LCOV - code coverage report
Current view: top level - src/backend/optimizer/path - indxpath.c (source / functions) Hit Total Coverage
Test: PostgreSQL 14devel Lines: 924 990 93.3 %
Date: 2021-01-26 03:06:49 Functions: 41 42 97.6 %
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) 1996-2021, 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_operator.h"
      24             : #include "catalog/pg_opfamily.h"
      25             : #include "catalog/pg_type.h"
      26             : #include "nodes/makefuncs.h"
      27             : #include "nodes/nodeFuncs.h"
      28             : #include "nodes/supportnodes.h"
      29             : #include "optimizer/cost.h"
      30             : #include "optimizer/optimizer.h"
      31             : #include "optimizer/pathnode.h"
      32             : #include "optimizer/paths.h"
      33             : #include "optimizer/prep.h"
      34             : #include "optimizer/restrictinfo.h"
      35             : #include "utils/lsyscache.h"
      36             : #include "utils/selfuncs.h"
      37             : 
      38             : 
      39             : /* XXX see PartCollMatchesExprColl */
      40             : #define IndexCollMatchesExprColl(idxcollation, exprcollation) \
      41             :     ((idxcollation) == InvalidOid || (idxcollation) == (exprcollation))
      42             : 
      43             : /* Whether we are looking for plain indexscan, bitmap scan, or either */
      44             : typedef enum
      45             : {
      46             :     ST_INDEXSCAN,               /* must support amgettuple */
      47             :     ST_BITMAPSCAN,              /* must support amgetbitmap */
      48             :     ST_ANYSCAN                  /* either is okay */
      49             : } ScanTypeControl;
      50             : 
      51             : /* Data structure for collecting qual clauses that match an index */
      52             : typedef struct
      53             : {
      54             :     bool        nonempty;       /* True if lists are not all empty */
      55             :     /* Lists of IndexClause nodes, one list per index column */
      56             :     List       *indexclauses[INDEX_MAX_KEYS];
      57             : } IndexClauseSet;
      58             : 
      59             : /* Per-path data used within choose_bitmap_and() */
      60             : typedef struct
      61             : {
      62             :     Path       *path;           /* IndexPath, BitmapAndPath, or BitmapOrPath */
      63             :     List       *quals;          /* the WHERE clauses it uses */
      64             :     List       *preds;          /* predicates of its partial index(es) */
      65             :     Bitmapset  *clauseids;      /* quals+preds represented as a bitmapset */
      66             :     bool        unclassifiable; /* has too many quals+preds to process? */
      67             : } PathClauseUsage;
      68             : 
      69             : /* Callback argument for ec_member_matches_indexcol */
      70             : typedef struct
      71             : {
      72             :     IndexOptInfo *index;        /* index we're considering */
      73             :     int         indexcol;       /* index column we want to match to */
      74             : } ec_member_matches_arg;
      75             : 
      76             : 
      77             : static void consider_index_join_clauses(PlannerInfo *root, RelOptInfo *rel,
      78             :                                         IndexOptInfo *index,
      79             :                                         IndexClauseSet *rclauseset,
      80             :                                         IndexClauseSet *jclauseset,
      81             :                                         IndexClauseSet *eclauseset,
      82             :                                         List **bitindexpaths);
      83             : static void consider_index_join_outer_rels(PlannerInfo *root, RelOptInfo *rel,
      84             :                                            IndexOptInfo *index,
      85             :                                            IndexClauseSet *rclauseset,
      86             :                                            IndexClauseSet *jclauseset,
      87             :                                            IndexClauseSet *eclauseset,
      88             :                                            List **bitindexpaths,
      89             :                                            List *indexjoinclauses,
      90             :                                            int considered_clauses,
      91             :                                            List **considered_relids);
      92             : static void get_join_index_paths(PlannerInfo *root, RelOptInfo *rel,
      93             :                                  IndexOptInfo *index,
      94             :                                  IndexClauseSet *rclauseset,
      95             :                                  IndexClauseSet *jclauseset,
      96             :                                  IndexClauseSet *eclauseset,
      97             :                                  List **bitindexpaths,
      98             :                                  Relids relids,
      99             :                                  List **considered_relids);
     100             : static bool eclass_already_used(EquivalenceClass *parent_ec, Relids oldrelids,
     101             :                                 List *indexjoinclauses);
     102             : static bool bms_equal_any(Relids relids, List *relids_list);
     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             :                                bool *skip_lower_saop);
     112             : static List *build_paths_for_OR(PlannerInfo *root, RelOptInfo *rel,
     113             :                                 List *clauses, List *other_clauses);
     114             : static List *generate_bitmap_or_paths(PlannerInfo *root, RelOptInfo *rel,
     115             :                                       List *clauses, List *other_clauses);
     116             : static Path *choose_bitmap_and(PlannerInfo *root, RelOptInfo *rel,
     117             :                                List *paths);
     118             : static int  path_usage_comparator(const void *a, const void *b);
     119             : static Cost bitmap_scan_cost_est(PlannerInfo *root, RelOptInfo *rel,
     120             :                                  Path *ipath);
     121             : static Cost bitmap_and_cost_est(PlannerInfo *root, RelOptInfo *rel,
     122             :                                 List *paths);
     123             : static PathClauseUsage *classify_index_clause_usage(Path *path,
     124             :                                                     List **clauselist);
     125             : static void find_indexpath_quals(Path *bitmapqual, List **quals, List **preds);
     126             : static int  find_list_position(Node *node, List **nodelist);
     127             : static bool check_index_only(RelOptInfo *rel, IndexOptInfo *index);
     128             : static double get_loop_count(PlannerInfo *root, Index cur_relid, Relids outer_relids);
     129             : static double adjust_rowcount_for_semijoins(PlannerInfo *root,
     130             :                                             Index cur_relid,
     131             :                                             Index outer_relid,
     132             :                                             double rowcount);
     133             : static double approximate_joinrel_size(PlannerInfo *root, Relids relids);
     134             : static void match_restriction_clauses_to_index(PlannerInfo *root,
     135             :                                                IndexOptInfo *index,
     136             :                                                IndexClauseSet *clauseset);
     137             : static void match_join_clauses_to_index(PlannerInfo *root,
     138             :                                         RelOptInfo *rel, IndexOptInfo *index,
     139             :                                         IndexClauseSet *clauseset,
     140             :                                         List **joinorclauses);
     141             : static void match_eclass_clauses_to_index(PlannerInfo *root,
     142             :                                           IndexOptInfo *index,
     143             :                                           IndexClauseSet *clauseset);
     144             : static void match_clauses_to_index(PlannerInfo *root,
     145             :                                    List *clauses,
     146             :                                    IndexOptInfo *index,
     147             :                                    IndexClauseSet *clauseset);
     148             : static void match_clause_to_index(PlannerInfo *root,
     149             :                                   RestrictInfo *rinfo,
     150             :                                   IndexOptInfo *index,
     151             :                                   IndexClauseSet *clauseset);
     152             : static IndexClause *match_clause_to_indexcol(PlannerInfo *root,
     153             :                                              RestrictInfo *rinfo,
     154             :                                              int indexcol,
     155             :                                              IndexOptInfo *index);
     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 *expand_indexqual_rowcompare(PlannerInfo *root,
     182             :                                                 RestrictInfo *rinfo,
     183             :                                                 int indexcol,
     184             :                                                 IndexOptInfo *index,
     185             :                                                 Oid expr_op,
     186             :                                                 bool var_on_left);
     187             : static void match_pathkeys_to_index(IndexOptInfo *index, List *pathkeys,
     188             :                                     List **orderby_clauses_p,
     189             :                                     List **clause_columns_p);
     190             : static Expr *match_clause_to_ordering_op(IndexOptInfo *index,
     191             :                                          int indexcol, Expr *clause, Oid pk_opfamily);
     192             : static bool ec_member_matches_indexcol(PlannerInfo *root, RelOptInfo *rel,
     193             :                                        EquivalenceClass *ec, EquivalenceMember *em,
     194             :                                        void *arg);
     195             : 
     196             : 
     197             : /*
     198             :  * create_index_paths()
     199             :  *    Generate all interesting index paths for the given relation.
     200             :  *    Candidate paths are added to the rel's pathlist (using add_path).
     201             :  *
     202             :  * To be considered for an index scan, an index must match one or more
     203             :  * restriction clauses or join clauses from the query's qual condition,
     204             :  * or match the query's ORDER BY condition, or have a predicate that
     205             :  * matches the query's qual condition.
     206             :  *
     207             :  * There are two basic kinds of index scans.  A "plain" index scan uses
     208             :  * only restriction clauses (possibly none at all) in its indexqual,
     209             :  * so it can be applied in any context.  A "parameterized" index scan uses
     210             :  * join clauses (plus restriction clauses, if available) in its indexqual.
     211             :  * When joining such a scan to one of the relations supplying the other
     212             :  * variables used in its indexqual, the parameterized scan must appear as
     213             :  * the inner relation of a nestloop join; it can't be used on the outer side,
     214             :  * nor in a merge or hash join.  In that context, values for the other rels'
     215             :  * attributes are available and fixed during any one scan of the indexpath.
     216             :  *
     217             :  * An IndexPath is generated and submitted to add_path() for each plain or
     218             :  * parameterized index scan this routine deems potentially interesting for
     219             :  * the current query.
     220             :  *
     221             :  * 'rel' is the relation for which we want to generate index paths
     222             :  *
     223             :  * Note: check_index_predicates() must have been run previously for this rel.
     224             :  *
     225             :  * Note: in cases involving LATERAL references in the relation's tlist, it's
     226             :  * possible that rel->lateral_relids is nonempty.  Currently, we include
     227             :  * lateral_relids into the parameterization reported for each path, but don't
     228             :  * take it into account otherwise.  The fact that any such rels *must* be
     229             :  * available as parameter sources perhaps should influence our choices of
     230             :  * index quals ... but for now, it doesn't seem worth troubling over.
     231             :  * In particular, comments below about "unparameterized" paths should be read
     232             :  * as meaning "unparameterized so far as the indexquals are concerned".
     233             :  */
     234             : void
     235      237388 : create_index_paths(PlannerInfo *root, RelOptInfo *rel)
     236             : {
     237             :     List       *indexpaths;
     238             :     List       *bitindexpaths;
     239             :     List       *bitjoinpaths;
     240             :     List       *joinorclauses;
     241             :     IndexClauseSet rclauseset;
     242             :     IndexClauseSet jclauseset;
     243             :     IndexClauseSet eclauseset;
     244             :     ListCell   *lc;
     245             : 
     246             :     /* Skip the whole mess if no indexes */
     247      237388 :     if (rel->indexlist == NIL)
     248       39922 :         return;
     249             : 
     250             :     /* Bitmap paths are collected and then dealt with at the end */
     251      197466 :     bitindexpaths = bitjoinpaths = joinorclauses = NIL;
     252             : 
     253             :     /* Examine each index in turn */
     254      606596 :     foreach(lc, rel->indexlist)
     255             :     {
     256      409130 :         IndexOptInfo *index = (IndexOptInfo *) lfirst(lc);
     257             : 
     258             :         /* Protect limited-size array in IndexClauseSets */
     259             :         Assert(index->nkeycolumns <= INDEX_MAX_KEYS);
     260             : 
     261             :         /*
     262             :          * Ignore partial indexes that do not match the query.
     263             :          * (generate_bitmap_or_paths() might be able to do something with
     264             :          * them, but that's of no concern here.)
     265             :          */
     266      409130 :         if (index->indpred != NIL && !index->predOK)
     267         330 :             continue;
     268             : 
     269             :         /*
     270             :          * Identify the restriction clauses that can match the index.
     271             :          */
     272    13899200 :         MemSet(&rclauseset, 0, sizeof(rclauseset));
     273      408800 :         match_restriction_clauses_to_index(root, index, &rclauseset);
     274             : 
     275             :         /*
     276             :          * Build index paths from the restriction clauses.  These will be
     277             :          * non-parameterized paths.  Plain paths go directly to add_path(),
     278             :          * bitmap paths are added to bitindexpaths to be handled below.
     279             :          */
     280      408800 :         get_index_paths(root, rel, index, &rclauseset,
     281             :                         &bitindexpaths);
     282             : 
     283             :         /*
     284             :          * Identify the join clauses that can match the index.  For the moment
     285             :          * we keep them separate from the restriction clauses.  Note that this
     286             :          * step finds only "loose" join clauses that have not been merged into
     287             :          * EquivalenceClasses.  Also, collect join OR clauses for later.
     288             :          */
     289    13899200 :         MemSet(&jclauseset, 0, sizeof(jclauseset));
     290      408800 :         match_join_clauses_to_index(root, rel, index,
     291             :                                     &jclauseset, &joinorclauses);
     292             : 
     293             :         /*
     294             :          * Look for EquivalenceClasses that can generate joinclauses matching
     295             :          * the index.
     296             :          */
     297    13899200 :         MemSet(&eclauseset, 0, sizeof(eclauseset));
     298      408800 :         match_eclass_clauses_to_index(root, index,
     299             :                                       &eclauseset);
     300             : 
     301             :         /*
     302             :          * If we found any plain or eclass join clauses, build parameterized
     303             :          * index paths using them.
     304             :          */
     305      408800 :         if (jclauseset.nonempty || eclauseset.nonempty)
     306       62002 :             consider_index_join_clauses(root, rel, index,
     307             :                                         &rclauseset,
     308             :                                         &jclauseset,
     309             :                                         &eclauseset,
     310             :                                         &bitjoinpaths);
     311             :     }
     312             : 
     313             :     /*
     314             :      * Generate BitmapOrPaths for any suitable OR-clauses present in the
     315             :      * restriction list.  Add these to bitindexpaths.
     316             :      */
     317      197466 :     indexpaths = generate_bitmap_or_paths(root, rel,
     318             :                                           rel->baserestrictinfo, NIL);
     319      197466 :     bitindexpaths = list_concat(bitindexpaths, indexpaths);
     320             : 
     321             :     /*
     322             :      * Likewise, generate BitmapOrPaths for any suitable OR-clauses present in
     323             :      * the joinclause list.  Add these to bitjoinpaths.
     324             :      */
     325      197466 :     indexpaths = generate_bitmap_or_paths(root, rel,
     326             :                                           joinorclauses, rel->baserestrictinfo);
     327      197466 :     bitjoinpaths = list_concat(bitjoinpaths, indexpaths);
     328             : 
     329             :     /*
     330             :      * If we found anything usable, generate a BitmapHeapPath for the most
     331             :      * promising combination of restriction bitmap index paths.  Note there
     332             :      * will be only one such path no matter how many indexes exist.  This
     333             :      * should be sufficient since there's basically only one figure of merit
     334             :      * (total cost) for such a path.
     335             :      */
     336      197466 :     if (bitindexpaths != NIL)
     337             :     {
     338             :         Path       *bitmapqual;
     339             :         BitmapHeapPath *bpath;
     340             : 
     341      125592 :         bitmapqual = choose_bitmap_and(root, rel, bitindexpaths);
     342      125592 :         bpath = create_bitmap_heap_path(root, rel, bitmapqual,
     343             :                                         rel->lateral_relids, 1.0, 0);
     344      125592 :         add_path(rel, (Path *) bpath);
     345             : 
     346             :         /* create a partial bitmap heap path */
     347      125592 :         if (rel->consider_parallel && rel->lateral_relids == NULL)
     348       76034 :             create_partial_bitmap_paths(root, rel, bitmapqual);
     349             :     }
     350             : 
     351             :     /*
     352             :      * Likewise, if we found anything usable, generate BitmapHeapPaths for the
     353             :      * most promising combinations of join bitmap index paths.  Our strategy
     354             :      * is to generate one such path for each distinct parameterization seen
     355             :      * among the available bitmap index paths.  This may look pretty
     356             :      * expensive, but usually there won't be very many distinct
     357             :      * parameterizations.  (This logic is quite similar to that in
     358             :      * consider_index_join_clauses, but we're working with whole paths not
     359             :      * individual clauses.)
     360             :      */
     361      197466 :     if (bitjoinpaths != NIL)
     362             :     {
     363             :         List       *all_path_outers;
     364             :         ListCell   *lc;
     365             : 
     366             :         /* Identify each distinct parameterization seen in bitjoinpaths */
     367       57500 :         all_path_outers = NIL;
     368      121472 :         foreach(lc, bitjoinpaths)
     369             :         {
     370       63972 :             Path       *path = (Path *) lfirst(lc);
     371       63972 :             Relids      required_outer = PATH_REQ_OUTER(path);
     372             : 
     373       63972 :             if (!bms_equal_any(required_outer, all_path_outers))
     374       62272 :                 all_path_outers = lappend(all_path_outers, required_outer);
     375             :         }
     376             : 
     377             :         /* Now, for each distinct parameterization set ... */
     378      119772 :         foreach(lc, all_path_outers)
     379             :         {
     380       62272 :             Relids      max_outers = (Relids) lfirst(lc);
     381             :             List       *this_path_set;
     382             :             Path       *bitmapqual;
     383             :             Relids      required_outer;
     384             :             double      loop_count;
     385             :             BitmapHeapPath *bpath;
     386             :             ListCell   *lcp;
     387             : 
     388             :             /* Identify all the bitmap join paths needing no more than that */
     389       62272 :             this_path_set = NIL;
     390      137440 :             foreach(lcp, bitjoinpaths)
     391             :             {
     392       75168 :                 Path       *path = (Path *) lfirst(lcp);
     393             : 
     394       75168 :                 if (bms_is_subset(PATH_REQ_OUTER(path), max_outers))
     395       64388 :                     this_path_set = lappend(this_path_set, path);
     396             :             }
     397             : 
     398             :             /*
     399             :              * Add in restriction bitmap paths, since they can be used
     400             :              * together with any join paths.
     401             :              */
     402       62272 :             this_path_set = list_concat(this_path_set, bitindexpaths);
     403             : 
     404             :             /* Select best AND combination for this parameterization */
     405       62272 :             bitmapqual = choose_bitmap_and(root, rel, this_path_set);
     406             : 
     407             :             /* And push that path into the mix */
     408       62272 :             required_outer = PATH_REQ_OUTER(bitmapqual);
     409       62272 :             loop_count = get_loop_count(root, rel->relid, required_outer);
     410       62272 :             bpath = create_bitmap_heap_path(root, rel, bitmapqual,
     411             :                                             required_outer, loop_count, 0);
     412       62272 :             add_path(rel, (Path *) bpath);
     413             :         }
     414             :     }
     415             : }
     416             : 
     417             : /*
     418             :  * consider_index_join_clauses
     419             :  *    Given sets of join clauses for an index, decide which parameterized
     420             :  *    index paths to build.
     421             :  *
     422             :  * Plain indexpaths are sent directly to add_path, while potential
     423             :  * bitmap indexpaths are added to *bitindexpaths for later processing.
     424             :  *
     425             :  * 'rel' is the index's heap relation
     426             :  * 'index' is the index for which we want to generate paths
     427             :  * 'rclauseset' is the collection of indexable restriction clauses
     428             :  * 'jclauseset' is the collection of indexable simple join clauses
     429             :  * 'eclauseset' is the collection of indexable clauses from EquivalenceClasses
     430             :  * '*bitindexpaths' is the list to add bitmap paths to
     431             :  */
     432             : static void
     433       62002 : consider_index_join_clauses(PlannerInfo *root, RelOptInfo *rel,
     434             :                             IndexOptInfo *index,
     435             :                             IndexClauseSet *rclauseset,
     436             :                             IndexClauseSet *jclauseset,
     437             :                             IndexClauseSet *eclauseset,
     438             :                             List **bitindexpaths)
     439             : {
     440       62002 :     int         considered_clauses = 0;
     441       62002 :     List       *considered_relids = NIL;
     442             :     int         indexcol;
     443             : 
     444             :     /*
     445             :      * The strategy here is to identify every potentially useful set of outer
     446             :      * rels that can provide indexable join clauses.  For each such set,
     447             :      * select all the join clauses available from those outer rels, add on all
     448             :      * the indexable restriction clauses, and generate plain and/or bitmap
     449             :      * index paths for that set of clauses.  This is based on the assumption
     450             :      * that it's always better to apply a clause as an indexqual than as a
     451             :      * filter (qpqual); which is where an available clause would end up being
     452             :      * applied if we omit it from the indexquals.
     453             :      *
     454             :      * This looks expensive, but in most practical cases there won't be very
     455             :      * many distinct sets of outer rels to consider.  As a safety valve when
     456             :      * that's not true, we use a heuristic: limit the number of outer rel sets
     457             :      * considered to a multiple of the number of clauses considered.  (We'll
     458             :      * always consider using each individual join clause, though.)
     459             :      *
     460             :      * For simplicity in selecting relevant clauses, we represent each set of
     461             :      * outer rels as a maximum set of clause_relids --- that is, the indexed
     462             :      * relation itself is also included in the relids set.  considered_relids
     463             :      * lists all relids sets we've already tried.
     464             :      */
     465      157746 :     for (indexcol = 0; indexcol < index->nkeycolumns; indexcol++)
     466             :     {
     467             :         /* Consider each applicable simple join clause */
     468       95744 :         considered_clauses += list_length(jclauseset->indexclauses[indexcol]);
     469       95744 :         consider_index_join_outer_rels(root, rel, index,
     470             :                                        rclauseset, jclauseset, eclauseset,
     471             :                                        bitindexpaths,
     472             :                                        jclauseset->indexclauses[indexcol],
     473             :                                        considered_clauses,
     474             :                                        &considered_relids);
     475             :         /* Consider each applicable eclass join clause */
     476       95744 :         considered_clauses += list_length(eclauseset->indexclauses[indexcol]);
     477       95744 :         consider_index_join_outer_rels(root, rel, index,
     478             :                                        rclauseset, jclauseset, eclauseset,
     479             :                                        bitindexpaths,
     480             :                                        eclauseset->indexclauses[indexcol],
     481             :                                        considered_clauses,
     482             :                                        &considered_relids);
     483             :     }
     484       62002 : }
     485             : 
     486             : /*
     487             :  * consider_index_join_outer_rels
     488             :  *    Generate parameterized paths based on clause relids in the clause list.
     489             :  *
     490             :  * Workhorse for consider_index_join_clauses; see notes therein for rationale.
     491             :  *
     492             :  * 'rel', 'index', 'rclauseset', 'jclauseset', 'eclauseset', and
     493             :  *      'bitindexpaths' as above
     494             :  * 'indexjoinclauses' is a list of IndexClauses for join clauses
     495             :  * 'considered_clauses' is the total number of clauses considered (so far)
     496             :  * '*considered_relids' is a list of all relids sets already considered
     497             :  */
     498             : static void
     499      191488 : consider_index_join_outer_rels(PlannerInfo *root, RelOptInfo *rel,
     500             :                                IndexOptInfo *index,
     501             :                                IndexClauseSet *rclauseset,
     502             :                                IndexClauseSet *jclauseset,
     503             :                                IndexClauseSet *eclauseset,
     504             :                                List **bitindexpaths,
     505             :                                List *indexjoinclauses,
     506             :                                int considered_clauses,
     507             :                                List **considered_relids)
     508             : {
     509             :     ListCell   *lc;
     510             : 
     511             :     /* Examine relids of each joinclause in the given list */
     512      256658 :     foreach(lc, indexjoinclauses)
     513             :     {
     514       65170 :         IndexClause *iclause = (IndexClause *) lfirst(lc);
     515       65170 :         Relids      clause_relids = iclause->rinfo->clause_relids;
     516       65170 :         EquivalenceClass *parent_ec = iclause->rinfo->parent_ec;
     517             :         int         num_considered_relids;
     518             : 
     519             :         /* If we already tried its relids set, no need to do so again */
     520       65170 :         if (bms_equal_any(clause_relids, *considered_relids))
     521        1446 :             continue;
     522             : 
     523             :         /*
     524             :          * Generate the union of this clause's relids set with each
     525             :          * previously-tried set.  This ensures we try this clause along with
     526             :          * every interesting subset of previous clauses.  However, to avoid
     527             :          * exponential growth of planning time when there are many clauses,
     528             :          * limit the number of relid sets accepted to 10 * considered_clauses.
     529             :          *
     530             :          * Note: get_join_index_paths appends entries to *considered_relids,
     531             :          * but we do not need to visit such newly-added entries within this
     532             :          * loop, so we don't use foreach() here.  No real harm would be done
     533             :          * if we did visit them, since the subset check would reject them; but
     534             :          * it would waste some cycles.
     535             :          */
     536       63724 :         num_considered_relids = list_length(*considered_relids);
     537       65486 :         for (int pos = 0; pos < num_considered_relids; pos++)
     538             :         {
     539        1762 :             Relids      oldrelids = (Relids) list_nth(*considered_relids, pos);
     540             : 
     541             :             /*
     542             :              * If either is a subset of the other, no new set is possible.
     543             :              * This isn't a complete test for redundancy, but it's easy and
     544             :              * cheap.  get_join_index_paths will check more carefully if we
     545             :              * already generated the same relids set.
     546             :              */
     547        1762 :             if (bms_subset_compare(clause_relids, oldrelids) != BMS_DIFFERENT)
     548          16 :                 continue;
     549             : 
     550             :             /*
     551             :              * If this clause was derived from an equivalence class, the
     552             :              * clause list may contain other clauses derived from the same
     553             :              * eclass.  We should not consider that combining this clause with
     554             :              * one of those clauses generates a usefully different
     555             :              * parameterization; so skip if any clause derived from the same
     556             :              * eclass would already have been included when using oldrelids.
     557             :              */
     558        3386 :             if (parent_ec &&
     559        1640 :                 eclass_already_used(parent_ec, oldrelids,
     560             :                                     indexjoinclauses))
     561        1574 :                 continue;
     562             : 
     563             :             /*
     564             :              * If the number of relid sets considered exceeds our heuristic
     565             :              * limit, stop considering combinations of clauses.  We'll still
     566             :              * consider the current clause alone, though (below this loop).
     567             :              */
     568         172 :             if (list_length(*considered_relids) >= 10 * considered_clauses)
     569           0 :                 break;
     570             : 
     571             :             /* OK, try the union set */
     572         172 :             get_join_index_paths(root, rel, index,
     573             :                                  rclauseset, jclauseset, eclauseset,
     574             :                                  bitindexpaths,
     575             :                                  bms_union(clause_relids, oldrelids),
     576             :                                  considered_relids);
     577             :         }
     578             : 
     579             :         /* Also try this set of relids by itself */
     580       63724 :         get_join_index_paths(root, rel, index,
     581             :                              rclauseset, jclauseset, eclauseset,
     582             :                              bitindexpaths,
     583             :                              clause_relids,
     584             :                              considered_relids);
     585             :     }
     586      191488 : }
     587             : 
     588             : /*
     589             :  * get_join_index_paths
     590             :  *    Generate index paths using clauses from the specified outer relations.
     591             :  *    In addition to generating paths, relids is added to *considered_relids
     592             :  *    if not already present.
     593             :  *
     594             :  * Workhorse for consider_index_join_clauses; see notes therein for rationale.
     595             :  *
     596             :  * 'rel', 'index', 'rclauseset', 'jclauseset', 'eclauseset',
     597             :  *      'bitindexpaths', 'considered_relids' as above
     598             :  * 'relids' is the current set of relids to consider (the target rel plus
     599             :  *      one or more outer rels)
     600             :  */
     601             : static void
     602       63896 : get_join_index_paths(PlannerInfo *root, RelOptInfo *rel,
     603             :                      IndexOptInfo *index,
     604             :                      IndexClauseSet *rclauseset,
     605             :                      IndexClauseSet *jclauseset,
     606             :                      IndexClauseSet *eclauseset,
     607             :                      List **bitindexpaths,
     608             :                      Relids relids,
     609             :                      List **considered_relids)
     610             : {
     611             :     IndexClauseSet clauseset;
     612             :     int         indexcol;
     613             : 
     614             :     /* If we already considered this relids set, don't repeat the work */
     615       63896 :     if (bms_equal_any(relids, *considered_relids))
     616           0 :         return;
     617             : 
     618             :     /* Identify indexclauses usable with this relids set */
     619     2172464 :     MemSet(&clauseset, 0, sizeof(clauseset));
     620             : 
     621      163096 :     for (indexcol = 0; indexcol < index->nkeycolumns; indexcol++)
     622             :     {
     623             :         ListCell   *lc;
     624             : 
     625             :         /* First find applicable simple join clauses */
     626      124464 :         foreach(lc, jclauseset->indexclauses[indexcol])
     627             :         {
     628       25264 :             IndexClause *iclause = (IndexClause *) lfirst(lc);
     629             : 
     630       25264 :             if (bms_is_subset(iclause->rinfo->clause_relids, relids))
     631       25030 :                 clauseset.indexclauses[indexcol] =
     632       25030 :                     lappend(clauseset.indexclauses[indexcol], iclause);
     633             :         }
     634             : 
     635             :         /*
     636             :          * Add applicable eclass join clauses.  The clauses generated for each
     637             :          * column are redundant (cf generate_implied_equalities_for_column),
     638             :          * so we need at most one.  This is the only exception to the general
     639             :          * rule of using all available index clauses.
     640             :          */
     641      101194 :         foreach(lc, eclauseset->indexclauses[indexcol])
     642             :         {
     643       42466 :             IndexClause *iclause = (IndexClause *) lfirst(lc);
     644             : 
     645       42466 :             if (bms_is_subset(iclause->rinfo->clause_relids, relids))
     646             :             {
     647       40472 :                 clauseset.indexclauses[indexcol] =
     648       40472 :                     lappend(clauseset.indexclauses[indexcol], iclause);
     649       40472 :                 break;
     650             :             }
     651             :         }
     652             : 
     653             :         /* Add restriction clauses */
     654       99200 :         clauseset.indexclauses[indexcol] =
     655       99200 :             list_concat(clauseset.indexclauses[indexcol],
     656       99200 :                         rclauseset->indexclauses[indexcol]);
     657             : 
     658       99200 :         if (clauseset.indexclauses[indexcol] != NIL)
     659       78252 :             clauseset.nonempty = true;
     660             :     }
     661             : 
     662             :     /* We should have found something, else caller passed silly relids */
     663             :     Assert(clauseset.nonempty);
     664             : 
     665             :     /* Build index path(s) using the collected set of clauses */
     666       63896 :     get_index_paths(root, rel, index, &clauseset, bitindexpaths);
     667             : 
     668             :     /*
     669             :      * Remember we considered paths for this set of relids.
     670             :      */
     671       63896 :     *considered_relids = lappend(*considered_relids, relids);
     672             : }
     673             : 
     674             : /*
     675             :  * eclass_already_used
     676             :  *      True if any join clause usable with oldrelids was generated from
     677             :  *      the specified equivalence class.
     678             :  */
     679             : static bool
     680        1640 : eclass_already_used(EquivalenceClass *parent_ec, Relids oldrelids,
     681             :                     List *indexjoinclauses)
     682             : {
     683             :     ListCell   *lc;
     684             : 
     685        1738 :     foreach(lc, indexjoinclauses)
     686             :     {
     687        1672 :         IndexClause *iclause = (IndexClause *) lfirst(lc);
     688        1672 :         RestrictInfo *rinfo = iclause->rinfo;
     689             : 
     690        3344 :         if (rinfo->parent_ec == parent_ec &&
     691        1672 :             bms_is_subset(rinfo->clause_relids, oldrelids))
     692        1574 :             return true;
     693             :     }
     694          66 :     return false;
     695             : }
     696             : 
     697             : /*
     698             :  * bms_equal_any
     699             :  *      True if relids is bms_equal to any member of relids_list
     700             :  *
     701             :  * Perhaps this should be in bitmapset.c someday.
     702             :  */
     703             : static bool
     704      193038 : bms_equal_any(Relids relids, List *relids_list)
     705             : {
     706             :     ListCell   *lc;
     707             : 
     708      202864 :     foreach(lc, relids_list)
     709             :     {
     710       12972 :         if (bms_equal(relids, (Relids) lfirst(lc)))
     711        3146 :             return true;
     712             :     }
     713      189892 :     return false;
     714             : }
     715             : 
     716             : 
     717             : /*
     718             :  * get_index_paths
     719             :  *    Given an index and a set of index clauses for it, construct IndexPaths.
     720             :  *
     721             :  * Plain indexpaths are sent directly to add_path, while potential
     722             :  * bitmap indexpaths are added to *bitindexpaths for later processing.
     723             :  *
     724             :  * This is a fairly simple frontend to build_index_paths().  Its reason for
     725             :  * existence is mainly to handle ScalarArrayOpExpr quals properly.  If the
     726             :  * index AM supports them natively, we should just include them in simple
     727             :  * index paths.  If not, we should exclude them while building simple index
     728             :  * paths, and then make a separate attempt to include them in bitmap paths.
     729             :  * Furthermore, we should consider excluding lower-order ScalarArrayOpExpr
     730             :  * quals so as to create ordered paths.
     731             :  */
     732             : static void
     733      472696 : get_index_paths(PlannerInfo *root, RelOptInfo *rel,
     734             :                 IndexOptInfo *index, IndexClauseSet *clauses,
     735             :                 List **bitindexpaths)
     736             : {
     737             :     List       *indexpaths;
     738      472696 :     bool        skip_nonnative_saop = false;
     739      472696 :     bool        skip_lower_saop = false;
     740             :     ListCell   *lc;
     741             : 
     742             :     /*
     743             :      * Build simple index paths using the clauses.  Allow ScalarArrayOpExpr
     744             :      * clauses only if the index AM supports them natively, and skip any such
     745             :      * clauses for index columns after the first (so that we produce ordered
     746             :      * paths if possible).
     747             :      */
     748      472696 :     indexpaths = build_index_paths(root, rel,
     749             :                                    index, clauses,
     750      472696 :                                    index->predOK,
     751             :                                    ST_ANYSCAN,
     752             :                                    &skip_nonnative_saop,
     753             :                                    &skip_lower_saop);
     754             : 
     755             :     /*
     756             :      * If we skipped any lower-order ScalarArrayOpExprs on an index with an AM
     757             :      * that supports them, then try again including those clauses.  This will
     758             :      * produce paths with more selectivity but no ordering.
     759             :      */
     760      472696 :     if (skip_lower_saop)
     761             :     {
     762         252 :         indexpaths = list_concat(indexpaths,
     763         252 :                                  build_index_paths(root, rel,
     764             :                                                    index, clauses,
     765         252 :                                                    index->predOK,
     766             :                                                    ST_ANYSCAN,
     767             :                                                    &skip_nonnative_saop,
     768             :                                                    NULL));
     769             :     }
     770             : 
     771             :     /*
     772             :      * Submit all the ones that can form plain IndexScan plans to add_path. (A
     773             :      * plain IndexPath can represent either a plain IndexScan or an
     774             :      * IndexOnlyScan, but for our purposes here that distinction does not
     775             :      * matter.  However, some of the indexes might support only bitmap scans,
     776             :      * and those we mustn't submit to add_path here.)
     777             :      *
     778             :      * Also, pick out the ones that are usable as bitmap scans.  For that, we
     779             :      * must discard indexes that don't support bitmap scans, and we also are
     780             :      * only interested in paths that have some selectivity; we should discard
     781             :      * anything that was generated solely for ordering purposes.
     782             :      */
     783      743576 :     foreach(lc, indexpaths)
     784             :     {
     785      270880 :         IndexPath  *ipath = (IndexPath *) lfirst(lc);
     786             : 
     787      270880 :         if (index->amhasgettuple)
     788      265414 :             add_path(rel, (Path *) ipath);
     789             : 
     790      270880 :         if (index->amhasgetbitmap &&
     791      270880 :             (ipath->path.pathkeys == NIL ||
     792      144758 :              ipath->indexselectivity < 1.0))
     793      210004 :             *bitindexpaths = lappend(*bitindexpaths, ipath);
     794             :     }
     795             : 
     796             :     /*
     797             :      * If there were ScalarArrayOpExpr clauses that the index can't handle
     798             :      * natively, generate bitmap scan paths relying on executor-managed
     799             :      * ScalarArrayOpExpr.
     800             :      */
     801      472696 :     if (skip_nonnative_saop)
     802             :     {
     803          20 :         indexpaths = build_index_paths(root, rel,
     804             :                                        index, clauses,
     805             :                                        false,
     806             :                                        ST_BITMAPSCAN,
     807             :                                        NULL,
     808             :                                        NULL);
     809          20 :         *bitindexpaths = list_concat(*bitindexpaths, indexpaths);
     810             :     }
     811      472696 : }
     812             : 
     813             : /*
     814             :  * build_index_paths
     815             :  *    Given an index and a set of index clauses for it, construct zero
     816             :  *    or more IndexPaths. It also constructs zero or more partial IndexPaths.
     817             :  *
     818             :  * We return a list of paths because (1) this routine checks some cases
     819             :  * that should cause us to not generate any IndexPath, and (2) in some
     820             :  * cases we want to consider both a forward and a backward scan, so as
     821             :  * to obtain both sort orders.  Note that the paths are just returned
     822             :  * to the caller and not immediately fed to add_path().
     823             :  *
     824             :  * At top level, useful_predicate should be exactly the index's predOK flag
     825             :  * (ie, true if it has a predicate that was proven from the restriction
     826             :  * clauses).  When working on an arm of an OR clause, useful_predicate
     827             :  * should be true if the predicate required the current OR list to be proven.
     828             :  * Note that this routine should never be called at all if the index has an
     829             :  * unprovable predicate.
     830             :  *
     831             :  * scantype indicates whether we want to create plain indexscans, bitmap
     832             :  * indexscans, or both.  When it's ST_BITMAPSCAN, we will not consider
     833             :  * index ordering while deciding if a Path is worth generating.
     834             :  *
     835             :  * If skip_nonnative_saop is non-NULL, we ignore ScalarArrayOpExpr clauses
     836             :  * unless the index AM supports them directly, and we set *skip_nonnative_saop
     837             :  * to true if we found any such clauses (caller must initialize the variable
     838             :  * to false).  If it's NULL, we do not ignore ScalarArrayOpExpr clauses.
     839             :  *
     840             :  * If skip_lower_saop is non-NULL, we ignore ScalarArrayOpExpr clauses for
     841             :  * non-first index columns, and we set *skip_lower_saop to true if we found
     842             :  * any such clauses (caller must initialize the variable to false).  If it's
     843             :  * NULL, we do not ignore non-first ScalarArrayOpExpr clauses, but they will
     844             :  * result in considering the scan's output to be unordered.
     845             :  *
     846             :  * 'rel' is the index's heap relation
     847             :  * 'index' is the index for which we want to generate paths
     848             :  * 'clauses' is the collection of indexable clauses (IndexClause nodes)
     849             :  * 'useful_predicate' indicates whether the index has a useful predicate
     850             :  * 'scantype' indicates whether we need plain or bitmap scan support
     851             :  * 'skip_nonnative_saop' indicates whether to accept SAOP if index AM doesn't
     852             :  * 'skip_lower_saop' indicates whether to accept non-first-column SAOP
     853             :  */
     854             : static List *
     855      474128 : build_index_paths(PlannerInfo *root, RelOptInfo *rel,
     856             :                   IndexOptInfo *index, IndexClauseSet *clauses,
     857             :                   bool useful_predicate,
     858             :                   ScanTypeControl scantype,
     859             :                   bool *skip_nonnative_saop,
     860             :                   bool *skip_lower_saop)
     861             : {
     862      474128 :     List       *result = NIL;
     863             :     IndexPath  *ipath;
     864             :     List       *index_clauses;
     865             :     Relids      outer_relids;
     866             :     double      loop_count;
     867             :     List       *orderbyclauses;
     868             :     List       *orderbyclausecols;
     869             :     List       *index_pathkeys;
     870             :     List       *useful_pathkeys;
     871             :     bool        found_lower_saop_clause;
     872             :     bool        pathkeys_possibly_useful;
     873             :     bool        index_is_ordered;
     874             :     bool        index_only_scan;
     875             :     int         indexcol;
     876             : 
     877             :     /*
     878             :      * Check that index supports the desired scan type(s)
     879             :      */
     880      474128 :     switch (scantype)
     881             :     {
     882           0 :         case ST_INDEXSCAN:
     883           0 :             if (!index->amhasgettuple)
     884           0 :                 return NIL;
     885           0 :             break;
     886        1180 :         case ST_BITMAPSCAN:
     887        1180 :             if (!index->amhasgetbitmap)
     888           0 :                 return NIL;
     889        1180 :             break;
     890      472948 :         case ST_ANYSCAN:
     891             :             /* either or both are OK */
     892      472948 :             break;
     893             :     }
     894             : 
     895             :     /*
     896             :      * 1. Combine the per-column IndexClause lists into an overall list.
     897             :      *
     898             :      * In the resulting list, clauses are ordered by index key, so that the
     899             :      * column numbers form a nondecreasing sequence.  (This order is depended
     900             :      * on by btree and possibly other places.)  The list can be empty, if the
     901             :      * index AM allows that.
     902             :      *
     903             :      * found_lower_saop_clause is set true if we accept a ScalarArrayOpExpr
     904             :      * index clause for a non-first index column.  This prevents us from
     905             :      * assuming that the scan result is ordered.  (Actually, the result is
     906             :      * still ordered if there are equality constraints for all earlier
     907             :      * columns, but it seems too expensive and non-modular for this code to be
     908             :      * aware of that refinement.)
     909             :      *
     910             :      * We also build a Relids set showing which outer rels are required by the
     911             :      * selected clauses.  Any lateral_relids are included in that, but not
     912             :      * otherwise accounted for.
     913             :      */
     914      474128 :     index_clauses = NIL;
     915      474128 :     found_lower_saop_clause = false;
     916      474128 :     outer_relids = bms_copy(rel->lateral_relids);
     917     1322770 :     for (indexcol = 0; indexcol < index->nkeycolumns; indexcol++)
     918             :     {
     919             :         ListCell   *lc;
     920             : 
     921     1100460 :         foreach(lc, clauses->indexclauses[indexcol])
     922             :         {
     923      251630 :             IndexClause *iclause = (IndexClause *) lfirst(lc);
     924      251630 :             RestrictInfo *rinfo = iclause->rinfo;
     925             : 
     926             :             /* We might need to omit ScalarArrayOpExpr clauses */
     927      251630 :             if (IsA(rinfo->clause, ScalarArrayOpExpr))
     928             :             {
     929        8492 :                 if (!index->amsearcharray)
     930             :                 {
     931          40 :                     if (skip_nonnative_saop)
     932             :                     {
     933             :                         /* Ignore because not supported by index */
     934          20 :                         *skip_nonnative_saop = true;
     935          20 :                         continue;
     936             :                     }
     937             :                     /* Caller had better intend this only for bitmap scan */
     938             :                     Assert(scantype == ST_BITMAPSCAN);
     939             :                 }
     940        8472 :                 if (indexcol > 0)
     941             :                 {
     942         552 :                     if (skip_lower_saop)
     943             :                     {
     944             :                         /* Caller doesn't want to lose index ordering */
     945         276 :                         *skip_lower_saop = true;
     946         276 :                         continue;
     947             :                     }
     948         276 :                     found_lower_saop_clause = true;
     949             :                 }
     950             :             }
     951             : 
     952             :             /* OK to include this clause */
     953      251334 :             index_clauses = lappend(index_clauses, iclause);
     954      251334 :             outer_relids = bms_add_members(outer_relids,
     955      251334 :                                            rinfo->clause_relids);
     956             :         }
     957             : 
     958             :         /*
     959             :          * If no clauses match the first index column, check for amoptionalkey
     960             :          * restriction.  We can't generate a scan over an index with
     961             :          * amoptionalkey = false unless there's at least one index clause.
     962             :          * (When working on columns after the first, this test cannot fail. It
     963             :          * is always okay for columns after the first to not have any
     964             :          * clauses.)
     965             :          */
     966      848830 :         if (index_clauses == NIL && !index->amoptionalkey)
     967         188 :             return NIL;
     968             :     }
     969             : 
     970             :     /* We do not want the index's rel itself listed in outer_relids */
     971      473940 :     outer_relids = bms_del_member(outer_relids, rel->relid);
     972             :     /* Enforce convention that outer_relids is exactly NULL if empty */
     973      473940 :     if (bms_is_empty(outer_relids))
     974      409904 :         outer_relids = NULL;
     975             : 
     976             :     /* Compute loop_count for cost estimation purposes */
     977      473940 :     loop_count = get_loop_count(root, rel->relid, outer_relids);
     978             : 
     979             :     /*
     980             :      * 2. Compute pathkeys describing index's ordering, if any, then see how
     981             :      * many of them are actually useful for this query.  This is not relevant
     982             :      * if we are only trying to build bitmap indexscans, nor if we have to
     983             :      * assume the scan is unordered.
     984             :      */
     985      946700 :     pathkeys_possibly_useful = (scantype != ST_BITMAPSCAN &&
     986      946448 :                                 !found_lower_saop_clause &&
     987      472508 :                                 has_useful_pathkeys(root, rel));
     988      473940 :     index_is_ordered = (index->sortopfamily != NULL);
     989      473940 :     if (index_is_ordered && pathkeys_possibly_useful)
     990             :     {
     991      271978 :         index_pathkeys = build_index_pathkeys(root, index,
     992             :                                               ForwardScanDirection);
     993      271978 :         useful_pathkeys = truncate_useless_pathkeys(root, rel,
     994             :                                                     index_pathkeys);
     995      271978 :         orderbyclauses = NIL;
     996      271978 :         orderbyclausecols = NIL;
     997             :     }
     998      201962 :     else if (index->amcanorderbyop && pathkeys_possibly_useful)
     999             :     {
    1000             :         /* see if we can generate ordering operators for query_pathkeys */
    1001         552 :         match_pathkeys_to_index(index, root->query_pathkeys,
    1002             :                                 &orderbyclauses,
    1003             :                                 &orderbyclausecols);
    1004        1104 :         if (orderbyclauses)
    1005         316 :             useful_pathkeys = root->query_pathkeys;
    1006             :         else
    1007         236 :             useful_pathkeys = NIL;
    1008             :     }
    1009             :     else
    1010             :     {
    1011      201410 :         useful_pathkeys = NIL;
    1012      201410 :         orderbyclauses = NIL;
    1013      201410 :         orderbyclausecols = NIL;
    1014             :     }
    1015             : 
    1016             :     /*
    1017             :      * 3. Check if an index-only scan is possible.  If we're not building
    1018             :      * plain indexscans, this isn't relevant since bitmap scans don't support
    1019             :      * index data retrieval anyway.
    1020             :      */
    1021      946700 :     index_only_scan = (scantype != ST_BITMAPSCAN &&
    1022      472760 :                        check_index_only(rel, index));
    1023             : 
    1024             :     /*
    1025             :      * 4. Generate an indexscan path if there are relevant restriction clauses
    1026             :      * in the current clauses, OR the index ordering is potentially useful for
    1027             :      * later merging or final output ordering, OR the index has a useful
    1028             :      * predicate, OR an index-only scan is possible.
    1029             :      */
    1030      473940 :     if (index_clauses != NIL || useful_pathkeys != NIL || useful_predicate ||
    1031             :         index_only_scan)
    1032             :     {
    1033      271788 :         ipath = create_index_path(root, index,
    1034             :                                   index_clauses,
    1035             :                                   orderbyclauses,
    1036             :                                   orderbyclausecols,
    1037             :                                   useful_pathkeys,
    1038             :                                   index_is_ordered ?
    1039             :                                   ForwardScanDirection :
    1040             :                                   NoMovementScanDirection,
    1041             :                                   index_only_scan,
    1042             :                                   outer_relids,
    1043             :                                   loop_count,
    1044             :                                   false);
    1045      271788 :         result = lappend(result, ipath);
    1046             : 
    1047             :         /*
    1048             :          * If appropriate, consider parallel index scan.  We don't allow
    1049             :          * parallel index scan for bitmap index scans.
    1050             :          */
    1051      271788 :         if (index->amcanparallel &&
    1052      262572 :             rel->consider_parallel && outer_relids == NULL &&
    1053             :             scantype != ST_BITMAPSCAN)
    1054             :         {
    1055      132556 :             ipath = create_index_path(root, index,
    1056             :                                       index_clauses,
    1057             :                                       orderbyclauses,
    1058             :                                       orderbyclausecols,
    1059             :                                       useful_pathkeys,
    1060             :                                       index_is_ordered ?
    1061             :                                       ForwardScanDirection :
    1062             :                                       NoMovementScanDirection,
    1063             :                                       index_only_scan,
    1064             :                                       outer_relids,
    1065             :                                       loop_count,
    1066             :                                       true);
    1067             : 
    1068             :             /*
    1069             :              * if, after costing the path, we find that it's not worth using
    1070             :              * parallel workers, just free it.
    1071             :              */
    1072      132556 :             if (ipath->path.parallel_workers > 0)
    1073        6742 :                 add_partial_path(rel, (Path *) ipath);
    1074             :             else
    1075      125814 :                 pfree(ipath);
    1076             :         }
    1077             :     }
    1078             : 
    1079             :     /*
    1080             :      * 5. If the index is ordered, a backwards scan might be interesting.
    1081             :      */
    1082      473940 :     if (index_is_ordered && pathkeys_possibly_useful)
    1083             :     {
    1084      271978 :         index_pathkeys = build_index_pathkeys(root, index,
    1085             :                                               BackwardScanDirection);
    1086      271978 :         useful_pathkeys = truncate_useless_pathkeys(root, rel,
    1087             :                                                     index_pathkeys);
    1088      271978 :         if (useful_pathkeys != NIL)
    1089             :         {
    1090         272 :             ipath = create_index_path(root, index,
    1091             :                                       index_clauses,
    1092             :                                       NIL,
    1093             :                                       NIL,
    1094             :                                       useful_pathkeys,
    1095             :                                       BackwardScanDirection,
    1096             :                                       index_only_scan,
    1097             :                                       outer_relids,
    1098             :                                       loop_count,
    1099             :                                       false);
    1100         272 :             result = lappend(result, ipath);
    1101             : 
    1102             :             /* If appropriate, consider parallel index scan */
    1103         272 :             if (index->amcanparallel &&
    1104         272 :                 rel->consider_parallel && outer_relids == NULL &&
    1105             :                 scantype != ST_BITMAPSCAN)
    1106             :             {
    1107         236 :                 ipath = create_index_path(root, index,
    1108             :                                           index_clauses,
    1109             :                                           NIL,
    1110             :                                           NIL,
    1111             :                                           useful_pathkeys,
    1112             :                                           BackwardScanDirection,
    1113             :                                           index_only_scan,
    1114             :                                           outer_relids,
    1115             :                                           loop_count,
    1116             :                                           true);
    1117             : 
    1118             :                 /*
    1119             :                  * if, after costing the path, we find that it's not worth
    1120             :                  * using parallel workers, just free it.
    1121             :                  */
    1122         236 :                 if (ipath->path.parallel_workers > 0)
    1123         112 :                     add_partial_path(rel, (Path *) ipath);
    1124             :                 else
    1125         124 :                     pfree(ipath);
    1126             :             }
    1127             :         }
    1128             :     }
    1129             : 
    1130      473940 :     return result;
    1131             : }
    1132             : 
    1133             : /*
    1134             :  * build_paths_for_OR
    1135             :  *    Given a list of restriction clauses from one arm of an OR clause,
    1136             :  *    construct all matching IndexPaths for the relation.
    1137             :  *
    1138             :  * Here we must scan all indexes of the relation, since a bitmap OR tree
    1139             :  * can use multiple indexes.
    1140             :  *
    1141             :  * The caller actually supplies two lists of restriction clauses: some
    1142             :  * "current" ones and some "other" ones.  Both lists can be used freely
    1143             :  * to match keys of the index, but an index must use at least one of the
    1144             :  * "current" clauses to be considered usable.  The motivation for this is
    1145             :  * examples like
    1146             :  *      WHERE (x = 42) AND (... OR (y = 52 AND z = 77) OR ....)
    1147             :  * While we are considering the y/z subclause of the OR, we can use "x = 42"
    1148             :  * as one of the available index conditions; but we shouldn't match the
    1149             :  * subclause to any index on x alone, because such a Path would already have
    1150             :  * been generated at the upper level.  So we could use an index on x,y,z
    1151             :  * or an index on x,y for the OR subclause, but not an index on just x.
    1152             :  * When dealing with a partial index, a match of the index predicate to
    1153             :  * one of the "current" clauses also makes the index usable.
    1154             :  *
    1155             :  * 'rel' is the relation for which we want to generate index paths
    1156             :  * 'clauses' is the current list of clauses (RestrictInfo nodes)
    1157             :  * 'other_clauses' is the list of additional upper-level clauses
    1158             :  */
    1159             : static List *
    1160       15828 : build_paths_for_OR(PlannerInfo *root, RelOptInfo *rel,
    1161             :                    List *clauses, List *other_clauses)
    1162             : {
    1163       15828 :     List       *result = NIL;
    1164       15828 :     List       *all_clauses = NIL;  /* not computed till needed */
    1165             :     ListCell   *lc;
    1166             : 
    1167       55446 :     foreach(lc, rel->indexlist)
    1168             :     {
    1169       39618 :         IndexOptInfo *index = (IndexOptInfo *) lfirst(lc);
    1170             :         IndexClauseSet clauseset;
    1171             :         List       *indexpaths;
    1172             :         bool        useful_predicate;
    1173             : 
    1174             :         /* Ignore index if it doesn't support bitmap scans */
    1175       39618 :         if (!index->amhasgetbitmap)
    1176       38458 :             continue;
    1177             : 
    1178             :         /*
    1179             :          * Ignore partial indexes that do not match the query.  If a partial
    1180             :          * index is marked predOK then we know it's OK.  Otherwise, we have to
    1181             :          * test whether the added clauses are sufficient to imply the
    1182             :          * predicate. If so, we can use the index in the current context.
    1183             :          *
    1184             :          * We set useful_predicate to true iff the predicate was proven using
    1185             :          * the current set of clauses.  This is needed to prevent matching a
    1186             :          * predOK index to an arm of an OR, which would be a legal but
    1187             :          * pointlessly inefficient plan.  (A better plan will be generated by
    1188             :          * just scanning the predOK index alone, no OR.)
    1189             :          */
    1190       39618 :         useful_predicate = false;
    1191       39618 :         if (index->indpred != NIL)
    1192             :         {
    1193          96 :             if (index->predOK)
    1194             :             {
    1195             :                 /* Usable, but don't set useful_predicate */
    1196             :             }
    1197             :             else
    1198             :             {
    1199             :                 /* Form all_clauses if not done already */
    1200          80 :                 if (all_clauses == NIL)
    1201          32 :                     all_clauses = list_concat_copy(clauses, other_clauses);
    1202             : 
    1203          80 :                 if (!predicate_implied_by(index->indpred, all_clauses, false))
    1204          56 :                     continue;   /* can't use it at all */
    1205             : 
    1206          24 :                 if (!predicate_implied_by(index->indpred, other_clauses, false))
    1207          24 :                     useful_predicate = true;
    1208             :             }
    1209             :         }
    1210             : 
    1211             :         /*
    1212             :          * Identify the restriction clauses that can match the index.
    1213             :          */
    1214     1345108 :         MemSet(&clauseset, 0, sizeof(clauseset));
    1215       39562 :         match_clauses_to_index(root, clauses, index, &clauseset);
    1216             : 
    1217             :         /*
    1218             :          * If no matches so far, and the index predicate isn't useful, we
    1219             :          * don't want it.
    1220             :          */
    1221       39562 :         if (!clauseset.nonempty && !useful_predicate)
    1222       38402 :             continue;
    1223             : 
    1224             :         /*
    1225             :          * Add "other" restriction clauses to the clauseset.
    1226             :          */
    1227        1160 :         match_clauses_to_index(root, other_clauses, index, &clauseset);
    1228             : 
    1229             :         /*
    1230             :          * Construct paths if possible.
    1231             :          */
    1232        1160 :         indexpaths = build_index_paths(root, rel,
    1233             :                                        index, &clauseset,
    1234             :                                        useful_predicate,
    1235             :                                        ST_BITMAPSCAN,
    1236             :                                        NULL,
    1237             :                                        NULL);
    1238        1160 :         result = list_concat(result, indexpaths);
    1239             :     }
    1240             : 
    1241       15828 :     return result;
    1242             : }
    1243             : 
    1244             : /*
    1245             :  * generate_bitmap_or_paths
    1246             :  *      Look through the list of clauses to find OR clauses, and generate
    1247             :  *      a BitmapOrPath for each one we can handle that way.  Return a list
    1248             :  *      of the generated BitmapOrPaths.
    1249             :  *
    1250             :  * other_clauses is a list of additional clauses that can be assumed true
    1251             :  * for the purpose of generating indexquals, but are not to be searched for
    1252             :  * ORs.  (See build_paths_for_OR() for motivation.)
    1253             :  */
    1254             : static List *
    1255      395436 : generate_bitmap_or_paths(PlannerInfo *root, RelOptInfo *rel,
    1256             :                          List *clauses, List *other_clauses)
    1257             : {
    1258      395436 :     List       *result = NIL;
    1259             :     List       *all_clauses;
    1260             :     ListCell   *lc;
    1261             : 
    1262             :     /*
    1263             :      * We can use both the current and other clauses as context for
    1264             :      * build_paths_for_OR; no need to remove ORs from the lists.
    1265             :      */
    1266      395436 :     all_clauses = list_concat_copy(clauses, other_clauses);
    1267             : 
    1268      616858 :     foreach(lc, clauses)
    1269             :     {
    1270      221422 :         RestrictInfo *rinfo = lfirst_node(RestrictInfo, lc);
    1271             :         List       *pathlist;
    1272             :         Path       *bitmapqual;
    1273             :         ListCell   *j;
    1274             : 
    1275             :         /* Ignore RestrictInfos that aren't ORs */
    1276      221422 :         if (!restriction_is_or_clause(rinfo))
    1277      206208 :             continue;
    1278             : 
    1279             :         /*
    1280             :          * We must be able to match at least one index to each of the arms of
    1281             :          * the OR, else we can't use it.
    1282             :          */
    1283       15214 :         pathlist = NIL;
    1284       16250 :         foreach(j, ((BoolExpr *) rinfo->orclause)->args)
    1285             :         {
    1286       15828 :             Node       *orarg = (Node *) lfirst(j);
    1287             :             List       *indlist;
    1288             : 
    1289             :             /* OR arguments should be ANDs or sub-RestrictInfos */
    1290       15828 :             if (is_andclause(orarg))
    1291             :             {
    1292         504 :                 List       *andargs = ((BoolExpr *) orarg)->args;
    1293             : 
    1294         504 :                 indlist = build_paths_for_OR(root, rel,
    1295             :                                              andargs,
    1296             :                                              all_clauses);
    1297             : 
    1298             :                 /* Recurse in case there are sub-ORs */
    1299         504 :                 indlist = list_concat(indlist,
    1300         504 :                                       generate_bitmap_or_paths(root, rel,
    1301             :                                                                andargs,
    1302             :                                                                all_clauses));
    1303             :             }
    1304             :             else
    1305             :             {
    1306       15324 :                 RestrictInfo *rinfo = castNode(RestrictInfo, orarg);
    1307             :                 List       *orargs;
    1308             : 
    1309             :                 Assert(!restriction_is_or_clause(rinfo));
    1310       15324 :                 orargs = list_make1(rinfo);
    1311             : 
    1312       15324 :                 indlist = build_paths_for_OR(root, rel,
    1313             :                                              orargs,
    1314             :                                              all_clauses);
    1315             :             }
    1316             : 
    1317             :             /*
    1318             :              * If nothing matched this arm, we can't do anything with this OR
    1319             :              * clause.
    1320             :              */
    1321       15828 :             if (indlist == NIL)
    1322             :             {
    1323       14792 :                 pathlist = NIL;
    1324       14792 :                 break;
    1325             :             }
    1326             : 
    1327             :             /*
    1328             :              * OK, pick the most promising AND combination, and add it to
    1329             :              * pathlist.
    1330             :              */
    1331        1036 :             bitmapqual = choose_bitmap_and(root, rel, indlist);
    1332        1036 :             pathlist = lappend(pathlist, bitmapqual);
    1333             :         }
    1334             : 
    1335             :         /*
    1336             :          * If we have a match for every arm, then turn them into a
    1337             :          * BitmapOrPath, and add to result list.
    1338             :          */
    1339       15214 :         if (pathlist != NIL)
    1340             :         {
    1341         422 :             bitmapqual = (Path *) create_bitmap_or_path(root, rel, pathlist);
    1342         422 :             result = lappend(result, bitmapqual);
    1343             :         }
    1344             :     }
    1345             : 
    1346      395436 :     return result;
    1347             : }
    1348             : 
    1349             : 
    1350             : /*
    1351             :  * choose_bitmap_and
    1352             :  *      Given a nonempty list of bitmap paths, AND them into one path.
    1353             :  *
    1354             :  * This is a nontrivial decision since we can legally use any subset of the
    1355             :  * given path set.  We want to choose a good tradeoff between selectivity
    1356             :  * and cost of computing the bitmap.
    1357             :  *
    1358             :  * The result is either a single one of the inputs, or a BitmapAndPath
    1359             :  * combining multiple inputs.
    1360             :  */
    1361             : static Path *
    1362      188900 : choose_bitmap_and(PlannerInfo *root, RelOptInfo *rel, List *paths)
    1363             : {
    1364      188900 :     int         npaths = list_length(paths);
    1365             :     PathClauseUsage **pathinfoarray;
    1366             :     PathClauseUsage *pathinfo;
    1367             :     List       *clauselist;
    1368      188900 :     List       *bestpaths = NIL;
    1369      188900 :     Cost        bestcost = 0;
    1370             :     int         i,
    1371             :                 j;
    1372             :     ListCell   *l;
    1373             : 
    1374             :     Assert(npaths > 0);          /* else caller error */
    1375      188900 :     if (npaths == 1)
    1376      146784 :         return (Path *) linitial(paths);    /* easy case */
    1377             : 
    1378             :     /*
    1379             :      * In theory we should consider every nonempty subset of the given paths.
    1380             :      * In practice that seems like overkill, given the crude nature of the
    1381             :      * estimates, not to mention the possible effects of higher-level AND and
    1382             :      * OR clauses.  Moreover, it's completely impractical if there are a large
    1383             :      * number of paths, since the work would grow as O(2^N).
    1384             :      *
    1385             :      * As a heuristic, we first check for paths using exactly the same sets of
    1386             :      * WHERE clauses + index predicate conditions, and reject all but the
    1387             :      * cheapest-to-scan in any such group.  This primarily gets rid of indexes
    1388             :      * that include the interesting columns but also irrelevant columns.  (In
    1389             :      * situations where the DBA has gone overboard on creating variant
    1390             :      * indexes, this can make for a very large reduction in the number of
    1391             :      * paths considered further.)
    1392             :      *
    1393             :      * We then sort the surviving paths with the cheapest-to-scan first, and
    1394             :      * for each path, consider using that path alone as the basis for a bitmap
    1395             :      * scan.  Then we consider bitmap AND scans formed from that path plus
    1396             :      * each subsequent (higher-cost) path, adding on a subsequent path if it
    1397             :      * results in a reduction in the estimated total scan cost. This means we
    1398             :      * consider about O(N^2) rather than O(2^N) path combinations, which is
    1399             :      * quite tolerable, especially given than N is usually reasonably small
    1400             :      * because of the prefiltering step.  The cheapest of these is returned.
    1401             :      *
    1402             :      * We will only consider AND combinations in which no two indexes use the
    1403             :      * same WHERE clause.  This is a bit of a kluge: it's needed because
    1404             :      * costsize.c and clausesel.c aren't very smart about redundant clauses.
    1405             :      * They will usually double-count the redundant clauses, producing a
    1406             :      * too-small selectivity that makes a redundant AND step look like it
    1407             :      * reduces the total cost.  Perhaps someday that code will be smarter and
    1408             :      * we can remove this limitation.  (But note that this also defends
    1409             :      * against flat-out duplicate input paths, which can happen because
    1410             :      * match_join_clauses_to_index will find the same OR join clauses that
    1411             :      * extract_restriction_or_clauses has pulled OR restriction clauses out
    1412             :      * of.)
    1413             :      *
    1414             :      * For the same reason, we reject AND combinations in which an index
    1415             :      * predicate clause duplicates another clause.  Here we find it necessary
    1416             :      * to be even stricter: we'll reject a partial index if any of its
    1417             :      * predicate clauses are implied by the set of WHERE clauses and predicate
    1418             :      * clauses used so far.  This covers cases such as a condition "x = 42"
    1419             :      * used with a plain index, followed by a clauseless scan of a partial
    1420             :      * index "WHERE x >= 40 AND x < 50".  The partial index has been accepted
    1421             :      * only because "x = 42" was present, and so allowing it would partially
    1422             :      * double-count selectivity.  (We could use predicate_implied_by on
    1423             :      * regular qual clauses too, to have a more intelligent, but much more
    1424             :      * expensive, check for redundancy --- but in most cases simple equality
    1425             :      * seems to suffice.)
    1426             :      */
    1427             : 
    1428             :     /*
    1429             :      * Extract clause usage info and detect any paths that use exactly the
    1430             :      * same set of clauses; keep only the cheapest-to-scan of any such groups.
    1431             :      * The surviving paths are put into an array for qsort'ing.
    1432             :      */
    1433             :     pathinfoarray = (PathClauseUsage **)
    1434       42116 :         palloc(npaths * sizeof(PathClauseUsage *));
    1435       42116 :     clauselist = NIL;
    1436       42116 :     npaths = 0;
    1437      131898 :     foreach(l, paths)
    1438             :     {
    1439       89782 :         Path       *ipath = (Path *) lfirst(l);
    1440             : 
    1441       89782 :         pathinfo = classify_index_clause_usage(ipath, &clauselist);
    1442             : 
    1443             :         /* If it's unclassifiable, treat it as distinct from all others */
    1444       89782 :         if (pathinfo->unclassifiable)
    1445             :         {
    1446           0 :             pathinfoarray[npaths++] = pathinfo;
    1447           0 :             continue;
    1448             :         }
    1449             : 
    1450      133788 :         for (i = 0; i < npaths; i++)
    1451             :         {
    1452      106248 :             if (!pathinfoarray[i]->unclassifiable &&
    1453       53124 :                 bms_equal(pathinfo->clauseids, pathinfoarray[i]->clauseids))
    1454        9118 :                 break;
    1455             :         }
    1456       89782 :         if (i < npaths)
    1457             :         {
    1458             :             /* duplicate clauseids, keep the cheaper one */
    1459             :             Cost        ncost;
    1460             :             Cost        ocost;
    1461             :             Selectivity nselec;
    1462             :             Selectivity oselec;
    1463             : 
    1464        9118 :             cost_bitmap_tree_node(pathinfo->path, &ncost, &nselec);
    1465        9118 :             cost_bitmap_tree_node(pathinfoarray[i]->path, &ocost, &oselec);
    1466        9118 :             if (ncost < ocost)
    1467         670 :                 pathinfoarray[i] = pathinfo;
    1468             :         }
    1469             :         else
    1470             :         {
    1471             :             /* not duplicate clauseids, add to array */
    1472       80664 :             pathinfoarray[npaths++] = pathinfo;
    1473             :         }
    1474             :     }
    1475             : 
    1476             :     /* If only one surviving path, we're done */
    1477       42116 :     if (npaths == 1)
    1478        7070 :         return pathinfoarray[0]->path;
    1479             : 
    1480             :     /* Sort the surviving paths by index access cost */
    1481       35046 :     qsort(pathinfoarray, npaths, sizeof(PathClauseUsage *),
    1482             :           path_usage_comparator);
    1483             : 
    1484             :     /*
    1485             :      * For each surviving index, consider it as an "AND group leader", and see
    1486             :      * whether adding on any of the later indexes results in an AND path with
    1487             :      * cheaper total cost than before.  Then take the cheapest AND group.
    1488             :      *
    1489             :      * Note: paths that are either clauseless or unclassifiable will have
    1490             :      * empty clauseids, so that they will not be rejected by the clauseids
    1491             :      * filter here, nor will they cause later paths to be rejected by it.
    1492             :      */
    1493      108640 :     for (i = 0; i < npaths; i++)
    1494             :     {
    1495             :         Cost        costsofar;
    1496             :         List       *qualsofar;
    1497             :         Bitmapset  *clauseidsofar;
    1498             : 
    1499       73594 :         pathinfo = pathinfoarray[i];
    1500       73594 :         paths = list_make1(pathinfo->path);
    1501       73594 :         costsofar = bitmap_scan_cost_est(root, rel, pathinfo->path);
    1502       73594 :         qualsofar = list_concat_copy(pathinfo->quals, pathinfo->preds);
    1503       73594 :         clauseidsofar = bms_copy(pathinfo->clauseids);
    1504             : 
    1505      115928 :         for (j = i + 1; j < npaths; j++)
    1506             :         {
    1507             :             Cost        newcost;
    1508             : 
    1509       42334 :             pathinfo = pathinfoarray[j];
    1510             :             /* Check for redundancy */
    1511       42334 :             if (bms_overlap(pathinfo->clauseids, clauseidsofar))
    1512       22736 :                 continue;       /* consider it redundant */
    1513       19598 :             if (pathinfo->preds)
    1514             :             {
    1515           8 :                 bool        redundant = false;
    1516             : 
    1517             :                 /* we check each predicate clause separately */
    1518           8 :                 foreach(l, pathinfo->preds)
    1519             :                 {
    1520           8 :                     Node       *np = (Node *) lfirst(l);
    1521             : 
    1522           8 :                     if (predicate_implied_by(list_make1(np), qualsofar, false))
    1523             :                     {
    1524           8 :                         redundant = true;
    1525           8 :                         break;  /* out of inner foreach loop */
    1526             :                     }
    1527             :                 }
    1528           8 :                 if (redundant)
    1529           8 :                     continue;
    1530             :             }
    1531             :             /* tentatively add new path to paths, so we can estimate cost */
    1532       19590 :             paths = lappend(paths, pathinfo->path);
    1533       19590 :             newcost = bitmap_and_cost_est(root, rel, paths);
    1534       19590 :             if (newcost < costsofar)
    1535             :             {
    1536             :                 /* keep new path in paths, update subsidiary variables */
    1537         364 :                 costsofar = newcost;
    1538         364 :                 qualsofar = list_concat(qualsofar, pathinfo->quals);
    1539         364 :                 qualsofar = list_concat(qualsofar, pathinfo->preds);
    1540         364 :                 clauseidsofar = bms_add_members(clauseidsofar,
    1541         364 :                                                 pathinfo->clauseids);
    1542             :             }
    1543             :             else
    1544             :             {
    1545             :                 /* reject new path, remove it from paths list */
    1546       19226 :                 paths = list_truncate(paths, list_length(paths) - 1);
    1547             :             }
    1548             :         }
    1549             : 
    1550             :         /* Keep the cheapest AND-group (or singleton) */
    1551       73594 :         if (i == 0 || costsofar < bestcost)
    1552             :         {
    1553       36548 :             bestpaths = paths;
    1554       36548 :             bestcost = costsofar;
    1555             :         }
    1556             : 
    1557             :         /* some easy cleanup (we don't try real hard though) */
    1558       73594 :         list_free(qualsofar);
    1559             :     }
    1560             : 
    1561       35046 :     if (list_length(bestpaths) == 1)
    1562       34978 :         return (Path *) linitial(bestpaths);    /* no need for AND */
    1563          68 :     return (Path *) create_bitmap_and_path(root, rel, bestpaths);
    1564             : }
    1565             : 
    1566             : /* qsort comparator to sort in increasing index access cost order */
    1567             : static int
    1568       41296 : path_usage_comparator(const void *a, const void *b)
    1569             : {
    1570       41296 :     PathClauseUsage *pa = *(PathClauseUsage *const *) a;
    1571       41296 :     PathClauseUsage *pb = *(PathClauseUsage *const *) b;
    1572             :     Cost        acost;
    1573             :     Cost        bcost;
    1574             :     Selectivity aselec;
    1575             :     Selectivity bselec;
    1576             : 
    1577       41296 :     cost_bitmap_tree_node(pa->path, &acost, &aselec);
    1578       41296 :     cost_bitmap_tree_node(pb->path, &bcost, &bselec);
    1579             : 
    1580             :     /*
    1581             :      * If costs are the same, sort by selectivity.
    1582             :      */
    1583       41296 :     if (acost < bcost)
    1584       23874 :         return -1;
    1585       17422 :     if (acost > bcost)
    1586       13870 :         return 1;
    1587             : 
    1588        3552 :     if (aselec < bselec)
    1589        2768 :         return -1;
    1590         784 :     if (aselec > bselec)
    1591          18 :         return 1;
    1592             : 
    1593         766 :     return 0;
    1594             : }
    1595             : 
    1596             : /*
    1597             :  * Estimate the cost of actually executing a bitmap scan with a single
    1598             :  * index path (which could be a BitmapAnd or BitmapOr node).
    1599             :  */
    1600             : static Cost
    1601       93184 : bitmap_scan_cost_est(PlannerInfo *root, RelOptInfo *rel, Path *ipath)
    1602             : {
    1603             :     BitmapHeapPath bpath;
    1604             : 
    1605             :     /* Set up a dummy BitmapHeapPath */
    1606       93184 :     bpath.path.type = T_BitmapHeapPath;
    1607       93184 :     bpath.path.pathtype = T_BitmapHeapScan;
    1608       93184 :     bpath.path.parent = rel;
    1609       93184 :     bpath.path.pathtarget = rel->reltarget;
    1610       93184 :     bpath.path.param_info = ipath->param_info;
    1611       93184 :     bpath.path.pathkeys = NIL;
    1612       93184 :     bpath.bitmapqual = ipath;
    1613             : 
    1614             :     /*
    1615             :      * Check the cost of temporary path without considering parallelism.
    1616             :      * Parallel bitmap heap path will be considered at later stage.
    1617             :      */
    1618       93184 :     bpath.path.parallel_workers = 0;
    1619             : 
    1620             :     /* Now we can do cost_bitmap_heap_scan */
    1621       93184 :     cost_bitmap_heap_scan(&bpath.path, root, rel,
    1622             :                           bpath.path.param_info,
    1623             :                           ipath,
    1624             :                           get_loop_count(root, rel->relid,
    1625       93184 :                                          PATH_REQ_OUTER(ipath)));
    1626             : 
    1627       93184 :     return bpath.path.total_cost;
    1628             : }
    1629             : 
    1630             : /*
    1631             :  * Estimate the cost of actually executing a BitmapAnd scan with the given
    1632             :  * inputs.
    1633             :  */
    1634             : static Cost
    1635       19590 : bitmap_and_cost_est(PlannerInfo *root, RelOptInfo *rel, List *paths)
    1636             : {
    1637             :     BitmapAndPath *apath;
    1638             : 
    1639             :     /*
    1640             :      * Might as well build a real BitmapAndPath here, as the work is slightly
    1641             :      * too complicated to be worth repeating just to save one palloc.
    1642             :      */
    1643       19590 :     apath = create_bitmap_and_path(root, rel, paths);
    1644             : 
    1645       19590 :     return bitmap_scan_cost_est(root, rel, (Path *) apath);
    1646             : }
    1647             : 
    1648             : 
    1649             : /*
    1650             :  * classify_index_clause_usage
    1651             :  *      Construct a PathClauseUsage struct describing the WHERE clauses and
    1652             :  *      index predicate clauses used by the given indexscan path.
    1653             :  *      We consider two clauses the same if they are equal().
    1654             :  *
    1655             :  * At some point we might want to migrate this info into the Path data
    1656             :  * structure proper, but for the moment it's only needed within
    1657             :  * choose_bitmap_and().
    1658             :  *
    1659             :  * *clauselist is used and expanded as needed to identify all the distinct
    1660             :  * clauses seen across successive calls.  Caller must initialize it to NIL
    1661             :  * before first call of a set.
    1662             :  */
    1663             : static PathClauseUsage *
    1664       89782 : classify_index_clause_usage(Path *path, List **clauselist)
    1665             : {
    1666             :     PathClauseUsage *result;
    1667             :     Bitmapset  *clauseids;
    1668             :     ListCell   *lc;
    1669             : 
    1670       89782 :     result = (PathClauseUsage *) palloc(sizeof(PathClauseUsage));
    1671       89782 :     result->path = path;
    1672             : 
    1673             :     /* Recursively find the quals and preds used by the path */
    1674       89782 :     result->quals = NIL;
    1675       89782 :     result->preds = NIL;
    1676       89782 :     find_indexpath_quals(path, &result->quals, &result->preds);
    1677             : 
    1678             :     /*
    1679             :      * Some machine-generated queries have outlandish numbers of qual clauses.
    1680             :      * To avoid getting into O(N^2) behavior even in this preliminary
    1681             :      * classification step, we want to limit the number of entries we can
    1682             :      * accumulate in *clauselist.  Treat any path with more than 100 quals +
    1683             :      * preds as unclassifiable, which will cause calling code to consider it
    1684             :      * distinct from all other paths.
    1685             :      */
    1686       89782 :     if (list_length(result->quals) + list_length(result->preds) > 100)
    1687             :     {
    1688           0 :         result->clauseids = NULL;
    1689           0 :         result->unclassifiable = true;
    1690           0 :         return result;
    1691             :     }
    1692             : 
    1693             :     /* Build up a bitmapset representing the quals and preds */
    1694       89782 :     clauseids = NULL;
    1695      218848 :     foreach(lc, result->quals)
    1696             :     {
    1697      129066 :         Node       *node = (Node *) lfirst(lc);
    1698             : 
    1699      129066 :         clauseids = bms_add_member(clauseids,
    1700             :                                    find_list_position(node, clauselist));
    1701             :     }
    1702       89958 :     foreach(lc, result->preds)
    1703             :     {
    1704         176 :         Node       *node = (Node *) lfirst(lc);
    1705             : 
    1706         176 :         clauseids = bms_add_member(clauseids,
    1707             :                                    find_list_position(node, clauselist));
    1708             :     }
    1709       89782 :     result->clauseids = clauseids;
    1710       89782 :     result->unclassifiable = false;
    1711             : 
    1712       89782 :     return result;
    1713             : }
    1714             : 
    1715             : 
    1716             : /*
    1717             :  * find_indexpath_quals
    1718             :  *
    1719             :  * Given the Path structure for a plain or bitmap indexscan, extract lists
    1720             :  * of all the index clauses and index predicate conditions used in the Path.
    1721             :  * These are appended to the initial contents of *quals and *preds (hence
    1722             :  * caller should initialize those to NIL).
    1723             :  *
    1724             :  * Note we are not trying to produce an accurate representation of the AND/OR
    1725             :  * semantics of the Path, but just find out all the base conditions used.
    1726             :  *
    1727             :  * The result lists contain pointers to the expressions used in the Path,
    1728             :  * but all the list cells are freshly built, so it's safe to destructively
    1729             :  * modify the lists (eg, by concat'ing with other lists).
    1730             :  */
    1731             : static void
    1732       90846 : find_indexpath_quals(Path *bitmapqual, List **quals, List **preds)
    1733             : {
    1734       90846 :     if (IsA(bitmapqual, BitmapAndPath))
    1735             :     {
    1736           0 :         BitmapAndPath *apath = (BitmapAndPath *) bitmapqual;
    1737             :         ListCell   *l;
    1738             : 
    1739           0 :         foreach(l, apath->bitmapquals)
    1740             :         {
    1741           0 :             find_indexpath_quals((Path *) lfirst(l), quals, preds);
    1742             :         }
    1743             :     }
    1744       90846 :     else if (IsA(bitmapqual, BitmapOrPath))
    1745             :     {
    1746         510 :         BitmapOrPath *opath = (BitmapOrPath *) bitmapqual;
    1747             :         ListCell   *l;
    1748             : 
    1749        1574 :         foreach(l, opath->bitmapquals)
    1750             :         {
    1751        1064 :             find_indexpath_quals((Path *) lfirst(l), quals, preds);
    1752             :         }
    1753             :     }
    1754       90336 :     else if (IsA(bitmapqual, IndexPath))
    1755             :     {
    1756       90336 :         IndexPath  *ipath = (IndexPath *) bitmapqual;
    1757             :         ListCell   *l;
    1758             : 
    1759      219402 :         foreach(l, ipath->indexclauses)
    1760             :         {
    1761      129066 :             IndexClause *iclause = (IndexClause *) lfirst(l);
    1762             : 
    1763      129066 :             *quals = lappend(*quals, iclause->rinfo->clause);
    1764             :         }
    1765       90336 :         *preds = list_concat(*preds, ipath->indexinfo->indpred);
    1766             :     }
    1767             :     else
    1768           0 :         elog(ERROR, "unrecognized node type: %d", nodeTag(bitmapqual));
    1769       90846 : }
    1770             : 
    1771             : 
    1772             : /*
    1773             :  * find_list_position
    1774             :  *      Return the given node's position (counting from 0) in the given
    1775             :  *      list of nodes.  If it's not equal() to any existing list member,
    1776             :  *      add it at the end, and return that position.
    1777             :  */
    1778             : static int
    1779      129242 : find_list_position(Node *node, List **nodelist)
    1780             : {
    1781             :     int         i;
    1782             :     ListCell   *lc;
    1783             : 
    1784      129242 :     i = 0;
    1785      221518 :     foreach(lc, *nodelist)
    1786             :     {
    1787      126808 :         Node       *oldnode = (Node *) lfirst(lc);
    1788             : 
    1789      126808 :         if (equal(node, oldnode))
    1790       34532 :             return i;
    1791       92276 :         i++;
    1792             :     }
    1793             : 
    1794       94710 :     *nodelist = lappend(*nodelist, node);
    1795             : 
    1796       94710 :     return i;
    1797             : }
    1798             : 
    1799             : 
    1800             : /*
    1801             :  * check_index_only
    1802             :  *      Determine whether an index-only scan is possible for this index.
    1803             :  */
    1804             : static bool
    1805      472760 : check_index_only(RelOptInfo *rel, IndexOptInfo *index)
    1806             : {
    1807             :     bool        result;
    1808      472760 :     Bitmapset  *attrs_used = NULL;
    1809      472760 :     Bitmapset  *index_canreturn_attrs = NULL;
    1810      472760 :     Bitmapset  *index_cannotreturn_attrs = NULL;
    1811             :     ListCell   *lc;
    1812             :     int         i;
    1813             : 
    1814             :     /* Index-only scans must be enabled */
    1815      472760 :     if (!enable_indexonlyscan)
    1816        2008 :         return false;
    1817             : 
    1818             :     /*
    1819             :      * Check that all needed attributes of the relation are available from the
    1820             :      * index.
    1821             :      */
    1822             : 
    1823             :     /*
    1824             :      * First, identify all the attributes needed for joins or final output.
    1825             :      * Note: we must look at rel's targetlist, not the attr_needed data,
    1826             :      * because attr_needed isn't computed for inheritance child rels.
    1827             :      */
    1828      470752 :     pull_varattnos((Node *) rel->reltarget->exprs, rel->relid, &attrs_used);
    1829             : 
    1830             :     /*
    1831             :      * Add all the attributes used by restriction clauses; but consider only
    1832             :      * those clauses not implied by the index predicate, since ones that are
    1833             :      * so implied don't need to be checked explicitly in the plan.
    1834             :      *
    1835             :      * Note: attributes used only in index quals would not be needed at
    1836             :      * runtime either, if we are certain that the index is not lossy.  However
    1837             :      * it'd be complicated to account for that accurately, and it doesn't
    1838             :      * matter in most cases, since we'd conclude that such attributes are
    1839             :      * available from the index anyway.
    1840             :      */
    1841      960106 :     foreach(lc, index->indrestrictinfo)
    1842             :     {
    1843      489354 :         RestrictInfo *rinfo = (RestrictInfo *) lfirst(lc);
    1844             : 
    1845      489354 :         pull_varattnos((Node *) rinfo->clause, rel->relid, &attrs_used);
    1846             :     }
    1847             : 
    1848             :     /*
    1849             :      * Construct a bitmapset of columns that the index can return back in an
    1850             :      * index-only scan.  If there are multiple index columns containing the
    1851             :      * same attribute, all of them must be capable of returning the value,
    1852             :      * since we might recheck operators on any of them.  (Potentially we could
    1853             :      * be smarter about that, but it's such a weird situation that it doesn't
    1854             :      * seem worth spending a lot of sweat on.)
    1855             :      */
    1856     1315578 :     for (i = 0; i < index->ncolumns; i++)
    1857             :     {
    1858      844826 :         int         attno = index->indexkeys[i];
    1859             : 
    1860             :         /*
    1861             :          * For the moment, we just ignore index expressions.  It might be nice
    1862             :          * to do something with them, later.
    1863             :          */
    1864      844826 :         if (attno == 0)
    1865        1860 :             continue;
    1866             : 
    1867      842966 :         if (index->canreturn[i])
    1868             :             index_canreturn_attrs =
    1869      720250 :                 bms_add_member(index_canreturn_attrs,
    1870             :                                attno - FirstLowInvalidHeapAttributeNumber);
    1871             :         else
    1872             :             index_cannotreturn_attrs =
    1873      122716 :                 bms_add_member(index_cannotreturn_attrs,
    1874             :                                attno - FirstLowInvalidHeapAttributeNumber);
    1875             :     }
    1876             : 
    1877      470752 :     index_canreturn_attrs = bms_del_members(index_canreturn_attrs,
    1878             :                                             index_cannotreturn_attrs);
    1879             : 
    1880             :     /* Do we have all the necessary attributes? */
    1881      470752 :     result = bms_is_subset(attrs_used, index_canreturn_attrs);
    1882             : 
    1883      470752 :     bms_free(attrs_used);
    1884      470752 :     bms_free(index_canreturn_attrs);
    1885      470752 :     bms_free(index_cannotreturn_attrs);
    1886             : 
    1887      470752 :     return result;
    1888             : }
    1889             : 
    1890             : /*
    1891             :  * get_loop_count
    1892             :  *      Choose the loop count estimate to use for costing a parameterized path
    1893             :  *      with the given set of outer relids.
    1894             :  *
    1895             :  * Since we produce parameterized paths before we've begun to generate join
    1896             :  * relations, it's impossible to predict exactly how many times a parameterized
    1897             :  * path will be iterated; we don't know the size of the relation that will be
    1898             :  * on the outside of the nestloop.  However, we should try to account for
    1899             :  * multiple iterations somehow in costing the path.  The heuristic embodied
    1900             :  * here is to use the rowcount of the smallest other base relation needed in
    1901             :  * the join clauses used by the path.  (We could alternatively consider the
    1902             :  * largest one, but that seems too optimistic.)  This is of course the right
    1903             :  * answer for single-other-relation cases, and it seems like a reasonable
    1904             :  * zero-order approximation for multiway-join cases.
    1905             :  *
    1906             :  * In addition, we check to see if the other side of each join clause is on
    1907             :  * the inside of some semijoin that the current relation is on the outside of.
    1908             :  * If so, the only way that a parameterized path could be used is if the
    1909             :  * semijoin RHS has been unique-ified, so we should use the number of unique
    1910             :  * RHS rows rather than using the relation's raw rowcount.
    1911             :  *
    1912             :  * Note: for this to work, allpaths.c must establish all baserel size
    1913             :  * estimates before it begins to compute paths, or at least before it
    1914             :  * calls create_index_paths().
    1915             :  */
    1916             : static double
    1917      629396 : get_loop_count(PlannerInfo *root, Index cur_relid, Relids outer_relids)
    1918             : {
    1919             :     double      result;
    1920             :     int         outer_relid;
    1921             : 
    1922             :     /* For a non-parameterized path, just return 1.0 quickly */
    1923      629396 :     if (outer_relids == NULL)
    1924      474726 :         return 1.0;
    1925             : 
    1926      154670 :     result = 0.0;
    1927      154670 :     outer_relid = -1;
    1928      310108 :     while ((outer_relid = bms_next_member(outer_relids, outer_relid)) >= 0)
    1929             :     {
    1930             :         RelOptInfo *outer_rel;
    1931             :         double      rowcount;
    1932             : 
    1933             :         /* Paranoia: ignore bogus relid indexes */
    1934      155438 :         if (outer_relid >= root->simple_rel_array_size)
    1935           0 :             continue;
    1936      155438 :         outer_rel = root->simple_rel_array[outer_relid];
    1937      155438 :         if (outer_rel == NULL)
    1938           0 :             continue;
    1939             :         Assert(outer_rel->relid == outer_relid); /* sanity check on array */
    1940             : 
    1941             :         /* Other relation could be proven empty, if so ignore */
    1942      155438 :         if (IS_DUMMY_REL(outer_rel))
    1943          16 :             continue;
    1944             : 
    1945             :         /* Otherwise, rel's rows estimate should be valid by now */
    1946             :         Assert(outer_rel->rows > 0);
    1947             : 
    1948             :         /* Check to see if rel is on the inside of any semijoins */
    1949      155422 :         rowcount = adjust_rowcount_for_semijoins(root,
    1950             :                                                  cur_relid,
    1951             :                                                  outer_relid,
    1952             :                                                  outer_rel->rows);
    1953             : 
    1954             :         /* Remember smallest row count estimate among the outer rels */
    1955      155422 :         if (result == 0.0 || result > rowcount)
    1956      154962 :             result = rowcount;
    1957             :     }
    1958             :     /* Return 1.0 if we found no valid relations (shouldn't happen) */
    1959      154670 :     return (result > 0.0) ? result : 1.0;
    1960             : }
    1961             : 
    1962             : /*
    1963             :  * Check to see if outer_relid is on the inside of any semijoin that cur_relid
    1964             :  * is on the outside of.  If so, replace rowcount with the estimated number of
    1965             :  * unique rows from the semijoin RHS (assuming that's smaller, which it might
    1966             :  * not be).  The estimate is crude but it's the best we can do at this stage
    1967             :  * of the proceedings.
    1968             :  */
    1969             : static double
    1970      155422 : adjust_rowcount_for_semijoins(PlannerInfo *root,
    1971             :                               Index cur_relid,
    1972             :                               Index outer_relid,
    1973             :                               double rowcount)
    1974             : {
    1975             :     ListCell   *lc;
    1976             : 
    1977      278766 :     foreach(lc, root->join_info_list)
    1978             :     {
    1979      123344 :         SpecialJoinInfo *sjinfo = (SpecialJoinInfo *) lfirst(lc);
    1980             : 
    1981      125800 :         if (sjinfo->jointype == JOIN_SEMI &&
    1982        2832 :             bms_is_member(cur_relid, sjinfo->syn_lefthand) &&
    1983         376 :             bms_is_member(outer_relid, sjinfo->syn_righthand))
    1984             :         {
    1985             :             /* Estimate number of unique-ified rows */
    1986             :             double      nraw;
    1987             :             double      nunique;
    1988             : 
    1989         288 :             nraw = approximate_joinrel_size(root, sjinfo->syn_righthand);
    1990         288 :             nunique = estimate_num_groups(root,
    1991             :                                           sjinfo->semi_rhs_exprs,
    1992             :                                           nraw,
    1993             :                                           NULL);
    1994         288 :             if (rowcount > nunique)
    1995         148 :                 rowcount = nunique;
    1996             :         }
    1997             :     }
    1998      155422 :     return rowcount;
    1999             : }
    2000             : 
    2001             : /*
    2002             :  * Make an approximate estimate of the size of a joinrel.
    2003             :  *
    2004             :  * We don't have enough info at this point to get a good estimate, so we
    2005             :  * just multiply the base relation sizes together.  Fortunately, this is
    2006             :  * the right answer anyway for the most common case with a single relation
    2007             :  * on the RHS of a semijoin.  Also, estimate_num_groups() has only a weak
    2008             :  * dependency on its input_rows argument (it basically uses it as a clamp).
    2009             :  * So we might be able to get a fairly decent end result even with a severe
    2010             :  * overestimate of the RHS's raw size.
    2011             :  */
    2012             : static double
    2013         288 : approximate_joinrel_size(PlannerInfo *root, Relids relids)
    2014             : {
    2015         288 :     double      rowcount = 1.0;
    2016             :     int         relid;
    2017             : 
    2018         288 :     relid = -1;
    2019         632 :     while ((relid = bms_next_member(relids, relid)) >= 0)
    2020             :     {
    2021             :         RelOptInfo *rel;
    2022             : 
    2023             :         /* Paranoia: ignore bogus relid indexes */
    2024         344 :         if (relid >= root->simple_rel_array_size)
    2025           0 :             continue;
    2026         344 :         rel = root->simple_rel_array[relid];
    2027         344 :         if (rel == NULL)
    2028           0 :             continue;
    2029             :         Assert(rel->relid == relid); /* sanity check on array */
    2030             : 
    2031             :         /* Relation could be proven empty, if so ignore */
    2032         344 :         if (IS_DUMMY_REL(rel))
    2033           0 :             continue;
    2034             : 
    2035             :         /* Otherwise, rel's rows estimate should be valid by now */
    2036             :         Assert(rel->rows > 0);
    2037             : 
    2038             :         /* Accumulate product */
    2039         344 :         rowcount *= rel->rows;
    2040             :     }
    2041         288 :     return rowcount;
    2042             : }
    2043             : 
    2044             : 
    2045             : /****************************************************************************
    2046             :  *              ----  ROUTINES TO CHECK QUERY CLAUSES  ----
    2047             :  ****************************************************************************/
    2048             : 
    2049             : /*
    2050             :  * match_restriction_clauses_to_index
    2051             :  *    Identify restriction clauses for the rel that match the index.
    2052             :  *    Matching clauses are added to *clauseset.
    2053             :  */
    2054             : static void
    2055      408800 : match_restriction_clauses_to_index(PlannerInfo *root,
    2056             :                                    IndexOptInfo *index,
    2057             :                                    IndexClauseSet *clauseset)
    2058             : {
    2059             :     /* We can ignore clauses that are implied by the index predicate */
    2060      408800 :     match_clauses_to_index(root, index->indrestrictinfo, index, clauseset);
    2061      408800 : }
    2062             : 
    2063             : /*
    2064             :  * match_join_clauses_to_index
    2065             :  *    Identify join clauses for the rel that match the index.
    2066             :  *    Matching clauses are added to *clauseset.
    2067             :  *    Also, add any potentially usable join OR clauses to *joinorclauses.
    2068             :  */
    2069             : static void
    2070      408800 : match_join_clauses_to_index(PlannerInfo *root,
    2071             :                             RelOptInfo *rel, IndexOptInfo *index,
    2072             :                             IndexClauseSet *clauseset,
    2073             :                             List **joinorclauses)
    2074             : {
    2075             :     ListCell   *lc;
    2076             : 
    2077             :     /* Scan the rel's join clauses */
    2078      556666 :     foreach(lc, rel->joininfo)
    2079             :     {
    2080      147866 :         RestrictInfo *rinfo = (RestrictInfo *) lfirst(lc);
    2081             : 
    2082             :         /* Check if clause can be moved to this rel */
    2083      147866 :         if (!join_clause_is_movable_to(rinfo, rel))
    2084       69086 :             continue;
    2085             : 
    2086             :         /* Potentially usable, so see if it matches the index or is an OR */
    2087       78780 :         if (restriction_is_or_clause(rinfo))
    2088       14072 :             *joinorclauses = lappend(*joinorclauses, rinfo);
    2089             :         else
    2090       64708 :             match_clause_to_index(root, rinfo, index, clauseset);
    2091             :     }
    2092      408800 : }
    2093             : 
    2094             : /*
    2095             :  * match_eclass_clauses_to_index
    2096             :  *    Identify EquivalenceClass join clauses for the rel that match the index.
    2097             :  *    Matching clauses are added to *clauseset.
    2098             :  */
    2099             : static void
    2100      408800 : match_eclass_clauses_to_index(PlannerInfo *root, IndexOptInfo *index,
    2101             :                               IndexClauseSet *clauseset)
    2102             : {
    2103             :     int         indexcol;
    2104             : 
    2105             :     /* No work if rel is not in any such ECs */
    2106      408800 :     if (!index->rel->has_eclass_joins)
    2107      313664 :         return;
    2108             : 
    2109      251138 :     for (indexcol = 0; indexcol < index->nkeycolumns; indexcol++)
    2110             :     {
    2111             :         ec_member_matches_arg arg;
    2112             :         List       *clauses;
    2113             : 
    2114             :         /* Generate clauses, skipping any that join to lateral_referencers */
    2115      156002 :         arg.index = index;
    2116      156002 :         arg.indexcol = indexcol;
    2117      156002 :         clauses = generate_implied_equalities_for_column(root,
    2118             :                                                          index->rel,
    2119             :                                                          ec_member_matches_indexcol,
    2120             :                                                          (void *) &arg,
    2121      156002 :                                                          index->rel->lateral_referencers);
    2122             : 
    2123             :         /*
    2124             :          * We have to check whether the results actually do match the index,
    2125             :          * since for non-btree indexes the EC's equality operators might not
    2126             :          * be in the index opclass (cf ec_member_matches_indexcol).
    2127             :          */
    2128      156002 :         match_clauses_to_index(root, clauses, index, clauseset);
    2129             :     }
    2130             : }
    2131             : 
    2132             : /*
    2133             :  * match_clauses_to_index
    2134             :  *    Perform match_clause_to_index() for each clause in a list.
    2135             :  *    Matching clauses are added to *clauseset.
    2136             :  */
    2137             : static void
    2138      605524 : match_clauses_to_index(PlannerInfo *root,
    2139             :                        List *clauses,
    2140             :                        IndexOptInfo *index,
    2141             :                        IndexClauseSet *clauseset)
    2142             : {
    2143             :     ListCell   *lc;
    2144             : 
    2145     1133334 :     foreach(lc, clauses)
    2146             :     {
    2147      527810 :         RestrictInfo *rinfo = lfirst_node(RestrictInfo, lc);
    2148             : 
    2149      527810 :         match_clause_to_index(root, rinfo, index, clauseset);
    2150             :     }
    2151      605524 : }
    2152             : 
    2153             : /*
    2154             :  * match_clause_to_index
    2155             :  *    Test whether a qual clause can be used with an index.
    2156             :  *
    2157             :  * If the clause is usable, add an IndexClause entry for it to the appropriate
    2158             :  * list in *clauseset.  (*clauseset must be initialized to zeroes before first
    2159             :  * call.)
    2160             :  *
    2161             :  * Note: in some circumstances we may find the same RestrictInfos coming from
    2162             :  * multiple places.  Defend against redundant outputs by refusing to add a
    2163             :  * clause twice (pointer equality should be a good enough check for this).
    2164             :  *
    2165             :  * Note: it's possible that a badly-defined index could have multiple matching
    2166             :  * columns.  We always select the first match if so; this avoids scenarios
    2167             :  * wherein we get an inflated idea of the index's selectivity by using the
    2168             :  * same clause multiple times with different index columns.
    2169             :  */
    2170             : static void
    2171      592518 : match_clause_to_index(PlannerInfo *root,
    2172             :                       RestrictInfo *rinfo,
    2173             :                       IndexOptInfo *index,
    2174             :                       IndexClauseSet *clauseset)
    2175             : {
    2176             :     int         indexcol;
    2177             : 
    2178             :     /*
    2179             :      * Never match pseudoconstants to indexes.  (Normally a match could not
    2180             :      * happen anyway, since a pseudoconstant clause couldn't contain a Var,
    2181             :      * but what if someone builds an expression index on a constant? It's not
    2182             :      * totally unreasonable to do so with a partial index, either.)
    2183             :      */
    2184      592518 :     if (rinfo->pseudoconstant)
    2185        5564 :         return;
    2186             : 
    2187             :     /*
    2188             :      * If clause can't be used as an indexqual because it must wait till after
    2189             :      * some lower-security-level restriction clause, reject it.
    2190             :      */
    2191      586954 :     if (!restriction_is_securely_promotable(rinfo, index->rel))
    2192         524 :         return;
    2193             : 
    2194             :     /* OK, check each index key column for a match */
    2195     1280516 :     for (indexcol = 0; indexcol < index->nkeycolumns; indexcol++)
    2196             :     {
    2197             :         IndexClause *iclause;
    2198             :         ListCell   *lc;
    2199             : 
    2200             :         /* Ignore duplicates */
    2201      983234 :         foreach(lc, clauseset->indexclauses[indexcol])
    2202             :         {
    2203       54064 :             IndexClause *iclause = (IndexClause *) lfirst(lc);
    2204             : 
    2205       54064 :             if (iclause->rinfo == rinfo)
    2206           0 :                 return;
    2207             :         }
    2208             : 
    2209             :         /* OK, try to match the clause to the index column */
    2210      929170 :         iclause = match_clause_to_indexcol(root,
    2211             :                                            rinfo,
    2212             :                                            indexcol,
    2213             :                                            index);
    2214      929170 :         if (iclause)
    2215             :         {
    2216             :             /* Success, so record it */
    2217      235084 :             clauseset->indexclauses[indexcol] =
    2218      235084 :                 lappend(clauseset->indexclauses[indexcol], iclause);
    2219      235084 :             clauseset->nonempty = true;
    2220      235084 :             return;
    2221             :         }
    2222             :     }
    2223             : }
    2224             : 
    2225             : /*
    2226             :  * match_clause_to_indexcol()
    2227             :  *    Determine whether a restriction clause matches a column of an index,
    2228             :  *    and if so, build an IndexClause node describing the details.
    2229             :  *
    2230             :  *    To match an index normally, an operator clause:
    2231             :  *
    2232             :  *    (1)  must be in the form (indexkey op const) or (const op indexkey);
    2233             :  *         and
    2234             :  *    (2)  must contain an operator which is in the index's operator family
    2235             :  *         for this column; and
    2236             :  *    (3)  must match the collation of the index, if collation is relevant.
    2237             :  *
    2238             :  *    Our definition of "const" is exceedingly liberal: we allow anything that
    2239             :  *    doesn't involve a volatile function or a Var of the index's relation.
    2240             :  *    In particular, Vars belonging to other relations of the query are
    2241             :  *    accepted here, since a clause of that form can be used in a
    2242             :  *    parameterized indexscan.  It's the responsibility of higher code levels
    2243             :  *    to manage restriction and join clauses appropriately.
    2244             :  *
    2245             :  *    Note: we do need to check for Vars of the index's relation on the
    2246             :  *    "const" side of the clause, since clauses like (a.f1 OP (b.f2 OP a.f3))
    2247             :  *    are not processable by a parameterized indexscan on a.f1, whereas
    2248             :  *    something like (a.f1 OP (b.f2 OP c.f3)) is.
    2249             :  *
    2250             :  *    Presently, the executor can only deal with indexquals that have the
    2251             :  *    indexkey on the left, so we can only use clauses that have the indexkey
    2252             :  *    on the right if we can commute the clause to put the key on the left.
    2253             :  *    We handle that by generating an IndexClause with the correctly-commuted
    2254             :  *    opclause as a derived indexqual.
    2255             :  *
    2256             :  *    If the index has a collation, the clause must have the same collation.
    2257             :  *    For collation-less indexes, we assume it doesn't matter; this is
    2258             :  *    necessary for cases like "hstore ? text", wherein hstore's operators
    2259             :  *    don't care about collation but the clause will get marked with a
    2260             :  *    collation anyway because of the text argument.  (This logic is
    2261             :  *    embodied in the macro IndexCollMatchesExprColl.)
    2262             :  *
    2263             :  *    It is also possible to match RowCompareExpr clauses to indexes (but
    2264             :  *    currently, only btree indexes handle this).
    2265             :  *
    2266             :  *    It is also possible to match ScalarArrayOpExpr clauses to indexes, when
    2267             :  *    the clause is of the form "indexkey op ANY (arrayconst)".
    2268             :  *
    2269             :  *    For boolean indexes, it is also possible to match the clause directly
    2270             :  *    to the indexkey; or perhaps the clause is (NOT indexkey).
    2271             :  *
    2272             :  *    And, last but not least, some operators and functions can be processed
    2273             :  *    to derive (typically lossy) indexquals from a clause that isn't in
    2274             :  *    itself indexable.  If we see that any operand of an OpExpr or FuncExpr
    2275             :  *    matches the index key, and the function has a planner support function
    2276             :  *    attached to it, we'll invoke the support function to see if such an
    2277             :  *    indexqual can be built.
    2278             :  *
    2279             :  * 'rinfo' is the clause to be tested (as a RestrictInfo node).
    2280             :  * 'indexcol' is a column number of 'index' (counting from 0).
    2281             :  * 'index' is the index of interest.
    2282             :  *
    2283             :  * Returns an IndexClause if the clause can be used with this index key,
    2284             :  * or NULL if not.
    2285             :  *
    2286             :  * NOTE:  returns NULL if clause is an OR or AND clause; it is the
    2287             :  * responsibility of higher-level routines to cope with those.
    2288             :  */
    2289             : static IndexClause *
    2290      929170 : match_clause_to_indexcol(PlannerInfo *root,
    2291             :                          RestrictInfo *rinfo,
    2292             :                          int indexcol,
    2293             :                          IndexOptInfo *index)
    2294             : {
    2295             :     IndexClause *iclause;
    2296      929170 :     Expr       *clause = rinfo->clause;
    2297             :     Oid         opfamily;
    2298             : 
    2299             :     Assert(indexcol < index->nkeycolumns);
    2300             : 
    2301             :     /*
    2302             :      * Historically this code has coped with NULL clauses.  That's probably
    2303             :      * not possible anymore, but we might as well continue to cope.
    2304             :      */
    2305      929170 :     if (clause == NULL)
    2306           0 :         return NULL;
    2307             : 
    2308             :     /* First check for boolean-index cases. */
    2309      929170 :     opfamily = index->opfamily[indexcol];
    2310      929170 :     if (IsBooleanOpfamily(opfamily))
    2311             :     {
    2312         100 :         iclause = match_boolean_index_clause(root, rinfo, indexcol, index);
    2313         100 :         if (iclause)
    2314          52 :             return iclause;
    2315             :     }
    2316             : 
    2317             :     /*
    2318             :      * Clause must be an opclause, funcclause, ScalarArrayOpExpr, or
    2319             :      * RowCompareExpr.  Or, if the index supports it, we can handle IS
    2320             :      * NULL/NOT NULL clauses.
    2321             :      */
    2322      929118 :     if (IsA(clause, OpExpr))
    2323             :     {
    2324      737630 :         return match_opclause_to_indexcol(root, rinfo, indexcol, index);
    2325             :     }
    2326      191488 :     else if (IsA(clause, FuncExpr))
    2327             :     {
    2328       12824 :         return match_funcclause_to_indexcol(root, rinfo, indexcol, index);
    2329             :     }
    2330      178664 :     else if (IsA(clause, ScalarArrayOpExpr))
    2331             :     {
    2332       56530 :         return match_saopclause_to_indexcol(root, rinfo, indexcol, index);
    2333             :     }
    2334      122134 :     else if (IsA(clause, RowCompareExpr))
    2335             :     {
    2336         192 :         return match_rowcompare_to_indexcol(root, rinfo, indexcol, index);
    2337             :     }
    2338      121942 :     else if (index->amsearchnulls && IsA(clause, NullTest))
    2339             :     {
    2340       47024 :         NullTest   *nt = (NullTest *) clause;
    2341             : 
    2342       94048 :         if (!nt->argisrow &&
    2343       47024 :             match_index_to_operand((Node *) nt->arg, indexcol, index))
    2344             :         {
    2345         922 :             iclause = makeNode(IndexClause);
    2346         922 :             iclause->rinfo = rinfo;
    2347         922 :             iclause->indexquals = list_make1(rinfo);
    2348         922 :             iclause->lossy = false;
    2349         922 :             iclause->indexcol = indexcol;
    2350         922 :             iclause->indexcols = NIL;
    2351         922 :             return iclause;
    2352             :         }
    2353             :     }
    2354             : 
    2355      121020 :     return NULL;
    2356             : }
    2357             : 
    2358             : /*
    2359             :  * match_boolean_index_clause
    2360             :  *    Recognize restriction clauses that can be matched to a boolean index.
    2361             :  *
    2362             :  * The idea here is that, for an index on a boolean column that supports the
    2363             :  * BooleanEqualOperator, we can transform a plain reference to the indexkey
    2364             :  * into "indexkey = true", or "NOT indexkey" into "indexkey = false", etc,
    2365             :  * so as to make the expression indexable using the index's "=" operator.
    2366             :  * Since Postgres 8.1, we must do this because constant simplification does
    2367             :  * the reverse transformation; without this code there'd be no way to use
    2368             :  * such an index at all.
    2369             :  *
    2370             :  * This should be called only when IsBooleanOpfamily() recognizes the
    2371             :  * index's operator family.  We check to see if the clause matches the
    2372             :  * index's key, and if so, build a suitable IndexClause.
    2373             :  */
    2374             : static IndexClause *
    2375         196 : match_boolean_index_clause(PlannerInfo *root,
    2376             :                            RestrictInfo *rinfo,
    2377             :                            int indexcol,
    2378             :                            IndexOptInfo *index)
    2379             : {
    2380         196 :     Node       *clause = (Node *) rinfo->clause;
    2381         196 :     Expr       *op = NULL;
    2382             : 
    2383             :     /* Direct match? */
    2384         196 :     if (match_index_to_operand(clause, indexcol, index))
    2385             :     {
    2386             :         /* convert to indexkey = TRUE */
    2387          56 :         op = make_opclause(BooleanEqualOperator, BOOLOID, false,
    2388             :                            (Expr *) clause,
    2389          56 :                            (Expr *) makeBoolConst(true, false),
    2390             :                            InvalidOid, InvalidOid);
    2391             :     }
    2392             :     /* NOT clause? */
    2393         140 :     else if (is_notclause(clause))
    2394             :     {
    2395          44 :         Node       *arg = (Node *) get_notclausearg((Expr *) clause);
    2396             : 
    2397          44 :         if (match_index_to_operand(arg, indexcol, index))
    2398             :         {
    2399             :             /* convert to indexkey = FALSE */
    2400          44 :             op = make_opclause(BooleanEqualOperator, BOOLOID, false,
    2401             :                                (Expr *) arg,
    2402          44 :                                (Expr *) makeBoolConst(false, false),
    2403             :                                InvalidOid, InvalidOid);
    2404             :         }
    2405             :     }
    2406             : 
    2407             :     /*
    2408             :      * Since we only consider clauses at top level of WHERE, we can convert
    2409             :      * indexkey IS TRUE and indexkey IS FALSE to index searches as well.  The
    2410             :      * different meaning for NULL isn't important.
    2411             :      */
    2412          96 :     else if (clause && IsA(clause, BooleanTest))
    2413             :     {
    2414          24 :         BooleanTest *btest = (BooleanTest *) clause;
    2415          24 :         Node       *arg = (Node *) btest->arg;
    2416             : 
    2417          36 :         if (btest->booltesttype == IS_TRUE &&
    2418          12 :             match_index_to_operand(arg, indexcol, index))
    2419             :         {
    2420             :             /* convert to indexkey = TRUE */
    2421          12 :             op = make_opclause(BooleanEqualOperator, BOOLOID, false,
    2422             :                                (Expr *) arg,
    2423          12 :                                (Expr *) makeBoolConst(true, false),
    2424             :                                InvalidOid, InvalidOid);
    2425             :         }
    2426          24 :         else if (btest->booltesttype == IS_FALSE &&
    2427          12 :                  match_index_to_operand(arg, indexcol, index))
    2428             :         {
    2429             :             /* convert to indexkey = FALSE */
    2430          12 :             op = make_opclause(BooleanEqualOperator, BOOLOID, false,
    2431             :                                (Expr *) arg,
    2432          12 :                                (Expr *) makeBoolConst(false, false),
    2433             :                                InvalidOid, InvalidOid);
    2434             :         }
    2435             :     }
    2436             : 
    2437             :     /*
    2438             :      * If we successfully made an operator clause from the given qual, we must
    2439             :      * wrap it in an IndexClause.  It's not lossy.
    2440             :      */
    2441         196 :     if (op)
    2442             :     {
    2443         124 :         IndexClause *iclause = makeNode(IndexClause);
    2444             : 
    2445         124 :         iclause->rinfo = rinfo;
    2446         124 :         iclause->indexquals = list_make1(make_simple_restrictinfo(root, op));
    2447         124 :         iclause->lossy = false;
    2448         124 :         iclause->indexcol = indexcol;
    2449         124 :         iclause->indexcols = NIL;
    2450         124 :         return iclause;
    2451             :     }
    2452             : 
    2453          72 :     return NULL;
    2454             : }
    2455             : 
    2456             : /*
    2457             :  * match_opclause_to_indexcol()
    2458             :  *    Handles the OpExpr case for match_clause_to_indexcol(),
    2459             :  *    which see for comments.
    2460             :  */
    2461             : static IndexClause *
    2462      737630 : match_opclause_to_indexcol(PlannerInfo *root,
    2463             :                            RestrictInfo *rinfo,
    2464             :                            int indexcol,
    2465             :                            IndexOptInfo *index)
    2466             : {
    2467             :     IndexClause *iclause;
    2468      737630 :     OpExpr     *clause = (OpExpr *) rinfo->clause;
    2469             :     Node       *leftop,
    2470             :                *rightop;
    2471             :     Oid         expr_op;
    2472             :     Oid         expr_coll;
    2473             :     Index       index_relid;
    2474             :     Oid         opfamily;
    2475             :     Oid         idxcollation;
    2476             : 
    2477             :     /*
    2478             :      * Only binary operators need apply.  (In theory, a planner support
    2479             :      * function could do something with a unary operator, but it seems
    2480             :      * unlikely to be worth the cycles to check.)
    2481             :      */
    2482      737630 :     if (list_length(clause->args) != 2)
    2483           0 :         return NULL;
    2484             : 
    2485      737630 :     leftop = (Node *) linitial(clause->args);
    2486      737630 :     rightop = (Node *) lsecond(clause->args);
    2487      737630 :     expr_op = clause->opno;
    2488      737630 :     expr_coll = clause->inputcollid;
    2489             : 
    2490      737630 :     index_relid = index->rel->relid;
    2491      737630 :     opfamily = index->opfamily[indexcol];
    2492      737630 :     idxcollation = index->indexcollations[indexcol];
    2493             : 
    2494             :     /*
    2495             :      * Check for clauses of the form: (indexkey operator constant) or
    2496             :      * (constant operator indexkey).  See match_clause_to_indexcol's notes
    2497             :      * about const-ness.
    2498             :      *
    2499             :      * Note that we don't ask the support function about clauses that don't
    2500             :      * have one of these forms.  Again, in principle it might be possible to
    2501             :      * do something, but it seems unlikely to be worth the cycles to check.
    2502             :      */
    2503      737630 :     if (match_index_to_operand(leftop, indexcol, index) &&
    2504      211038 :         !bms_is_member(index_relid, rinfo->right_relids) &&
    2505      210974 :         !contain_volatile_functions(rightop))
    2506             :     {
    2507      419478 :         if (IndexCollMatchesExprColl(idxcollation, expr_coll) &&
    2508      208504 :             op_in_opfamily(expr_op, opfamily))
    2509             :         {
    2510      203890 :             iclause = makeNode(IndexClause);
    2511      203890 :             iclause->rinfo = rinfo;
    2512      203890 :             iclause->indexquals = list_make1(rinfo);
    2513      203890 :             iclause->lossy = false;
    2514      203890 :             iclause->indexcol = indexcol;
    2515      203890 :             iclause->indexcols = NIL;
    2516      203890 :             return iclause;
    2517             :         }
    2518             : 
    2519             :         /*
    2520             :          * If we didn't find a member of the index's opfamily, try the support
    2521             :          * function for the operator's underlying function.
    2522             :          */
    2523        7084 :         set_opfuncid(clause);   /* make sure we have opfuncid */
    2524        7084 :         return get_index_clause_from_support(root,
    2525             :                                              rinfo,
    2526             :                                              clause->opfuncid,
    2527             :                                              0, /* indexarg on left */
    2528             :                                              indexcol,
    2529             :                                              index);
    2530             :     }
    2531             : 
    2532      526656 :     if (match_index_to_operand(rightop, indexcol, index) &&
    2533       19044 :         !bms_is_member(index_relid, rinfo->left_relids) &&
    2534       19008 :         !contain_volatile_functions(leftop))
    2535             :     {
    2536       19008 :         if (IndexCollMatchesExprColl(idxcollation, expr_coll))
    2537             :         {
    2538       19008 :             Oid         comm_op = get_commutator(expr_op);
    2539             : 
    2540       38016 :             if (OidIsValid(comm_op) &&
    2541       19008 :                 op_in_opfamily(comm_op, opfamily))
    2542             :             {
    2543             :                 RestrictInfo *commrinfo;
    2544             : 
    2545             :                 /* Build a commuted OpExpr and RestrictInfo */
    2546       18752 :                 commrinfo = commute_restrictinfo(rinfo, comm_op);
    2547             : 
    2548             :                 /* Make an IndexClause showing that as a derived qual */
    2549       18752 :                 iclause = makeNode(IndexClause);
    2550       18752 :                 iclause->rinfo = rinfo;
    2551       18752 :                 iclause->indexquals = list_make1(commrinfo);
    2552       18752 :                 iclause->lossy = false;
    2553       18752 :                 iclause->indexcol = indexcol;
    2554       18752 :                 iclause->indexcols = NIL;
    2555       18752 :                 return iclause;
    2556             :             }
    2557             :         }
    2558             : 
    2559             :         /*
    2560             :          * If we didn't find a member of the index's opfamily, try the support
    2561             :          * function for the operator's underlying function.
    2562             :          */
    2563         256 :         set_opfuncid(clause);   /* make sure we have opfuncid */
    2564         256 :         return get_index_clause_from_support(root,
    2565             :                                              rinfo,
    2566             :                                              clause->opfuncid,
    2567             :                                              1, /* indexarg on right */
    2568             :                                              indexcol,
    2569             :                                              index);
    2570             :     }
    2571             : 
    2572      507648 :     return NULL;
    2573             : }
    2574             : 
    2575             : /*
    2576             :  * match_funcclause_to_indexcol()
    2577             :  *    Handles the FuncExpr case for match_clause_to_indexcol(),
    2578             :  *    which see for comments.
    2579             :  */
    2580             : static IndexClause *
    2581       12824 : match_funcclause_to_indexcol(PlannerInfo *root,
    2582             :                              RestrictInfo *rinfo,
    2583             :                              int indexcol,
    2584             :                              IndexOptInfo *index)
    2585             : {
    2586       12824 :     FuncExpr   *clause = (FuncExpr *) rinfo->clause;
    2587             :     int         indexarg;
    2588             :     ListCell   *lc;
    2589             : 
    2590             :     /*
    2591             :      * We have no built-in intelligence about function clauses, but if there's
    2592             :      * a planner support function, it might be able to do something.  But, to
    2593             :      * cut down on wasted planning cycles, only call the support function if
    2594             :      * at least one argument matches the target index column.
    2595             :      *
    2596             :      * Note that we don't insist on the other arguments being pseudoconstants;
    2597             :      * the support function has to check that.  This is to allow cases where
    2598             :      * only some of the other arguments need to be included in the indexqual.
    2599             :      */
    2600       12824 :     indexarg = 0;
    2601       27562 :     foreach(lc, clause->args)
    2602             :     {
    2603       17036 :         Node       *op = (Node *) lfirst(lc);
    2604             : 
    2605       17036 :         if (match_index_to_operand(op, indexcol, index))
    2606             :         {
    2607        2298 :             return get_index_clause_from_support(root,
    2608             :                                                  rinfo,
    2609             :                                                  clause->funcid,
    2610             :                                                  indexarg,
    2611             :                                                  indexcol,
    2612             :                                                  index);
    2613             :         }
    2614             : 
    2615       14738 :         indexarg++;
    2616             :     }
    2617             : 
    2618       10526 :     return NULL;
    2619             : }
    2620             : 
    2621             : /*
    2622             :  * get_index_clause_from_support()
    2623             :  *      If the function has a planner support function, try to construct
    2624             :  *      an IndexClause using indexquals created by the support function.
    2625             :  */
    2626             : static IndexClause *
    2627        9638 : get_index_clause_from_support(PlannerInfo *root,
    2628             :                               RestrictInfo *rinfo,
    2629             :                               Oid funcid,
    2630             :                               int indexarg,
    2631             :                               int indexcol,
    2632             :                               IndexOptInfo *index)
    2633             : {
    2634        9638 :     Oid         prosupport = get_func_support(funcid);
    2635             :     SupportRequestIndexCondition req;
    2636             :     List       *sresult;
    2637             : 
    2638        9638 :     if (!OidIsValid(prosupport))
    2639        6046 :         return NULL;
    2640             : 
    2641        3592 :     req.type = T_SupportRequestIndexCondition;
    2642        3592 :     req.root = root;
    2643        3592 :     req.funcid = funcid;
    2644        3592 :     req.node = (Node *) rinfo->clause;
    2645        3592 :     req.indexarg = indexarg;
    2646        3592 :     req.index = index;
    2647        3592 :     req.indexcol = indexcol;
    2648        3592 :     req.opfamily = index->opfamily[indexcol];
    2649        3592 :     req.indexcollation = index->indexcollations[indexcol];
    2650             : 
    2651        3592 :     req.lossy = true;           /* default assumption */
    2652             : 
    2653        3592 :     sresult = (List *)
    2654        3592 :         DatumGetPointer(OidFunctionCall1(prosupport,
    2655             :                                          PointerGetDatum(&req)));
    2656             : 
    2657        3592 :     if (sresult != NIL)
    2658             :     {
    2659        3462 :         IndexClause *iclause = makeNode(IndexClause);
    2660        3462 :         List       *indexquals = NIL;
    2661             :         ListCell   *lc;
    2662             : 
    2663             :         /*
    2664             :          * The support function API says it should just give back bare
    2665             :          * clauses, so here we must wrap each one in a RestrictInfo.
    2666             :          */
    2667        7982 :         foreach(lc, sresult)
    2668             :         {
    2669        4520 :             Expr       *clause = (Expr *) lfirst(lc);
    2670             : 
    2671        4520 :             indexquals = lappend(indexquals,
    2672        4520 :                                  make_simple_restrictinfo(root, clause));
    2673             :         }
    2674             : 
    2675        3462 :         iclause->rinfo = rinfo;
    2676        3462 :         iclause->indexquals = indexquals;
    2677        3462 :         iclause->lossy = req.lossy;
    2678        3462 :         iclause->indexcol = indexcol;
    2679        3462 :         iclause->indexcols = NIL;
    2680             : 
    2681        3462 :         return iclause;
    2682             :     }
    2683             : 
    2684         130 :     return NULL;
    2685             : }
    2686             : 
    2687             : /*
    2688             :  * match_saopclause_to_indexcol()
    2689             :  *    Handles the ScalarArrayOpExpr case for match_clause_to_indexcol(),
    2690             :  *    which see for comments.
    2691             :  */
    2692             : static IndexClause *
    2693       56530 : match_saopclause_to_indexcol(PlannerInfo *root,
    2694             :                              RestrictInfo *rinfo,
    2695             :                              int indexcol,
    2696             :                              IndexOptInfo *index)
    2697             : {
    2698       56530 :     ScalarArrayOpExpr *saop = (ScalarArrayOpExpr *) rinfo->clause;
    2699             :     Node       *leftop,
    2700             :                *rightop;
    2701             :     Relids      right_relids;
    2702             :     Oid         expr_op;
    2703             :     Oid         expr_coll;
    2704             :     Index       index_relid;
    2705             :     Oid         opfamily;
    2706             :     Oid         idxcollation;
    2707             : 
    2708             :     /* We only accept ANY clauses, not ALL */
    2709       56530 :     if (!saop->useOr)
    2710        3590 :         return NULL;
    2711       52940 :     leftop = (Node *) linitial(saop->args);
    2712       52940 :     rightop = (Node *) lsecond(saop->args);
    2713       52940 :     right_relids = pull_varnos(root, rightop);
    2714       52940 :     expr_op = saop->opno;
    2715       52940 :     expr_coll = saop->inputcollid;
    2716             : 
    2717       52940 :     index_relid = index->rel->relid;
    2718       52940 :     opfamily = index->opfamily[indexcol];
    2719       52940 :     idxcollation = index->indexcollations[indexcol];
    2720             : 
    2721             :     /*
    2722             :      * We must have indexkey on the left and a pseudo-constant array argument.
    2723             :      */
    2724       52940 :     if (match_index_to_operand(leftop, indexcol, index) &&
    2725        7958 :         !bms_is_member(index_relid, right_relids) &&
    2726        7958 :         !contain_volatile_functions(rightop))
    2727             :     {
    2728       15912 :         if (IndexCollMatchesExprColl(idxcollation, expr_coll) &&
    2729        7954 :             op_in_opfamily(expr_op, opfamily))
    2730             :         {
    2731        7946 :             IndexClause *iclause = makeNode(IndexClause);
    2732             : 
    2733        7946 :             iclause->rinfo = rinfo;
    2734        7946 :             iclause->indexquals = list_make1(rinfo);
    2735        7946 :             iclause->lossy = false;
    2736        7946 :             iclause->indexcol = indexcol;
    2737        7946 :             iclause->indexcols = NIL;
    2738        7946 :             return iclause;
    2739             :         }
    2740             : 
    2741             :         /*
    2742             :          * We do not currently ask support functions about ScalarArrayOpExprs,
    2743             :          * though in principle we could.
    2744             :          */
    2745             :     }
    2746             : 
    2747       44994 :     return NULL;
    2748             : }
    2749             : 
    2750             : /*
    2751             :  * match_rowcompare_to_indexcol()
    2752             :  *    Handles the RowCompareExpr case for match_clause_to_indexcol(),
    2753             :  *    which see for comments.
    2754             :  *
    2755             :  * In this routine we check whether the first column of the row comparison
    2756             :  * matches the target index column.  This is sufficient to guarantee that some
    2757             :  * index condition can be constructed from the RowCompareExpr --- the rest
    2758             :  * is handled by expand_indexqual_rowcompare().
    2759             :  */
    2760             : static IndexClause *
    2761         192 : match_rowcompare_to_indexcol(PlannerInfo *root,
    2762             :                              RestrictInfo *rinfo,
    2763             :                              int indexcol,
    2764             :                              IndexOptInfo *index)
    2765             : {
    2766         192 :     RowCompareExpr *clause = (RowCompareExpr *) rinfo->clause;
    2767             :     Index       index_relid;
    2768             :     Oid         opfamily;
    2769             :     Oid         idxcollation;
    2770             :     Node       *leftop,
    2771             :                *rightop;
    2772             :     bool        var_on_left;
    2773             :     Oid         expr_op;
    2774             :     Oid         expr_coll;
    2775             : 
    2776             :     /* Forget it if we're not dealing with a btree index */
    2777         192 :     if (index->relam != BTREE_AM_OID)
    2778           0 :         return NULL;
    2779             : 
    2780         192 :     index_relid = index->rel->relid;
    2781         192 :     opfamily = index->opfamily[indexcol];
    2782         192 :     idxcollation = index->indexcollations[indexcol];
    2783             : 
    2784             :     /*
    2785             :      * We could do the matching on the basis of insisting that the opfamily
    2786             :      * shown in the RowCompareExpr be the same as the index column's opfamily,
    2787             :      * but that could fail in the presence of reverse-sort opfamilies: it'd be
    2788             :      * a matter of chance whether RowCompareExpr had picked the forward or
    2789             :      * reverse-sort family.  So look only at the operator, and match if it is
    2790             :      * a member of the index's opfamily (after commutation, if the indexkey is
    2791             :      * on the right).  We'll worry later about whether any additional
    2792             :      * operators are matchable to the index.
    2793             :      */
    2794         192 :     leftop = (Node *) linitial(clause->largs);
    2795         192 :     rightop = (Node *) linitial(clause->rargs);
    2796         192 :     expr_op = linitial_oid(clause->opnos);
    2797         192 :     expr_coll = linitial_oid(clause->inputcollids);
    2798             : 
    2799             :     /* Collations must match, if relevant */
    2800         192 :     if (!IndexCollMatchesExprColl(idxcollation, expr_coll))
    2801           0 :         return NULL;
    2802             : 
    2803             :     /*
    2804             :      * These syntactic tests are the same as in match_opclause_to_indexcol()
    2805             :      */
    2806         192 :     if (match_index_to_operand(leftop, indexcol, index) &&
    2807          44 :         !bms_is_member(index_relid, pull_varnos(root, rightop)) &&
    2808          44 :         !contain_volatile_functions(rightop))
    2809             :     {
    2810             :         /* OK, indexkey is on left */
    2811          44 :         var_on_left = true;
    2812             :     }
    2813         148 :     else if (match_index_to_operand(rightop, indexcol, index) &&
    2814          16 :              !bms_is_member(index_relid, pull_varnos(root, leftop)) &&
    2815          16 :              !contain_volatile_functions(leftop))
    2816             :     {
    2817             :         /* indexkey is on right, so commute the operator */
    2818          16 :         expr_op = get_commutator(expr_op);
    2819          16 :         if (expr_op == InvalidOid)
    2820           0 :             return NULL;
    2821          16 :         var_on_left = false;
    2822             :     }
    2823             :     else
    2824         132 :         return NULL;
    2825             : 
    2826             :     /* We're good if the operator is the right type of opfamily member */
    2827          60 :     switch (get_op_opfamily_strategy(expr_op, opfamily))
    2828             :     {
    2829          60 :         case BTLessStrategyNumber:
    2830             :         case BTLessEqualStrategyNumber:
    2831             :         case BTGreaterEqualStrategyNumber:
    2832             :         case BTGreaterStrategyNumber:
    2833          60 :             return expand_indexqual_rowcompare(root,
    2834             :                                                rinfo,
    2835             :                                                indexcol,
    2836             :                                                index,
    2837             :                                                expr_op,
    2838             :                                                var_on_left);
    2839             :     }
    2840             : 
    2841           0 :     return NULL;
    2842             : }
    2843             : 
    2844             : /*
    2845             :  * expand_indexqual_rowcompare --- expand a single indexqual condition
    2846             :  *      that is a RowCompareExpr
    2847             :  *
    2848             :  * It's already known that the first column of the row comparison matches
    2849             :  * the specified column of the index.  We can use additional columns of the
    2850             :  * row comparison as index qualifications, so long as they match the index
    2851             :  * in the "same direction", ie, the indexkeys are all on the same side of the
    2852             :  * clause and the operators are all the same-type members of the opfamilies.
    2853             :  *
    2854             :  * If all the columns of the RowCompareExpr match in this way, we just use it
    2855             :  * as-is, except for possibly commuting it to put the indexkeys on the left.
    2856             :  *
    2857             :  * Otherwise, we build a shortened RowCompareExpr (if more than one
    2858             :  * column matches) or a simple OpExpr (if the first-column match is all
    2859             :  * there is).  In these cases the modified clause is always "<=" or ">="
    2860             :  * even when the original was "<" or ">" --- this is necessary to match all
    2861             :  * the rows that could match the original.  (We are building a lossy version
    2862             :  * of the row comparison when we do this, so we set lossy = true.)
    2863             :  *
    2864             :  * Note: this is really just the last half of match_rowcompare_to_indexcol,
    2865             :  * but we split it out for comprehensibility.
    2866             :  */
    2867             : static IndexClause *
    2868          60 : expand_indexqual_rowcompare(PlannerInfo *root,
    2869             :                             RestrictInfo *rinfo,
    2870             :                             int indexcol,
    2871             :                             IndexOptInfo *index,
    2872             :                             Oid expr_op,
    2873             :                             bool var_on_left)
    2874             : {
    2875          60 :     IndexClause *iclause = makeNode(IndexClause);
    2876          60 :     RowCompareExpr *clause = (RowCompareExpr *) rinfo->clause;
    2877             :     int         op_strategy;
    2878             :     Oid         op_lefttype;
    2879             :     Oid         op_righttype;
    2880             :     int         matching_cols;
    2881             :     List       *expr_ops;
    2882             :     List       *opfamilies;
    2883             :     List       *lefttypes;
    2884             :     List       *righttypes;
    2885             :     List       *new_ops;
    2886             :     List       *var_args;
    2887             :     List       *non_var_args;
    2888             : 
    2889          60 :     iclause->rinfo = rinfo;
    2890          60 :     iclause->indexcol = indexcol;
    2891             : 
    2892          60 :     if (var_on_left)
    2893             :     {
    2894          44 :         var_args = clause->largs;
    2895          44 :         non_var_args = clause->rargs;
    2896             :     }
    2897             :     else
    2898             :     {
    2899          16 :         var_args = clause->rargs;
    2900          16 :         non_var_args = clause->largs;
    2901             :     }
    2902             : 
    2903          60 :     get_op_opfamily_properties(expr_op, index->opfamily[indexcol], false,
    2904             :                                &op_strategy,
    2905             :                                &op_lefttype,
    2906             :                                &op_righttype);
    2907             : 
    2908             :     /* Initialize returned list of which index columns are used */
    2909          60 :     iclause->indexcols = list_make1_int(indexcol);
    2910             : 
    2911             :     /* Build lists of ops, opfamilies and operator datatypes in case needed */
    2912          60 :     expr_ops = list_make1_oid(expr_op);
    2913          60 :     opfamilies = list_make1_oid(index->opfamily[indexcol]);
    2914          60 :     lefttypes = list_make1_oid(op_lefttype);
    2915          60 :     righttypes = list_make1_oid(op_righttype);
    2916             : 
    2917             :     /*
    2918             :      * See how many of the remaining columns match some index column in the
    2919             :      * same way.  As in match_clause_to_indexcol(), the "other" side of any
    2920             :      * potential index condition is OK as long as it doesn't use Vars from the
    2921             :      * indexed relation.
    2922             :      */
    2923          60 :     matching_cols = 1;
    2924             : 
    2925         108 :     while (matching_cols < list_length(var_args))
    2926             :     {
    2927          84 :         Node       *varop = (Node *) list_nth(var_args, matching_cols);
    2928          84 :         Node       *constop = (Node *) list_nth(non_var_args, matching_cols);
    2929             :         int         i;
    2930             : 
    2931          84 :         expr_op = list_nth_oid(clause->opnos, matching_cols);
    2932          84 :         if (!var_on_left)
    2933             :         {
    2934             :             /* indexkey is on right, so commute the operator */
    2935          16 :             expr_op = get_commutator(expr_op);
    2936          16 :             if (expr_op == InvalidOid)
    2937           0 :                 break;          /* operator is not usable */
    2938             :         }
    2939          84 :         if (bms_is_member(index->rel->relid, pull_varnos(root, constop)))
    2940           0 :             break;              /* no good, Var on wrong side */
    2941          84 :         if (contain_volatile_functions(constop))
    2942           0 :             break;              /* no good, volatile comparison value */
    2943             : 
    2944             :         /*
    2945             :          * The Var side can match any key column of the index.
    2946             :          */
    2947         200 :         for (i = 0; i < index->nkeycolumns; i++)
    2948             :         {
    2949         164 :             if (match_index_to_operand(varop, i, index) &&
    2950          48 :                 get_op_opfamily_strategy(expr_op,
    2951          48 :                                          index->opfamily[i]) == op_strategy &&
    2952          48 :                 IndexCollMatchesExprColl(index->indexcollations[i],
    2953             :                                          list_nth_oid(clause->inputcollids,
    2954             :                                                       matching_cols)))
    2955             :                 break;
    2956             :         }
    2957          84 :         if (i >= index->nkeycolumns)
    2958          36 :             break;              /* no match found */
    2959             : 
    2960             :         /* Add column number to returned list */
    2961          48 :         iclause->indexcols = lappend_int(iclause->indexcols, i);
    2962             : 
    2963             :         /* Add operator info to lists */
    2964          48 :         get_op_opfamily_properties(expr_op, index->opfamily[i], false,
    2965             :                                    &op_strategy,
    2966             :                                    &op_lefttype,
    2967             :                                    &op_righttype);
    2968          48 :         expr_ops = lappend_oid(expr_ops, expr_op);
    2969          48 :         opfamilies = lappend_oid(opfamilies, index->opfamily[i]);
    2970          48 :         lefttypes = lappend_oid(lefttypes, op_lefttype);
    2971          48 :         righttypes = lappend_oid(righttypes, op_righttype);
    2972             : 
    2973             :         /* This column matches, keep scanning */
    2974          48 :         matching_cols++;
    2975             :     }
    2976             : 
    2977             :     /* Result is non-lossy if all columns are usable as index quals */
    2978          60 :     iclause->lossy = (matching_cols != list_length(clause->opnos));
    2979             : 
    2980             :     /*
    2981             :      * We can use rinfo->clause as-is if we have var on left and it's all
    2982             :      * usable as index quals.
    2983             :      */
    2984          60 :     if (var_on_left && !iclause->lossy)
    2985          16 :         iclause->indexquals = list_make1(rinfo);
    2986             :     else
    2987             :     {
    2988             :         /*
    2989             :          * We have to generate a modified rowcompare (possibly just one
    2990             :          * OpExpr).  The painful part of this is changing < to <= or > to >=,
    2991             :          * so deal with that first.
    2992             :          */
    2993          44 :         if (!iclause->lossy)
    2994             :         {
    2995             :             /* very easy, just use the commuted operators */
    2996           8 :             new_ops = expr_ops;
    2997             :         }
    2998          36 :         else if (op_strategy == BTLessEqualStrategyNumber ||
    2999          36 :                  op_strategy == BTGreaterEqualStrategyNumber)
    3000             :         {
    3001             :             /* easy, just use the same (possibly commuted) operators */
    3002           0 :             new_ops = list_truncate(expr_ops, matching_cols);
    3003             :         }
    3004             :         else
    3005             :         {
    3006             :             ListCell   *opfamilies_cell;
    3007             :             ListCell   *lefttypes_cell;
    3008             :             ListCell   *righttypes_cell;
    3009             : 
    3010          36 :             if (op_strategy == BTLessStrategyNumber)
    3011          20 :                 op_strategy = BTLessEqualStrategyNumber;
    3012          16 :             else if (op_strategy == BTGreaterStrategyNumber)
    3013          16 :                 op_strategy = BTGreaterEqualStrategyNumber;
    3014             :             else
    3015           0 :                 elog(ERROR, "unexpected strategy number %d", op_strategy);
    3016          36 :             new_ops = NIL;
    3017          96 :             forthree(opfamilies_cell, opfamilies,
    3018             :                      lefttypes_cell, lefttypes,
    3019             :                      righttypes_cell, righttypes)
    3020             :             {
    3021          60 :                 Oid         opfam = lfirst_oid(opfamilies_cell);
    3022          60 :                 Oid         lefttype = lfirst_oid(lefttypes_cell);
    3023          60 :                 Oid         righttype = lfirst_oid(righttypes_cell);
    3024             : 
    3025          60 :                 expr_op = get_opfamily_member(opfam, lefttype, righttype,
    3026             :                                               op_strategy);
    3027          60 :                 if (!OidIsValid(expr_op))   /* should not happen */
    3028           0 :                     elog(ERROR, "missing operator %d(%u,%u) in opfamily %u",
    3029             :                          op_strategy, lefttype, righttype, opfam);
    3030          60 :                 new_ops = lappend_oid(new_ops, expr_op);
    3031             :             }
    3032             :         }
    3033             : 
    3034             :         /* If we have more than one matching col, create a subset rowcompare */
    3035          44 :         if (matching_cols > 1)
    3036             :         {
    3037          32 :             RowCompareExpr *rc = makeNode(RowCompareExpr);
    3038             : 
    3039          32 :             rc->rctype = (RowCompareType) op_strategy;
    3040          32 :             rc->opnos = new_ops;
    3041          32 :             rc->opfamilies = list_truncate(list_copy(clause->opfamilies),
    3042             :                                            matching_cols);
    3043          32 :             rc->inputcollids = list_truncate(list_copy(clause->inputcollids),
    3044             :                                              matching_cols);
    3045          32 :             rc->largs = list_truncate(copyObject(var_args),
    3046             :                                       matching_cols);
    3047          32 :             rc->rargs = list_truncate(copyObject(non_var_args),
    3048             :                                       matching_cols);
    3049          32 :             iclause->indexquals = list_make1(make_simple_restrictinfo(root,
    3050             :                                                                       (Expr *) rc));
    3051             :         }
    3052             :         else
    3053             :         {
    3054             :             Expr       *op;
    3055             : 
    3056             :             /* We don't report an index column list in this case */
    3057          12 :             iclause->indexcols = NIL;
    3058             : 
    3059          12 :             op = make_opclause(linitial_oid(new_ops), BOOLOID, false,
    3060          12 :                                copyObject(linitial(var_args)),
    3061          12 :                                copyObject(linitial(non_var_args)),
    3062             :                                InvalidOid,
    3063          12 :                                linitial_oid(clause->inputcollids));
    3064          12 :             iclause->indexquals = list_make1(make_simple_restrictinfo(root, op));
    3065             :         }
    3066             :     }
    3067             : 
    3068          60 :     return iclause;
    3069             : }
    3070             : 
    3071             : 
    3072             : /****************************************************************************
    3073             :  *              ----  ROUTINES TO CHECK ORDERING OPERATORS  ----
    3074             :  ****************************************************************************/
    3075             : 
    3076             : /*
    3077             :  * match_pathkeys_to_index
    3078             :  *      Test whether an index can produce output ordered according to the
    3079             :  *      given pathkeys using "ordering operators".
    3080             :  *
    3081             :  * If it can, return a list of suitable ORDER BY expressions, each of the form
    3082             :  * "indexedcol operator pseudoconstant", along with an integer list of the
    3083             :  * index column numbers (zero based) that each clause would be used with.
    3084             :  * NIL lists are returned if the ordering is not achievable this way.
    3085             :  *
    3086             :  * On success, the result list is ordered by pathkeys, and in fact is
    3087             :  * one-to-one with the requested pathkeys.
    3088             :  */
    3089             : static void
    3090         552 : match_pathkeys_to_index(IndexOptInfo *index, List *pathkeys,
    3091             :                         List **orderby_clauses_p,
    3092             :                         List **clause_columns_p)
    3093             : {
    3094         552 :     List       *orderby_clauses = NIL;
    3095         552 :     List       *clause_columns = NIL;
    3096             :     ListCell   *lc1;
    3097             : 
    3098         552 :     *orderby_clauses_p = NIL;   /* set default results */
    3099         552 :     *clause_columns_p = NIL;
    3100             : 
    3101             :     /* Only indexes with the amcanorderbyop property are interesting here */
    3102         552 :     if (!index->amcanorderbyop)
    3103           0 :         return;
    3104             : 
    3105         872 :     foreach(lc1, pathkeys)
    3106             :     {
    3107         544 :         PathKey    *pathkey = (PathKey *) lfirst(lc1);
    3108         544 :         bool        found = false;
    3109             :         ListCell   *lc2;
    3110             : 
    3111             :         /*
    3112             :          * Note: for any failure to match, we just return NIL immediately.
    3113             :          * There is no value in matching just some of the pathkeys.
    3114             :          */
    3115             : 
    3116             :         /* Pathkey must request default sort order for the target opfamily */
    3117         544 :         if (pathkey->pk_strategy != BTLessStrategyNumber ||
    3118         516 :             pathkey->pk_nulls_first)
    3119         224 :             return;
    3120             : 
    3121             :         /* If eclass is volatile, no hope of using an indexscan */
    3122         516 :         if (pathkey->pk_eclass->ec_has_volatile)
    3123           0 :             return;
    3124             : 
    3125             :         /*
    3126             :          * Try to match eclass member expression(s) to index.  Note that child
    3127             :          * EC members are considered, but only when they belong to the target
    3128             :          * relation.  (Unlike regular members, the same expression could be a
    3129             :          * child member of more than one EC.  Therefore, the same index could
    3130             :          * be considered to match more than one pathkey list, which is OK
    3131             :          * here.  See also get_eclass_for_sort_expr.)
    3132             :          */
    3133         712 :         foreach(lc2, pathkey->pk_eclass->ec_members)
    3134             :         {
    3135         516 :             EquivalenceMember *member = (EquivalenceMember *) lfirst(lc2);
    3136             :             int         indexcol;
    3137             : 
    3138             :             /* No possibility of match if it references other relations */
    3139         516 :             if (!bms_equal(member->em_relids, index->rel->relids))
    3140           0 :                 continue;
    3141             : 
    3142             :             /*
    3143             :              * We allow any column of the index to match each pathkey; they
    3144             :              * don't have to match left-to-right as you might expect.  This is
    3145             :              * correct for GiST, and it doesn't matter for SP-GiST because
    3146             :              * that doesn't handle multiple columns anyway, and no other
    3147             :              * existing AMs support amcanorderbyop.  We might need different
    3148             :              * logic in future for other implementations.
    3149             :              */
    3150         712 :             for (indexcol = 0; indexcol < index->nkeycolumns; indexcol++)
    3151             :             {
    3152             :                 Expr       *expr;
    3153             : 
    3154         516 :                 expr = match_clause_to_ordering_op(index,
    3155             :                                                    indexcol,
    3156             :                                                    member->em_expr,
    3157             :                                                    pathkey->pk_opfamily);
    3158         516 :                 if (expr)
    3159             :                 {
    3160         320 :                     orderby_clauses = lappend(orderby_clauses, expr);
    3161         320 :                     clause_columns = lappend_int(clause_columns, indexcol);
    3162         320 :                     found = true;
    3163         320 :                     break;
    3164             :                 }
    3165             :             }
    3166             : 
    3167         516 :             if (found)          /* don't want to look at remaining members */
    3168         320 :                 break;
    3169             :         }
    3170             : 
    3171         516 :         if (!found)             /* fail if no match for this pathkey */
    3172         196 :             return;
    3173             :     }
    3174             : 
    3175         328 :     *orderby_clauses_p = orderby_clauses;   /* success! */
    3176         328 :     *clause_columns_p = clause_columns;
    3177             : }
    3178             : 
    3179             : /*
    3180             :  * match_clause_to_ordering_op
    3181             :  *    Determines whether an ordering operator expression matches an
    3182             :  *    index column.
    3183             :  *
    3184             :  *    This is similar to, but simpler than, match_clause_to_indexcol.
    3185             :  *    We only care about simple OpExpr cases.  The input is a bare
    3186             :  *    expression that is being ordered by, which must be of the form
    3187             :  *    (indexkey op const) or (const op indexkey) where op is an ordering
    3188             :  *    operator for the column's opfamily.
    3189             :  *
    3190             :  * 'index' is the index of interest.
    3191             :  * 'indexcol' is a column number of 'index' (counting from 0).
    3192             :  * 'clause' is the ordering expression to be tested.
    3193             :  * 'pk_opfamily' is the btree opfamily describing the required sort order.
    3194             :  *
    3195             :  * Note that we currently do not consider the collation of the ordering
    3196             :  * operator's result.  In practical cases the result type will be numeric
    3197             :  * and thus have no collation, and it's not very clear what to match to
    3198             :  * if it did have a collation.  The index's collation should match the
    3199             :  * ordering operator's input collation, not its result.
    3200             :  *
    3201             :  * If successful, return 'clause' as-is if the indexkey is on the left,
    3202             :  * otherwise a commuted copy of 'clause'.  If no match, return NULL.
    3203             :  */
    3204             : static Expr *
    3205         516 : match_clause_to_ordering_op(IndexOptInfo *index,
    3206             :                             int indexcol,
    3207             :                             Expr *clause,
    3208             :                             Oid pk_opfamily)
    3209             : {
    3210             :     Oid         opfamily;
    3211             :     Oid         idxcollation;
    3212             :     Node       *leftop,
    3213             :                *rightop;
    3214             :     Oid         expr_op;
    3215             :     Oid         expr_coll;
    3216             :     Oid         sortfamily;
    3217             :     bool        commuted;
    3218             : 
    3219             :     Assert(indexcol < index->nkeycolumns);
    3220             : 
    3221         516 :     opfamily = index->opfamily[indexcol];
    3222         516 :     idxcollation = index->indexcollations[indexcol];
    3223             : 
    3224             :     /*
    3225             :      * Clause must be a binary opclause.
    3226             :      */
    3227         516 :     if (!is_opclause(clause))
    3228         196 :         return NULL;
    3229         320 :     leftop = get_leftop(clause);
    3230         320 :     rightop = get_rightop(clause);
    3231         320 :     if (!leftop || !rightop)
    3232           0 :         return NULL;
    3233         320 :     expr_op = ((OpExpr *) clause)->opno;
    3234         320 :     expr_coll = ((OpExpr *) clause)->inputcollid;
    3235             : 
    3236             :     /*
    3237             :      * We can forget the whole thing right away if wrong collation.
    3238             :      */
    3239         320 :     if (!IndexCollMatchesExprColl(idxcollation, expr_coll))
    3240           0 :         return NULL;
    3241             : 
    3242             :     /*
    3243             :      * Check for clauses of the form: (indexkey operator constant) or
    3244             :      * (constant operator indexkey).
    3245             :      */
    3246         320 :     if (match_index_to_operand(leftop, indexcol, index) &&
    3247         304 :         !contain_var_clause(rightop) &&
    3248         304 :         !contain_volatile_functions(rightop))
    3249             :     {
    3250         304 :         commuted = false;
    3251             :     }
    3252          16 :     else if (match_index_to_operand(rightop, indexcol, index) &&
    3253          16 :              !contain_var_clause(leftop) &&
    3254          16 :              !contain_volatile_functions(leftop))
    3255             :     {
    3256             :         /* Might match, but we need a commuted operator */
    3257          16 :         expr_op = get_commutator(expr_op);
    3258          16 :         if (expr_op == InvalidOid)
    3259           0 :             return NULL;
    3260          16 :         commuted = true;
    3261             :     }
    3262             :     else
    3263           0 :         return NULL;
    3264             : 
    3265             :     /*
    3266             :      * Is the (commuted) operator an ordering operator for the opfamily? And
    3267             :      * if so, does it yield the right sorting semantics?
    3268             :      */
    3269         320 :     sortfamily = get_op_opfamily_sortfamily(expr_op, opfamily);
    3270         320 :     if (sortfamily != pk_opfamily)
    3271           0 :         return NULL;
    3272             : 
    3273             :     /* We have a match.  Return clause or a commuted version thereof. */
    3274         320 :     if (commuted)
    3275             :     {
    3276          16 :         OpExpr     *newclause = makeNode(OpExpr);
    3277             : 
    3278             :         /* flat-copy all the fields of clause */
    3279          16 :         memcpy(newclause, clause, sizeof(OpExpr));
    3280             : 
    3281             :         /* commute it */
    3282          16 :         newclause->opno = expr_op;
    3283          16 :         newclause->opfuncid = InvalidOid;
    3284          16 :         newclause->args = list_make2(rightop, leftop);
    3285             : 
    3286          16 :         clause = (Expr *) newclause;
    3287             :     }
    3288             : 
    3289         320 :     return clause;
    3290             : }
    3291             : 
    3292             : 
    3293             : /****************************************************************************
    3294             :  *              ----  ROUTINES TO DO PARTIAL INDEX PREDICATE TESTS  ----
    3295             :  ****************************************************************************/
    3296             : 
    3297             : /*
    3298             :  * check_index_predicates
    3299             :  *      Set the predicate-derived IndexOptInfo fields for each index
    3300             :  *      of the specified relation.
    3301             :  *
    3302             :  * predOK is set true if the index is partial and its predicate is satisfied
    3303             :  * for this query, ie the query's WHERE clauses imply the predicate.
    3304             :  *
    3305             :  * indrestrictinfo is set to the relation's baserestrictinfo list less any
    3306             :  * conditions that are implied by the index's predicate.  (Obviously, for a
    3307             :  * non-partial index, this is the same as baserestrictinfo.)  Such conditions
    3308             :  * can be dropped from the plan when using the index, in certain cases.
    3309             :  *
    3310             :  * At one time it was possible for this to get re-run after adding more
    3311             :  * restrictions to the rel, thus possibly letting us prove more indexes OK.
    3312             :  * That doesn't happen any more (at least not in the core code's usage),
    3313             :  * but this code still supports it in case extensions want to mess with the
    3314             :  * baserestrictinfo list.  We assume that adding more restrictions can't make
    3315             :  * an index not predOK.  We must recompute indrestrictinfo each time, though,
    3316             :  * to make sure any newly-added restrictions get into it if needed.
    3317             :  */
    3318             : void
    3319      237568 : check_index_predicates(PlannerInfo *root, RelOptInfo *rel)
    3320             : {
    3321             :     List       *clauselist;
    3322             :     bool        have_partial;
    3323             :     bool        is_target_rel;
    3324             :     Relids      otherrels;
    3325             :     ListCell   *lc;
    3326             : 
    3327             :     /* Indexes are available only on base or "other" member relations. */
    3328             :     Assert(IS_SIMPLE_REL(rel));
    3329             : 
    3330             :     /*
    3331             :      * Initialize the indrestrictinfo lists to be identical to
    3332             :      * baserestrictinfo, and check whether there are any partial indexes.  If
    3333             :      * not, this is all we need to do.
    3334             :      */
    3335      237568 :     have_partial = false;
    3336      646786 :     foreach(lc, rel->indexlist)
    3337             :     {
    3338      409218 :         IndexOptInfo *index = (IndexOptInfo *) lfirst(lc);
    3339             : 
    3340      409218 :         index->indrestrictinfo = rel->baserestrictinfo;
    3341      409218 :         if (index->indpred)
    3342         678 :             have_partial = true;
    3343             :     }
    3344      237568 :     if (!have_partial)
    3345      237118 :         return;
    3346             : 
    3347             :     /*
    3348             :      * Construct a list of clauses that we can assume true for the purpose of
    3349             :      * proving the index(es) usable.  Restriction clauses for the rel are
    3350             :      * always usable, and so are any join clauses that are "movable to" this
    3351             :      * rel.  Also, we can consider any EC-derivable join clauses (which must
    3352             :      * be "movable to" this rel, by definition).
    3353             :      */
    3354         450 :     clauselist = list_copy(rel->baserestrictinfo);
    3355             : 
    3356             :     /* Scan the rel's join clauses */
    3357         450 :     foreach(lc, rel->joininfo)
    3358             :     {
    3359           0 :         RestrictInfo *rinfo = (RestrictInfo *) lfirst(lc);
    3360             : 
    3361             :         /* Check if clause can be moved to this rel */
    3362           0 :         if (!join_clause_is_movable_to(rinfo, rel))
    3363           0 :             continue;
    3364             : 
    3365           0 :         clauselist = lappend(clauselist, rinfo);
    3366             :     }
    3367             : 
    3368             :     /*
    3369             :      * Add on any equivalence-derivable join clauses.  Computing the correct
    3370             :      * relid sets for generate_join_implied_equalities is slightly tricky
    3371             :      * because the rel could be a child rel rather than a true baserel, and in
    3372             :      * that case we must remove its parents' relid(s) from all_baserels.
    3373             :      */
    3374         450 :     if (rel->reloptkind == RELOPT_OTHER_MEMBER_REL)
    3375          48 :         otherrels = bms_difference(root->all_baserels,
    3376          48 :                                    find_childrel_parents(root, rel));
    3377             :     else
    3378         402 :         otherrels = bms_difference(root->all_baserels, rel->relids);
    3379             : 
    3380         450 :     if (!bms_is_empty(otherrels))
    3381             :         clauselist =
    3382          56 :             list_concat(clauselist,
    3383          56 :                         generate_join_implied_equalities(root,
    3384          56 :                                                          bms_union(rel->relids,
    3385             :                                                                    otherrels),
    3386             :                                                          otherrels,
    3387             :                                                          rel));
    3388             : 
    3389             :     /*
    3390             :      * Normally we remove quals that are implied by a partial index's
    3391             :      * predicate from indrestrictinfo, indicating that they need not be
    3392             :      * checked explicitly by an indexscan plan using this index.  However, if
    3393             :      * the rel is a target relation of UPDATE/DELETE/SELECT FOR UPDATE, we
    3394             :      * cannot remove such quals from the plan, because they need to be in the
    3395             :      * plan so that they will be properly rechecked by EvalPlanQual testing.
    3396             :      * Some day we might want to remove such quals from the main plan anyway
    3397             :      * and pass them through to EvalPlanQual via a side channel; but for now,
    3398             :      * we just don't remove implied quals at all for target relations.
    3399             :      */
    3400         796 :     is_target_rel = (rel->relid == root->parse->resultRelation ||
    3401         346 :                      get_plan_rowmark(root->rowMarks, rel->relid) != NULL);
    3402             : 
    3403             :     /*
    3404             :      * Now try to prove each index predicate true, and compute the
    3405             :      * indrestrictinfo lists for partial indexes.  Note that we compute the
    3406             :      * indrestrictinfo list even for non-predOK indexes; this might seem
    3407             :      * wasteful, but we may be able to use such indexes in OR clauses, cf
    3408             :      * generate_bitmap_or_paths().
    3409             :      */
    3410        1328 :     foreach(lc, rel->indexlist)
    3411             :     {
    3412         878 :         IndexOptInfo *index = (IndexOptInfo *) lfirst(lc);
    3413             :         ListCell   *lcr;
    3414             : 
    3415         878 :         if (index->indpred == NIL)
    3416         200 :             continue;           /* ignore non-partial indexes here */
    3417             : 
    3418         678 :         if (!index->predOK)      /* don't repeat work if already proven OK */
    3419         678 :             index->predOK = predicate_implied_by(index->indpred, clauselist,
    3420             :                                                  false);
    3421             : 
    3422             :         /* If rel is an update target, leave indrestrictinfo as set above */
    3423         678 :         if (is_target_rel)
    3424         152 :             continue;
    3425             : 
    3426             :         /* Else compute indrestrictinfo as the non-implied quals */
    3427         526 :         index->indrestrictinfo = NIL;
    3428        1222 :         foreach(lcr, rel->baserestrictinfo)
    3429             :         {
    3430         696 :             RestrictInfo *rinfo = (RestrictInfo *) lfirst(lcr);
    3431             : 
    3432             :             /* predicate_implied_by() assumes first arg is immutable */
    3433         696 :             if (contain_mutable_functions((Node *) rinfo->clause) ||
    3434         696 :                 !predicate_implied_by(list_make1(rinfo->clause),
    3435             :                                       index->indpred, false))
    3436         488 :                 index->indrestrictinfo = lappend(index->indrestrictinfo, rinfo);
    3437             :         }
    3438             :     }
    3439             : }
    3440             : 
    3441             : /****************************************************************************
    3442             :  *              ----  ROUTINES TO CHECK EXTERNALLY-VISIBLE CONDITIONS  ----
    3443             :  ****************************************************************************/
    3444             : 
    3445             : /*
    3446             :  * ec_member_matches_indexcol
    3447             :  *    Test whether an EquivalenceClass member matches an index column.
    3448             :  *
    3449             :  * This is a callback for use by generate_implied_equalities_for_column.
    3450             :  */
    3451             : static bool
    3452      147332 : ec_member_matches_indexcol(PlannerInfo *root, RelOptInfo *rel,
    3453             :                            EquivalenceClass *ec, EquivalenceMember *em,
    3454             :                            void *arg)
    3455             : {
    3456      147332 :     IndexOptInfo *index = ((ec_member_matches_arg *) arg)->index;
    3457      147332 :     int         indexcol = ((ec_member_matches_arg *) arg)->indexcol;
    3458             :     Oid         curFamily;
    3459             :     Oid         curCollation;
    3460             : 
    3461             :     Assert(indexcol < index->nkeycolumns);
    3462             : 
    3463      147332 :     curFamily = index->opfamily[indexcol];
    3464      147332 :     curCollation = index->indexcollations[indexcol];
    3465             : 
    3466             :     /*
    3467             :      * If it's a btree index, we can reject it if its opfamily isn't
    3468             :      * compatible with the EC, since no clause generated from the EC could be
    3469             :      * used with the index.  For non-btree indexes, we can't easily tell
    3470             :      * whether clauses generated from the EC could be used with the index, so
    3471             :      * don't check the opfamily.  This might mean we return "true" for a
    3472             :      * useless EC, so we have to recheck the results of
    3473             :      * generate_implied_equalities_for_column; see
    3474             :      * match_eclass_clauses_to_index.
    3475             :      */
    3476      147332 :     if (index->relam == BTREE_AM_OID &&
    3477      147304 :         !list_member_oid(ec->ec_opfamilies, curFamily))
    3478       46058 :         return false;
    3479             : 
    3480             :     /* We insist on collation match for all index types, though */
    3481      101274 :     if (!IndexCollMatchesExprColl(curCollation, ec->ec_collation))
    3482           6 :         return false;
    3483             : 
    3484      101268 :     return match_index_to_operand((Node *) em->em_expr, indexcol, index);
    3485             : }
    3486             : 
    3487             : /*
    3488             :  * relation_has_unique_index_for
    3489             :  *    Determine whether the relation provably has at most one row satisfying
    3490             :  *    a set of equality conditions, because the conditions constrain all
    3491             :  *    columns of some unique index.
    3492             :  *
    3493             :  * The conditions can be represented in either or both of two ways:
    3494             :  * 1. A list of RestrictInfo nodes, where the caller has already determined
    3495             :  * that each condition is a mergejoinable equality with an expression in
    3496             :  * this relation on one side, and an expression not involving this relation
    3497             :  * on the other.  The transient outer_is_left flag is used to identify which
    3498             :  * side we should look at: left side if outer_is_left is false, right side
    3499             :  * if it is true.
    3500             :  * 2. A list of expressions in this relation, and a corresponding list of
    3501             :  * equality operators. The caller must have already checked that the operators
    3502             :  * represent equality.  (Note: the operators could be cross-type; the
    3503             :  * expressions should correspond to their RHS inputs.)
    3504             :  *
    3505             :  * The caller need only supply equality conditions arising from joins;
    3506             :  * this routine automatically adds in any usable baserestrictinfo clauses.
    3507             :  * (Note that the passed-in restrictlist will be destructively modified!)
    3508             :  */
    3509             : bool
    3510      116814 : relation_has_unique_index_for(PlannerInfo *root, RelOptInfo *rel,
    3511             :                               List *restrictlist,
    3512             :                               List *exprlist, List *oprlist)
    3513             : {
    3514             :     ListCell   *ic;
    3515             : 
    3516             :     Assert(list_length(exprlist) == list_length(oprlist));
    3517             : 
    3518             :     /* Short-circuit if no indexes... */
    3519      116814 :     if (rel->indexlist == NIL)
    3520         284 :         return false;
    3521             : 
    3522             :     /*
    3523             :      * Examine the rel's restriction clauses for usable var = const clauses
    3524             :      * that we can add to the restrictlist.
    3525             :      */
    3526      221916 :     foreach(ic, rel->baserestrictinfo)
    3527             :     {
    3528      105386 :         RestrictInfo *restrictinfo = (RestrictInfo *) lfirst(ic);
    3529             : 
    3530             :         /*
    3531             :          * Note: can_join won't be set for a restriction clause, but
    3532             :          * mergeopfamilies will be if it has a mergejoinable operator and
    3533             :          * doesn't contain volatile functions.
    3534             :          */
    3535      105386 :         if (restrictinfo->mergeopfamilies == NIL)
    3536       42362 :             continue;           /* not mergejoinable */
    3537             : 
    3538             :         /*
    3539             :          * The clause certainly doesn't refer to anything but the given rel.
    3540             :          * If either side is pseudoconstant then we can use it.
    3541             :          */
    3542       63024 :         if (bms_is_empty(restrictinfo->left_relids))
    3543             :         {
    3544             :             /* righthand side is inner */
    3545        1458 :             restrictinfo->outer_is_left = true;
    3546             :         }
    3547       61566 :         else if (bms_is_empty(restrictinfo->right_relids))
    3548             :         {
    3549             :             /* lefthand side is inner */
    3550       61536 :             restrictinfo->outer_is_left = false;
    3551             :         }
    3552             :         else
    3553          30 :             continue;
    3554             : 
    3555             :         /* OK, add to list */
    3556       62994 :         restrictlist = lappend(restrictlist, restrictinfo);
    3557             :     }
    3558             : 
    3559             :     /* Short-circuit the easy case */
    3560      116530 :     if (restrictlist == NIL && exprlist == NIL)
    3561         148 :         return false;
    3562             : 
    3563             :     /* Examine each index of the relation ... */
    3564      307794 :     foreach(ic, rel->indexlist)
    3565             :     {
    3566      257602 :         IndexOptInfo *ind = (IndexOptInfo *) lfirst(ic);
    3567             :         int         c;
    3568             : 
    3569             :         /*
    3570             :          * If the index is not unique, or not immediately enforced, or if it's
    3571             :          * a partial index that doesn't match the query, it's useless here.
    3572             :          */
    3573      257602 :         if (!ind->unique || !ind->immediate ||
    3574      176392 :             (ind->indpred != NIL && !ind->predOK))
    3575       81210 :             continue;
    3576             : 
    3577             :         /*
    3578             :          * Try to find each index column in the lists of conditions.  This is
    3579             :          * O(N^2) or worse, but we expect all the lists to be short.
    3580             :          */
    3581      306162 :         for (c = 0; c < ind->nkeycolumns; c++)
    3582             :         {
    3583      239972 :             bool        matched = false;
    3584             :             ListCell   *lc;
    3585             :             ListCell   *lc2;
    3586             : 
    3587      478266 :             foreach(lc, restrictlist)
    3588             :             {
    3589      368064 :                 RestrictInfo *rinfo = (RestrictInfo *) lfirst(lc);
    3590             :                 Node       *rexpr;
    3591             : 
    3592             :                 /*
    3593             :                  * The condition's equality operator must be a member of the
    3594             :                  * index opfamily, else it is not asserting the right kind of
    3595             :                  * equality behavior for this index.  We check this first
    3596             :                  * since it's probably cheaper than match_index_to_operand().
    3597             :                  */
    3598      368064 :                 if (!list_member_oid(rinfo->mergeopfamilies, ind->opfamily[c]))
    3599       93608 :                     continue;
    3600             : 
    3601             :                 /*
    3602             :                  * XXX at some point we may need to check collations here too.
    3603             :                  * For the moment we assume all collations reduce to the same
    3604             :                  * notion of equality.
    3605             :                  */
    3606             : 
    3607             :                 /* OK, see if the condition operand matches the index key */
    3608      274456 :                 if (rinfo->outer_is_left)
    3609      135844 :                     rexpr = get_rightop(rinfo->clause);
    3610             :                 else
    3611      138612 :                     rexpr = get_leftop(rinfo->clause);
    3612             : 
    3613      274456 :                 if (match_index_to_operand(rexpr, c, ind))
    3614             :                 {
    3615      129770 :                     matched = true; /* column is unique */
    3616      129770 :                     break;
    3617             :                 }
    3618             :             }
    3619             : 
    3620      239972 :             if (matched)
    3621      129770 :                 continue;
    3622             : 
    3623      110202 :             forboth(lc, exprlist, lc2, oprlist)
    3624             :             {
    3625           0 :                 Node       *expr = (Node *) lfirst(lc);
    3626           0 :                 Oid         opr = lfirst_oid(lc2);
    3627             : 
    3628             :                 /* See if the expression matches the index key */
    3629           0 :                 if (!match_index_to_operand(expr, c, ind))
    3630           0 :                     continue;
    3631             : 
    3632             :                 /*
    3633             :                  * The equality operator must be a member of the index
    3634             :                  * opfamily, else it is not asserting the right kind of
    3635             :                  * equality behavior for this index.  We assume the caller
    3636             :                  * determined it is an equality operator, so we don't need to
    3637             :                  * check any more tightly than this.
    3638             :                  */
    3639           0 :                 if (!op_in_opfamily(opr, ind->opfamily[c]))
    3640           0 :                     continue;
    3641             : 
    3642             :                 /*
    3643             :                  * XXX at some point we may need to check collations here too.
    3644             :                  * For the moment we assume all collations reduce to the same
    3645             :                  * notion of equality.
    3646             :                  */
    3647             : 
    3648           0 :                 matched = true; /* column is unique */
    3649           0 :                 break;
    3650             :             }
    3651             : 
    3652      110202 :             if (!matched)
    3653      110202 :                 break;          /* no match; this index doesn't help us */
    3654             :         }
    3655             : 
    3656             :         /* Matched all key columns of this index? */
    3657      176392 :         if (c == ind->nkeycolumns)
    3658       66190 :             return true;
    3659             :     }
    3660             : 
    3661       50192 :     return false;
    3662             : }
    3663             : 
    3664             : /*
    3665             :  * indexcol_is_bool_constant_for_query
    3666             :  *
    3667             :  * If an index column is constrained to have a constant value by the query's
    3668             :  * WHERE conditions, then it's irrelevant for sort-order considerations.
    3669             :  * Usually that means we have a restriction clause WHERE indexcol = constant,
    3670             :  * which gets turned into an EquivalenceClass containing a constant, which
    3671             :  * is recognized as redundant by build_index_pathkeys().  But if the index
    3672             :  * column is a boolean variable (or expression), then we are not going to
    3673             :  * see WHERE indexcol = constant, because expression preprocessing will have
    3674             :  * simplified that to "WHERE indexcol" or "WHERE NOT indexcol".  So we are not
    3675             :  * going to have a matching EquivalenceClass (unless the query also contains
    3676             :  * "ORDER BY indexcol").  To allow such cases to work the same as they would
    3677             :  * for non-boolean values, this function is provided to detect whether the
    3678             :  * specified index column matches a boolean restriction clause.
    3679             :  */
    3680             : bool
    3681      264204 : indexcol_is_bool_constant_for_query(PlannerInfo *root,
    3682             :                                     IndexOptInfo *index,
    3683             :                                     int indexcol)
    3684             : {
    3685             :     ListCell   *lc;
    3686             : 
    3687             :     /* If the index isn't boolean, we can't possibly get a match */
    3688      264204 :     if (!IsBooleanOpfamily(index->opfamily[indexcol]))
    3689      263988 :         return false;
    3690             : 
    3691             :     /* Check each restriction clause for the index's rel */
    3692         240 :     foreach(lc, index->rel->baserestrictinfo)
    3693             :     {
    3694          96 :         RestrictInfo *rinfo = (RestrictInfo *) lfirst(lc);
    3695             : 
    3696             :         /*
    3697             :          * As in match_clause_to_indexcol, never match pseudoconstants to
    3698             :          * indexes.  (It might be semantically okay to do so here, but the
    3699             :          * odds of getting a match are negligible, so don't waste the cycles.)
    3700             :          */
    3701          96 :         if (rinfo->pseudoconstant)
    3702           0 :             continue;
    3703             : 
    3704             :         /* See if we can match the clause's expression to the index column */
    3705          96 :         if (match_boolean_index_clause(root, rinfo, indexcol, index))
    3706          72 :             return true;
    3707             :     }
    3708             : 
    3709         144 :     return false;
    3710             : }
    3711             : 
    3712             : 
    3713             : /****************************************************************************
    3714             :  *              ----  ROUTINES TO CHECK OPERANDS  ----
    3715             :  ****************************************************************************/
    3716             : 
    3717             : /*
    3718             :  * match_index_to_operand()
    3719             :  *    Generalized test for a match between an index's key
    3720             :  *    and the operand on one side of a restriction or join clause.
    3721             :  *
    3722             :  * operand: the nodetree to be compared to the index
    3723             :  * indexcol: the column number of the index (counting from 0)
    3724             :  * index: the index of interest
    3725             :  *
    3726             :  * Note that we aren't interested in collations here; the caller must check
    3727             :  * for a collation match, if it's dealing with an operator where that matters.
    3728             :  *
    3729             :  * This is exported for use in selfuncs.c.
    3730             :  */
    3731             : bool
    3732     1932602 : match_index_to_operand(Node *operand,
    3733             :                        int indexcol,
    3734             :                        IndexOptInfo *index)
    3735             : {
    3736             :     int         indkey;
    3737             : 
    3738             :     /*
    3739             :      * Ignore any RelabelType node above the operand.   This is needed to be
    3740             :      * able to apply indexscanning in binary-compatible-operator cases. Note:
    3741             :      * we can assume there is at most one RelabelType node;
    3742             :      * eval_const_expressions() will have simplified if more than one.
    3743             :      */
    3744     1932602 :     if (operand && IsA(operand, RelabelType))
    3745       13340 :         operand = (Node *) ((RelabelType *) operand)->arg;
    3746             : 
    3747     1932602 :     indkey = index->indexkeys[indexcol];
    3748     1932602 :     if (indkey != 0)
    3749             :     {
    3750             :         /*
    3751             :          * Simple index column; operand must be a matching Var.
    3752             :          */
    3753     1929428 :         if (operand && IsA(operand, Var) &&
    3754     1476118 :             index->rel->relid == ((Var *) operand)->varno &&
    3755     1372676 :             indkey == ((Var *) operand)->varattno)
    3756      487316 :             return true;
    3757             :     }
    3758             :     else
    3759             :     {
    3760             :         /*
    3761             :          * Index expression; find the correct expression.  (This search could
    3762             :          * be avoided, at the cost of complicating all the callers of this
    3763             :          * routine; doesn't seem worth it.)
    3764             :          */
    3765             :         ListCell   *indexpr_item;
    3766             :         int         i;
    3767             :         Node       *indexkey;
    3768             : 
    3769        3174 :         indexpr_item = list_head(index->indexprs);
    3770        3174 :         for (i = 0; i < indexcol; i++)
    3771             :         {
    3772           0 :             if (index->indexkeys[i] == 0)
    3773             :             {
    3774           0 :                 if (indexpr_item == NULL)
    3775           0 :                     elog(ERROR, "wrong number of index expressions");
    3776           0 :                 indexpr_item = lnext(index->indexprs, indexpr_item);
    3777             :             }
    3778             :         }
    3779        3174 :         if (indexpr_item == NULL)
    3780           0 :             elog(ERROR, "wrong number of index expressions");
    3781        3174 :         indexkey = (Node *) lfirst(indexpr_item);
    3782             : 
    3783             :         /*
    3784             :          * Does it match the operand?  Again, strip any relabeling.
    3785             :          */
    3786        3174 :         if (indexkey && IsA(indexkey, RelabelType))
    3787          10 :             indexkey = (Node *) ((RelabelType *) indexkey)->arg;
    3788             : 
    3789        3174 :         if (equal(indexkey, operand))
    3790        1346 :             return true;
    3791             :     }
    3792             : 
    3793     1443940 :     return false;
    3794             : }
    3795             : 
    3796             : /*
    3797             :  * is_pseudo_constant_for_index()
    3798             :  *    Test whether the given expression can be used as an indexscan
    3799             :  *    comparison value.
    3800             :  *
    3801             :  * An indexscan comparison value must not contain any volatile functions,
    3802             :  * and it can't contain any Vars of the index's own table.  Vars of
    3803             :  * other tables are okay, though; in that case we'd be producing an
    3804             :  * indexqual usable in a parameterized indexscan.  This is, therefore,
    3805             :  * a weaker condition than is_pseudo_constant_clause().
    3806             :  *
    3807             :  * This function is exported for use by planner support functions,
    3808             :  * which will have available the IndexOptInfo, but not any RestrictInfo
    3809             :  * infrastructure.  It is making the same test made by functions above
    3810             :  * such as match_opclause_to_indexcol(), but those rely where possible
    3811             :  * on RestrictInfo information about variable membership.
    3812             :  *
    3813             :  * expr: the nodetree to be checked
    3814             :  * index: the index of interest
    3815             :  */
    3816             : bool
    3817           0 : is_pseudo_constant_for_index(PlannerInfo *root, Node *expr, IndexOptInfo *index)
    3818             : {
    3819             :     /* pull_varnos is cheaper than volatility check, so do that first */
    3820           0 :     if (bms_is_member(index->rel->relid, pull_varnos(root, expr)))
    3821           0 :         return false;           /* no good, contains Var of table */
    3822           0 :     if (contain_volatile_functions(expr))
    3823           0 :         return false;           /* no good, volatile comparison value */
    3824           0 :     return true;
    3825             : }

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