses out
    1834             :      * of.)
    1835             :      *
    1836             :      * For the same reason, we reject AND combinations in which an index
    1837             :      * predicate clause duplicates another clause.  Here we find it necessary
    1838             :      * to be even stricter: we'll reject a partial index if any of its
    1839             :      * predicate clauses are implied by the set of WHERE clauses and predicate
    1840             :      * clauses used so far.  This covers cases such as a condition "x = 42"
    1841             :      * used with a plain index, followed by a clauseless scan of a partial
    1842             :      * index "WHERE x >= 40 AND x < 50".  The partial index has been accepted
    1843             :      * only because "x = 42" was present, and so allowing it would partially
    1844             :      * double-count selectivity.  (We could use predicate_implied_by on
    1845             :      * regular qual clauses too, to have a more intelligent, but much more
    1846             :      * expensive, check for redundancy --- but in most cases simple equality
    1847             :      * seems to suffice.)
    1848             :      */
    1849             : 
    1850             :     /*
    1851             :      * Extract clause usage info and detect any paths that use exactly the
    1852             :      * same set of clauses; keep only the cheapest-to-scan of any such groups.
    1853             :      * The surviving paths are put into an array for qsort'ing.
    1854             :      */
    1855             :     pathinfoarray = (PathClauseUsage **)
    1856       79186 :         palloc(npaths * sizeof(PathClauseUsage *));
    1857       79186 :     clauselist = NIL;
    1858       79186 :     npaths = 0;
    1859      260992 :     foreach(l, paths)
    1860             :     {
    1861      181806 :         Path       *ipath = (Path *) lfirst(l);
    1862             : 
    1863      181806 :         pathinfo = classify_index_clause_usage(ipath, &clauselist);
    1864             : 
    1865             :         /* If it's unclassifiable, treat it as distinct from all others */
    1866      181806 :         if (pathinfo->unclassifiable)
    1867             :         {
    1868           0 :             pathinfoarray[npaths++] = pathinfo;
    1869           0 :             continue;
    1870             :         }
    1871             : 
    1872      284164 :         for (i = 0; i < npaths; i++)
    1873             :         {
    1874      252068 :             if (!pathinfoarray[i]->unclassifiable &&
    1875      126034 :                 bms_equal(pathinfo->clauseids, pathinfoarray[i]->clauseids))
    1876       23676 :                 break;
    1877             :         }
    1878      181806 :         if (i < npaths)
    1879             :         {
    1880             :             /* duplicate clauseids, keep the cheaper one */
    1881             :             Cost        ncost;
    1882             :             Cost        ocost;
    1883             :             Selectivity nselec;
    1884             :             Selectivity oselec;
    1885             : 
    1886       23676 :             cost_bitmap_tree_node(pathinfo->path, &ncost, &nselec);
    1887       23676 :             cost_bitmap_tree_node(pathinfoarray[i]->path, &ocost, &oselec);
    1888       23676 :             if (ncost < ocost)
    1889        5286 :                 pathinfoarray[i] = pathinfo;
    1890             :         }
    1891             :         else
    1892             :         {
    1893             :             /* not duplicate clauseids, add to array */
    1894      158130 :             pathinfoarray[npaths++] = pathinfo;
    1895             :         }
    1896             :     }
    1897             : 
    1898             :     /* If only one surviving path, we're done */
    1899       79186 :     if (npaths == 1)
    1900       14964 :         return pathinfoarray[0]->path;
    1901             : 
    1902             :     /* Sort the surviving paths by index access cost */
    1903       64222 :     qsort(pathinfoarray, npaths, sizeof(PathClauseUsage *),
    1904             :           path_usage_comparator);
    1905             : 
    1906             :     /*
    1907             :      * For each surviving index, consider it as an "AND group leader", and see
    1908             :      * whether adding on any of the later indexes results in an AND path with
    1909             :      * cheaper total cost than before.  Then take the cheapest AND group.
    1910             :      *
    1911             :      * Note: paths that are either clauseless or unclassifiable will have
    1912             :      * empty clauseids, so that they will not be rejected by the clauseids
    1913             :      * filter here, nor will they cause later paths to be rejected by it.
    1914             :      */
    1915      207388 :     for (i = 0; i < npaths; i++)
    1916             :     {
    1917             :         Cost        costsofar;
    1918             :         List       *qualsofar;
    1919             :         Bitmapset  *clauseidsofar;
    1920             : 
    1921      143166 :         pathinfo = pathinfoarray[i];
    1922      143166 :         paths = list_make1(pathinfo->path);
    1923      143166 :         costsofar = bitmap_scan_cost_est(root, rel, pathinfo->path);
    1924      143166 :         qualsofar = list_concat_copy(pathinfo->quals, pathinfo->preds);
    1925      143166 :         clauseidsofar = bms_copy(pathinfo->clauseids);
    1926             : 
    1927      237270 :         for (j = i + 1; j < npaths; j++)
    1928             :         {
    1929             :             Cost        newcost;
    1930             : 
    1931       94104 :             pathinfo = pathinfoarray[j];
    1932             :             /* Check for redundancy */
    1933       94104 :             if (bms_overlap(pathinfo->clauseids, clauseidsofar))
    1934       42494 :                 continue;       /* consider it redundant */
    1935       51610 :             if (pathinfo->preds)
    1936             :             {
    1937          24 :                 bool        redundant = false;
    1938             : 
    1939             :                 /* we check each predicate clause separately */
    1940          24 :                 foreach(l, pathinfo->preds)
    1941             :                 {
    1942          24 :                     Node       *np = (Node *) lfirst(l);
    1943             : 
    1944          24 :                     if (predicate_implied_by(list_make1(np), qualsofar, false))
    1945             :                     {
    1946          24 :                         redundant = true;
    1947          24 :                         break;  /* out of inner foreach loop */
    1948             :                     }
    1949             :                 }
    1950          24 :                 if (redundant)
    1951          24 :                     continue;
    1952             :             }
    1953             :             /* tentatively add new path to paths, so we can estimate cost */
    1954       51586 :             paths = lappend(paths, pathinfo->path);
    1955       51586 :             newcost = bitmap_and_cost_est(root, rel, paths);
    1956       51586 :             if (newcost < costsofar)
    1957             :             {
    1958             :                 /* keep new path in paths, update subsidiary variables */
    1959         272 :                 costsofar = newcost;
    1960         272 :                 qualsofar = list_concat(qualsofar, pathinfo->quals);
    1961         272 :                 qualsofar = list_concat(qualsofar, pathinfo->preds);
    1962         272 :                 clauseidsofar = bms_add_members(clauseidsofar,
    1963         272 :                                                 pathinfo->clauseids);
    1964             :             }
    1965             :             else
    1966             :             {
    1967             :                 /* reject new path, remove it from paths list */
    1968       51314 :                 paths = list_truncate(paths, list_length(paths) - 1);
    1969             :             }
    1970             :         }
    1971             : 
    1972             :         /* Keep the cheapest AND-group (or singleton) */
    1973      143166 :         if (i == 0 || costsofar < bestcost)
    1974             :         {
    1975       67334 :             bestpaths = paths;
    1976       67334 :             bestcost = costsofar;
    1977             :         }
    1978             : 
    1979             :         /* some easy cleanup (we don't try real hard though) */
    1980      143166 :         list_free(qualsofar);
    1981             :     }
    1982             : 
    1983       64222 :     if (list_length(bestpaths) == 1)
    1984       63974 :         return (Path *) linitial(bestpaths);    /* no need for AND */
    1985         248 :     return (Path *) create_bitmap_and_path(root, rel, bestpaths);
    1986             : }
    1987             : 
    1988             : /* qsort comparator to sort in increasing index access cost order */
    1989             : static int
    1990       88956 : path_usage_comparator(const void *a, const void *b)
    1991             : {
    1992       88956 :     PathClauseUsage *pa = *(PathClauseUsage *const *) a;
    1993       88956 :     PathClauseUsage *pb = *(PathClauseUsage *const *) b;
    1994             :     Cost        acost;
    1995             :     Cost        bcost;
    1996             :     Selectivity aselec;
    1997             :     Selectivity bselec;
    1998             : 
    1999       88956 :     cost_bitmap_tree_node(pa->path, &acost, &aselec);
    2000       88956 :     cost_bitmap_tree_node(pb->path, &bcost, &bselec);
    2001             : 
    2002             :     /*
    2003             :      * If costs are the same, sort by selectivity.
    2004             :      */
    2005       88956 :     if (acost < bcost)
    2006       52110 :         return -1;
    2007       36846 :     if (acost > bcost)
    2008       25226 :         return 1;
    2009             : 
    2010       11620 :     if (aselec < bselec)
    2011        4358 :         return -1;
    2012        7262 :     if (aselec > bselec)
    2013        3020 :         return 1;
    2014             : 
    2015        4242 :     return 0;
    2016             : }
    2017             : 
    2018             : /*
    2019             :  * Estimate the cost of actually executing a bitmap scan with a single
    2020             :  * index path (which could be a BitmapAnd or BitmapOr node).
    2021             :  */
    2022             : static Cost
    2023      194752 : bitmap_scan_cost_est(PlannerInfo *root, RelOptInfo *rel, Path *ipath)
    2024             : {
    2025             :     BitmapHeapPath bpath;
    2026             : 
    2027             :     /* Set up a dummy BitmapHeapPath */
    2028      194752 :     bpath.path.type = T_BitmapHeapPath;
    2029      194752 :     bpath.path.pathtype = T_BitmapHeapScan;
    2030      194752 :     bpath.path.parent = rel;
    2031      194752 :     bpath.path.pathtarget = rel->reltarget;
    2032      194752 :     bpath.path.param_info = ipath->param_info;
    2033      194752 :     bpath.path.pathkeys = NIL;
    2034      194752 :     bpath.bitmapqual = ipath;
    2035             : 
    2036             :     /*
    2037             :      * Check the cost of temporary path without considering parallelism.
    2038             :      * Parallel bitmap heap path will be considered at later stage.
    2039             :      */
    2040      194752 :     bpath.path.parallel_workers = 0;
    2041             : 
    2042             :     /* Now we can do cost_bitmap_heap_scan */
    2043      194752 :     cost_bitmap_heap_scan(&bpath.path, root, rel,
    2044             :                           bpath.path.param_info,
    2045             :                           ipath,
    2046             :                           get_loop_count(root, rel->relid,
    2047      194752 :                                          PATH_REQ_OUTER(ipath)));
    2048             : 
    2049      194752 :     return bpath.path.total_cost;
    2050             : }
    2051             : 
    2052             : /*
    2053             :  * Estimate the cost of actually executing a BitmapAnd scan with the given
    2054             :  * inputs.
    2055             :  */
    2056             : static Cost
    2057       51586 : bitmap_and_cost_est(PlannerInfo *root, RelOptInfo *rel, List *paths)
    2058             : {
    2059             :     BitmapAndPath *apath;
    2060             : 
    2061             :     /*
    2062             :      * Might as well build a real BitmapAndPath here, as the work is slightly
    2063             :      * too complicated to be worth repeating just to save one palloc.
    2064             :      */
    2065       51586 :     apath = create_bitmap_and_path(root, rel, paths);
    2066             : 
    2067       51586 :     return bitmap_scan_cost_est(root, rel, (Path *) apath);
    2068             : }
    2069             : 
    2070             : 
    2071             : /*
    2072             :  * classify_index_clause_usage
    2073             :  *      Construct a PathClauseUsage struct describing the WHERE clauses and
    2074             :  *      index predicate clauses used by the given indexscan path.
    2075             :  *      We consider two clauses the same if they are equal().
    2076             :  *
    2077             :  * At some point we might want to migrate this info into the Path data
    2078             :  * structure proper, but for the moment it's only needed within
    2079             :  * choose_bitmap_and().
    2080             :  *
    2081             :  * *clauselist is used and expanded as needed to identify all the distinct
    2082             :  * clauses seen across successive calls.  Caller must initialize it to NIL
    2083             :  * before first call of a set.
    2084             :  */
    2085             : static PathClauseUsage *
    2086      181806 : classify_index_clause_usage(Path *path, List **clauselist)
    2087             : {
    2088             :     PathClauseUsage *result;
    2089             :     Bitmapset  *clauseids;
    2090             :     ListCell   *lc;
    2091             : 
    2092      181806 :     result = (PathClauseUsage *) palloc(sizeof(PathClauseUsage));
    2093      181806 :     result->path = path;
    2094             : 
    2095             :     /* Recursively find the quals and preds used by the path */
    2096      181806 :     result->quals = NIL;
    2097      181806 :     result->preds = NIL;
    2098      181806 :     find_indexpath_quals(path, &result->quals, &result->preds);
    2099             : 
    2100             :     /*
    2101             :      * Some machine-generated queries have outlandish numbers of qual clauses.
    2102             :      * To avoid getting into O(N^2) behavior even in this preliminary
    2103             :      * classification step, we want to limit the number of entries we can
    2104             :      * accumulate in *clauselist.  Treat any path with more than 100 quals +
    2105             :      * preds as unclassifiable, which will cause calling code to consider it
    2106             :      * distinct from all other paths.
    2107             :      */
    2108      181806 :     if (list_length(result->quals) + list_length(result->preds) > 100)
    2109             :     {
    2110           0 :         result->clauseids = NULL;
    2111           0 :         result->unclassifiable = true;
    2112           0 :         return result;
    2113             :     }
    2114             : 
    2115             :     /* Build up a bitmapset representing the quals and preds */
    2116      181806 :     clauseids = NULL;
    2117      416668 :     foreach(lc, result->quals)
    2118             :     {
    2119      234862 :         Node       *node = (Node *) lfirst(lc);
    2120             : 
    2121      234862 :         clauseids = bms_add_member(clauseids,
    2122             :                                    find_list_position(node, clauselist));
    2123             :     }
    2124      182100 :     foreach(lc, result->preds)
    2125             :     {
    2126         294 :         Node       *node = (Node *) lfirst(lc);
    2127             : 
    2128         294 :         clauseids = bms_add_member(clauseids,
    2129             :                                    find_list_position(node, clauselist));
    2130             :     }
    2131      181806 :     result->clauseids = clauseids;
    2132      181806 :     result->unclassifiable = false;
    2133             : 
    2134      181806 :     return result;
    2135             : }
    2136             : 
    2137             : 
    2138             : /*
    2139             :  * find_indexpath_quals
    2140             :  *
    2141             :  * Given the Path structure for a plain or bitmap indexscan, extract lists
    2142             :  * of all the index clauses and index predicate conditions used in the Path.
    2143             :  * These are appended to the initial contents of *quals and *preds (hence
    2144             :  * caller should initialize those to NIL).
    2145             :  *
    2146             :  * Note we are not trying to produce an accurate representation of the AND/OR
    2147             :  * semantics of the Path, but just find out all the base conditions used.
    2148             :  *
    2149             :  * The result lists contain pointers to the expressions used in the Path,
    2150             :  * but all the list cells are freshly built, so it's safe to destructively
    2151             :  * modify the lists (eg, by concat'ing with other lists).
    2152             :  */
    2153             : static void
    2154      183924 : find_indexpath_quals(Path *bitmapqual, List **quals, List **preds)
    2155             : {
    2156      183924 :     if (IsA(bitmapqual, BitmapAndPath))
    2157             :     {
    2158           0 :         BitmapAndPath *apath = (BitmapAndPath *) bitmapqual;
    2159             :         ListCell   *l;
    2160             : 
    2161           0 :         foreach(l, apath->bitmapquals)
    2162             :         {
    2163           0 :             find_indexpath_quals((Path *) lfirst(l), quals, preds);
    2164             :         }
    2165             :     }
    2166      183924 :     else if (IsA(bitmapqual, BitmapOrPath))
    2167             :     {
    2168        1158 :         BitmapOrPath *opath = (BitmapOrPath *) bitmapqual;
    2169             :         ListCell   *l;
    2170             : 
    2171        3276 :         foreach(l, opath->bitmapquals)
    2172             :         {
    2173        2118 :             find_indexpath_quals((Path *) lfirst(l), quals, preds);
    2174             :         }
    2175             :     }
    2176      182766 :     else if (IsA(bitmapqual, IndexPath))
    2177             :     {
    2178      182766 :         IndexPath  *ipath = (IndexPath *) bitmapqual;
    2179             :         ListCell   *l;
    2180             : 
    2181      417628 :         foreach(l, ipath->indexclauses)
    2182             :         {
    2183      234862 :             IndexClause *iclause = (IndexClause *) lfirst(l);
    2184             : 
    2185      234862 :             *quals = lappend(*quals, iclause->rinfo->clause);
    2186             :         }
    2187      182766 :         *preds = list_concat(*preds, ipath->indexinfo->indpred);
    2188             :     }
    2189             :     else
    2190           0 :         elog(ERROR, "unrecognized node type: %d", nodeTag(bitmapqual));
    2191      183924 : }
    2192             : 
    2193             : 
    2194             : /*
    2195             :  * find_list_position
    2196             :  *      Return the given node's position (counting from 0) in the given
    2197             :  *      list of nodes.  If it's not equal() to any existing list member,
    2198             :  *      add it at the end, and return that position.
    2199             :  */
    2200             : static int
    2201      235156 : find_list_position(Node *node, List **nodelist)
    2202             : {
    2203             :     int         i;
    2204             :     ListCell   *lc;
    2205             : 
    2206      235156 :     i = 0;
    2207      371422 :     foreach(lc, *nodelist)
    2208             :     {
    2209      205786 :         Node       *oldnode = (Node *) lfirst(lc);
    2210             : 
    2211      205786 :         if (equal(node, oldnode))
    2212       69520 :             return i;
    2213      136266 :         i++;
    2214             :     }
    2215             : 
    2216      165636 :     *nodelist = lappend(*nodelist, node);
    2217             : 
    2218      165636 :     return i;
    2219             : }
    2220             : 
    2221             : 
    2222             : /*
    2223             :  * check_index_only
    2224             :  *      Determine whether an index-only scan is possible for this index.
    2225             :  */
    2226             : static bool
    2227      861786 : check_index_only(RelOptInfo *rel, IndexOptInfo *index)
    2228             : {
    2229             :     bool        result;
    2230      861786 :     Bitmapset  *attrs_used = NULL;
    2231      861786 :     Bitmapset  *index_canreturn_attrs = NULL;
    2232             :     ListCell   *lc;
    2233             :     int         i;
    2234             : 
    2235             :     /* Index-only scans must be enabled */
    2236      861786 :     if (!enable_indexonlyscan)
    2237        3688 :         return false;
    2238             : 
    2239             :     /*
    2240             :      * Check that all needed attributes of the relation are available from the
    2241             :      * index.
    2242             :      */
    2243             : 
    2244             :     /*
    2245             :      * First, identify all the attributes needed for joins or final output.
    2246             :      * Note: we must look at rel's targetlist, not the attr_needed data,
    2247             :      * because attr_needed isn't computed for inheritance child rels.
    2248             :      */
    2249      858098 :     pull_varattnos((Node *) rel->reltarget->exprs, rel->relid, &attrs_used);
    2250             : 
    2251             :     /*
    2252             :      * Add all the attributes used by restriction clauses; but consider only
    2253             :      * those clauses not implied by the index predicate, since ones that are
    2254             :      * so implied don't need to be checked explicitly in the plan.
    2255             :      *
    2256             :      * Note: attributes used only in index quals would not be needed at
    2257             :      * runtime either, if we are certain that the index is not lossy.  However
    2258             :      * it'd be complicated to account for that accurately, and it doesn't
    2259             :      * matter in most cases, since we'd conclude that such attributes are
    2260             :      * available from the index anyway.
    2261             :      */
    2262     1791998 :     foreach(lc, index->indrestrictinfo)
    2263             :     {
    2264      933900 :         RestrictInfo *rinfo = (RestrictInfo *) lfirst(lc);
    2265             : 
    2266      933900 :         pull_varattnos((Node *) rinfo->clause, rel->relid, &attrs_used);
    2267             :     }
    2268             : 
    2269             :     /*
    2270             :      * Construct a bitmapset of columns that the index can return back in an
    2271             :      * index-only scan.
    2272             :      */
    2273     2442276 :     for (i = 0; i < index->ncolumns; i++)
    2274             :     {
    2275     1584178 :         int         attno = index->indexkeys[i];
    2276             : 
    2277             :         /*
    2278             :          * For the moment, we just ignore index expressions.  It might be nice
    2279             :          * to do something with them, later.
    2280             :          */
    2281     1584178 :         if (attno == 0)
    2282        3274 :             continue;
    2283             : 
    2284     1580904 :         if (index->canreturn[i])
    2285             :             index_canreturn_attrs =
    2286     1305766 :                 bms_add_member(index_canreturn_attrs,
    2287             :                                attno - FirstLowInvalidHeapAttributeNumber);
    2288             :     }
    2289             : 
    2290             :     /* Do we have all the necessary attributes? */
    2291      858098 :     result = bms_is_subset(attrs_used, index_canreturn_attrs);
    2292             : 
    2293      858098 :     bms_free(attrs_used);
    2294      858098 :     bms_free(index_canreturn_attrs);
    2295             : 
    2296      858098 :     return result;
    2297             : }
    2298             : 
    2299             : /*
    2300             :  * get_loop_count
    2301             :  *      Choose the loop count estimate to use for costing a parameterized path
    2302             :  *      with the given set of outer relids.
    2303             :  *
    2304             :  * Since we produce parameterized paths before we've begun to generate join
    2305             :  * relations, it's impossible to predict exactly how many times a parameterized
    2306             :  * path will be iterated; we don't know the size of the relation that will be
    2307             :  * on the outside of the nestloop.  However, we should try to account for
    2308             :  * multiple iterations somehow in costing the path.  The heuristic embodied
    2309             :  * here is to use the rowcount of the smallest other base relation needed in
    2310             :  * the join clauses used by the path.  (We could alternatively consider the
    2311             :  * largest one, but that seems too optimistic.)  This is of course the right
    2312             :  * answer for single-other-relation cases, and it seems like a reasonable
    2313             :  * zero-order approximation for multiway-join cases.
    2314             :  *
    2315             :  * In addition, we check to see if the other side of each join clause is on
    2316             :  * the inside of some semijoin that the current relation is on the outside of.
    2317             :  * If so, the only way that a parameterized path could be used is if the
    2318             :  * semijoin RHS has been unique-ified, so we should use the number of unique
    2319             :  * RHS rows rather than using the relation's raw rowcount.
    2320             :  *
    2321             :  * Note: for this to work, allpaths.c must establish all baserel size
    2322             :  * estimates before it begins to compute paths, or at least before it
    2323             :  * calls create_index_paths().
    2324             :  */
    2325             : static double
    2326     1197072 : get_loop_count(PlannerInfo *root, Index cur_relid, Relids outer_relids)
    2327             : {
    2328             :     double      result;
    2329             :     int         outer_relid;
    2330             : 
    2331             :     /* For a non-parameterized path, just return 1.0 quickly */
    2332     1197072 :     if (outer_relids == NULL)
    2333      827738 :         return 1.0;
    2334             : 
    2335      369334 :     result = 0.0;
    2336      369334 :     outer_relid = -1;
    2337      749596 :     while ((outer_relid = bms_next_member(outer_relids, outer_relid)) >= 0)
    2338             :     {
    2339             :         RelOptInfo *outer_rel;
    2340             :         double      rowcount;
    2341             : 
    2342             :         /* Paranoia: ignore bogus relid indexes */
    2343      380262 :         if (outer_relid >= root->simple_rel_array_size)
    2344           0 :             continue;
    2345      380262 :         outer_rel = root->simple_rel_array[outer_relid];
    2346      380262 :         if (outer_rel == NULL)
    2347         254 :             continue;
    2348             :         Assert(outer_rel->relid == outer_relid); /* sanity check on array */
    2349             : 
    2350             :         /* Other relation could be proven empty, if so ignore */
    2351      380008 :         if (IS_DUMMY_REL(outer_rel))
    2352          24 :             continue;
    2353             : 
    2354             :         /* Otherwise, rel's rows estimate should be valid by now */
    2355             :         Assert(outer_rel->rows > 0);
    2356             : 
    2357             :         /* Check to see if rel is on the inside of any semijoins */
    2358      379984 :         rowcount = adjust_rowcount_for_semijoins(root,
    2359             :                                                  cur_relid,
    2360             :                                                  outer_relid,
    2361             :                                                  outer_rel->rows);
    2362             : 
    2363             :         /* Remember smallest row count estimate among the outer rels */
    2364      379984 :         if (result == 0.0 || result > rowcount)
    2365      375868 :             result = rowcount;
    2366             :     }
    2367             :     /* Return 1.0 if we found no valid relations (shouldn't happen) */
    2368      369334 :     return (result > 0.0) ? result : 1.0;
    2369             : }
    2370             : 
    2371             : /*
    2372             :  * Check to see if outer_relid is on the inside of any semijoin that cur_relid
    2373             :  * is on the outside of.  If so, replace rowcount with the estimated number of
    2374             :  * unique rows from the semijoin RHS (assuming that's smaller, which it might
    2375             :  * not be).  The estimate is crude but it's the best we can do at this stage
    2376             :  * of the proceedings.
    2377             :  */
    2378             : static double
    2379      379984 : adjust_rowcount_for_semijoins(PlannerInfo *root,
    2380             :                               Index cur_relid,
    2381             :                               Index outer_relid,
    2382             :                               double rowcount)
    2383             : {
    2384             :     ListCell   *lc;
    2385             : 
    2386      610346 :     foreach(lc, root->join_info_list)
    2387             :     {
    2388      230362 :         SpecialJoinInfo *sjinfo = (SpecialJoinInfo *) lfirst(lc);
    2389             : 
    2390      237710 :         if (sjinfo->jointype == JOIN_SEMI &&
    2391       10530 :             bms_is_member(cur_relid, sjinfo->syn_lefthand) &&
    2392        3182 :             bms_is_member(outer_relid, sjinfo->syn_righthand))
    2393             :         {
    2394             :             /* Estimate number of unique-ified rows */
    2395             :             double      nraw;
    2396             :             double      nunique;
    2397             : 
    2398        1140 :             nraw = approximate_joinrel_size(root, sjinfo->syn_righthand);
    2399        1140 :             nunique = estimate_num_groups(root,
    2400             :                                           sjinfo->semi_rhs_exprs,
    2401             :                                           nraw,
    2402             :                                           NULL,
    2403             :                                           NULL);
    2404        1140 :             if (rowcount > nunique)
    2405         386 :                 rowcount = nunique;
    2406             :         }
    2407             :     }
    2408      379984 :     return rowcount;
    2409             : }
    2410             : 
    2411             : /*
    2412             :  * Make an approximate estimate of the size of a joinrel.
    2413             :  *
    2414             :  * We don't have enough info at this point to get a good estimate, so we
    2415             :  * just multiply the base relation sizes together.  Fortunately, this is
    2416             :  * the right answer anyway for the most common case with a single relation
    2417             :  * on the RHS of a semijoin.  Also, estimate_num_groups() has only a weak
    2418             :  * dependency on its input_rows argument (it basically uses it as a clamp).
    2419             :  * So we might be able to get a fairly decent end result even with a severe
    2420             :  * overestimate of the RHS's raw size.
    2421             :  */
    2422             : static double
    2423        1140 : approximate_joinrel_size(PlannerInfo *root, Relids relids)
    2424             : {
    2425        1140 :     double      rowcount = 1.0;
    2426             :     int         relid;
    2427             : 
    2428        1140 :     relid = -1;
    2429        2436 :     while ((relid = bms_next_member(relids, relid)) >= 0)
    2430             :     {
    2431             :         RelOptInfo *rel;
    2432             : 
    2433             :         /* Paranoia: ignore bogus relid indexes */
    2434        1296 :         if (relid >= root->simple_rel_array_size)
    2435           0 :             continue;
    2436        1296 :         rel = root->simple_rel_array[relid];
    2437        1296 :         if (rel == NULL)
    2438           0 :             continue;
    2439             :         Assert(rel->relid == relid); /* sanity check on array */
    2440             : 
    2441             :         /* Relation could be proven empty, if so ignore */
    2442        1296 :         if (IS_DUMMY_REL(rel))
    2443           0 :             continue;
    2444             : 
    2445             :         /* Otherwise, rel's rows estimate should be valid by now */
    2446             :         Assert(rel->rows > 0);
    2447             : 
    2448             :         /* Accumulate product */
    2449        1296 :         rowcount *= rel->rows;
    2450             :     }
    2451        1140 :     return rowcount;
    2452             : }
    2453             : 
    2454             : 
    2455             : /****************************************************************************
    2456             :  *              ----  ROUTINES TO CHECK QUERY CLAUSES  ----
    2457             :  ****************************************************************************/
    2458             : 
    2459             : /*
    2460             :  * match_restriction_clauses_to_index
    2461             :  *    Identify restriction clauses for the rel that match the index.
    2462             :  *    Matching clauses are added to *clauseset.
    2463             :  */
    2464             : static void
    2465      717600 : match_restriction_clauses_to_index(PlannerInfo *root,
    2466             :                                    IndexOptInfo *index,
    2467             :                                    IndexClauseSet *clauseset)
    2468             : {
    2469             :     /* We can ignore clauses that are implied by the index predicate */
    2470      717600 :     match_clauses_to_index(root, index->indrestrictinfo, index, clauseset);
    2471      717600 : }
    2472             : 
    2473             : /*
    2474             :  * match_join_clauses_to_index
    2475             :  *    Identify join clauses for the rel that match the index.
    2476             :  *    Matching clauses are added to *clauseset.
    2477             :  *    Also, add any potentially usable join OR clauses to *joinorclauses.
    2478             :  *    They also might be processed by match_clause_to_index() as a whole.
    2479             :  */
    2480             : static void
    2481      717600 : match_join_clauses_to_index(PlannerInfo *root,
    2482             :                             RelOptInfo *rel, IndexOptInfo *index,
    2483             :                             IndexClauseSet *clauseset,
    2484             :                             List **joinorclauses)
    2485             : {
    2486             :     ListCell   *lc;
    2487             : 
    2488             :     /* Scan the rel's join clauses */
    2489      974300 :     foreach(lc, rel->joininfo)
    2490             :     {
    2491      256700 :         RestrictInfo *rinfo = (RestrictInfo *) lfirst(lc);
    2492             : 
    2493             :         /* Check if clause can be moved to this rel */
    2494      256700 :         if (!join_clause_is_movable_to(rinfo, rel))
    2495      151826 :             continue;
    2496             : 
    2497             :         /*
    2498             :          * Potentially usable, so see if it matches the index or is an OR. Use
    2499             :          * list_append_unique_ptr() here to avoid possible duplicates when
    2500             :          * processing the same clauses with different indexes.
    2501             :          */
    2502      104874 :         if (restriction_is_or_clause(rinfo))
    2503       15342 :             *joinorclauses = list_append_unique_ptr(*joinorclauses, rinfo);
    2504             : 
    2505      104874 :         match_clause_to_index(root, rinfo, index, clauseset);
    2506             :     }
    2507      717600 : }
    2508             : 
    2509             : /*
    2510             :  * match_eclass_clauses_to_index
    2511             :  *    Identify EquivalenceClass join clauses for the rel that match the index.
    2512             :  *    Matching clauses are added to *clauseset.
    2513             :  */
    2514             : static void
    2515      717600 : match_eclass_clauses_to_index(PlannerInfo *root, IndexOptInfo *index,
    2516             :                               IndexClauseSet *clauseset)
    2517             : {
    2518             :     int         indexcol;
    2519             : 
    2520             :     /* No work if rel is not in any such ECs */
    2521      717600 :     if (!index->rel->has_eclass_joins)
    2522      422884 :         return;
    2523             : 
    2524      773358 :     for (indexcol = 0; indexcol < index->nkeycolumns; indexcol++)
    2525             :     {
    2526             :         ec_member_matches_arg arg;
    2527             :         List       *clauses;
    2528             : 
    2529             :         /* Generate clauses, skipping any that join to lateral_referencers */
    2530      478642 :         arg.index = index;
    2531      478642 :         arg.indexcol = indexcol;
    2532      478642 :         clauses = generate_implied_equalities_for_column(root,
    2533             :                                                          index->rel,
    2534             :                                                          ec_member_matches_indexcol,
    2535             :                                                          &arg,
    2536      478642 :                                                          index->rel->lateral_referencers);
    2537             : 
    2538             :         /*
    2539             :          * We have to check whether the results actually do match the index,
    2540             :          * since for non-btree indexes the EC's equality operators might not
    2541             :          * be in the index opclass (cf ec_member_matches_indexcol).
    2542             :          */
    2543      478642 :         match_clauses_to_index(root, clauses, index, clauseset);
    2544             :     }
    2545             : }
    2546             : 
    2547             : /*
    2548             :  * match_clauses_to_index
    2549             :  *    Perform match_clause_to_index() for each clause in a list.
    2550             :  *    Matching clauses are added to *clauseset.
    2551             :  */
    2552             : static void
    2553     1228316 : match_clauses_to_index(PlannerInfo *root,
    2554             :                        List *clauses,
    2555             :                        IndexOptInfo *index,
    2556             :                        IndexClauseSet *clauseset)
    2557             : {
    2558             :     ListCell   *lc;
    2559             : 
    2560     2217494 :     foreach(lc, clauses)
    2561             :     {
    2562      989178 :         RestrictInfo *rinfo = lfirst_node(RestrictInfo, lc);
    2563             : 
    2564      989178 :         match_clause_to_index(root, rinfo, index, clauseset);
    2565             :     }
    2566     1228316 : }
    2567             : 
    2568             : /*
    2569             :  * match_clause_to_index
    2570             :  *    Test whether a qual clause can be used with an index.
    2571             :  *
    2572             :  * If the clause is usable, add an IndexClause entry for it to the appropriate
    2573             :  * list in *clauseset.  (*clauseset must be initialized to zeroes before first
    2574             :  * call.)
    2575             :  *
    2576             :  * Note: in some circumstances we may find the same RestrictInfos coming from
    2577             :  * multiple places.  Defend against redundant outputs by refusing to add a
    2578             :  * clause twice (pointer equality should be a good enough check for this).
    2579             :  *
    2580             :  * Note: it's possible that a badly-defined index could have multiple matching
    2581             :  * columns.  We always select the first match if so; this avoids scenarios
    2582             :  * wherein we get an inflated idea of the index's selectivity by using the
    2583             :  * same clause multiple times with different index columns.
    2584             :  */
    2585             : static void
    2586     1094052 : match_clause_to_index(PlannerInfo *root,
    2587             :                       RestrictInfo *rinfo,
    2588             :                       IndexOptInfo *index,
    2589             :                       IndexClauseSet *clauseset)
    2590             : {
    2591             :     int         indexcol;
    2592             : 
    2593             :     /*
    2594             :      * Never match pseudoconstants to indexes.  (Normally a match could not
    2595             :      * happen anyway, since a pseudoconstant clause couldn't contain a Var,
    2596             :      * but what if someone builds an expression index on a constant? It's not
    2597             :      * totally unreasonable to do so with a partial index, either.)
    2598             :      */
    2599     1094052 :     if (rinfo->pseudoconstant)
    2600       13164 :         return;
    2601             : 
    2602             :     /*
    2603             :      * If clause can't be used as an indexqual because it must wait till after
    2604             :      * some lower-security-level restriction clause, reject it.
    2605             :      */
    2606     1080888 :     if (!restriction_is_securely_promotable(rinfo, index->rel))
    2607         474 :         return;
    2608             : 
    2609             :     /* OK, check each index key column for a match */
    2610     2400994 :     for (indexcol = 0; indexcol < index->nkeycolumns; indexcol++)
    2611             :     {
    2612             :         IndexClause *iclause;
    2613             :         ListCell   *lc;
    2614             : 
    2615             :         /* Ignore duplicates */
    2616     1794436 :         foreach(lc, clauseset->indexclauses[indexcol])
    2617             :         {
    2618       74708 :             iclause = (IndexClause *) lfirst(lc);
    2619             : 
    2620       74708 :             if (iclause->rinfo == rinfo)
    2621           0 :                 return;
    2622             :         }
    2623             : 
    2624             :         /* OK, try to match the clause to the index column */
    2625     1719728 :         iclause = match_clause_to_indexcol(root,
    2626             :                                            rinfo,
    2627             :                                            indexcol,
    2628             :                                            index);
    2629     1719728 :         if (iclause)
    2630             :         {
    2631             :             /* Success, so record it */
    2632      399148 :             clauseset->indexclauses[indexcol] =
    2633      399148 :                 lappend(clauseset->indexclauses[indexcol], iclause);
    2634      399148 :             clauseset->nonempty = true;
    2635      399148 :             return;
    2636             :         }
    2637             :     }
    2638             : }
    2639             : 
    2640             : /*
    2641             :  * match_clause_to_indexcol()
    2642             :  *    Determine whether a restriction clause matches a column of an index,
    2643             :  *    and if so, build an IndexClause node describing the details.
    2644             :  *
    2645             :  *    To match an index normally, an operator clause:
    2646             :  *
    2647             :  *    (1)  must be in the form (indexkey op const) or (const op indexkey);
    2648             :  *         and
    2649             :  *    (2)  must contain an operator which is in the index's operator family
    2650             :  *         for this column; and
    2651             :  *    (3)  must match the collation of the index, if collation is relevant.
    2652             :  *
    2653             :  *    Our definition of "const" is exceedingly liberal: we allow anything that
    2654             :  *    doesn't involve a volatile function or a Var of the index's relation.
    2655             :  *    In particular, Vars belonging to other relations of the query are
    2656             :  *    accepted here, since a clause of that form can be used in a
    2657             :  *    parameterized indexscan.  It's the responsibility of higher code levels
    2658             :  *    to manage restriction and join clauses appropriately.
    2659             :  *
    2660             :  *    Note: we do need to check for Vars of the index's relation on the
    2661             :  *    "const" side of the clause, since clauses like (a.f1 OP (b.f2 OP a.f3))
    2662             :  *    are not processable by a parameterized indexscan on a.f1, whereas
    2663             :  *    something like (a.f1 OP (b.f2 OP c.f3)) is.
    2664             :  *
    2665             :  *    Presently, the executor can only deal with indexquals that have the
    2666             :  *    indexkey on the left, so we can only use clauses that have the indexkey
    2667             :  *    on the right if we can commute the clause to put the key on the left.
    2668             :  *    We handle that by generating an IndexClause with the correctly-commuted
    2669             :  *    opclause as a derived indexqual.
    2670             :  *
    2671             :  *    If the index has a collation, the clause must have the same collation.
    2672             :  *    For collation-less indexes, we assume it doesn't matter; this is
    2673             :  *    necessary for cases like "hstore ? text", wherein hstore's operators
    2674             :  *    don't care about collation but the clause will get marked with a
    2675             :  *    collation anyway because of the text argument.  (This logic is
    2676             :  *    embodied in the macro IndexCollMatchesExprColl.)
    2677             :  *
    2678             :  *    It is also possible to match RowCompareExpr clauses to indexes (but
    2679             :  *    currently, only btree indexes handle this).
    2680             :  *
    2681             :  *    It is also possible to match ScalarArrayOpExpr clauses to indexes, when
    2682             :  *    the clause is of the form "indexkey op ANY (arrayconst)".
    2683             :  *
    2684             :  *    It is also possible to match a list of OR clauses if it might be
    2685             :  *    transformed into a single ScalarArrayOpExpr clause.  On success,
    2686             :  *    the returning index clause will contain a transformed clause.
    2687             :  *
    2688             :  *    For boolean indexes, it is also possible to match the clause directly
    2689             :  *    to the indexkey; or perhaps the clause is (NOT indexkey).
    2690             :  *
    2691             :  *    And, last but not least, some operators and functions can be processed
    2692             :  *    to derive (typically lossy) indexquals from a clause that isn't in
    2693             :  *    itself indexable.  If we see that any operand of an OpExpr or FuncExpr
    2694             :  *    matches the index key, and the function has a planner support function
    2695             :  *    attached to it, we'll invoke the support function to see if such an
    2696             :  *    indexqual can be built.
    2697             :  *
    2698             :  * 'rinfo' is the clause to be tested (as a RestrictInfo node).
    2699             :  * 'indexcol' is a column number of 'index' (counting from 0).
    2700             :  * 'index' is the index of interest.
    2701             :  *
    2702             :  * Returns an IndexClause if the clause can be used with this index key,
    2703             :  * or NULL if not.
    2704             :  *
    2705             :  * NOTE:  This routine always returns NULL if the clause is an AND clause.
    2706             :  * Higher-level routines deal with OR and AND clauses. OR clause can be
    2707             :  * matched as a whole by match_orclause_to_indexcol() though.
    2708             :  */
    2709             : static IndexClause *
    2710     1719728 : match_clause_to_indexcol(PlannerInfo *root,
    2711             :                          RestrictInfo *rinfo,
    2712             :                          int indexcol,
    2713             :                          IndexOptInfo *index)
    2714             : {
    2715             :     IndexClause *iclause;
    2716     1719728 :     Expr       *clause = rinfo->clause;
    2717             :     Oid         opfamily;
    2718             : 
    2719             :     Assert(indexcol < index->nkeycolumns);
    2720             : 
    2721             :     /*
    2722             :      * Historically this code has coped with NULL clauses.  That's probably
    2723             :      * not possible anymore, but we might as well continue to cope.
    2724             :      */
    2725     1719728 :     if (clause == NULL)
    2726           0 :         return NULL;
    2727             : 
    2728             :     /* First check for boolean-index cases. */
    2729     1719728 :     opfamily = index->opfamily[indexcol];
    2730     1719728 :     if (IsBooleanOpfamily(opfamily))
    2731             :     {
    2732         446 :         iclause = match_boolean_index_clause(root, rinfo, indexcol, index);
    2733         446 :         if (iclause)
    2734         294 :             return iclause;
    2735             :     }
    2736             : 
    2737             :     /*
    2738             :      * Clause must be an opclause, funcclause, ScalarArrayOpExpr,
    2739             :      * RowCompareExpr, or OR-clause that could be converted to SAOP.  Or, if
    2740             :      * the index supports it, we can handle IS NULL/NOT NULL clauses.
    2741             :      */
    2742     1719434 :     if (IsA(clause, OpExpr))
    2743             :     {
    2744     1437872 :         return match_opclause_to_indexcol(root, rinfo, indexcol, index);
    2745             :     }
    2746      281562 :     else if (IsA(clause, FuncExpr))
    2747             :     {
    2748       30894 :         return match_funcclause_to_indexcol(root, rinfo, indexcol, index);
    2749             :     }
    2750      250668 :     else if (IsA(clause, ScalarArrayOpExpr))
    2751             :     {
    2752       77036 :         return match_saopclause_to_indexcol(root, rinfo, indexcol, index);
    2753             :     }
    2754      173632 :     else if (IsA(clause, RowCompareExpr))
    2755             :     {
    2756         432 :         return match_rowcompare_to_indexcol(root, rinfo, indexcol, index);
    2757             :     }
    2758      173200 :     else if (restriction_is_or_clause(rinfo))
    2759             :     {
    2760       48676 :         return match_orclause_to_indexcol(root, rinfo, indexcol, index);
    2761             :     }
    2762      124524 :     else if (index->amsearchnulls && IsA(clause, NullTest))
    2763             :     {
    2764       16216 :         NullTest   *nt = (NullTest *) clause;
    2765             : 
    2766       32432 :         if (!nt->argisrow &&
    2767       16216 :             match_index_to_operand((Node *) nt->arg, indexcol, index))
    2768             :         {
    2769        1474 :             iclause = makeNode(IndexClause);
    2770        1474 :             iclause->rinfo = rinfo;
    2771        1474 :             iclause->indexquals = list_make1(rinfo);
    2772        1474 :             iclause->lossy = false;
    2773        1474 :             iclause->indexcol = indexcol;
    2774        1474 :             iclause->indexcols = NIL;
    2775        1474 :             return iclause;
    2776             :         }
    2777             :     }
    2778             : 
    2779      123050 :     return NULL;
    2780             : }
    2781             : 
    2782             : /*
    2783             :  * IsBooleanOpfamily
    2784             :  *    Detect whether an opfamily supports boolean equality as an operator.
    2785             :  *
    2786             :  * If the opfamily OID is in the range of built-in objects, we can rely
    2787             :  * on hard-wired knowledge of which built-in opfamilies support this.
    2788             :  * For extension opfamilies, there's no choice but to do a catcache lookup.
    2789             :  */
    2790             : static bool
    2791     2362092 : IsBooleanOpfamily(Oid opfamily)
    2792             : {
    2793     2362092 :     if (opfamily < FirstNormalObjectId)
    2794     2358876 :         return IsBuiltinBooleanOpfamily(opfamily);
    2795             :     else
    2796        3216 :         return op_in_opfamily(BooleanEqualOperator, opfamily);
    2797             : }
    2798             : 
    2799             : /*
    2800             :  * match_boolean_index_clause
    2801             :  *    Recognize restriction clauses that can be matched to a boolean index.
    2802             :  *
    2803             :  * The idea here is that, for an index on a boolean column that supports the
    2804             :  * BooleanEqualOperator, we can transform a plain reference to the indexkey
    2805             :  * into "indexkey = true", or "NOT indexkey" into "indexkey = false", etc,
    2806             :  * so as to make the expression indexable using the index's "=" operator.
    2807             :  * Since Postgres 8.1, we must do this because constant simplification does
    2808             :  * the reverse transformation; without this code there'd be no way to use
    2809             :  * such an index at all.
    2810             :  *
    2811             :  * This should be called only when IsBooleanOpfamily() recognizes the
    2812             :  * index's operator family.  We check to see if the clause matches the
    2813             :  * index's key, and if so, build a suitable IndexClause.
    2814             :  */
    2815             : static IndexClause *
    2816        1706 : match_boolean_index_clause(PlannerInfo *root,
    2817             :                            RestrictInfo *rinfo,
    2818             :                            int indexcol,
    2819             :                            IndexOptInfo *index)
    2820             : {
    2821        1706 :     Node       *clause = (Node *) rinfo->clause;
    2822        1706 :     Expr       *op = NULL;
    2823             : 
    2824             :     /* Direct match? */
    2825        1706 :     if (match_index_to_operand(clause, indexcol, index))
    2826             :     {
    2827             :         /* convert to indexkey = TRUE */
    2828         274 :         op = make_opclause(BooleanEqualOperator, BOOLOID, false,
    2829             :                            (Expr *) clause,
    2830         274 :                            (Expr *) makeBoolConst(true, false),
    2831             :                            InvalidOid, InvalidOid);
    2832             :     }
    2833             :     /* NOT clause? */
    2834        1432 :     else if (is_notclause(clause))
    2835             :     {
    2836        1208 :         Node       *arg = (Node *) get_notclausearg((Expr *) clause);
    2837             : 
    2838        1208 :         if (match_index_to_operand(arg, indexcol, index))
    2839             :         {
    2840             :             /* convert to indexkey = FALSE */
    2841        1208 :             op = make_opclause(BooleanEqualOperator, BOOLOID, false,
    2842             :                                (Expr *) arg,
    2843        1208 :                                (Expr *) makeBoolConst(false, false),
    2844             :                                InvalidOid, InvalidOid);
    2845             :         }
    2846             :     }
    2847             : 
    2848             :     /*
    2849             :      * Since we only consider clauses at top level of WHERE, we can convert
    2850             :      * indexkey IS TRUE and indexkey IS FALSE to index searches as well.  The
    2851             :      * different meaning for NULL isn't important.
    2852             :      */
    2853         224 :     else if (clause && IsA(clause, BooleanTest))
    2854             :     {
    2855          36 :         BooleanTest *btest = (BooleanTest *) clause;
    2856          36 :         Node       *arg = (Node *) btest->arg;
    2857             : 
    2858          54 :         if (btest->booltesttype == IS_TRUE &&
    2859          18 :             match_index_to_operand(arg, indexcol, index))
    2860             :         {
    2861             :             /* convert to indexkey = TRUE */
    2862          18 :             op = make_opclause(BooleanEqualOperator, BOOLOID, false,
    2863             :                                (Expr *) arg,
    2864          18 :                                (Expr *) makeBoolConst(true, false),
    2865             :                                InvalidOid, InvalidOid);
    2866             :         }
    2867          36 :         else if (btest->booltesttype == IS_FALSE &&
    2868          18 :                  match_index_to_operand(arg, indexcol, index))
    2869             :         {
    2870             :             /* convert to indexkey = FALSE */
    2871          18 :             op = make_opclause(BooleanEqualOperator, BOOLOID, false,
    2872             :                                (Expr *) arg,
    2873          18 :                                (Expr *) makeBoolConst(false, false),
    2874             :                                InvalidOid, InvalidOid);
    2875             :         }
    2876             :     }
    2877             : 
    2878             :     /*
    2879             :      * If we successfully made an operator clause from the given qual, we must
    2880             :      * wrap it in an IndexClause.  It's not lossy.
    2881             :      */
    2882        1706 :     if (op)
    2883             :     {
    2884        1518 :         IndexClause *iclause = makeNode(IndexClause);
    2885             : 
    2886        1518 :         iclause->rinfo = rinfo;
    2887        1518 :         iclause->indexquals = list_make1(make_simple_restrictinfo(root, op));
    2888        1518 :         iclause->lossy = false;
    2889        1518 :         iclause->indexcol = indexcol;
    2890        1518 :         iclause->indexcols = NIL;
    2891        1518 :         return iclause;
    2892             :     }
    2893             : 
    2894         188 :     return NULL;
    2895             : }
    2896             : 
    2897             : /*
    2898             :  * match_opclause_to_indexcol()
    2899             :  *    Handles the OpExpr case for match_clause_to_indexcol(),
    2900             :  *    which see for comments.
    2901             :  */
    2902             : static IndexClause *
    2903     1437872 : match_opclause_to_indexcol(PlannerInfo *root,
    2904             :                            RestrictInfo *rinfo,
    2905             :                            int indexcol,
    2906             :                            IndexOptInfo *index)
    2907             : {
    2908             :     IndexClause *iclause;
    2909     1437872 :     OpExpr     *clause = (OpExpr *) rinfo->clause;
    2910             :     Node       *leftop,
    2911             :                *rightop;
    2912             :     Oid         expr_op;
    2913             :     Oid         expr_coll;
    2914             :     Index       index_relid;
    2915             :     Oid         opfamily;
    2916             :     Oid         idxcollation;
    2917             : 
    2918             :     /*
    2919             :      * Only binary operators need apply.  (In theory, a planner support
    2920             :      * function could do something with a unary operator, but it seems
    2921             :      * unlikely to be worth the cycles to check.)
    2922             :      */
    2923     1437872 :     if (list_length(clause->args) != 2)
    2924           0 :         return NULL;
    2925             : 
    2926     1437872 :     leftop = (Node *) linitial(clause->args);
    2927     1437872 :     rightop = (Node *) lsecond(clause->args);
    2928     1437872 :     expr_op = clause->opno;
    2929     1437872 :     expr_coll = clause->inputcollid;
    2930             : 
    2931     1437872 :     index_relid = index->rel->relid;
    2932     1437872 :     opfamily = index->opfamily[indexcol];
    2933     1437872 :     idxcollation = index->indexcollations[indexcol];
    2934             : 
    2935             :     /*
    2936             :      * Check for clauses of the form: (indexkey operator constant) or
    2937             :      * (constant operator indexkey).  See match_clause_to_indexcol's notes
    2938             :      * about const-ness.
    2939             :      *
    2940             :      * Note that we don't ask the support function about clauses that don't
    2941             :      * have one of these forms.  Again, in principle it might be possible to
    2942             :      * do something, but it seems unlikely to be worth the cycles to check.
    2943             :      */
    2944     1437872 :     if (match_index_to_operand(leftop, indexcol, index) &&
    2945      340358 :         !bms_is_member(index_relid, rinfo->right_relids) &&
    2946      340184 :         !contain_volatile_functions(rightop))
    2947             :     {
    2948      673778 :         if (IndexCollMatchesExprColl(idxcollation, expr_coll) &&
    2949      333594 :             op_in_opfamily(expr_op, opfamily))
    2950             :         {
    2951      326016 :             iclause = makeNode(IndexClause);
    2952      326016 :             iclause->rinfo = rinfo;
    2953      326016 :             iclause->indexquals = list_make1(rinfo);
    2954      326016 :             iclause->lossy = false;
    2955      326016 :             iclause->indexcol = indexcol;
    2956      326016 :             iclause->indexcols = NIL;
    2957      326016 :             return iclause;
    2958             :         }
    2959             : 
    2960             :         /*
    2961             :          * If we didn't find a member of the index's opfamily, try the support
    2962             :          * function for the operator's underlying function.
    2963             :          */
    2964       14168 :         set_opfuncid(clause);   /* make sure we have opfuncid */
    2965       14168 :         return get_index_clause_from_support(root,
    2966             :                                              rinfo,
    2967             :                                              clause->opfuncid,
    2968             :                                              0, /* indexarg on left */
    2969             :                                              indexcol,
    2970             :                                              index);
    2971             :     }
    2972             : 
    2973     1097688 :     if (match_index_to_operand(rightop, indexcol, index) &&
    2974       62562 :         !bms_is_member(index_relid, rinfo->left_relids) &&
    2975       62436 :         !contain_volatile_functions(leftop))
    2976             :     {
    2977       62436 :         if (IndexCollMatchesExprColl(idxcollation, expr_coll))
    2978             :         {
    2979       62424 :             Oid         comm_op = get_commutator(expr_op);
    2980             : 
    2981      124848 :             if (OidIsValid(comm_op) &&
    2982       62424 :                 op_in_opfamily(comm_op, opfamily))
    2983             :             {
    2984             :                 RestrictInfo *commrinfo;
    2985             : 
    2986             :                 /* Build a commuted OpExpr and RestrictInfo */
    2987       61844 :                 commrinfo = commute_restrictinfo(rinfo, comm_op);
    2988             : 
    2989             :                 /* Make an IndexClause showing that as a derived qual */
    2990       61844 :                 iclause = makeNode(IndexClause);
    2991       61844 :                 iclause->rinfo = rinfo;
    2992       61844 :                 iclause->indexquals = list_make1(commrinfo);
    2993       61844 :                 iclause->lossy = false;
    2994       61844 :                 iclause->indexcol = indexcol;
    2995       61844 :                 iclause->indexcols = NIL;
    2996       61844 :                 return iclause;
    2997             :             }
    2998             :         }
    2999             : 
    3000             :         /*
    3001             :          * If we didn't find a member of the index's opfamily, try the support
    3002             :          * function for the operator's underlying function.
    3003             :          */
    3004         592 :         set_opfuncid(clause);   /* make sure we have opfuncid */
    3005         592 :         return get_index_clause_from_support(root,
    3006             :                                              rinfo,
    3007             :                                              clause->opfuncid,
    3008             :                                              1, /* indexarg on right */
    3009             :                                              indexcol,
    3010             :                                              index);
    3011             :     }
    3012             : 
    3013     1035252 :     return NULL;
    3014             : }
    3015             : 
    3016             : /*
    3017             :  * match_funcclause_to_indexcol()
    3018             :  *    Handles the FuncExpr case for match_clause_to_indexcol(),
    3019             :  *    which see for comments.
    3020             :  */
    3021             : static IndexClause *
    3022       30894 : match_funcclause_to_indexcol(PlannerInfo *root,
    3023             :                              RestrictInfo *rinfo,
    3024             :                              int indexcol,
    3025             :                              IndexOptInfo *index)
    3026             : {
    3027       30894 :     FuncExpr   *clause = (FuncExpr *) rinfo->clause;
    3028             :     int         indexarg;
    3029             :     ListCell   *lc;
    3030             : 
    3031             :     /*
    3032             :      * We have no built-in intelligence about function clauses, but if there's
    3033             :      * a planner support function, it might be able to do something.  But, to
    3034             :      * cut down on wasted planning cycles, only call the support function if
    3035             :      * at least one argument matches the target index column.
    3036             :      *
    3037             :      * Note that we don't insist on the other arguments being pseudoconstants;
    3038             :      * the support function has to check that.  This is to allow cases where
    3039             :      * only some of the other arguments need to be included in the indexqual.
    3040             :      */
    3041       30894 :     indexarg = 0;
    3042       68688 :     foreach(lc, clause->args)
    3043             :     {
    3044       43868 :         Node       *op = (Node *) lfirst(lc);
    3045             : 
    3046       43868 :         if (match_index_to_operand(op, indexcol, index))
    3047             :         {
    3048        6074 :             return get_index_clause_from_support(root,
    3049             :                                                  rinfo,
    3050             :                                                  clause->funcid,
    3051             :                                                  indexarg,
    3052             :                                                  indexcol,
    3053             :                                                  index);
    3054             :         }
    3055             : 
    3056       37794 :         indexarg++;
    3057             :     }
    3058             : 
    3059       24820 :     return NULL;
    3060             : }
    3061             : 
    3062             : /*
    3063             :  * get_index_clause_from_support()
    3064             :  *      If the function has a planner support function, try to construct
    3065             :  *      an IndexClause using indexquals created by the support function.
    3066             :  */
    3067             : static IndexClause *
    3068       20834 : get_index_clause_from_support(PlannerInfo *root,
    3069             :                               RestrictInfo *rinfo,
    3070             :                               Oid funcid,
    3071             :                               int indexarg,
    3072             :                               int indexcol,
    3073             :                               IndexOptInfo *index)
    3074             : {
    3075       20834 :     Oid         prosupport = get_func_support(funcid);
    3076             :     SupportRequestIndexCondition req;
    3077             :     List       *sresult;
    3078             : 
    3079       20834 :     if (!OidIsValid(prosupport))
    3080       12770 :         return NULL;
    3081             : 
    3082        8064 :     req.type = T_SupportRequestIndexCondition;
    3083        8064 :     req.root = root;
    3084        8064 :     req.funcid = funcid;
    3085        8064 :     req.node = (Node *) rinfo->clause;
    3086        8064 :     req.indexarg = indexarg;
    3087        8064 :     req.index = index;
    3088        8064 :     req.indexcol = indexcol;
    3089        8064 :     req.opfamily = index->opfamily[indexcol];
    3090        8064 :     req.indexcollation = index->indexcollations[indexcol];
    3091             : 
    3092        8064 :     req.lossy = true;           /* default assumption */
    3093             : 
    3094             :     sresult = (List *)
    3095        8064 :         DatumGetPointer(OidFunctionCall1(prosupport,
    3096             :                                          PointerGetDatum(&req)));
    3097             : 
    3098        8064 :     if (sresult != NIL)
    3099             :     {
    3100        1404 :         IndexClause *iclause = makeNode(IndexClause);
    3101        1404 :         List       *indexquals = NIL;
    3102             :         ListCell   *lc;
    3103             : 
    3104             :         /*
    3105             :          * The support function API says it should just give back bare
    3106             :          * clauses, so here we must wrap each one in a RestrictInfo.
    3107             :          */
    3108        4134 :         foreach(lc, sresult)
    3109             :         {
    3110        2730 :             Expr       *clause = (Expr *) lfirst(lc);
    3111             : 
    3112        2730 :             indexquals = lappend(indexquals,
    3113        2730 :                                  make_simple_restrictinfo(root, clause));
    3114             :         }
    3115             : 
    3116        1404 :         iclause->rinfo = rinfo;
    3117        1404 :         iclause->indexquals = indexquals;
    3118        1404 :         iclause->lossy = req.lossy;
    3119        1404 :         iclause->indexcol = indexcol;
    3120        1404 :         iclause->indexcols = NIL;
    3121             : 
    3122        1404 :         return iclause;
    3123             :     }
    3124             : 
    3125        6660 :     return NULL;
    3126             : }
    3127             : 
    3128             : /*
    3129             :  * match_saopclause_to_indexcol()
    3130             :  *    Handles the ScalarArrayOpExpr case for match_clause_to_indexcol(),
    3131             :  *    which see for comments.
    3132             :  */
    3133             : static IndexClause *
    3134       77036 : match_saopclause_to_indexcol(PlannerInfo *root,
    3135             :                              RestrictInfo *rinfo,
    3136             :                              int indexcol,
    3137             :                              IndexOptInfo *index)
    3138             : {
    3139       77036 :     ScalarArrayOpExpr *saop = (ScalarArrayOpExpr *) rinfo->clause;
    3140             :     Node       *leftop,
    3141             :                *rightop;
    3142             :     Relids      right_relids;
    3143             :     Oid         expr_op;
    3144             :     Oid         expr_coll;
    3145             :     Index       index_relid;
    3146             :     Oid         opfamily;
    3147             :     Oid         idxcollation;
    3148             : 
    3149             :     /* We only accept ANY clauses, not ALL */
    3150       77036 :     if (!saop->useOr)
    3151        9948 :         return NULL;
    3152       67088 :     leftop = (Node *) linitial(saop->args);
    3153       67088 :     rightop = (Node *) lsecond(saop->args);
    3154       67088 :     right_relids = pull_varnos(root, rightop);
    3155       67088 :     expr_op = saop->opno;
    3156       67088 :     expr_coll = saop->inputcollid;
    3157             : 
    3158       67088 :     index_relid = index->rel->relid;
    3159       67088 :     opfamily = index->opfamily[indexcol];
    3160       67088 :     idxcollation = index->indexcollations[indexcol];
    3161             : 
    3162             :     /*
    3163             :      * We must have indexkey on the left and a pseudo-constant array argument.
    3164             :      */
    3165       67088 :     if (match_index_to_operand(leftop, indexcol, index) &&
    3166        6934 :         !bms_is_member(index_relid, right_relids) &&
    3167        6934 :         !contain_volatile_functions(rightop))
    3168             :     {
    3169       13862 :         if (IndexCollMatchesExprColl(idxcollation, expr_coll) &&
    3170        6928 :             op_in_opfamily(expr_op, opfamily))
    3171             :         {
    3172        6916 :             IndexClause *iclause = makeNode(IndexClause);
    3173             : 
    3174        6916 :             iclause->rinfo = rinfo;
    3175        6916 :             iclause->indexquals = list_make1(rinfo);
    3176        6916 :             iclause->lossy = false;
    3177        6916 :             iclause->indexcol = indexcol;
    3178        6916 :             iclause->indexcols = NIL;
    3179        6916 :             return iclause;
    3180             :         }
    3181             : 
    3182             :         /*
    3183             :          * We do not currently ask support functions about ScalarArrayOpExprs,
    3184             :          * though in principle we could.
    3185             :          */
    3186             :     }
    3187             : 
    3188       60172 :     return NULL;
    3189             : }
    3190             : 
    3191             : /*
    3192             :  * match_rowcompare_to_indexcol()
    3193             :  *    Handles the RowCompareExpr case for match_clause_to_indexcol(),
    3194             :  *    which see for comments.
    3195             :  *
    3196             :  * In this routine we check whether the first column of the row comparison
    3197             :  * matches the target index column.  This is sufficient to guarantee that some
    3198             :  * index condition can be constructed from the RowCompareExpr --- the rest
    3199             :  * is handled by expand_indexqual_rowcompare().
    3200             :  */
    3201             : static IndexClause *
    3202         432 : match_rowcompare_to_indexcol(PlannerInfo *root,
    3203             :                              RestrictInfo *rinfo,
    3204             :                              int indexcol,
    3205             :                              IndexOptInfo *index)
    3206             : {
    3207         432 :     RowCompareExpr *clause = (RowCompareExpr *) rinfo->clause;
    3208             :     Index       index_relid;
    3209             :     Oid         opfamily;
    3210             :     Oid         idxcollation;
    3211             :     Node       *leftop,
    3212             :                *rightop;
    3213             :     bool        var_on_left;
    3214             :     Oid         expr_op;
    3215             :     Oid         expr_coll;
    3216             : 
    3217             :     /* Forget it if we're not dealing with a btree index */
    3218         432 :     if (index->relam != BTREE_AM_OID)
    3219           0 :         return NULL;
    3220             : 
    3221         432 :     index_relid = index->rel->relid;
    3222         432 :     opfamily = index->opfamily[indexcol];
    3223         432 :     idxcollation = index->indexcollations[indexcol];
    3224             : 
    3225             :     /*
    3226             :      * We could do the matching on the basis of insisting that the opfamily
    3227             :      * shown in the RowCompareExpr be the same as the index column's opfamily,
    3228             :      * but that could fail in the presence of reverse-sort opfamilies: it'd be
    3229             :      * a matter of chance whether RowCompareExpr had picked the forward or
    3230             :      * reverse-sort family.  So look only at the operator, and match if it is
    3231             :      * a member of the index's opfamily (after commutation, if the indexkey is
    3232             :      * on the right).  We'll worry later about whether any additional
    3233             :      * operators are matchable to the index.
    3234             :      */
    3235         432 :     leftop = (Node *) linitial(clause->largs);
    3236         432 :     rightop = (Node *) linitial(clause->rargs);
    3237         432 :     expr_op = linitial_oid(clause->opnos);
    3238         432 :     expr_coll = linitial_oid(clause->inputcollids);
    3239             : 
    3240             :     /* Collations must match, if relevant */
    3241         432 :     if (!IndexCollMatchesExprColl(idxcollation, expr_coll))
    3242           0 :         return NULL;
    3243             : 
    3244             :     /*
    3245             :      * These syntactic tests are the same as in match_opclause_to_indexcol()
    3246             :      */
    3247         432 :     if (match_index_to_operand(leftop, indexcol, index) &&
    3248         126 :         !bms_is_member(index_relid, pull_varnos(root, rightop)) &&
    3249         126 :         !contain_volatile_functions(rightop))
    3250             :     {
    3251             :         /* OK, indexkey is on left */
    3252         126 :         var_on_left = true;
    3253             :     }
    3254         306 :     else if (match_index_to_operand(rightop, indexcol, index) &&
    3255          24 :              !bms_is_member(index_relid, pull_varnos(root, leftop)) &&
    3256          24 :              !contain_volatile_functions(leftop))
    3257             :     {
    3258             :         /* indexkey is on right, so commute the operator */
    3259          24 :         expr_op = get_commutator(expr_op);
    3260          24 :         if (expr_op == InvalidOid)
    3261           0 :             return NULL;
    3262          24 :         var_on_left = false;
    3263             :     }
    3264             :     else
    3265         282 :         return NULL;
    3266             : 
    3267             :     /* We're good if the operator is the right type of opfamily member */
    3268         150 :     switch (get_op_opfamily_strategy(expr_op, opfamily))
    3269             :     {
    3270         150 :         case BTLessStrategyNumber:
    3271             :         case BTLessEqualStrategyNumber:
    3272             :         case BTGreaterEqualStrategyNumber:
    3273             :         case BTGreaterStrategyNumber:
    3274         150 :             return expand_indexqual_rowcompare(root,
    3275             :                                                rinfo,
    3276             :                                                indexcol,
    3277             :                                                index,
    3278             :                                                expr_op,
    3279             :                                                var_on_left);
    3280             :     }
    3281             : 
    3282           0 :     return NULL;
    3283             : }
    3284             : 
    3285             : /*
    3286             :  * match_orclause_to_indexcol()
    3287             :  *    Handles the OR-expr case for match_clause_to_indexcol() in the case
    3288             :  *    when it could be transformed to ScalarArrayOpExpr.
    3289             :  *
    3290             :  * In this routine, we attempt to transform a list of OR-clause args into a
    3291             :  * single SAOP expression matching the target index column.  On success,
    3292             :  * return an IndexClause, containing the transformed expression or NULL,
    3293             :  * if failed.
    3294             :  */
    3295             : static IndexClause *
    3296       48676 : match_orclause_to_indexcol(PlannerInfo *root,
    3297             :                            RestrictInfo *rinfo,
    3298             :                            int indexcol,
    3299             :                            IndexOptInfo *index)
    3300             : {
    3301             :     ListCell   *lc;
    3302       48676 :     BoolExpr   *orclause = (BoolExpr *) rinfo->orclause;
    3303       48676 :     Node       *indexExpr = NULL;
    3304       48676 :     List       *consts = NIL;
    3305       48676 :     ScalarArrayOpExpr *saopexpr = NULL;
    3306       48676 :     Oid         matchOpno = InvalidOid;
    3307             :     IndexClause *iclause;
    3308       48676 :     Oid         consttype = InvalidOid;
    3309       48676 :     Oid         arraytype = InvalidOid;
    3310       48676 :     Oid         inputcollid = InvalidOid;
    3311       48676 :     bool        firstTime = true;
    3312       48676 :     bool        haveNonConst = false;
    3313       48676 :     Index       indexRelid = index->rel->relid;
    3314             : 
    3315             :     Assert(IsA(orclause, BoolExpr));
    3316             :     Assert(orclause->boolop == OR_EXPR);
    3317             : 
    3318             :     /* Ignore index if it doesn't support SAOP clauses */
    3319       48676 :     if (!index->amsearcharray)
    3320         106 :         return NULL;
    3321             : 
    3322             :     /*
    3323             :      * Try to convert a list of OR-clauses to a single SAOP expression. Each
    3324             :      * OR entry must be in the form: (indexkey operator constant) or (constant
    3325             :      * operator indexkey).  Operators of all the entries must match.  To be
    3326             :      * effective, give up on the first non-matching entry.  Exit is
    3327             :      * implemented as a break from the loop, which is catched afterwards.
    3328             :      */
    3329       52958 :     foreach(lc, orclause->args)
    3330             :     {
    3331             :         RestrictInfo *subRinfo;
    3332             :         OpExpr     *subClause;
    3333             :         Oid         opno;
    3334             :         Node       *leftop,
    3335             :                    *rightop;
    3336             :         Node       *constExpr;
    3337             : 
    3338       51908 :         if (!IsA(lfirst(lc), RestrictInfo))
    3339        5198 :             break;
    3340             : 
    3341       46710 :         subRinfo = (RestrictInfo *) lfirst(lc);
    3342             : 
    3343             :         /* Only operator clauses can match  */
    3344       46710 :         if (!IsA(subRinfo->clause, OpExpr))
    3345       14302 :             break;
    3346             : 
    3347       32408 :         subClause = (OpExpr *) subRinfo->clause;
    3348       32408 :         opno = subClause->opno;
    3349             : 
    3350             :         /* Only binary operators can match  */
    3351       32408 :         if (list_length(subClause->args) != 2)
    3352           0 :             break;
    3353             : 
    3354             :         /*
    3355             :          * The parameters below must match between sub-rinfo and its parent as
    3356             :          * make_restrictinfo() fills them with the same values, and further
    3357             :          * modifications are also the same for the whole subtree.  However,
    3358             :          * still make a sanity check.
    3359             :          */
    3360             :         Assert(subRinfo->is_pushed_down == rinfo->is_pushed_down);
    3361             :         Assert(subRinfo->is_clone == rinfo->is_clone);
    3362             :         Assert(subRinfo->security_level == rinfo->security_level);
    3363             :         Assert(bms_equal(subRinfo->incompatible_relids, rinfo->incompatible_relids));
    3364             :         Assert(bms_equal(subRinfo->outer_relids, rinfo->outer_relids));
    3365             : 
    3366             :         /*
    3367             :          * Also, check that required_relids in sub-rinfo is subset of parent's
    3368             :          * required_relids.
    3369             :          */
    3370             :         Assert(bms_is_subset(subRinfo->required_relids, rinfo->required_relids));
    3371             : 
    3372             :         /* Only the operator returning a boolean suit the transformation. */
    3373       32408 :         if (get_op_rettype(opno) != BOOLOID)
    3374           0 :             break;
    3375             : 
    3376             :         /*
    3377             :          * Check for clauses of the form: (indexkey operator constant) or
    3378             :          * (constant operator indexkey).  See match_clause_to_indexcol's notes
    3379             :          * about const-ness.
    3380             :          */
    3381       32408 :         leftop = (Node *) linitial(subClause->args);
    3382       32408 :         rightop = (Node *) lsecond(subClause->args);
    3383       32408 :         if (match_index_to_operand(leftop, indexcol, index) &&
    3384        6604 :             !bms_is_member(indexRelid, subRinfo->right_relids) &&
    3385        6574 :             !contain_volatile_functions(rightop))
    3386             :         {
    3387        6574 :             indexExpr = leftop;
    3388        6574 :             constExpr = rightop;
    3389             :         }
    3390       25834 :         else if (match_index_to_operand(rightop, indexcol, index) &&
    3391         170 :                  !bms_is_member(indexRelid, subRinfo->left_relids) &&
    3392         164 :                  !contain_volatile_functions(leftop))
    3393             :         {
    3394         164 :             opno = get_commutator(opno);
    3395         164 :             if (!OidIsValid(opno))
    3396             :             {
    3397             :                 /* commutator doesn't exist, we can't reverse the order */
    3398           0 :                 break;
    3399             :             }
    3400         164 :             indexExpr = rightop;
    3401         164 :             constExpr = leftop;
    3402             :         }
    3403             :         else
    3404             :         {
    3405             :             break;
    3406             :         }
    3407             : 
    3408             :         /*
    3409             :          * Ignore any RelabelType node above the operands.  This is needed to
    3410             :          * be able to apply indexscanning in binary-compatible-operator cases.
    3411             :          * Note: we can assume there is at most one RelabelType node;
    3412             :          * eval_const_expressions() will have simplified if more than one.
    3413             :          */
    3414        6738 :         if (IsA(constExpr, RelabelType))
    3415           0 :             constExpr = (Node *) ((RelabelType *) constExpr)->arg;
    3416        6738 :         if (IsA(indexExpr, RelabelType))
    3417          12 :             indexExpr = (Node *) ((RelabelType *) indexExpr)->arg;
    3418             : 
    3419             :         /* Forbid transformation for composite types, records. */
    3420       13476 :         if (type_is_rowtype(exprType(constExpr)) ||
    3421        6738 :             type_is_rowtype(exprType(indexExpr)))
    3422             :             break;
    3423             : 
    3424             :         /*
    3425             :          * Save information about the operator, type, and collation for the
    3426             :          * first matching qual.  Then, check that subsequent quals match the
    3427             :          * first.
    3428             :          */
    3429        6738 :         if (firstTime)
    3430             :         {
    3431        4998 :             matchOpno = opno;
    3432        4998 :             consttype = exprType(constExpr);
    3433        4998 :             arraytype = get_array_type(consttype);
    3434        4998 :             inputcollid = subClause->inputcollid;
    3435             : 
    3436             :             /*
    3437             :              * Check that the operator is presented in the opfamily and that
    3438             :              * the expression collation matches the index collation.  Also,
    3439             :              * there must be an array type to construct an array later.
    3440             :              */
    3441        4998 :             if (!IndexCollMatchesExprColl(index->indexcollations[indexcol], inputcollid) ||
    3442        4872 :                 !op_in_opfamily(matchOpno, index->opfamily[indexcol]) ||
    3443             :                 !OidIsValid(arraytype))
    3444             :                 break;
    3445        2774 :             firstTime = false;
    3446             :         }
    3447             :         else
    3448             :         {
    3449        1740 :             if (opno != matchOpno ||
    3450        3228 :                 inputcollid != subClause->inputcollid ||
    3451        1614 :                 consttype != exprType(constExpr))
    3452             :                 break;
    3453             :         }
    3454             : 
    3455             :         /*
    3456             :          * Check if our list of constants in match_clause_to_indexcol's
    3457             :          * understanding of const-ness have something other than Const.
    3458             :          */
    3459        4388 :         if (!IsA(constExpr, Const))
    3460         344 :             haveNonConst = true;
    3461        4388 :         consts = lappend(consts, constExpr);
    3462             :     }
    3463             : 
    3464             :     /*
    3465             :      * Catch the break from the loop above.  Normally, a foreach() loop ends
    3466             :      * up with a NULL list cell.  A non-NULL list cell indicates a break from
    3467             :      * the foreach() loop.  Free the consts list and return NULL then.
    3468             :      */
    3469       48570 :     if (lc != NULL)
    3470             :     {
    3471       47520 :         list_free(consts);
    3472       47520 :         return NULL;
    3473             :     }
    3474             : 
    3475        1050 :     saopexpr = make_SAOP_expr(matchOpno, indexExpr, consttype, inputcollid,
    3476             :                               inputcollid, consts, haveNonConst);
    3477             : 
    3478             :     /*
    3479             :      * Finally, build an IndexClause based on the SAOP node.  Use
    3480             :      * make_simple_restrictinfo() to get RestrictInfo with clean selectivity
    3481             :      * estimations, because they may differ from the estimation made for an OR
    3482             :      * clause.  Although it is not a lossy expression, keep the original rinfo
    3483             :      * in iclause->rinfo as prescribed.
    3484             :      */
    3485        1050 :     iclause = makeNode(IndexClause);
    3486        1050 :     iclause->rinfo = rinfo;
    3487        1050 :     iclause->indexquals = list_make1(make_simple_restrictinfo(root,
    3488             :                                                               &saopexpr->xpr));
    3489        1050 :     iclause->lossy = false;
    3490        1050 :     iclause->indexcol = indexcol;
    3491        1050 :     iclause->indexcols = NIL;
    3492        1050 :     return iclause;
    3493             : }
    3494             : 
    3495             : /*
    3496             :  * expand_indexqual_rowcompare --- expand a single indexqual condition
    3497             :  *      that is a RowCompareExpr
    3498             :  *
    3499             :  * It's already known that the first column of the row comparison matches
    3500             :  * the specified column of the index.  We can use additional columns of the
    3501             :  * row comparison as index qualifications, so long as they match the index
    3502             :  * in the "same direction", ie, the indexkeys are all on the same side of the
    3503             :  * clause and the operators are all the same-type members of the opfamilies.
    3504             :  *
    3505             :  * If all the columns of the RowCompareExpr match in this way, we just use it
    3506             :  * as-is, except for possibly commuting it to put the indexkeys on the left.
    3507             :  *
    3508             :  * Otherwise, we build a shortened RowCompareExpr (if more than one
    3509             :  * column matches) or a simple OpExpr (if the first-column match is all
    3510             :  * there is).  In these cases the modified clause is always "<=" or ">="
    3511             :  * even when the original was "<" or ">" --- this is necessary to match all
    3512             :  * the rows that could match the original.  (We are building a lossy version
    3513             :  * of the row comparison when we do this, so we set lossy = true.)
    3514             :  *
    3515             :  * Note: this is really just the last half of match_rowcompare_to_indexcol,
    3516             :  * but we split it out for comprehensibility.
    3517             :  */
    3518             : static IndexClause *
    3519         150 : expand_indexqual_rowcompare(PlannerInfo *root,
    3520             :                             RestrictInfo *rinfo,
    3521             :                             int indexcol,
    3522             :                             IndexOptInfo *index,
    3523             :                             Oid expr_op,
    3524             :                             bool var_on_left)
    3525             : {
    3526         150 :     IndexClause *iclause = makeNode(IndexClause);
    3527         150 :     RowCompareExpr *clause = (RowCompareExpr *) rinfo->clause;
    3528             :     int         op_strategy;
    3529             :     Oid         op_lefttype;
    3530             :     Oid         op_righttype;
    3531             :     int         matching_cols;
    3532             :     List       *expr_ops;
    3533             :     List       *opfamilies;
    3534             :     List       *lefttypes;
    3535             :     List       *righttypes;
    3536             :     List       *new_ops;
    3537             :     List       *var_args;
    3538             :     List       *non_var_args;
    3539             : 
    3540         150 :     iclause->rinfo = rinfo;
    3541         150 :     iclause->indexcol = indexcol;
    3542             : 
    3543         150 :     if (var_on_left)
    3544             :     {
    3545         126 :         var_args = clause->largs;
    3546         126 :         non_var_args = clause->rargs;
    3547             :     }
    3548             :     else
    3549             :     {
    3550          24 :         var_args = clause->rargs;
    3551          24 :         non_var_args = clause->largs;
    3552             :     }
    3553             : 
    3554         150 :     get_op_opfamily_properties(expr_op, index->opfamily[indexcol], false,
    3555             :                                &op_strategy,
    3556             :                                &op_lefttype,
    3557             :                                &op_righttype);
    3558             : 
    3559             :     /* Initialize returned list of which index columns are used */
    3560         150 :     iclause->indexcols = list_make1_int(indexcol);
    3561             : 
    3562             :     /* Build lists of ops, opfamilies and operator datatypes in case needed */
    3563         150 :     expr_ops = list_make1_oid(expr_op);
    3564         150 :     opfamilies = list_make1_oid(index->opfamily[indexcol]);
    3565         150 :     lefttypes = list_make1_oid(op_lefttype);
    3566         150 :     righttypes = list_make1_oid(op_righttype);
    3567             : 
    3568             :     /*
    3569             :      * See how many of the remaining columns match some index column in the
    3570             :      * same way.  As in match_clause_to_indexcol(), the "other" side of any
    3571             :      * potential index condition is OK as long as it doesn't use Vars from the
    3572             :      * indexed relation.
    3573             :      */
    3574         150 :     matching_cols = 1;
    3575             : 
    3576         282 :     while (matching_cols < list_length(var_args))
    3577             :     {
    3578         186 :         Node       *varop = (Node *) list_nth(var_args, matching_cols);
    3579         186 :         Node       *constop = (Node *) list_nth(non_var_args, matching_cols);
    3580             :         int         i;
    3581             : 
    3582         186 :         expr_op = list_nth_oid(clause->opnos, matching_cols);
    3583         186 :         if (!var_on_left)
    3584             :         {
    3585             :             /* indexkey is on right, so commute the operator */
    3586          24 :             expr_op = get_commutator(expr_op);
    3587          24 :             if (expr_op == InvalidOid)
    3588           0 :                 break;          /* operator is not usable */
    3589             :         }
    3590         186 :         if (bms_is_member(index->rel->relid, pull_varnos(root, constop)))
    3591           0 :             break;              /* no good, Var on wrong side */
    3592         186 :         if (contain_volatile_functions(constop))
    3593           0 :             break;              /* no good, volatile comparison value */
    3594             : 
    3595             :         /*
    3596             :          * The Var side can match any key column of the index.
    3597             :          */
    3598         444 :         for (i = 0; i < index->nkeycolumns; i++)
    3599             :         {
    3600         390 :             if (match_index_to_operand(varop, i, index) &&
    3601         132 :                 get_op_opfamily_strategy(expr_op,
    3602         132 :                                          index->opfamily[i]) == op_strategy &&
    3603         132 :                 IndexCollMatchesExprColl(index->indexcollations[i],
    3604             :                                          list_nth_oid(clause->inputcollids,
    3605             :                                                       matching_cols)))
    3606             :                 break;
    3607             :         }
    3608         186 :         if (i >= index->nkeycolumns)
    3609          54 :             break;              /* no match found */
    3610             : 
    3611             :         /* Add column number to returned list */
    3612         132 :         iclause->indexcols = lappend_int(iclause->indexcols, i);
    3613             : 
    3614             :         /* Add operator info to lists */
    3615         132 :         get_op_opfamily_properties(expr_op, index->opfamily[i], false,
    3616             :                                    &op_strategy,
    3617             :                                    &op_lefttype,
    3618             :                                    &op_righttype);
    3619         132 :         expr_ops = lappend_oid(expr_ops, expr_op);
    3620         132 :         opfamilies = lappend_oid(opfamilies, index->opfamily[i]);
    3621         132 :         lefttypes = lappend_oid(lefttypes, op_lefttype);
    3622         132 :         righttypes = lappend_oid(righttypes, op_righttype);
    3623             : 
    3624             :         /* This column matches, keep scanning */
    3625         132 :         matching_cols++;
    3626             :     }
    3627             : 
    3628             :     /* Result is non-lossy if all columns are usable as index quals */
    3629         150 :     iclause->lossy = (matching_cols != list_length(clause->opnos));
    3630             : 
    3631             :     /*
    3632             :      * We can use rinfo->clause as-is if we have var on left and it's all
    3633             :      * usable as index quals.
    3634             :      */
    3635         150 :     if (var_on_left && !iclause->lossy)
    3636          84 :         iclause->indexquals = list_make1(rinfo);
    3637             :     else
    3638             :     {
    3639             :         /*
    3640             :          * We have to generate a modified rowcompare (possibly just one
    3641             :          * OpExpr).  The painful part of this is changing < to <= or > to >=,
    3642             :          * so deal with that first.
    3643             :          */
    3644          66 :         if (!iclause->lossy)
    3645             :         {
    3646             :             /* very easy, just use the commuted operators */
    3647          12 :             new_ops = expr_ops;
    3648             :         }
    3649          54 :         else if (op_strategy == BTLessEqualStrategyNumber ||
    3650          54 :                  op_strategy == BTGreaterEqualStrategyNumber)
    3651             :         {
    3652             :             /* easy, just use the same (possibly commuted) operators */
    3653           0 :             new_ops = list_truncate(expr_ops, matching_cols);
    3654             :         }
    3655             :         else
    3656             :         {
    3657             :             ListCell   *opfamilies_cell;
    3658             :             ListCell   *lefttypes_cell;
    3659             :             ListCell   *righttypes_cell;
    3660             : 
    3661          54 :             if (op_strategy == BTLessStrategyNumber)
    3662          30 :                 op_strategy = BTLessEqualStrategyNumber;
    3663          24 :             else if (op_strategy == BTGreaterStrategyNumber)
    3664          24 :                 op_strategy = BTGreaterEqualStrategyNumber;
    3665             :             else
    3666           0 :                 elog(ERROR, "unexpected strategy number %d", op_strategy);
    3667          54 :             new_ops = NIL;
    3668         144 :             forthree(opfamilies_cell, opfamilies,
    3669             :                      lefttypes_cell, lefttypes,
    3670             :                      righttypes_cell, righttypes)
    3671             :             {
    3672          90 :                 Oid         opfam = lfirst_oid(opfamilies_cell);
    3673          90 :                 Oid         lefttype = lfirst_oid(lefttypes_cell);
    3674          90 :                 Oid         righttype = lfirst_oid(righttypes_cell);
    3675             : 
    3676          90 :                 expr_op = get_opfamily_member(opfam, lefttype, righttype,
    3677             :                                               op_strategy);
    3678          90 :                 if (!OidIsValid(expr_op))   /* should not happen */
    3679           0 :                     elog(ERROR, "missing operator %d(%u,%u) in opfamily %u",
    3680             :                          op_strategy, lefttype, righttype, opfam);
    3681          90 :                 new_ops = lappend_oid(new_ops, expr_op);
    3682             :             }
    3683             :         }
    3684             : 
    3685             :         /* If we have more than one matching col, create a subset rowcompare */
    3686          66 :         if (matching_cols > 1)
    3687             :         {
    3688          48 :             RowCompareExpr *rc = makeNode(RowCompareExpr);
    3689             : 
    3690          48 :             rc->cmptype = (CompareType) op_strategy;
    3691          48 :             rc->opnos = new_ops;
    3692          48 :             rc->opfamilies = list_copy_head(clause->opfamilies,
    3693             :                                             matching_cols);
    3694          48 :             rc->inputcollids = list_copy_head(clause->inputcollids,
    3695             :                                               matching_cols);
    3696          48 :             rc->largs = list_copy_head(var_args, matching_cols);
    3697          48 :             rc->rargs = list_copy_head(non_var_args, matching_cols);
    3698          48 :             iclause->indexquals = list_make1(make_simple_restrictinfo(root,
    3699             :                                                                       (Expr *) rc));
    3700             :         }
    3701             :         else
    3702             :         {
    3703             :             Expr       *op;
    3704             : 
    3705             :             /* We don't report an index column list in this case */
    3706          18 :             iclause->indexcols = NIL;
    3707             : 
    3708          18 :             op = make_opclause(linitial_oid(new_ops), BOOLOID, false,
    3709          18 :                                copyObject(linitial(var_args)),
    3710          18 :                                copyObject(linitial(non_var_args)),
    3711             :                                InvalidOid,
    3712          18 :                                linitial_oid(clause->inputcollids));
    3713          18 :             iclause->indexquals = list_make1(make_simple_restrictinfo(root, op));
    3714             :         }
    3715             :     }
    3716             : 
    3717         150 :     return iclause;
    3718             : }
    3719             : 
    3720             : 
    3721             : /****************************************************************************
    3722             :  *              ----  ROUTINES TO CHECK ORDERING OPERATORS  ----
    3723             :  ****************************************************************************/
    3724             : 
    3725             : /*
    3726             :  * match_pathkeys_to_index
    3727             :  *      For the given 'index' and 'pathkeys', output a list of suitable ORDER
    3728             :  *      BY expressions, each of the form "indexedcol operator pseudoconstant",
    3729             :  *      along with an integer list of the index column numbers (zero based)
    3730             :  *      that each clause would be used with.
    3731             :  *
    3732             :  * This attempts to find an ORDER BY and index column number for all items in
    3733             :  * the pathkey list, however, if we're unable to match any given pathkey to an
    3734             :  * index column, we return just the ones matched by the function so far.  This
    3735             :  * allows callers who are interested in partial matches to get them.  Callers
    3736             :  * can determine a partial match vs a full match by checking the outputted
    3737             :  * list lengths.  A full match will have one item in the output lists for each
    3738             :  * item in the given 'pathkeys' list.
    3739             :  */
    3740             : static void
    3741        1076 : match_pathkeys_to_index(IndexOptInfo *index, List *pathkeys,
    3742             :                         List **orderby_clauses_p,
    3743             :                         List **clause_columns_p)
    3744             : {
    3745             :     ListCell   *lc1;
    3746             : 
    3747        1076 :     *orderby_clauses_p = NIL;   /* set default results */
    3748        1076 :     *clause_columns_p = NIL;
    3749             : 
    3750             :     /* Only indexes with the amcanorderbyop property are interesting here */
    3751        1076 :     if (!index->amcanorderbyop)
    3752           0 :         return;
    3753             : 
    3754        1550 :     foreach(lc1, pathkeys)
    3755             :     {
    3756        1080 :         PathKey    *pathkey = (PathKey *) lfirst(lc1);
    3757        1080 :         bool        found = false;
    3758             :         EquivalenceMemberIterator it;
    3759             :         EquivalenceMember *member;
    3760             : 
    3761             : 
    3762             :         /* Pathkey must request default sort order for the target opfamily */
    3763        1080 :         if (pathkey->pk_cmptype != COMPARE_LT || pathkey->pk_nulls_first)
    3764         606 :             return;
    3765             : 
    3766             :         /* If eclass is volatile, no hope of using an indexscan */
    3767        1046 :         if (pathkey->pk_eclass->ec_has_volatile)
    3768           0 :             return;
    3769             : 
    3770             :         /*
    3771             :          * Try to match eclass member expression(s) to index.  Note that child
    3772             :          * EC members are considered, but only when they belong to the target
    3773             :          * relation.  (Unlike regular members, the same expression could be a
    3774             :          * child member of more than one EC.  Therefore, the same index could
    3775             :          * be considered to match more than one pathkey list, which is OK
    3776             :          * here.  See also get_eclass_for_sort_expr.)
    3777             :          */
    3778        1046 :         setup_eclass_member_iterator(&it, pathkey->pk_eclass,
    3779        1046 :                                      index->rel->relids);
    3780        1650 :         while ((member = eclass_member_iterator_next(&it)) != NULL)
    3781             :         {
    3782             :             int         indexcol;
    3783             : 
    3784             :             /* No possibility of match if it references other relations */
    3785        1078 :             if (!bms_equal(member->em_relids, index->rel->relids))
    3786          32 :                 continue;
    3787             : 
    3788             :             /*
    3789             :              * We allow any column of the index to match each pathkey; they
    3790             :              * don't have to match left-to-right as you might expect.  This is
    3791             :              * correct for GiST, and it doesn't matter for SP-GiST because
    3792             :              * that doesn't handle multiple columns anyway, and no other
    3793             :              * existing AMs support amcanorderbyop.  We might need different
    3794             :              * logic in future for other implementations.
    3795             :              */
    3796        1906 :             for (indexcol = 0; indexcol < index->nkeycolumns; indexcol++)
    3797             :             {
    3798             :                 Expr       *expr;
    3799             : 
    3800        1334 :                 expr = match_clause_to_ordering_op(index,
    3801             :                                                    indexcol,
    3802             :                                                    member->em_expr,
    3803             :                                                    pathkey->pk_opfamily);
    3804        1334 :                 if (expr)
    3805             :                 {
    3806         474 :                     *orderby_clauses_p = lappend(*orderby_clauses_p, expr);
    3807         474 :                     *clause_columns_p = lappend_int(*clause_columns_p, indexcol);
    3808         474 :                     found = true;
    3809         474 :                     break;
    3810             :                 }
    3811             :             }
    3812             : 
    3813        1046 :             if (found)          /* don't want to look at remaining members */
    3814         474 :                 break;
    3815             :         }
    3816             : 
    3817             :         /*
    3818             :          * Return the matches found so far when this pathkey couldn't be
    3819             :          * matched to the index.
    3820             :          */
    3821        1046 :         if (!found)
    3822         572 :             return;
    3823             :     }
    3824             : }
    3825             : 
    3826             : /*
    3827             :  * match_clause_to_ordering_op
    3828             :  *    Determines whether an ordering operator expression matches an
    3829             :  *    index column.
    3830             :  *
    3831             :  *    This is similar to, but simpler than, match_clause_to_indexcol.
    3832             :  *    We only care about simple OpExpr cases.  The input is a bare
    3833             :  *    expression that is being ordered by, which must be of the form
    3834             :  *    (indexkey op const) or (const op indexkey) where op is an ordering
    3835             :  *    operator for the column's opfamily.
    3836             :  *
    3837             :  * 'index' is the index of interest.
    3838             :  * 'indexcol' is a column number of 'index' (counting from 0).
    3839             :  * 'clause' is the ordering expression to be tested.
    3840             :  * 'pk_opfamily' is the btree opfamily describing the required sort order.
    3841             :  *
    3842             :  * Note that we currently do not consider the collation of the ordering
    3843             :  * operator's result.  In practical cases the result type will be numeric
    3844             :  * and thus have no collation, and it's not very clear what to match to
    3845             :  * if it did have a collation.  The index's collation should match the
    3846             :  * ordering operator's input collation, not its result.
    3847             :  *
    3848             :  * If successful, return 'clause' as-is if the indexkey is on the left,
    3849             :  * otherwise a commuted copy of 'clause'.  If no match, return NULL.
    3850             :  */
    3851             : static Expr *
    3852        1334 : match_clause_to_ordering_op(IndexOptInfo *index,
    3853             :                             int indexcol,
    3854             :                             Expr *clause,
    3855             :                             Oid pk_opfamily)
    3856             : {
    3857             :     Oid         opfamily;
    3858             :     Oid         idxcollation;
    3859             :     Node       *leftop,
    3860             :                *rightop;
    3861             :     Oid         expr_op;
    3862             :     Oid         expr_coll;
    3863             :     Oid         sortfamily;
    3864             :     bool        commuted;
    3865             : 
    3866             :     Assert(indexcol < index->nkeycolumns);
    3867             : 
    3868        1334 :     opfamily = index->opfamily[indexcol];
    3869        1334 :     idxcollation = index->indexcollations[indexcol];
    3870             : 
    3871             :     /*
    3872             :      * Clause must be a binary opclause.
    3873             :      */
    3874        1334 :     if (!is_opclause(clause))
    3875         860 :         return NULL;
    3876         474 :     leftop = get_leftop(clause);
    3877         474 :     rightop = get_rightop(clause);
    3878         474 :     if (!leftop || !rightop)
    3879           0 :         return NULL;
    3880         474 :     expr_op = ((OpExpr *) clause)->opno;
    3881         474 :     expr_coll = ((OpExpr *) clause)->inputcollid;
    3882             : 
    3883             :     /*
    3884             :      * We can forget the whole thing right away if wrong collation.
    3885             :      */
    3886         474 :     if (!IndexCollMatchesExprColl(idxcollation, expr_coll))
    3887           0 :         return NULL;
    3888             : 
    3889             :     /*
    3890             :      * Check for clauses of the form: (indexkey operator constant) or
    3891             :      * (constant operator indexkey).
    3892             :      */
    3893         474 :     if (match_index_to_operand(leftop, indexcol, index) &&
    3894         450 :         !contain_var_clause(rightop) &&
    3895         450 :         !contain_volatile_functions(rightop))
    3896             :     {
    3897         450 :         commuted = false;
    3898             :     }
    3899          24 :     else if (match_index_to_operand(rightop, indexcol, index) &&
    3900          24 :              !contain_var_clause(leftop) &&
    3901          24 :              !contain_volatile_functions(leftop))
    3902             :     {
    3903             :         /* Might match, but we need a commuted operator */
    3904          24 :         expr_op = get_commutator(expr_op);
    3905          24 :         if (expr_op == InvalidOid)
    3906           0 :             return NULL;
    3907          24 :         commuted = true;
    3908             :     }
    3909             :     else
    3910           0 :         return NULL;
    3911             : 
    3912             :     /*
    3913             :      * Is the (commuted) operator an ordering operator for the opfamily? And
    3914             :      * if so, does it yield the right sorting semantics?
    3915             :      */
    3916         474 :     sortfamily = get_op_opfamily_sortfamily(expr_op, opfamily);
    3917         474 :     if (sortfamily != pk_opfamily)
    3918           0 :         return NULL;
    3919             : 
    3920             :     /* We have a match.  Return clause or a commuted version thereof. */
    3921         474 :     if (commuted)
    3922             :     {
    3923          24 :         OpExpr     *newclause = makeNode(OpExpr);
    3924             : 
    3925             :         /* flat-copy all the fields of clause */
    3926          24 :         memcpy(newclause, clause, sizeof(OpExpr));
    3927             : 
    3928             :         /* commute it */
    3929          24 :         newclause->opno = expr_op;
    3930          24 :         newclause->opfuncid = InvalidOid;
    3931          24 :         newclause->args = list_make2(rightop, leftop);
    3932             : 
    3933          24 :         clause = (Expr *) newclause;
    3934             :     }
    3935             : 
    3936         474 :     return clause;
    3937             : }
    3938             : 
    3939             : 
    3940             : /****************************************************************************
    3941             :  *              ----  ROUTINES TO DO PARTIAL INDEX PREDICATE TESTS  ----
    3942             :  ****************************************************************************/
    3943             : 
    3944             : /*
    3945             :  * check_index_predicates
    3946             :  *      Set the predicate-derived IndexOptInfo fields for each index
    3947             :  *      of the specified relation.
    3948             :  *
    3949             :  * predOK is set true if the index is partial and its predicate is satisfied
    3950             :  * for this query, ie the query's WHERE clauses imply the predicate.
    3951             :  *
    3952             :  * indrestrictinfo is set to the relation's baserestrictinfo list less any
    3953             :  * conditions that are implied by the index's predicate.  (Obviously, for a
    3954             :  * non-partial index, this is the same as baserestrictinfo.)  Such conditions
    3955             :  * can be dropped from the plan when using the index, in certain cases.
    3956             :  *
    3957             :  * At one time it was possible for this to get re-run after adding more
    3958             :  * restrictions to the rel, thus possibly letting us prove more indexes OK.
    3959             :  * That doesn't happen any more (at least not in the core code's usage),
    3960             :  * but this code still supports it in case extensions want to mess with the
    3961             :  * baserestrictinfo list.  We assume that adding more restrictions can't make
    3962             :  * an index not predOK.  We must recompute indrestrictinfo each time, though,
    3963             :  * to make sure any newly-added restrictions get into it if needed.
    3964             :  */
    3965             : void
    3966      400598 : check_index_predicates(PlannerInfo *root, RelOptInfo *rel)
    3967             : {
    3968             :     List       *clauselist;
    3969             :     bool        have_partial;
    3970             :     bool        is_target_rel;
    3971             :     Relids      otherrels;
    3972             :     ListCell   *lc;
    3973             : 
    3974             :     /* Indexes are available only on base or "other" member relations. */
    3975             :     Assert(IS_SIMPLE_REL(rel));
    3976             : 
    3977             :     /*
    3978             :      * Initialize the indrestrictinfo lists to be identical to
    3979             :      * baserestrictinfo, and check whether there are any partial indexes.  If
    3980             :      * not, this is all we need to do.
    3981             :      */
    3982      400598 :     have_partial = false;
    3983     1118922 :     foreach(lc, rel->indexlist)
    3984             :     {
    3985      718324 :         IndexOptInfo *index = (IndexOptInfo *) lfirst(lc);
    3986             : 
    3987      718324 :         index->indrestrictinfo = rel->baserestrictinfo;
    3988      718324 :         if (index->indpred)
    3989         984 :             have_partial = true;
    3990             :     }
    3991      400598 :     if (!have_partial)
    3992      399938 :         return;
    3993             : 
    3994             :     /*
    3995             :      * Construct a list of clauses that we can assume true for the purpose of
    3996             :      * proving the index(es) usable.  Restriction clauses for the rel are
    3997             :      * always usable, and so are any join clauses that are "movable to" this
    3998             :      * rel.  Also, we can consider any EC-derivable join clauses (which must
    3999             :      * be "movable to" this rel, by definition).
    4000             :      */
    4001         660 :     clauselist = list_copy(rel->baserestrictinfo);
    4002             : 
    4003             :     /* Scan the rel's join clauses */
    4004         660 :     foreach(lc, rel->joininfo)
    4005             :     {
    4006           0 :         RestrictInfo *rinfo = (RestrictInfo *) lfirst(lc);
    4007             : 
    4008             :         /* Check if clause can be moved to this rel */
    4009           0 :         if (!join_clause_is_movable_to(rinfo, rel))
    4010           0 :             continue;
    4011             : 
    4012           0 :         clauselist = lappend(clauselist, rinfo);
    4013             :     }
    4014             : 
    4015             :     /*
    4016             :      * Add on any equivalence-derivable join clauses.  Computing the correct
    4017             :      * relid sets for generate_join_implied_equalities is slightly tricky
    4018             :      * because the rel could be a child rel rather than a true baserel, and in
    4019             :      * that case we must subtract its parents' relid(s) from all_query_rels.
    4020             :      * Additionally, we mustn't consider clauses that are only computable
    4021             :      * after outer joins that can null the rel.
    4022             :      */
    4023         660 :     if (rel->reloptkind == RELOPT_OTHER_MEMBER_REL)
    4024          72 :         otherrels = bms_difference(root->all_query_rels,
    4025          72 :                                    find_childrel_parents(root, rel));
    4026             :     else
    4027         588 :         otherrels = bms_difference(root->all_query_rels, rel->relids);
    4028         660 :     otherrels = bms_del_members(otherrels, rel->nulling_relids);
    4029             : 
    4030         660 :     if (!bms_is_empty(otherrels))
    4031             :         clauselist =
    4032          88 :             list_concat(clauselist,
    4033          88 :                         generate_join_implied_equalities(root,
    4034          88 :                                                          bms_union(rel->relids,
    4035             :                                                                    otherrels),
    4036             :                                                          otherrels,
    4037             :                                                          rel,
    4038             :                                                          NULL));
    4039             : 
    4040             :     /*
    4041             :      * Normally we remove quals that are implied by a partial index's
    4042             :      * predicate from indrestrictinfo, indicating that they need not be
    4043             :      * checked explicitly by an indexscan plan using this index.  However, if
    4044             :      * the rel is a target relation of UPDATE/DELETE/MERGE/SELECT FOR UPDATE,
    4045             :      * we cannot remove such quals from the plan, because they need to be in
    4046             :      * the plan so that they will be properly rechecked by EvalPlanQual
    4047             :      * testing.  Some day we might want to remove such quals from the main
    4048             :      * plan anyway and pass them through to EvalPlanQual via a side channel;
    4049             :      * but for now, we just don't remove implied quals at all for target
    4050             :      * relations.
    4051             :      */
    4052        1208 :     is_target_rel = (bms_is_member(rel->relid, root->all_result_relids) ||
    4053         548 :                      get_plan_rowmark(root->rowMarks, rel->relid) != NULL);
    4054             : 
    4055             :     /*
    4056             :      * Now try to prove each index predicate true, and compute the
    4057             :      * indrestrictinfo lists for partial indexes.  Note that we compute the
    4058             :      * indrestrictinfo list even for non-predOK indexes; this might seem
    4059             :      * wasteful, but we may be able to use such indexes in OR clauses, cf
    4060             :      * generate_bitmap_or_paths().
    4061             :      */
    4062        2030 :     foreach(lc, rel->indexlist)
    4063             :     {
    4064        1370 :         IndexOptInfo *index = (IndexOptInfo *) lfirst(lc);
    4065             :         ListCell   *lcr;
    4066             : 
    4067        1370 :         if (index->indpred == NIL)
    4068         386 :             continue;           /* ignore non-partial indexes here */
    4069             : 
    4070         984 :         if (!index->predOK)      /* don't repeat work if already proven OK */
    4071         984 :             index->predOK = predicate_implied_by(index->indpred, clauselist,
    4072             :                                                  false);
    4073             : 
    4074             :         /* If rel is an update target, leave indrestrictinfo as set above */
    4075         984 :         if (is_target_rel)
    4076         172 :             continue;
    4077             : 
    4078             :         /* Else compute indrestrictinfo as the non-implied quals */
    4079         812 :         index->indrestrictinfo = NIL;
    4080        1914 :         foreach(lcr, rel->baserestrictinfo)
    4081             :         {
    4082        1102 :             RestrictInfo *rinfo = (RestrictInfo *) lfirst(lcr);
    4083             : 
    4084             :             /* predicate_implied_by() assumes first arg is immutable */
    4085        1102 :             if (contain_mutable_functions((Node *) rinfo->clause) ||
    4086        1102 :                 !predicate_implied_by(list_make1(rinfo->clause),
    4087             :                                       index->indpred, false))
    4088         782 :                 index->indrestrictinfo = lappend(index->indrestrictinfo, rinfo);
    4089             :         }
    4090             :     }
    4091             : }
    4092             : 
    4093             : /****************************************************************************
    4094             :  *              ----  ROUTINES TO CHECK EXTERNALLY-VISIBLE CONDITIONS  ----
    4095             :  ****************************************************************************/
    4096             : 
    4097             : /*
    4098             :  * ec_member_matches_indexcol
    4099             :  *    Test whether an EquivalenceClass member matches an index column.
    4100             :  *
    4101             :  * This is a callback for use by generate_implied_equalities_for_column.
    4102             :  */
    4103             : static bool
    4104      424058 : ec_member_matches_indexcol(PlannerInfo *root, RelOptInfo *rel,
    4105             :                            EquivalenceClass *ec, EquivalenceMember *em,
    4106             :                            void *arg)
    4107             : {
    4108      424058 :     IndexOptInfo *index = ((ec_member_matches_arg *) arg)->index;
    4109      424058 :     int         indexcol = ((ec_member_matches_arg *) arg)->indexcol;
    4110             :     Oid         curFamily;
    4111             :     Oid         curCollation;
    4112             : 
    4113             :     Assert(indexcol < index->nkeycolumns);
    4114             : 
    4115      424058 :     curFamily = index->opfamily[indexcol];
    4116      424058 :     curCollation = index->indexcollations[indexcol];
    4117             : 
    4118             :     /*
    4119             :      * If it's a btree index, we can reject it if its opfamily isn't
    4120             :      * compatible with the EC, since no clause generated from the EC could be
    4121             :      * used with the index.  For non-btree indexes, we can't easily tell
    4122             :      * whether clauses generated from the EC could be used with the index, so
    4123             :      * don't check the opfamily.  This might mean we return "true" for a
    4124             :      * useless EC, so we have to recheck the results of
    4125             :      * generate_implied_equalities_for_column; see
    4126             :      * match_eclass_clauses_to_index.
    4127             :      */
    4128      424058 :     if (index->relam == BTREE_AM_OID &&
    4129      424016 :         !list_member_oid(ec->ec_opfamilies, curFamily))
    4130      129054 :         return false;
    4131             : 
    4132             :     /* We insist on collation match for all index types, though */
    4133      295004 :     if (!IndexCollMatchesExprColl(curCollation, ec->ec_collation))
    4134          18 :         return false;
    4135             : 
    4136      294986 :     return match_index_to_operand((Node *) em->em_expr, indexcol, index);
    4137             : }
    4138             : 
    4139             : /*
    4140             :  * relation_has_unique_index_for
    4141             :  *    Determine whether the relation provably has at most one row satisfying
    4142             :  *    a set of equality conditions, because the conditions constrain all
    4143             :  *    columns of some unique index.
    4144             :  *
    4145             :  * The conditions can be represented in either or both of two ways:
    4146             :  * 1. A list of RestrictInfo nodes, where the caller has already determined
    4147             :  * that each condition is a mergejoinable equality with an expression in
    4148             :  * this relation on one side, and an expression not involving this relation
    4149             :  * on the other.  The transient outer_is_left flag is used to identify which
    4150             :  * side we should look at: left side if outer_is_left is false, right side
    4151             :  * if it is true.
    4152             :  * 2. A list of expressions in this relation, and a corresponding list of
    4153             :  * equality operators. The caller must have already checked that the operators
    4154             :  * represent equality.  (Note: the operators could be cross-type; the
    4155             :  * expressions should correspond to their RHS inputs.)
    4156             :  *
    4157             :  * The caller need only supply equality conditions arising from joins;
    4158             :  * this routine automatically adds in any usable baserestrictinfo clauses.
    4159             :  * (Note that the passed-in restrictlist will be destructively modified!)
    4160             :  */
    4161             : bool
    4162         936 : relation_has_unique_index_for(PlannerInfo *root, RelOptInfo *rel,
    4163             :                               List *restrictlist,
    4164             :                               List *exprlist, List *oprlist)
    4165             : {
    4166         936 :     return relation_has_unique_index_ext(root, rel, restrictlist,
    4167             :                                          exprlist, oprlist, NULL);
    4168             : }
    4169             : 
    4170             : /*
    4171             :  * relation_has_unique_index_ext
    4172             :  *    Same as relation_has_unique_index_for(), but supports extra_clauses
    4173             :  *    parameter.  If extra_clauses isn't NULL, return baserestrictinfo clauses
    4174             :  *    which were used to derive uniqueness.
    4175             :  */
    4176             : bool
    4177      205478 : relation_has_unique_index_ext(PlannerInfo *root, RelOptInfo *rel,
    4178             :                               List *restrictlist,
    4179             :                               List *exprlist, List *oprlist,
    4180             :                               List **extra_clauses)
    4181             : {
    4182             :     ListCell   *ic;
    4183             : 
    4184             :     Assert(list_length(exprlist) == list_length(oprlist));
    4185             : 
    4186             :     /* Short-circuit if no indexes... */
    4187      205478 :     if (rel->indexlist == NIL)
    4188         466 :         return false;
    4189             : 
    4190             :     /*
    4191             :      * Examine the rel's restriction clauses for usable var = const clauses
    4192             :      * that we can add to the restrictlist.
    4193             :      */
    4194      345134 :     foreach(ic, rel->baserestrictinfo)
    4195             :     {
    4196      140122 :         RestrictInfo *restrictinfo = (RestrictInfo *) lfirst(ic);
    4197             : 
    4198             :         /*
    4199             :          * Note: can_join won't be set for a restriction clause, but
    4200             :          * mergeopfamilies will be if it has a mergejoinable operator and
    4201             :          * doesn't contain volatile functions.
    4202             :          */
    4203      140122 :         if (restrictinfo->mergeopfamilies == NIL)
    4204       58474 :             continue;           /* not mergejoinable */
    4205             : 
    4206             :         /*
    4207             :          * The clause certainly doesn't refer to anything but the given rel.
    4208             :          * If either side is pseudoconstant then we can use it.
    4209             :          */
    4210       81648 :         if (bms_is_empty(restrictinfo->left_relids))
    4211             :         {
    4212             :             /* righthand side is inner */
    4213          58 :             restrictinfo->outer_is_left = true;
    4214             :         }
    4215       81590 :         else if (bms_is_empty(restrictinfo->right_relids))
    4216             :         {
    4217             :             /* lefthand side is inner */
    4218       81464 :             restrictinfo->outer_is_left = false;
    4219             :         }
    4220             :         else
    4221         126 :             continue;
    4222             : 
    4223             :         /* OK, add to list */
    4224       81522 :         restrictlist = lappend(restrictlist, restrictinfo);
    4225             :     }
    4226             : 
    4227             :     /* Short-circuit the easy case */
    4228      205012 :     if (restrictlist == NIL && exprlist == NIL)
    4229         972 :         return false;
    4230             : 
    4231             :     /* Examine each index of the relation ... */
    4232      539418 :     foreach(ic, rel->indexlist)
    4233             :     {
    4234      452544 :         IndexOptInfo *ind = (IndexOptInfo *) lfirst(ic);
    4235             :         int         c;
    4236      452544 :         List       *exprs = NIL;
    4237             : 
    4238             :         /*
    4239             :          * If the index is not unique, or not immediately enforced, or if it's
    4240             :          * a partial index, it's useless here.  We're unable to make use of
    4241             :          * predOK partial unique indexes due to the fact that
    4242             :          * check_index_predicates() also makes use of join predicates to
    4243             :          * determine if the partial index is usable. Here we need proofs that
    4244             :          * hold true before any joins are evaluated.
    4245             :          */
    4246      452544 :         if (!ind->unique || !ind->immediate || ind->indpred != NIL)
    4247      132950 :             continue;
    4248             : 
    4249             :         /*
    4250             :          * Try to find each index column in the lists of conditions.  This is
    4251             :          * O(N^2) or worse, but we expect all the lists to be short.
    4252             :          */
    4253      518822 :         for (c = 0; c < ind->nkeycolumns; c++)
    4254             :         {
    4255      401656 :             bool        matched = false;
    4256             :             ListCell   *lc;
    4257             :             ListCell   *lc2;
    4258             : 
    4259      773668 :             foreach(lc, restrictlist)
    4260             :             {
    4261      571240 :                 RestrictInfo *rinfo = (RestrictInfo *) lfirst(lc);
    4262             :                 Node       *rexpr;
    4263             : 
    4264             :                 /*
    4265             :                  * The condition's equality operator must be a member of the
    4266             :                  * index opfamily, else it is not asserting the right kind of
    4267             :                  * equality behavior for this index.  We check this first
    4268             :                  * since it's probably cheaper than match_index_to_operand().
    4269             :                  */
    4270      571240 :                 if (!list_member_oid(rinfo->mergeopfamilies, ind->opfamily[c]))
    4271      160068 :                     continue;
    4272             : 
    4273             :                 /*
    4274             :                  * XXX at some point we may need to check collations here too.
    4275             :                  * For the moment we assume all collations reduce to the same
    4276             :                  * notion of equality.
    4277             :                  */
    4278             : 
    4279             :                 /* OK, see if the condition operand matches the index key */
    4280      411172 :                 if (rinfo->outer_is_left)
    4281      177124 :                     rexpr = get_rightop(rinfo->clause);
    4282             :                 else
    4283      234048 :                     rexpr = get_leftop(rinfo->clause);
    4284             : 
    4285      411172 :                 if (match_index_to_operand(rexpr, c, ind))
    4286             :                 {
    4287      199228 :                     matched = true; /* column is unique */
    4288             : 
    4289      199228 :                     if (bms_membership(rinfo->clause_relids) == BMS_SINGLETON)
    4290             :                     {
    4291             :                         MemoryContext oldMemCtx =
    4292       49294 :                             MemoryContextSwitchTo(root->planner_cxt);
    4293             : 
    4294             :                         /*
    4295             :                          * Add filter clause into a list allowing caller to
    4296             :                          * know if uniqueness have made not only by join
    4297             :                          * clauses.
    4298             :                          */
    4299             :                         Assert(bms_is_empty(rinfo->left_relids) ||
    4300             :                                bms_is_empty(rinfo->right_relids));
    4301       49294 :                         if (extra_clauses)
    4302         144 :                             exprs = lappend(exprs, rinfo);
    4303       49294 :                         MemoryContextSwitchTo(oldMemCtx);
    4304             :                     }
    4305             : 
    4306      199228 :                     break;
    4307             :                 }
    4308             :             }
    4309             : 
    4310      401656 :             if (matched)
    4311      199228 :                 continue;
    4312             : 
    4313      202586 :             forboth(lc, exprlist, lc2, oprlist)
    4314             :             {
    4315         158 :                 Node       *expr = (Node *) lfirst(lc);
    4316         158 :                 Oid         opr = lfirst_oid(lc2);
    4317             : 
    4318             :                 /* See if the expression matches the index key */
    4319         158 :                 if (!match_index_to_operand(expr, c, ind))
    4320         158 :                     continue;
    4321             : 
    4322             :                 /*
    4323             :                  * The equality operator must be a member of the index
    4324             :                  * opfamily, else it is not asserting the right kind of
    4325             :                  * equality behavior for this index.  We assume the caller
    4326             :                  * determined it is an equality operator, so we don't need to
    4327             :                  * check any more tightly than this.
    4328             :                  */
    4329           0 :                 if (!op_in_opfamily(opr, ind->opfamily[c]))
    4330           0 :                     continue;
    4331             : 
    4332             :                 /*
    4333             :                  * XXX at some point we may need to check collations here too.
    4334             :                  * For the moment we assume all collations reduce to the same
    4335             :                  * notion of equality.
    4336             :                  */
    4337             : 
    4338           0 :                 matched = true; /* column is unique */
    4339           0 :                 break;
    4340             :             }
    4341             : 
    4342      202428 :             if (!matched)
    4343      202428 :                 break;          /* no match; this index doesn't help us */
    4344             :         }
    4345             : 
    4346             :         /* Matched all key columns of this index? */
    4347      319594 :         if (c == ind->nkeycolumns)
    4348             :         {
    4349      117166 :             if (extra_clauses)
    4350         642 :                 *extra_clauses = exprs;
    4351      117166 :             return true;
    4352             :         }
    4353             :     }
    4354             : 
    4355       86874 :     return false;
    4356             : }
    4357             : 
    4358             : /*
    4359             :  * indexcol_is_bool_constant_for_query
    4360             :  *
    4361             :  * If an index column is constrained to have a constant value by the query's
    4362             :  * WHERE conditions, then it's irrelevant for sort-order considerations.
    4363             :  * Usually that means we have a restriction clause WHERE indexcol = constant,
    4364             :  * which gets turned into an EquivalenceClass containing a constant, which
    4365             :  * is recognized as redundant by build_index_pathkeys().  But if the index
    4366             :  * column is a boolean variable (or expression), then we are not going to
    4367             :  * see WHERE indexcol = constant, because expression preprocessing will have
    4368             :  * simplified that to "WHERE indexcol" or "WHERE NOT indexcol".  So we are not
    4369             :  * going to have a matching EquivalenceClass (unless the query also contains
    4370             :  * "ORDER BY indexcol").  To allow such cases to work the same as they would
    4371             :  * for non-boolean values, this function is provided to detect whether the
    4372             :  * specified index column matches a boolean restriction clause.
    4373             :  */
    4374             : bool
    4375      642364 : indexcol_is_bool_constant_for_query(PlannerInfo *root,
    4376             :                                     IndexOptInfo *index,
    4377             :                                     int indexcol)
    4378             : {
    4379             :     ListCell   *lc;
    4380             : 
    4381             :     /* If the index isn't boolean, we can't possibly get a match */
    4382      642364 :     if (!IsBooleanOpfamily(index->opfamily[indexcol]))
    4383      638248 :         return false;
    4384             : 
    4385             :     /* Check each restriction clause for the index's rel */
    4386        4152 :     foreach(lc, index->rel->baserestrictinfo)
    4387             :     {
    4388        1260 :         RestrictInfo *rinfo = (RestrictInfo *) lfirst(lc);
    4389             : 
    4390             :         /*
    4391             :          * As in match_clause_to_indexcol, never match pseudoconstants to
    4392             :          * indexes.  (It might be semantically okay to do so here, but the
    4393             :          * odds of getting a match are negligible, so don't waste the cycles.)
    4394             :          */
    4395        1260 :         if (rinfo->pseudoconstant)
    4396           0 :             continue;
    4397             : 
    4398             :         /* See if we can match the clause's expression to the index column */
    4399        1260 :         if (match_boolean_index_clause(root, rinfo, indexcol, index))
    4400        1224 :             return true;
    4401             :     }
    4402             : 
    4403        2892 :     return false;
    4404             : }
    4405             : 
    4406             : 
    4407             : /****************************************************************************
    4408             :  *              ----  ROUTINES TO CHECK OPERANDS  ----
    4409             :  ****************************************************************************/
    4410             : 
    4411             : /*
    4412             :  * match_index_to_operand()
    4413             :  *    Generalized test for a match between an index's key
    4414             :  *    and the operand on one side of a restriction or join clause.
    4415             :  *
    4416             :  * operand: the nodetree to be compared to the index
    4417             :  * indexcol: the column number of the index (counting from 0)
    4418             :  * index: the index of interest
    4419             :  *
    4420             :  * Note that we aren't interested in collations here; the caller must check
    4421             :  * for a collation match, if it's dealing with an operator where that matters.
    4422             :  *
    4423             :  * This is exported for use in selfuncs.c.
    4424             :  */
    4425             : bool
    4426     3707962 : match_index_to_operand(Node *operand,
    4427             :                        int indexcol,
    4428             :                        IndexOptInfo *index)
    4429             : {
    4430             :     int         indkey;
    4431             : 
    4432             :     /*
    4433             :      * Ignore any RelabelType node above the operand.   This is needed to be
    4434             :      * able to apply indexscanning in binary-compatible-operator cases. Note:
    4435             :      * we can assume there is at most one RelabelType node;
    4436             :      * eval_const_expressions() will have simplified if more than one.
    4437             :      */
    4438     3707962 :     if (operand && IsA(operand, RelabelType))
    4439       23896 :         operand = (Node *) ((RelabelType *) operand)->arg;
    4440             : 
    4441     3707962 :     indkey = index->indexkeys[indexcol];
    4442     3707962 :     if (indkey != 0)
    4443             :     {
    4444             :         /*
    4445             :          * Simple index column; operand must be a matching Var.
    4446             :          */
    4447     3701976 :         if (operand && IsA(operand, Var) &&
    4448     2725200 :             index->rel->relid == ((Var *) operand)->varno &&
    4449     2530984 :             indkey == ((Var *) operand)->varattno &&
    4450      854674 :             ((Var *) operand)->varnullingrels == NULL)
    4451      853748 :             return true;
    4452             :     }
    4453             :     else
    4454             :     {
    4455             :         /*
    4456             :          * Index expression; find the correct expression.  (This search could
    4457             :          * be avoided, at the cost of complicating all the callers of this
    4458             :          * routine; doesn't seem worth it.)
    4459             :          */
    4460             :         ListCell   *indexpr_item;
    4461             :         int         i;
    4462             :         Node       *indexkey;
    4463             : 
    4464        5986 :         indexpr_item = list_head(index->indexprs);
    4465        5986 :         for (i = 0; i < indexcol; i++)
    4466             :         {
    4467           0 :             if (index->indexkeys[i] == 0)
    4468             :             {
    4469           0 :                 if (indexpr_item == NULL)
    4470           0 :                     elog(ERROR, "wrong number of index expressions");
    4471           0 :                 indexpr_item = lnext(index->indexprs, indexpr_item);
    4472             :             }
    4473             :         }
    4474        5986 :         if (indexpr_item == NULL)
    4475           0 :             elog(ERROR, "wrong number of index expressions");
    4476        5986 :         indexkey = (Node *) lfirst(indexpr_item);
    4477             : 
    4478             :         /*
    4479             :          * Does it match the operand?  Again, strip any relabeling.
    4480             :          */
    4481        5986 :         if (indexkey && IsA(indexkey, RelabelType))
    4482          10 :             indexkey = (Node *) ((RelabelType *) indexkey)->arg;
    4483             : 
    4484        5986 :         if (equal(indexkey, operand))
    4485        2164 :             return true;
    4486             :     }
    4487             : 
    4488     2852050 :     return false;
    4489             : }
    4490             : 
    4491             : /*
    4492             :  * is_pseudo_constant_for_index()
    4493             :  *    Test whether the given expression can be used as an indexscan
    4494             :  *    comparison value.
    4495             :  *
    4496             :  * An indexscan comparison value must not contain any volatile functions,
    4497             :  * and it can't contain any Vars of the index's own table.  Vars of
    4498             :  * other tables are okay, though; in that case we'd be producing an
    4499             :  * indexqual usable in a parameterized indexscan.  This is, therefore,
    4500             :  * a weaker condition than is_pseudo_constant_clause().
    4501             :  *
    4502             :  * This function is exported for use by planner support functions,
    4503             :  * which will have available the IndexOptInfo, but not any RestrictInfo
    4504             :  * infrastructure.  It is making the same test made by functions above
    4505             :  * such as match_opclause_to_indexcol(), but those rely where possible
    4506             :  * on RestrictInfo information about variable membership.
    4507             :  *
    4508             :  * expr: the nodetree to be checked
    4509             :  * index: the index of interest
    4510             :  */
    4511             : bool
    4512           0 : is_pseudo_constant_for_index(PlannerInfo *root, Node *expr, IndexOptInfo *index)
    4513             : {
    4514             :     /* pull_varnos is cheaper than volatility check, so do that first */
    4515           0 :     if (bms_is_member(index->rel->relid, pull_varnos(root, expr)))
    4516           0 :         return false;           /* no good, contains Var of table */
    4517           0 :     if (contain_volatile_functions(expr))
    4518           0 :         return false;           /* no good, volatile comparison value */
    4519           0 :     return true;
    4520             : }

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