LCOV - code coverage report
Current view: top level - src/backend/optimizer/path - allpaths.c (source / functions) Hit Total Coverage
Test: PostgreSQL 12beta2 Lines: 868 918 94.6 %
Date: 2019-06-18 07:06:57 Functions: 46 46 100.0 %
Legend: Lines: hit not hit

          Line data    Source code
       1             : /*-------------------------------------------------------------------------
       2             :  *
       3             :  * allpaths.c
       4             :  *    Routines to find possible search paths for processing a query
       5             :  *
       6             :  * Portions Copyright (c) 1996-2019, PostgreSQL Global Development Group
       7             :  * Portions Copyright (c) 1994, Regents of the University of California
       8             :  *
       9             :  *
      10             :  * IDENTIFICATION
      11             :  *    src/backend/optimizer/path/allpaths.c
      12             :  *
      13             :  *-------------------------------------------------------------------------
      14             :  */
      15             : 
      16             : #include "postgres.h"
      17             : 
      18             : #include <limits.h>
      19             : #include <math.h>
      20             : 
      21             : #include "access/sysattr.h"
      22             : #include "access/tsmapi.h"
      23             : #include "catalog/pg_class.h"
      24             : #include "catalog/pg_operator.h"
      25             : #include "catalog/pg_proc.h"
      26             : #include "foreign/fdwapi.h"
      27             : #include "miscadmin.h"
      28             : #include "nodes/makefuncs.h"
      29             : #include "nodes/nodeFuncs.h"
      30             : #ifdef OPTIMIZER_DEBUG
      31             : #include "nodes/print.h"
      32             : #endif
      33             : #include "optimizer/appendinfo.h"
      34             : #include "optimizer/clauses.h"
      35             : #include "optimizer/cost.h"
      36             : #include "optimizer/geqo.h"
      37             : #include "optimizer/inherit.h"
      38             : #include "optimizer/optimizer.h"
      39             : #include "optimizer/pathnode.h"
      40             : #include "optimizer/paths.h"
      41             : #include "optimizer/plancat.h"
      42             : #include "optimizer/planner.h"
      43             : #include "optimizer/restrictinfo.h"
      44             : #include "optimizer/tlist.h"
      45             : #include "parser/parse_clause.h"
      46             : #include "parser/parsetree.h"
      47             : #include "partitioning/partbounds.h"
      48             : #include "partitioning/partprune.h"
      49             : #include "rewrite/rewriteManip.h"
      50             : #include "utils/lsyscache.h"
      51             : 
      52             : 
      53             : /* results of subquery_is_pushdown_safe */
      54             : typedef struct pushdown_safety_info
      55             : {
      56             :     bool       *unsafeColumns;  /* which output columns are unsafe to use */
      57             :     bool        unsafeVolatile; /* don't push down volatile quals */
      58             :     bool        unsafeLeaky;    /* don't push down leaky quals */
      59             : } pushdown_safety_info;
      60             : 
      61             : /* These parameters are set by GUC */
      62             : bool        enable_geqo = false;    /* just in case GUC doesn't set it */
      63             : int         geqo_threshold;
      64             : int         min_parallel_table_scan_size;
      65             : int         min_parallel_index_scan_size;
      66             : 
      67             : /* Hook for plugins to get control in set_rel_pathlist() */
      68             : set_rel_pathlist_hook_type set_rel_pathlist_hook = NULL;
      69             : 
      70             : /* Hook for plugins to replace standard_join_search() */
      71             : join_search_hook_type join_search_hook = NULL;
      72             : 
      73             : 
      74             : static void set_base_rel_consider_startup(PlannerInfo *root);
      75             : static void set_base_rel_sizes(PlannerInfo *root);
      76             : static void set_base_rel_pathlists(PlannerInfo *root);
      77             : static void set_rel_size(PlannerInfo *root, RelOptInfo *rel,
      78             :                          Index rti, RangeTblEntry *rte);
      79             : static void set_rel_pathlist(PlannerInfo *root, RelOptInfo *rel,
      80             :                              Index rti, RangeTblEntry *rte);
      81             : static void set_plain_rel_size(PlannerInfo *root, RelOptInfo *rel,
      82             :                                RangeTblEntry *rte);
      83             : static void create_plain_partial_paths(PlannerInfo *root, RelOptInfo *rel);
      84             : static void set_rel_consider_parallel(PlannerInfo *root, RelOptInfo *rel,
      85             :                                       RangeTblEntry *rte);
      86             : static void set_plain_rel_pathlist(PlannerInfo *root, RelOptInfo *rel,
      87             :                                    RangeTblEntry *rte);
      88             : static void set_tablesample_rel_size(PlannerInfo *root, RelOptInfo *rel,
      89             :                                      RangeTblEntry *rte);
      90             : static void set_tablesample_rel_pathlist(PlannerInfo *root, RelOptInfo *rel,
      91             :                                          RangeTblEntry *rte);
      92             : static void set_foreign_size(PlannerInfo *root, RelOptInfo *rel,
      93             :                              RangeTblEntry *rte);
      94             : static void set_foreign_pathlist(PlannerInfo *root, RelOptInfo *rel,
      95             :                                  RangeTblEntry *rte);
      96             : static void set_append_rel_size(PlannerInfo *root, RelOptInfo *rel,
      97             :                                 Index rti, RangeTblEntry *rte);
      98             : static void set_append_rel_pathlist(PlannerInfo *root, RelOptInfo *rel,
      99             :                                     Index rti, RangeTblEntry *rte);
     100             : static void generate_orderedappend_paths(PlannerInfo *root, RelOptInfo *rel,
     101             :                                          List *live_childrels,
     102             :                                          List *all_child_pathkeys,
     103             :                                          List *partitioned_rels);
     104             : static Path *get_cheapest_parameterized_child_path(PlannerInfo *root,
     105             :                                                    RelOptInfo *rel,
     106             :                                                    Relids required_outer);
     107             : static void accumulate_append_subpath(Path *path,
     108             :                                       List **subpaths, List **special_subpaths);
     109             : static Path *get_singleton_append_subpath(Path *path);
     110             : static void set_dummy_rel_pathlist(RelOptInfo *rel);
     111             : static void set_subquery_pathlist(PlannerInfo *root, RelOptInfo *rel,
     112             :                                   Index rti, RangeTblEntry *rte);
     113             : static void set_function_pathlist(PlannerInfo *root, RelOptInfo *rel,
     114             :                                   RangeTblEntry *rte);
     115             : static void set_values_pathlist(PlannerInfo *root, RelOptInfo *rel,
     116             :                                 RangeTblEntry *rte);
     117             : static void set_tablefunc_pathlist(PlannerInfo *root, RelOptInfo *rel,
     118             :                                    RangeTblEntry *rte);
     119             : static void set_cte_pathlist(PlannerInfo *root, RelOptInfo *rel,
     120             :                              RangeTblEntry *rte);
     121             : static void set_namedtuplestore_pathlist(PlannerInfo *root, RelOptInfo *rel,
     122             :                                          RangeTblEntry *rte);
     123             : static void set_result_pathlist(PlannerInfo *root, RelOptInfo *rel,
     124             :                                 RangeTblEntry *rte);
     125             : static void set_worktable_pathlist(PlannerInfo *root, RelOptInfo *rel,
     126             :                                    RangeTblEntry *rte);
     127             : static RelOptInfo *make_rel_from_joinlist(PlannerInfo *root, List *joinlist);
     128             : static bool subquery_is_pushdown_safe(Query *subquery, Query *topquery,
     129             :                                       pushdown_safety_info *safetyInfo);
     130             : static bool recurse_pushdown_safe(Node *setOp, Query *topquery,
     131             :                                   pushdown_safety_info *safetyInfo);
     132             : static void check_output_expressions(Query *subquery,
     133             :                                      pushdown_safety_info *safetyInfo);
     134             : static void compare_tlist_datatypes(List *tlist, List *colTypes,
     135             :                                     pushdown_safety_info *safetyInfo);
     136             : static bool targetIsInAllPartitionLists(TargetEntry *tle, Query *query);
     137             : static bool qual_is_pushdown_safe(Query *subquery, Index rti, Node *qual,
     138             :                                   pushdown_safety_info *safetyInfo);
     139             : static void subquery_push_qual(Query *subquery,
     140             :                                RangeTblEntry *rte, Index rti, Node *qual);
     141             : static void recurse_push_qual(Node *setOp, Query *topquery,
     142             :                               RangeTblEntry *rte, Index rti, Node *qual);
     143             : static void remove_unused_subquery_outputs(Query *subquery, RelOptInfo *rel);
     144             : 
     145             : 
     146             : /*
     147             :  * make_one_rel
     148             :  *    Finds all possible access paths for executing a query, returning a
     149             :  *    single rel that represents the join of all base rels in the query.
     150             :  */
     151             : RelOptInfo *
     152      186668 : make_one_rel(PlannerInfo *root, List *joinlist)
     153             : {
     154             :     RelOptInfo *rel;
     155             :     Index       rti;
     156             :     double      total_pages;
     157             : 
     158             :     /*
     159             :      * Construct the all_baserels Relids set.
     160             :      */
     161      186668 :     root->all_baserels = NULL;
     162      608996 :     for (rti = 1; rti < root->simple_rel_array_size; rti++)
     163             :     {
     164      422328 :         RelOptInfo *brel = root->simple_rel_array[rti];
     165             : 
     166             :         /* there may be empty slots corresponding to non-baserel RTEs */
     167      422328 :         if (brel == NULL)
     168      141726 :             continue;
     169             : 
     170             :         Assert(brel->relid == rti); /* sanity check on array */
     171             : 
     172             :         /* ignore RTEs that are "other rels" */
     173      280602 :         if (brel->reloptkind != RELOPT_BASEREL)
     174       34282 :             continue;
     175             : 
     176      246320 :         root->all_baserels = bms_add_member(root->all_baserels, brel->relid);
     177             :     }
     178             : 
     179             :     /* Mark base rels as to whether we care about fast-start plans */
     180      186668 :     set_base_rel_consider_startup(root);
     181             : 
     182             :     /*
     183             :      * Compute size estimates and consider_parallel flags for each base rel.
     184             :      */
     185      186668 :     set_base_rel_sizes(root);
     186             : 
     187             :     /*
     188             :      * We should now have size estimates for every actual table involved in
     189             :      * the query, and we also know which if any have been deleted from the
     190             :      * query by join removal, pruned by partition pruning, or eliminated by
     191             :      * constraint exclusion.  So we can now compute total_table_pages.
     192             :      *
     193             :      * Note that appendrels are not double-counted here, even though we don't
     194             :      * bother to distinguish RelOptInfos for appendrel parents, because the
     195             :      * parents will have pages = 0.
     196             :      *
     197             :      * XXX if a table is self-joined, we will count it once per appearance,
     198             :      * which perhaps is the wrong thing ... but that's not completely clear,
     199             :      * and detecting self-joins here is difficult, so ignore it for now.
     200             :      */
     201      186668 :     total_pages = 0;
     202      608996 :     for (rti = 1; rti < root->simple_rel_array_size; rti++)
     203             :     {
     204      422328 :         RelOptInfo *brel = root->simple_rel_array[rti];
     205             : 
     206      422328 :         if (brel == NULL)
     207      141726 :             continue;
     208             : 
     209             :         Assert(brel->relid == rti); /* sanity check on array */
     210             : 
     211      280602 :         if (IS_DUMMY_REL(brel))
     212         604 :             continue;
     213             : 
     214      279998 :         if (IS_SIMPLE_REL(brel))
     215      268046 :             total_pages += (double) brel->pages;
     216             :     }
     217      186668 :     root->total_table_pages = total_pages;
     218             : 
     219             :     /*
     220             :      * Generate access paths for each base rel.
     221             :      */
     222      186668 :     set_base_rel_pathlists(root);
     223             : 
     224             :     /*
     225             :      * Generate access paths for the entire join tree.
     226             :      */
     227      186668 :     rel = make_rel_from_joinlist(root, joinlist);
     228             : 
     229             :     /*
     230             :      * The result should join all and only the query's base rels.
     231             :      */
     232             :     Assert(bms_equal(rel->relids, root->all_baserels));
     233             : 
     234      186668 :     return rel;
     235             : }
     236             : 
     237             : /*
     238             :  * set_base_rel_consider_startup
     239             :  *    Set the consider_[param_]startup flags for each base-relation entry.
     240             :  *
     241             :  * For the moment, we only deal with consider_param_startup here; because the
     242             :  * logic for consider_startup is pretty trivial and is the same for every base
     243             :  * relation, we just let build_simple_rel() initialize that flag correctly to
     244             :  * start with.  If that logic ever gets more complicated it would probably
     245             :  * be better to move it here.
     246             :  */
     247             : static void
     248      186668 : set_base_rel_consider_startup(PlannerInfo *root)
     249             : {
     250             :     /*
     251             :      * Since parameterized paths can only be used on the inside of a nestloop
     252             :      * join plan, there is usually little value in considering fast-start
     253             :      * plans for them.  However, for relations that are on the RHS of a SEMI
     254             :      * or ANTI join, a fast-start plan can be useful because we're only going
     255             :      * to care about fetching one tuple anyway.
     256             :      *
     257             :      * To minimize growth of planning time, we currently restrict this to
     258             :      * cases where the RHS is a single base relation, not a join; there is no
     259             :      * provision for consider_param_startup to get set at all on joinrels.
     260             :      * Also we don't worry about appendrels.  costsize.c's costing rules for
     261             :      * nestloop semi/antijoins don't consider such cases either.
     262             :      */
     263             :     ListCell   *lc;
     264             : 
     265      217360 :     foreach(lc, root->join_info_list)
     266             :     {
     267       30692 :         SpecialJoinInfo *sjinfo = (SpecialJoinInfo *) lfirst(lc);
     268             :         int         varno;
     269             : 
     270       39630 :         if ((sjinfo->jointype == JOIN_SEMI || sjinfo->jointype == JOIN_ANTI) &&
     271        8938 :             bms_get_singleton_member(sjinfo->syn_righthand, &varno))
     272             :         {
     273        8830 :             RelOptInfo *rel = find_base_rel(root, varno);
     274             : 
     275        8830 :             rel->consider_param_startup = true;
     276             :         }
     277             :     }
     278      186668 : }
     279             : 
     280             : /*
     281             :  * set_base_rel_sizes
     282             :  *    Set the size estimates (rows and widths) for each base-relation entry.
     283             :  *    Also determine whether to consider parallel paths for base relations.
     284             :  *
     285             :  * We do this in a separate pass over the base rels so that rowcount
     286             :  * estimates are available for parameterized path generation, and also so
     287             :  * that each rel's consider_parallel flag is set correctly before we begin to
     288             :  * generate paths.
     289             :  */
     290             : static void
     291      186668 : set_base_rel_sizes(PlannerInfo *root)
     292             : {
     293             :     Index       rti;
     294             : 
     295      608996 :     for (rti = 1; rti < root->simple_rel_array_size; rti++)
     296             :     {
     297      422328 :         RelOptInfo *rel = root->simple_rel_array[rti];
     298             :         RangeTblEntry *rte;
     299             : 
     300             :         /* there may be empty slots corresponding to non-baserel RTEs */
     301      422328 :         if (rel == NULL)
     302      141726 :             continue;
     303             : 
     304             :         Assert(rel->relid == rti);   /* sanity check on array */
     305             : 
     306             :         /* ignore RTEs that are "other rels" */
     307      280602 :         if (rel->reloptkind != RELOPT_BASEREL)
     308       34282 :             continue;
     309             : 
     310      246320 :         rte = root->simple_rte_array[rti];
     311             : 
     312             :         /*
     313             :          * If parallelism is allowable for this query in general, see whether
     314             :          * it's allowable for this rel in particular.  We have to do this
     315             :          * before set_rel_size(), because (a) if this rel is an inheritance
     316             :          * parent, set_append_rel_size() will use and perhaps change the rel's
     317             :          * consider_parallel flag, and (b) for some RTE types, set_rel_size()
     318             :          * goes ahead and makes paths immediately.
     319             :          */
     320      246320 :         if (root->glob->parallelModeOK)
     321      188734 :             set_rel_consider_parallel(root, rel, rte);
     322             : 
     323      246320 :         set_rel_size(root, rel, rti, rte);
     324             :     }
     325      186668 : }
     326             : 
     327             : /*
     328             :  * set_base_rel_pathlists
     329             :  *    Finds all paths available for scanning each base-relation entry.
     330             :  *    Sequential scan and any available indices are considered.
     331             :  *    Each useful path is attached to its relation's 'pathlist' field.
     332             :  */
     333             : static void
     334      186668 : set_base_rel_pathlists(PlannerInfo *root)
     335             : {
     336             :     Index       rti;
     337             : 
     338      608996 :     for (rti = 1; rti < root->simple_rel_array_size; rti++)
     339             :     {
     340      422328 :         RelOptInfo *rel = root->simple_rel_array[rti];
     341             : 
     342             :         /* there may be empty slots corresponding to non-baserel RTEs */
     343      422328 :         if (rel == NULL)
     344      141726 :             continue;
     345             : 
     346             :         Assert(rel->relid == rti);   /* sanity check on array */
     347             : 
     348             :         /* ignore RTEs that are "other rels" */
     349      280602 :         if (rel->reloptkind != RELOPT_BASEREL)
     350       34282 :             continue;
     351             : 
     352      246320 :         set_rel_pathlist(root, rel, rti, root->simple_rte_array[rti]);
     353             :     }
     354      186668 : }
     355             : 
     356             : /*
     357             :  * set_rel_size
     358             :  *    Set size estimates for a base relation
     359             :  */
     360             : static void
     361      268514 : set_rel_size(PlannerInfo *root, RelOptInfo *rel,
     362             :              Index rti, RangeTblEntry *rte)
     363             : {
     364      514834 :     if (rel->reloptkind == RELOPT_BASEREL &&
     365      246320 :         relation_excluded_by_constraints(root, rel, rte))
     366             :     {
     367             :         /*
     368             :          * We proved we don't need to scan the rel via constraint exclusion,
     369             :          * so set up a single dummy path for it.  Here we only check this for
     370             :          * regular baserels; if it's an otherrel, CE was already checked in
     371             :          * set_append_rel_size().
     372             :          *
     373             :          * In this case, we go ahead and set up the relation's path right away
     374             :          * instead of leaving it for set_rel_pathlist to do.  This is because
     375             :          * we don't have a convention for marking a rel as dummy except by
     376             :          * assigning a dummy path to it.
     377             :          */
     378         250 :         set_dummy_rel_pathlist(rel);
     379             :     }
     380      268264 :     else if (rte->inh)
     381             :     {
     382             :         /* It's an "append relation", process accordingly */
     383        9604 :         set_append_rel_size(root, rel, rti, rte);
     384             :     }
     385             :     else
     386             :     {
     387      258660 :         switch (rel->rtekind)
     388             :         {
     389             :             case RTE_RELATION:
     390      218476 :                 if (rte->relkind == RELKIND_FOREIGN_TABLE)
     391             :                 {
     392             :                     /* Foreign table */
     393        1786 :                     set_foreign_size(root, rel, rte);
     394             :                 }
     395      216690 :                 else if (rte->relkind == RELKIND_PARTITIONED_TABLE)
     396             :                 {
     397             :                     /*
     398             :                      * We could get here if asked to scan a partitioned table
     399             :                      * with ONLY.  In that case we shouldn't scan any of the
     400             :                      * partitions, so mark it as a dummy rel.
     401             :                      */
     402          30 :                     set_dummy_rel_pathlist(rel);
     403             :                 }
     404      216660 :                 else if (rte->tablesample != NULL)
     405             :                 {
     406             :                     /* Sampled relation */
     407         180 :                     set_tablesample_rel_size(root, rel, rte);
     408             :                 }
     409             :                 else
     410             :                 {
     411             :                     /* Plain relation */
     412      216480 :                     set_plain_rel_size(root, rel, rte);
     413             :                 }
     414      218476 :                 break;
     415             :             case RTE_SUBQUERY:
     416             : 
     417             :                 /*
     418             :                  * Subqueries don't support making a choice between
     419             :                  * parameterized and unparameterized paths, so just go ahead
     420             :                  * and build their paths immediately.
     421             :                  */
     422        5488 :                 set_subquery_pathlist(root, rel, rti, rte);
     423        5488 :                 break;
     424             :             case RTE_FUNCTION:
     425       28740 :                 set_function_size_estimates(root, rel);
     426       28740 :                 break;
     427             :             case RTE_TABLEFUNC:
     428         140 :                 set_tablefunc_size_estimates(root, rel);
     429         140 :                 break;
     430             :             case RTE_VALUES:
     431        3774 :                 set_values_size_estimates(root, rel);
     432        3774 :                 break;
     433             :             case RTE_CTE:
     434             : 
     435             :                 /*
     436             :                  * CTEs don't support making a choice between parameterized
     437             :                  * and unparameterized paths, so just go ahead and build their
     438             :                  * paths immediately.
     439             :                  */
     440        1220 :                 if (rte->self_reference)
     441         326 :                     set_worktable_pathlist(root, rel, rte);
     442             :                 else
     443         894 :                     set_cte_pathlist(root, rel, rte);
     444        1220 :                 break;
     445             :             case RTE_NAMEDTUPLESTORE:
     446             :                 /* Might as well just build the path immediately */
     447         256 :                 set_namedtuplestore_pathlist(root, rel, rte);
     448         256 :                 break;
     449             :             case RTE_RESULT:
     450             :                 /* Might as well just build the path immediately */
     451         566 :                 set_result_pathlist(root, rel, rte);
     452         566 :                 break;
     453             :             default:
     454           0 :                 elog(ERROR, "unexpected rtekind: %d", (int) rel->rtekind);
     455             :                 break;
     456             :         }
     457             :     }
     458             : 
     459             :     /*
     460             :      * We insist that all non-dummy rels have a nonzero rowcount estimate.
     461             :      */
     462             :     Assert(rel->rows > 0 || IS_DUMMY_REL(rel));
     463      268514 : }
     464             : 
     465             : /*
     466             :  * set_rel_pathlist
     467             :  *    Build access paths for a base relation
     468             :  */
     469             : static void
     470      268530 : set_rel_pathlist(PlannerInfo *root, RelOptInfo *rel,
     471             :                  Index rti, RangeTblEntry *rte)
     472             : {
     473      268530 :     if (IS_DUMMY_REL(rel))
     474             :     {
     475             :         /* We already proved the relation empty, so nothing more to do */
     476             :     }
     477      268022 :     else if (rte->inh)
     478             :     {
     479             :         /* It's an "append relation", process accordingly */
     480        9460 :         set_append_rel_pathlist(root, rel, rti, rte);
     481             :     }
     482             :     else
     483             :     {
     484      258562 :         switch (rel->rtekind)
     485             :         {
     486             :             case RTE_RELATION:
     487      218446 :                 if (rte->relkind == RELKIND_FOREIGN_TABLE)
     488             :                 {
     489             :                     /* Foreign table */
     490        1786 :                     set_foreign_pathlist(root, rel, rte);
     491             :                 }
     492      216660 :                 else if (rte->tablesample != NULL)
     493             :                 {
     494             :                     /* Sampled relation */
     495         180 :                     set_tablesample_rel_pathlist(root, rel, rte);
     496             :                 }
     497             :                 else
     498             :                 {
     499             :                     /* Plain relation */
     500      216480 :                     set_plain_rel_pathlist(root, rel, rte);
     501             :                 }
     502      218446 :                 break;
     503             :             case RTE_SUBQUERY:
     504             :                 /* Subquery --- fully handled during set_rel_size */
     505        5420 :                 break;
     506             :             case RTE_FUNCTION:
     507             :                 /* RangeFunction */
     508       28740 :                 set_function_pathlist(root, rel, rte);
     509       28740 :                 break;
     510             :             case RTE_TABLEFUNC:
     511             :                 /* Table Function */
     512         140 :                 set_tablefunc_pathlist(root, rel, rte);
     513         140 :                 break;
     514             :             case RTE_VALUES:
     515             :                 /* Values list */
     516        3774 :                 set_values_pathlist(root, rel, rte);
     517        3774 :                 break;
     518             :             case RTE_CTE:
     519             :                 /* CTE reference --- fully handled during set_rel_size */
     520        1220 :                 break;
     521             :             case RTE_NAMEDTUPLESTORE:
     522             :                 /* tuplestore reference --- fully handled during set_rel_size */
     523         256 :                 break;
     524             :             case RTE_RESULT:
     525             :                 /* simple Result --- fully handled during set_rel_size */
     526         566 :                 break;
     527             :             default:
     528           0 :                 elog(ERROR, "unexpected rtekind: %d", (int) rel->rtekind);
     529             :                 break;
     530             :         }
     531             :     }
     532             : 
     533             :     /*
     534             :      * Allow a plugin to editorialize on the set of Paths for this base
     535             :      * relation.  It could add new paths (such as CustomPaths) by calling
     536             :      * add_path(), or add_partial_path() if parallel aware.  It could also
     537             :      * delete or modify paths added by the core code.
     538             :      */
     539      268530 :     if (set_rel_pathlist_hook)
     540           0 :         (*set_rel_pathlist_hook) (root, rel, rti, rte);
     541             : 
     542             :     /*
     543             :      * If this is a baserel, we should normally consider gathering any partial
     544             :      * paths we may have created for it.  We have to do this after calling the
     545             :      * set_rel_pathlist_hook, else it cannot add partial paths to be included
     546             :      * here.
     547             :      *
     548             :      * However, if this is an inheritance child, skip it.  Otherwise, we could
     549             :      * end up with a very large number of gather nodes, each trying to grab
     550             :      * its own pool of workers.  Instead, we'll consider gathering partial
     551             :      * paths for the parent appendrel.
     552             :      *
     553             :      * Also, if this is the topmost scan/join rel (that is, the only baserel),
     554             :      * we postpone gathering until the final scan/join targetlist is available
     555             :      * (see grouping_planner).
     556             :      */
     557      514850 :     if (rel->reloptkind == RELOPT_BASEREL &&
     558      246320 :         bms_membership(root->all_baserels) != BMS_SINGLETON)
     559      106118 :         generate_gather_paths(root, rel, false);
     560             : 
     561             :     /* Now find the cheapest of the paths for this rel */
     562      268530 :     set_cheapest(rel);
     563             : 
     564             : #ifdef OPTIMIZER_DEBUG
     565             :     debug_print_rel(root, rel);
     566             : #endif
     567      268530 : }
     568             : 
     569             : /*
     570             :  * set_plain_rel_size
     571             :  *    Set size estimates for a plain relation (no subquery, no inheritance)
     572             :  */
     573             : static void
     574      216480 : set_plain_rel_size(PlannerInfo *root, RelOptInfo *rel, RangeTblEntry *rte)
     575             : {
     576             :     /*
     577             :      * Test any partial indexes of rel for applicability.  We must do this
     578             :      * first since partial unique indexes can affect size estimates.
     579             :      */
     580      216480 :     check_index_predicates(root, rel);
     581             : 
     582             :     /* Mark rel with estimated output rows, width, etc */
     583      216480 :     set_baserel_size_estimates(root, rel);
     584      216480 : }
     585             : 
     586             : /*
     587             :  * If this relation could possibly be scanned from within a worker, then set
     588             :  * its consider_parallel flag.
     589             :  */
     590             : static void
     591      204294 : set_rel_consider_parallel(PlannerInfo *root, RelOptInfo *rel,
     592             :                           RangeTblEntry *rte)
     593             : {
     594             :     /*
     595             :      * The flag has previously been initialized to false, so we can just
     596             :      * return if it becomes clear that we can't safely set it.
     597             :      */
     598             :     Assert(!rel->consider_parallel);
     599             : 
     600             :     /* Don't call this if parallelism is disallowed for the entire query. */
     601             :     Assert(root->glob->parallelModeOK);
     602             : 
     603             :     /* This should only be called for baserels and appendrel children. */
     604             :     Assert(IS_SIMPLE_REL(rel));
     605             : 
     606             :     /* Assorted checks based on rtekind. */
     607      204294 :     switch (rte->rtekind)
     608             :     {
     609             :         case RTE_RELATION:
     610             : 
     611             :             /*
     612             :              * Currently, parallel workers can't access the leader's temporary
     613             :              * tables.  We could possibly relax this if the wrote all of its
     614             :              * local buffers at the start of the query and made no changes
     615             :              * thereafter (maybe we could allow hint bit changes), and if we
     616             :              * taught the workers to read them.  Writing a large number of
     617             :              * temporary buffers could be expensive, though, and we don't have
     618             :              * the rest of the necessary infrastructure right now anyway.  So
     619             :              * for now, bail out if we see a temporary table.
     620             :              */
     621      172498 :             if (get_rel_persistence(rte->relid) == RELPERSISTENCE_TEMP)
     622        3334 :                 return;
     623             : 
     624             :             /*
     625             :              * Table sampling can be pushed down to workers if the sample
     626             :              * function and its arguments are safe.
     627             :              */
     628      169164 :             if (rte->tablesample != NULL)
     629             :             {
     630         180 :                 char        proparallel = func_parallel(rte->tablesample->tsmhandler);
     631             : 
     632         180 :                 if (proparallel != PROPARALLEL_SAFE)
     633          36 :                     return;
     634         144 :                 if (!is_parallel_safe(root, (Node *) rte->tablesample->args))
     635           8 :                     return;
     636             :             }
     637             : 
     638             :             /*
     639             :              * Ask FDWs whether they can support performing a ForeignScan
     640             :              * within a worker.  Most often, the answer will be no.  For
     641             :              * example, if the nature of the FDW is such that it opens a TCP
     642             :              * connection with a remote server, each parallel worker would end
     643             :              * up with a separate connection, and these connections might not
     644             :              * be appropriately coordinated between workers and the leader.
     645             :              */
     646      169120 :             if (rte->relkind == RELKIND_FOREIGN_TABLE)
     647             :             {
     648             :                 Assert(rel->fdwroutine);
     649        1134 :                 if (!rel->fdwroutine->IsForeignScanParallelSafe)
     650        1076 :                     return;
     651          58 :                 if (!rel->fdwroutine->IsForeignScanParallelSafe(root, rel, rte))
     652           0 :                     return;
     653             :             }
     654             : 
     655             :             /*
     656             :              * There are additional considerations for appendrels, which we'll
     657             :              * deal with in set_append_rel_size and set_append_rel_pathlist.
     658             :              * For now, just set consider_parallel based on the rel's own
     659             :              * quals and targetlist.
     660             :              */
     661      168044 :             break;
     662             : 
     663             :         case RTE_SUBQUERY:
     664             : 
     665             :             /*
     666             :              * There's no intrinsic problem with scanning a subquery-in-FROM
     667             :              * (as distinct from a SubPlan or InitPlan) in a parallel worker.
     668             :              * If the subquery doesn't happen to have any parallel-safe paths,
     669             :              * then flagging it as consider_parallel won't change anything,
     670             :              * but that's true for plain tables, too.  We must set
     671             :              * consider_parallel based on the rel's own quals and targetlist,
     672             :              * so that if a subquery path is parallel-safe but the quals and
     673             :              * projection we're sticking onto it are not, we correctly mark
     674             :              * the SubqueryScanPath as not parallel-safe.  (Note that
     675             :              * set_subquery_pathlist() might push some of these quals down
     676             :              * into the subquery itself, but that doesn't change anything.)
     677             :              *
     678             :              * We can't push sub-select containing LIMIT/OFFSET to workers as
     679             :              * there is no guarantee that the row order will be fully
     680             :              * deterministic, and applying LIMIT/OFFSET will lead to
     681             :              * inconsistent results at the top-level.  (In some cases, where
     682             :              * the result is ordered, we could relax this restriction.  But it
     683             :              * doesn't currently seem worth expending extra effort to do so.)
     684             :              */
     685             :             {
     686        5264 :                 Query      *subquery = castNode(Query, rte->subquery);
     687             : 
     688        5264 :                 if (limit_needed(subquery))
     689         214 :                     return;
     690             :             }
     691        5050 :             break;
     692             : 
     693             :         case RTE_JOIN:
     694             :             /* Shouldn't happen; we're only considering baserels here. */
     695             :             Assert(false);
     696           0 :             return;
     697             : 
     698             :         case RTE_FUNCTION:
     699             :             /* Check for parallel-restricted functions. */
     700       23608 :             if (!is_parallel_safe(root, (Node *) rte->functions))
     701       20332 :                 return;
     702        3276 :             break;
     703             : 
     704             :         case RTE_TABLEFUNC:
     705             :             /* not parallel safe */
     706         140 :             return;
     707             : 
     708             :         case RTE_VALUES:
     709             :             /* Check for parallel-restricted functions. */
     710        1146 :             if (!is_parallel_safe(root, (Node *) rte->values_lists))
     711           4 :                 return;
     712        1142 :             break;
     713             : 
     714             :         case RTE_CTE:
     715             : 
     716             :             /*
     717             :              * CTE tuplestores aren't shared among parallel workers, so we
     718             :              * force all CTE scans to happen in the leader.  Also, populating
     719             :              * the CTE would require executing a subplan that's not available
     720             :              * in the worker, might be parallel-restricted, and must get
     721             :              * executed only once.
     722             :              */
     723         864 :             return;
     724             : 
     725             :         case RTE_NAMEDTUPLESTORE:
     726             : 
     727             :             /*
     728             :              * tuplestore cannot be shared, at least without more
     729             :              * infrastructure to support that.
     730             :              */
     731         240 :             return;
     732             : 
     733             :         case RTE_RESULT:
     734             :             /* RESULT RTEs, in themselves, are no problem. */
     735         534 :             break;
     736             :     }
     737             : 
     738             :     /*
     739             :      * If there's anything in baserestrictinfo that's parallel-restricted, we
     740             :      * give up on parallelizing access to this relation.  We could consider
     741             :      * instead postponing application of the restricted quals until we're
     742             :      * above all the parallelism in the plan tree, but it's not clear that
     743             :      * that would be a win in very many cases, and it might be tricky to make
     744             :      * outer join clauses work correctly.  It would likely break equivalence
     745             :      * classes, too.
     746             :      */
     747      178046 :     if (!is_parallel_safe(root, (Node *) rel->baserestrictinfo))
     748       23412 :         return;
     749             : 
     750             :     /*
     751             :      * Likewise, if the relation's outputs are not parallel-safe, give up.
     752             :      * (Usually, they're just Vars, but sometimes they're not.)
     753             :      */
     754      154634 :     if (!is_parallel_safe(root, (Node *) rel->reltarget->exprs))
     755          12 :         return;
     756             : 
     757             :     /* We have a winner. */
     758      154622 :     rel->consider_parallel = true;
     759             : }
     760             : 
     761             : /*
     762             :  * set_plain_rel_pathlist
     763             :  *    Build access paths for a plain relation (no subquery, no inheritance)
     764             :  */
     765             : static void
     766      216480 : set_plain_rel_pathlist(PlannerInfo *root, RelOptInfo *rel, RangeTblEntry *rte)
     767             : {
     768             :     Relids      required_outer;
     769             : 
     770             :     /*
     771             :      * We don't support pushing join clauses into the quals of a seqscan, but
     772             :      * it could still have required parameterization due to LATERAL refs in
     773             :      * its tlist.
     774             :      */
     775      216480 :     required_outer = rel->lateral_relids;
     776             : 
     777             :     /* Consider sequential scan */
     778      216480 :     add_path(rel, create_seqscan_path(root, rel, required_outer, 0));
     779             : 
     780             :     /* If appropriate, consider parallel sequential scan */
     781      216480 :     if (rel->consider_parallel && required_outer == NULL)
     782      139446 :         create_plain_partial_paths(root, rel);
     783             : 
     784             :     /* Consider index scans */
     785      216480 :     create_index_paths(root, rel);
     786             : 
     787             :     /* Consider TID scans */
     788      216480 :     create_tidscan_paths(root, rel);
     789      216480 : }
     790             : 
     791             : /*
     792             :  * create_plain_partial_paths
     793             :  *    Build partial access paths for parallel scan of a plain relation
     794             :  */
     795             : static void
     796      139446 : create_plain_partial_paths(PlannerInfo *root, RelOptInfo *rel)
     797             : {
     798             :     int         parallel_workers;
     799             : 
     800      139446 :     parallel_workers = compute_parallel_worker(rel, rel->pages, -1,
     801             :                                                max_parallel_workers_per_gather);
     802             : 
     803             :     /* If any limit was set to zero, the user doesn't want a parallel scan. */
     804      139446 :     if (parallel_workers <= 0)
     805      127434 :         return;
     806             : 
     807             :     /* Add an unordered partial path based on a parallel sequential scan. */
     808       12012 :     add_partial_path(rel, create_seqscan_path(root, rel, NULL, parallel_workers));
     809             : }
     810             : 
     811             : /*
     812             :  * set_tablesample_rel_size
     813             :  *    Set size estimates for a sampled relation
     814             :  */
     815             : static void
     816         180 : set_tablesample_rel_size(PlannerInfo *root, RelOptInfo *rel, RangeTblEntry *rte)
     817             : {
     818         180 :     TableSampleClause *tsc = rte->tablesample;
     819             :     TsmRoutine *tsm;
     820             :     BlockNumber pages;
     821             :     double      tuples;
     822             : 
     823             :     /*
     824             :      * Test any partial indexes of rel for applicability.  We must do this
     825             :      * first since partial unique indexes can affect size estimates.
     826             :      */
     827         180 :     check_index_predicates(root, rel);
     828             : 
     829             :     /*
     830             :      * Call the sampling method's estimation function to estimate the number
     831             :      * of pages it will read and the number of tuples it will return.  (Note:
     832             :      * we assume the function returns sane values.)
     833             :      */
     834         180 :     tsm = GetTsmRoutine(tsc->tsmhandler);
     835         180 :     tsm->SampleScanGetSampleSize(root, rel, tsc->args,
     836             :                                  &pages, &tuples);
     837             : 
     838             :     /*
     839             :      * For the moment, because we will only consider a SampleScan path for the
     840             :      * rel, it's okay to just overwrite the pages and tuples estimates for the
     841             :      * whole relation.  If we ever consider multiple path types for sampled
     842             :      * rels, we'll need more complication.
     843             :      */
     844         180 :     rel->pages = pages;
     845         180 :     rel->tuples = tuples;
     846             : 
     847             :     /* Mark rel with estimated output rows, width, etc */
     848         180 :     set_baserel_size_estimates(root, rel);
     849         180 : }
     850             : 
     851             : /*
     852             :  * set_tablesample_rel_pathlist
     853             :  *    Build access paths for a sampled relation
     854             :  */
     855             : static void
     856         180 : set_tablesample_rel_pathlist(PlannerInfo *root, RelOptInfo *rel, RangeTblEntry *rte)
     857             : {
     858             :     Relids      required_outer;
     859             :     Path       *path;
     860             : 
     861             :     /*
     862             :      * We don't support pushing join clauses into the quals of a samplescan,
     863             :      * but it could still have required parameterization due to LATERAL refs
     864             :      * in its tlist or TABLESAMPLE arguments.
     865             :      */
     866         180 :     required_outer = rel->lateral_relids;
     867             : 
     868             :     /* Consider sampled scan */
     869         180 :     path = create_samplescan_path(root, rel, required_outer);
     870             : 
     871             :     /*
     872             :      * If the sampling method does not support repeatable scans, we must avoid
     873             :      * plans that would scan the rel multiple times.  Ideally, we'd simply
     874             :      * avoid putting the rel on the inside of a nestloop join; but adding such
     875             :      * a consideration to the planner seems like a great deal of complication
     876             :      * to support an uncommon usage of second-rate sampling methods.  Instead,
     877             :      * if there is a risk that the query might perform an unsafe join, just
     878             :      * wrap the SampleScan in a Materialize node.  We can check for joins by
     879             :      * counting the membership of all_baserels (note that this correctly
     880             :      * counts inheritance trees as single rels).  If we're inside a subquery,
     881             :      * we can't easily check whether a join might occur in the outer query, so
     882             :      * just assume one is possible.
     883             :      *
     884             :      * GetTsmRoutine is relatively expensive compared to the other tests here,
     885             :      * so check repeatable_across_scans last, even though that's a bit odd.
     886             :      */
     887         338 :     if ((root->query_level > 1 ||
     888         192 :          bms_membership(root->all_baserels) != BMS_SINGLETON) &&
     889          34 :         !(GetTsmRoutine(rte->tablesample->tsmhandler)->repeatable_across_scans))
     890             :     {
     891           8 :         path = (Path *) create_material_path(rel, path);
     892             :     }
     893             : 
     894         180 :     add_path(rel, path);
     895             : 
     896             :     /* For the moment, at least, there are no other paths to consider */
     897         180 : }
     898             : 
     899             : /*
     900             :  * set_foreign_size
     901             :  *      Set size estimates for a foreign table RTE
     902             :  */
     903             : static void
     904        1786 : set_foreign_size(PlannerInfo *root, RelOptInfo *rel, RangeTblEntry *rte)
     905             : {
     906             :     /* Mark rel with estimated output rows, width, etc */
     907        1786 :     set_foreign_size_estimates(root, rel);
     908             : 
     909             :     /* Let FDW adjust the size estimates, if it can */
     910        1786 :     rel->fdwroutine->GetForeignRelSize(root, rel, rte->relid);
     911             : 
     912             :     /* ... but do not let it set the rows estimate to zero */
     913        1786 :     rel->rows = clamp_row_est(rel->rows);
     914        1786 : }
     915             : 
     916             : /*
     917             :  * set_foreign_pathlist
     918             :  *      Build access paths for a foreign table RTE
     919             :  */
     920             : static void
     921        1786 : set_foreign_pathlist(PlannerInfo *root, RelOptInfo *rel, RangeTblEntry *rte)
     922             : {
     923             :     /* Call the FDW's GetForeignPaths function to generate path(s) */
     924        1786 :     rel->fdwroutine->GetForeignPaths(root, rel, rte->relid);
     925        1786 : }
     926             : 
     927             : /*
     928             :  * set_append_rel_size
     929             :  *    Set size estimates for a simple "append relation"
     930             :  *
     931             :  * The passed-in rel and RTE represent the entire append relation.  The
     932             :  * relation's contents are computed by appending together the output of the
     933             :  * individual member relations.  Note that in the non-partitioned inheritance
     934             :  * case, the first member relation is actually the same table as is mentioned
     935             :  * in the parent RTE ... but it has a different RTE and RelOptInfo.  This is
     936             :  * a good thing because their outputs are not the same size.
     937             :  */
     938             : static void
     939        9604 : set_append_rel_size(PlannerInfo *root, RelOptInfo *rel,
     940             :                     Index rti, RangeTblEntry *rte)
     941             : {
     942        9604 :     int         parentRTindex = rti;
     943             :     bool        has_live_children;
     944             :     double      parent_rows;
     945             :     double      parent_size;
     946             :     double     *parent_attrsizes;
     947             :     int         nattrs;
     948             :     ListCell   *l;
     949             : 
     950             :     /* Guard against stack overflow due to overly deep inheritance tree. */
     951        9604 :     check_stack_depth();
     952             : 
     953             :     Assert(IS_SIMPLE_REL(rel));
     954             : 
     955             :     /*
     956             :      * Initialize partitioned_child_rels to contain this RT index.
     957             :      *
     958             :      * Note that during the set_append_rel_pathlist() phase, we will bubble up
     959             :      * the indexes of partitioned relations that appear down in the tree, so
     960             :      * that when we've created Paths for all the children, the root
     961             :      * partitioned table's list will contain all such indexes.
     962             :      */
     963        9604 :     if (rte->relkind == RELKIND_PARTITIONED_TABLE)
     964        5978 :         rel->partitioned_child_rels = list_make1_int(rti);
     965             : 
     966             :     /*
     967             :      * If this is a partitioned baserel, set the consider_partitionwise_join
     968             :      * flag; currently, we only consider partitionwise joins with the baserel
     969             :      * if its targetlist doesn't contain a whole-row Var.
     970             :      */
     971       11060 :     if (enable_partitionwise_join &&
     972        2600 :         rel->reloptkind == RELOPT_BASEREL &&
     973        2288 :         rte->relkind == RELKIND_PARTITIONED_TABLE &&
     974        1144 :         rel->attr_needed[InvalidAttrNumber - rel->min_attr] == NULL)
     975        1088 :         rel->consider_partitionwise_join = true;
     976             : 
     977             :     /*
     978             :      * Initialize to compute size estimates for whole append relation.
     979             :      *
     980             :      * We handle width estimates by weighting the widths of different child
     981             :      * rels proportionally to their number of rows.  This is sensible because
     982             :      * the use of width estimates is mainly to compute the total relation
     983             :      * "footprint" if we have to sort or hash it.  To do this, we sum the
     984             :      * total equivalent size (in "double" arithmetic) and then divide by the
     985             :      * total rowcount estimate.  This is done separately for the total rel
     986             :      * width and each attribute.
     987             :      *
     988             :      * Note: if you consider changing this logic, beware that child rels could
     989             :      * have zero rows and/or width, if they were excluded by constraints.
     990             :      */
     991        9604 :     has_live_children = false;
     992        9604 :     parent_rows = 0;
     993        9604 :     parent_size = 0;
     994        9604 :     nattrs = rel->max_attr - rel->min_attr + 1;
     995        9604 :     parent_attrsizes = (double *) palloc0(nattrs * sizeof(double));
     996             : 
     997       57576 :     foreach(l, root->append_rel_list)
     998             :     {
     999       47972 :         AppendRelInfo *appinfo = (AppendRelInfo *) lfirst(l);
    1000             :         int         childRTindex;
    1001             :         RangeTblEntry *childRTE;
    1002             :         RelOptInfo *childrel;
    1003             :         ListCell   *parentvars;
    1004             :         ListCell   *childvars;
    1005             : 
    1006             :         /* append_rel_list contains all append rels; ignore others */
    1007       47972 :         if (appinfo->parent_relid != parentRTindex)
    1008       51584 :             continue;
    1009             : 
    1010       22258 :         childRTindex = appinfo->child_relid;
    1011       22258 :         childRTE = root->simple_rte_array[childRTindex];
    1012             : 
    1013             :         /*
    1014             :          * The child rel's RelOptInfo was already created during
    1015             :          * add_other_rels_to_query.
    1016             :          */
    1017       22258 :         childrel = find_base_rel(root, childRTindex);
    1018             :         Assert(childrel->reloptkind == RELOPT_OTHER_MEMBER_REL);
    1019             : 
    1020             :         /* We may have already proven the child to be dummy. */
    1021       22258 :         if (IS_DUMMY_REL(childrel))
    1022           4 :             continue;
    1023             : 
    1024             :         /*
    1025             :          * We have to copy the parent's targetlist and quals to the child,
    1026             :          * with appropriate substitution of variables.  However, the
    1027             :          * baserestrictinfo quals were already copied/substituted when the
    1028             :          * child RelOptInfo was built.  So we don't need any additional setup
    1029             :          * before applying constraint exclusion.
    1030             :          */
    1031       22254 :         if (relation_excluded_by_constraints(root, childrel, childRTE))
    1032             :         {
    1033             :             /*
    1034             :              * This child need not be scanned, so we can omit it from the
    1035             :              * appendrel.
    1036             :              */
    1037          60 :             set_dummy_rel_pathlist(childrel);
    1038          60 :             continue;
    1039             :         }
    1040             : 
    1041             :         /*
    1042             :          * Constraint exclusion failed, so copy the parent's join quals and
    1043             :          * targetlist to the child, with appropriate variable substitutions.
    1044             :          *
    1045             :          * NB: the resulting childrel->reltarget->exprs may contain arbitrary
    1046             :          * expressions, which otherwise would not occur in a rel's targetlist.
    1047             :          * Code that might be looking at an appendrel child must cope with
    1048             :          * such.  (Normally, a rel's targetlist would only include Vars and
    1049             :          * PlaceHolderVars.)  XXX we do not bother to update the cost or width
    1050             :          * fields of childrel->reltarget; not clear if that would be useful.
    1051             :          */
    1052       22194 :         childrel->joininfo = (List *)
    1053       22194 :             adjust_appendrel_attrs(root,
    1054       22194 :                                    (Node *) rel->joininfo,
    1055             :                                    1, &appinfo);
    1056       44388 :         childrel->reltarget->exprs = (List *)
    1057       22194 :             adjust_appendrel_attrs(root,
    1058       22194 :                                    (Node *) rel->reltarget->exprs,
    1059             :                                    1, &appinfo);
    1060             : 
    1061             :         /*
    1062             :          * We have to make child entries in the EquivalenceClass data
    1063             :          * structures as well.  This is needed either if the parent
    1064             :          * participates in some eclass joins (because we will want to consider
    1065             :          * inner-indexscan joins on the individual children) or if the parent
    1066             :          * has useful pathkeys (because we should try to build MergeAppend
    1067             :          * paths that produce those sort orderings).
    1068             :          */
    1069       22194 :         if (rel->has_eclass_joins || has_useful_pathkeys(root, rel))
    1070       11660 :             add_child_rel_equivalences(root, appinfo, rel, childrel);
    1071       22194 :         childrel->has_eclass_joins = rel->has_eclass_joins;
    1072             : 
    1073             :         /*
    1074             :          * Note: we could compute appropriate attr_needed data for the child's
    1075             :          * variables, by transforming the parent's attr_needed through the
    1076             :          * translated_vars mapping.  However, currently there's no need
    1077             :          * because attr_needed is only examined for base relations not
    1078             :          * otherrels.  So we just leave the child's attr_needed empty.
    1079             :          */
    1080             : 
    1081             :         /*
    1082             :          * If we consider partitionwise joins with the parent rel, do the same
    1083             :          * for partitioned child rels.
    1084             :          *
    1085             :          * Note: here we abuse the consider_partitionwise_join flag by setting
    1086             :          * it for child rels that are not themselves partitioned.  We do so to
    1087             :          * tell try_partitionwise_join() that the child rel is sufficiently
    1088             :          * valid to be used as a per-partition input, even if it later gets
    1089             :          * proven to be dummy.  (It's not usable until we've set up the
    1090             :          * reltarget and EC entries, which we just did.)
    1091             :          */
    1092       22194 :         if (rel->consider_partitionwise_join)
    1093        3540 :             childrel->consider_partitionwise_join = true;
    1094             : 
    1095             :         /*
    1096             :          * If parallelism is allowable for this query in general, see whether
    1097             :          * it's allowable for this childrel in particular.  But if we've
    1098             :          * already decided the appendrel is not parallel-safe as a whole,
    1099             :          * there's no point in considering parallelism for this child.  For
    1100             :          * consistency, do this before calling set_rel_size() for the child.
    1101             :          */
    1102       22194 :         if (root->glob->parallelModeOK && rel->consider_parallel)
    1103       15560 :             set_rel_consider_parallel(root, childrel, childRTE);
    1104             : 
    1105             :         /*
    1106             :          * Compute the child's size.
    1107             :          */
    1108       22194 :         set_rel_size(root, childrel, childRTindex, childRTE);
    1109             : 
    1110             :         /*
    1111             :          * It is possible that constraint exclusion detected a contradiction
    1112             :          * within a child subquery, even though we didn't prove one above. If
    1113             :          * so, we can skip this child.
    1114             :          */
    1115       22194 :         if (IS_DUMMY_REL(childrel))
    1116          92 :             continue;
    1117             : 
    1118             :         /* We have at least one live child. */
    1119       22102 :         has_live_children = true;
    1120             : 
    1121             :         /*
    1122             :          * If any live child is not parallel-safe, treat the whole appendrel
    1123             :          * as not parallel-safe.  In future we might be able to generate plans
    1124             :          * in which some children are farmed out to workers while others are
    1125             :          * not; but we don't have that today, so it's a waste to consider
    1126             :          * partial paths anywhere in the appendrel unless it's all safe.
    1127             :          * (Child rels visited before this one will be unmarked in
    1128             :          * set_append_rel_pathlist().)
    1129             :          */
    1130       22102 :         if (!childrel->consider_parallel)
    1131        6864 :             rel->consider_parallel = false;
    1132             : 
    1133             :         /*
    1134             :          * Accumulate size information from each live child.
    1135             :          */
    1136             :         Assert(childrel->rows > 0);
    1137             : 
    1138       22102 :         parent_rows += childrel->rows;
    1139       22102 :         parent_size += childrel->reltarget->width * childrel->rows;
    1140             : 
    1141             :         /*
    1142             :          * Accumulate per-column estimates too.  We need not do anything for
    1143             :          * PlaceHolderVars in the parent list.  If child expression isn't a
    1144             :          * Var, or we didn't record a width estimate for it, we have to fall
    1145             :          * back on a datatype-based estimate.
    1146             :          *
    1147             :          * By construction, child's targetlist is 1-to-1 with parent's.
    1148             :          */
    1149       62702 :         forboth(parentvars, rel->reltarget->exprs,
    1150             :                 childvars, childrel->reltarget->exprs)
    1151             :         {
    1152       40600 :             Var        *parentvar = (Var *) lfirst(parentvars);
    1153       40600 :             Node       *childvar = (Node *) lfirst(childvars);
    1154             : 
    1155       40600 :             if (IsA(parentvar, Var))
    1156             :             {
    1157       39744 :                 int         pndx = parentvar->varattno - rel->min_attr;
    1158       39744 :                 int32       child_width = 0;
    1159             : 
    1160       78098 :                 if (IsA(childvar, Var) &&
    1161       38354 :                     ((Var *) childvar)->varno == childrel->relid)
    1162             :                 {
    1163       38314 :                     int         cndx = ((Var *) childvar)->varattno - childrel->min_attr;
    1164             : 
    1165       38314 :                     child_width = childrel->attr_widths[cndx];
    1166             :                 }
    1167       39744 :                 if (child_width <= 0)
    1168        1430 :                     child_width = get_typavgwidth(exprType(childvar),
    1169             :                                                   exprTypmod(childvar));
    1170             :                 Assert(child_width > 0);
    1171       39744 :                 parent_attrsizes[pndx] += child_width * childrel->rows;
    1172             :             }
    1173             :         }
    1174             :     }
    1175             : 
    1176        9604 :     if (has_live_children)
    1177             :     {
    1178             :         /*
    1179             :          * Save the finished size estimates.
    1180             :          */
    1181             :         int         i;
    1182             : 
    1183             :         Assert(parent_rows > 0);
    1184        9460 :         rel->rows = parent_rows;
    1185        9460 :         rel->reltarget->width = rint(parent_size / parent_rows);
    1186       85872 :         for (i = 0; i < nattrs; i++)
    1187       76412 :             rel->attr_widths[i] = rint(parent_attrsizes[i] / parent_rows);
    1188             : 
    1189             :         /*
    1190             :          * Set "raw tuples" count equal to "rows" for the appendrel; needed
    1191             :          * because some places assume rel->tuples is valid for any baserel.
    1192             :          */
    1193        9460 :         rel->tuples = parent_rows;
    1194             : 
    1195             :         /*
    1196             :          * Note that we leave rel->pages as zero; this is important to avoid
    1197             :          * double-counting the appendrel tree in total_table_pages.
    1198             :          */
    1199             :     }
    1200             :     else
    1201             :     {
    1202             :         /*
    1203             :          * All children were excluded by constraints, so mark the whole
    1204             :          * appendrel dummy.  We must do this in this phase so that the rel's
    1205             :          * dummy-ness is visible when we generate paths for other rels.
    1206             :          */
    1207         144 :         set_dummy_rel_pathlist(rel);
    1208             :     }
    1209             : 
    1210        9604 :     pfree(parent_attrsizes);
    1211        9604 : }
    1212             : 
    1213             : /*
    1214             :  * set_append_rel_pathlist
    1215             :  *    Build access paths for an "append relation"
    1216             :  */
    1217             : static void
    1218        9460 : set_append_rel_pathlist(PlannerInfo *root, RelOptInfo *rel,
    1219             :                         Index rti, RangeTblEntry *rte)
    1220             : {
    1221        9460 :     int         parentRTindex = rti;
    1222        9460 :     List       *live_childrels = NIL;
    1223             :     ListCell   *l;
    1224             : 
    1225             :     /*
    1226             :      * Generate access paths for each member relation, and remember the
    1227             :      * non-dummy children.
    1228             :      */
    1229       57076 :     foreach(l, root->append_rel_list)
    1230             :     {
    1231       47616 :         AppendRelInfo *appinfo = (AppendRelInfo *) lfirst(l);
    1232             :         int         childRTindex;
    1233             :         RangeTblEntry *childRTE;
    1234             :         RelOptInfo *childrel;
    1235             : 
    1236             :         /* append_rel_list contains all append rels; ignore others */
    1237       47616 :         if (appinfo->parent_relid != parentRTindex)
    1238       25406 :             continue;
    1239             : 
    1240             :         /* Re-locate the child RTE and RelOptInfo */
    1241       22210 :         childRTindex = appinfo->child_relid;
    1242       22210 :         childRTE = root->simple_rte_array[childRTindex];
    1243       22210 :         childrel = root->simple_rel_array[childRTindex];
    1244             : 
    1245             :         /*
    1246             :          * If set_append_rel_size() decided the parent appendrel was
    1247             :          * parallel-unsafe at some point after visiting this child rel, we
    1248             :          * need to propagate the unsafety marking down to the child, so that
    1249             :          * we don't generate useless partial paths for it.
    1250             :          */
    1251       22210 :         if (!rel->consider_parallel)
    1252        6940 :             childrel->consider_parallel = false;
    1253             : 
    1254             :         /*
    1255             :          * Compute the child's access paths.
    1256             :          */
    1257       22210 :         set_rel_pathlist(root, childrel, childRTindex, childRTE);
    1258             : 
    1259             :         /*
    1260             :          * If child is dummy, ignore it.
    1261             :          */
    1262       22210 :         if (IS_DUMMY_REL(childrel))
    1263         108 :             continue;
    1264             : 
    1265             :         /* Bubble up childrel's partitioned children. */
    1266       22102 :         if (rel->part_scheme)
    1267       13534 :             rel->partitioned_child_rels =
    1268       13534 :                 list_concat(rel->partitioned_child_rels,
    1269       13534 :                             list_copy(childrel->partitioned_child_rels));
    1270             : 
    1271             :         /*
    1272             :          * Child is live, so add it to the live_childrels list for use below.
    1273             :          */
    1274       22102 :         live_childrels = lappend(live_childrels, childrel);
    1275             :     }
    1276             : 
    1277             :     /* Add paths to the append relation. */
    1278        9460 :     add_paths_to_append_rel(root, rel, live_childrels);
    1279        9460 : }
    1280             : 
    1281             : 
    1282             : /*
    1283             :  * add_paths_to_append_rel
    1284             :  *      Generate paths for the given append relation given the set of non-dummy
    1285             :  *      child rels.
    1286             :  *
    1287             :  * The function collects all parameterizations and orderings supported by the
    1288             :  * non-dummy children. For every such parameterization or ordering, it creates
    1289             :  * an append path collecting one path from each non-dummy child with given
    1290             :  * parameterization or ordering. Similarly it collects partial paths from
    1291             :  * non-dummy children to create partial append paths.
    1292             :  */
    1293             : void
    1294       14802 : add_paths_to_append_rel(PlannerInfo *root, RelOptInfo *rel,
    1295             :                         List *live_childrels)
    1296             : {
    1297       14802 :     List       *subpaths = NIL;
    1298       14802 :     bool        subpaths_valid = true;
    1299       14802 :     List       *partial_subpaths = NIL;
    1300       14802 :     List       *pa_partial_subpaths = NIL;
    1301       14802 :     List       *pa_nonpartial_subpaths = NIL;
    1302       14802 :     bool        partial_subpaths_valid = true;
    1303             :     bool        pa_subpaths_valid;
    1304       14802 :     List       *all_child_pathkeys = NIL;
    1305       14802 :     List       *all_child_outers = NIL;
    1306             :     ListCell   *l;
    1307       14802 :     List       *partitioned_rels = NIL;
    1308       14802 :     double      partial_rows = -1;
    1309             : 
    1310             :     /* If appropriate, consider parallel append */
    1311       14802 :     pa_subpaths_valid = enable_parallel_append && rel->consider_parallel;
    1312             : 
    1313             :     /*
    1314             :      * AppendPath generated for partitioned tables must record the RT indexes
    1315             :      * of partitioned tables that are direct or indirect children of this
    1316             :      * Append rel.
    1317             :      *
    1318             :      * AppendPath may be for a sub-query RTE (UNION ALL), in which case, 'rel'
    1319             :      * itself does not represent a partitioned relation, but the child sub-
    1320             :      * queries may contain references to partitioned relations.  The loop
    1321             :      * below will look for such children and collect them in a list to be
    1322             :      * passed to the path creation function.  (This assumes that we don't need
    1323             :      * to look through multiple levels of subquery RTEs; if we ever do, we
    1324             :      * could consider stuffing the list we generate here into sub-query RTE's
    1325             :      * RelOptInfo, just like we do for partitioned rels, which would be used
    1326             :      * when populating our parent rel with paths.  For the present, that
    1327             :      * appears to be unnecessary.)
    1328             :      */
    1329       14802 :     if (rel->part_scheme != NULL)
    1330             :     {
    1331       10782 :         if (IS_SIMPLE_REL(rel))
    1332        9994 :             partitioned_rels = list_make1(rel->partitioned_child_rels);
    1333         788 :         else if (IS_JOIN_REL(rel))
    1334             :         {
    1335         788 :             int         relid = -1;
    1336         788 :             List       *partrels = NIL;
    1337             : 
    1338             :             /*
    1339             :              * For a partitioned joinrel, concatenate the component rels'
    1340             :              * partitioned_child_rels lists.
    1341             :              */
    1342        3368 :             while ((relid = bms_next_member(rel->relids, relid)) >= 0)
    1343             :             {
    1344             :                 RelOptInfo *component;
    1345             : 
    1346             :                 Assert(relid >= 1 && relid < root->simple_rel_array_size);
    1347        1792 :                 component = root->simple_rel_array[relid];
    1348             :                 Assert(component->part_scheme != NULL);
    1349             :                 Assert(list_length(component->partitioned_child_rels) >= 1);
    1350        1792 :                 partrels =
    1351        1792 :                     list_concat(partrels,
    1352        1792 :                                 list_copy(component->partitioned_child_rels));
    1353             :             }
    1354             : 
    1355         788 :             partitioned_rels = list_make1(partrels);
    1356             :         }
    1357             : 
    1358             :         Assert(list_length(partitioned_rels) >= 1);
    1359             :     }
    1360             : 
    1361             :     /*
    1362             :      * For every non-dummy child, remember the cheapest path.  Also, identify
    1363             :      * all pathkeys (orderings) and parameterizations (required_outer sets)
    1364             :      * available for the non-dummy member relations.
    1365             :      */
    1366       49382 :     foreach(l, live_childrels)
    1367             :     {
    1368       34580 :         RelOptInfo *childrel = lfirst(l);
    1369             :         ListCell   *lcp;
    1370       34580 :         Path       *cheapest_partial_path = NULL;
    1371             : 
    1372             :         /*
    1373             :          * For UNION ALLs with non-empty partitioned_child_rels, accumulate
    1374             :          * the Lists of child relations.
    1375             :          */
    1376       34580 :         if (rel->rtekind == RTE_SUBQUERY && childrel->partitioned_child_rels != NIL)
    1377          72 :             partitioned_rels = lappend(partitioned_rels,
    1378          72 :                                        childrel->partitioned_child_rels);
    1379             : 
    1380             :         /*
    1381             :          * If child has an unparameterized cheapest-total path, add that to
    1382             :          * the unparameterized Append path we are constructing for the parent.
    1383             :          * If not, there's no workable unparameterized path.
    1384             :          *
    1385             :          * With partitionwise aggregates, the child rel's pathlist may be
    1386             :          * empty, so don't assume that a path exists here.
    1387             :          */
    1388       69160 :         if (childrel->pathlist != NIL &&
    1389       34580 :             childrel->cheapest_total_path->param_info == NULL)
    1390       34276 :             accumulate_append_subpath(childrel->cheapest_total_path,
    1391             :                                       &subpaths, NULL);
    1392             :         else
    1393         304 :             subpaths_valid = false;
    1394             : 
    1395             :         /* Same idea, but for a partial plan. */
    1396       34580 :         if (childrel->partial_pathlist != NIL)
    1397             :         {
    1398       20514 :             cheapest_partial_path = linitial(childrel->partial_pathlist);
    1399       20514 :             accumulate_append_subpath(cheapest_partial_path,
    1400             :                                       &partial_subpaths, NULL);
    1401             :         }
    1402             :         else
    1403       14066 :             partial_subpaths_valid = false;
    1404             : 
    1405             :         /*
    1406             :          * Same idea, but for a parallel append mixing partial and non-partial
    1407             :          * paths.
    1408             :          */
    1409       34580 :         if (pa_subpaths_valid)
    1410             :         {
    1411       23918 :             Path       *nppath = NULL;
    1412             : 
    1413       23918 :             nppath =
    1414       23918 :                 get_cheapest_parallel_safe_total_inner(childrel->pathlist);
    1415             : 
    1416       23918 :             if (cheapest_partial_path == NULL && nppath == NULL)
    1417             :             {
    1418             :                 /* Neither a partial nor a parallel-safe path?  Forget it. */
    1419         360 :                 pa_subpaths_valid = false;
    1420             :             }
    1421       23558 :             else if (nppath == NULL ||
    1422       20214 :                      (cheapest_partial_path != NULL &&
    1423       20214 :                       cheapest_partial_path->total_cost < nppath->total_cost))
    1424             :             {
    1425             :                 /* Partial path is cheaper or the only option. */
    1426             :                 Assert(cheapest_partial_path != NULL);
    1427       20172 :                 accumulate_append_subpath(cheapest_partial_path,
    1428             :                                           &pa_partial_subpaths,
    1429             :                                           &pa_nonpartial_subpaths);
    1430             : 
    1431             :             }
    1432             :             else
    1433             :             {
    1434             :                 /*
    1435             :                  * Either we've got only a non-partial path, or we think that
    1436             :                  * a single backend can execute the best non-partial path
    1437             :                  * faster than all the parallel backends working together can
    1438             :                  * execute the best partial path.
    1439             :                  *
    1440             :                  * It might make sense to be more aggressive here.  Even if
    1441             :                  * the best non-partial path is more expensive than the best
    1442             :                  * partial path, it could still be better to choose the
    1443             :                  * non-partial path if there are several such paths that can
    1444             :                  * be given to different workers.  For now, we don't try to
    1445             :                  * figure that out.
    1446             :                  */
    1447        3386 :                 accumulate_append_subpath(nppath,
    1448             :                                           &pa_nonpartial_subpaths,
    1449             :                                           NULL);
    1450             :             }
    1451             :         }
    1452             : 
    1453             :         /*
    1454             :          * Collect lists of all the available path orderings and
    1455             :          * parameterizations for all the children.  We use these as a
    1456             :          * heuristic to indicate which sort orderings and parameterizations we
    1457             :          * should build Append and MergeAppend paths for.
    1458             :          */
    1459       77278 :         foreach(lcp, childrel->pathlist)
    1460             :         {
    1461       42698 :             Path       *childpath = (Path *) lfirst(lcp);
    1462       42698 :             List       *childkeys = childpath->pathkeys;
    1463       42698 :             Relids      childouter = PATH_REQ_OUTER(childpath);
    1464             : 
    1465             :             /* Unsorted paths don't contribute to pathkey list */
    1466       42698 :             if (childkeys != NIL)
    1467             :             {
    1468             :                 ListCell   *lpk;
    1469        8290 :                 bool        found = false;
    1470             : 
    1471             :                 /* Have we already seen this ordering? */
    1472        8322 :                 foreach(lpk, all_child_pathkeys)
    1473             :                 {
    1474        6050 :                     List       *existing_pathkeys = (List *) lfirst(lpk);
    1475             : 
    1476        6050 :                     if (compare_pathkeys(existing_pathkeys,
    1477             :                                          childkeys) == PATHKEYS_EQUAL)
    1478             :                     {
    1479        6018 :                         found = true;
    1480        6018 :                         break;
    1481             :                     }
    1482             :                 }
    1483        8290 :                 if (!found)
    1484             :                 {
    1485             :                     /* No, so add it to all_child_pathkeys */
    1486        2272 :                     all_child_pathkeys = lappend(all_child_pathkeys,
    1487             :                                                  childkeys);
    1488             :                 }
    1489             :             }
    1490             : 
    1491             :             /* Unparameterized paths don't contribute to param-set list */
    1492       42698 :             if (childouter)
    1493             :             {
    1494             :                 ListCell   *lco;
    1495        2842 :                 bool        found = false;
    1496             : 
    1497             :                 /* Have we already seen this param set? */
    1498        3254 :                 foreach(lco, all_child_outers)
    1499             :                 {
    1500        2164 :                     Relids      existing_outers = (Relids) lfirst(lco);
    1501             : 
    1502        2164 :                     if (bms_equal(existing_outers, childouter))
    1503             :                     {
    1504        1752 :                         found = true;
    1505        1752 :                         break;
    1506             :                     }
    1507             :                 }
    1508        2842 :                 if (!found)
    1509             :                 {
    1510             :                     /* No, so add it to all_child_outers */
    1511        1090 :                     all_child_outers = lappend(all_child_outers,
    1512             :                                                childouter);
    1513             :                 }
    1514             :             }
    1515             :         }
    1516             :     }
    1517             : 
    1518             :     /*
    1519             :      * If we found unparameterized paths for all children, build an unordered,
    1520             :      * unparameterized Append path for the rel.  (Note: this is correct even
    1521             :      * if we have zero or one live subpath due to constraint exclusion.)
    1522             :      */
    1523       14802 :     if (subpaths_valid)
    1524       14670 :         add_path(rel, (Path *) create_append_path(root, rel, subpaths, NIL,
    1525             :                                                   NIL, NULL, 0, false,
    1526             :                                                   partitioned_rels, -1));
    1527             : 
    1528             :     /*
    1529             :      * Consider an append of unordered, unparameterized partial paths.  Make
    1530             :      * it parallel-aware if possible.
    1531             :      */
    1532       14802 :     if (partial_subpaths_valid && partial_subpaths != NIL)
    1533             :     {
    1534             :         AppendPath *appendpath;
    1535             :         ListCell   *lc;
    1536        7838 :         int         parallel_workers = 0;
    1537             : 
    1538             :         /* Find the highest number of workers requested for any subpath. */
    1539       31994 :         foreach(lc, partial_subpaths)
    1540             :         {
    1541       24156 :             Path       *path = lfirst(lc);
    1542             : 
    1543       24156 :             parallel_workers = Max(parallel_workers, path->parallel_workers);
    1544             :         }
    1545             :         Assert(parallel_workers > 0);
    1546             : 
    1547             :         /*
    1548             :          * If the use of parallel append is permitted, always request at least
    1549             :          * log2(# of children) workers.  We assume it can be useful to have
    1550             :          * extra workers in this case because they will be spread out across
    1551             :          * the children.  The precise formula is just a guess, but we don't
    1552             :          * want to end up with a radically different answer for a table with N
    1553             :          * partitions vs. an unpartitioned table with the same data, so the
    1554             :          * use of some kind of log-scaling here seems to make some sense.
    1555             :          */
    1556        7838 :         if (enable_parallel_append)
    1557             :         {
    1558        7806 :             parallel_workers = Max(parallel_workers,
    1559             :                                    fls(list_length(live_childrels)));
    1560        7806 :             parallel_workers = Min(parallel_workers,
    1561             :                                    max_parallel_workers_per_gather);
    1562             :         }
    1563             :         Assert(parallel_workers > 0);
    1564             : 
    1565             :         /* Generate a partial append path. */
    1566        7838 :         appendpath = create_append_path(root, rel, NIL, partial_subpaths,
    1567             :                                         NIL, NULL, parallel_workers,
    1568             :                                         enable_parallel_append,
    1569             :                                         partitioned_rels, -1);
    1570             : 
    1571             :         /*
    1572             :          * Make sure any subsequent partial paths use the same row count
    1573             :          * estimate.
    1574             :          */
    1575        7838 :         partial_rows = appendpath->path.rows;
    1576             : 
    1577             :         /* Add the path. */
    1578        7838 :         add_partial_path(rel, (Path *) appendpath);
    1579             :     }
    1580             : 
    1581             :     /*
    1582             :      * Consider a parallel-aware append using a mix of partial and non-partial
    1583             :      * paths.  (This only makes sense if there's at least one child which has
    1584             :      * a non-partial path that is substantially cheaper than any partial path;
    1585             :      * otherwise, we should use the append path added in the previous step.)
    1586             :      */
    1587       14802 :     if (pa_subpaths_valid && pa_nonpartial_subpaths != NIL)
    1588             :     {
    1589             :         AppendPath *appendpath;
    1590             :         ListCell   *lc;
    1591        1674 :         int         parallel_workers = 0;
    1592             : 
    1593             :         /*
    1594             :          * Find the highest number of workers requested for any partial
    1595             :          * subpath.
    1596             :          */
    1597        2118 :         foreach(lc, pa_partial_subpaths)
    1598             :         {
    1599         444 :             Path       *path = lfirst(lc);
    1600             : 
    1601         444 :             parallel_workers = Max(parallel_workers, path->parallel_workers);
    1602             :         }
    1603             : 
    1604             :         /*
    1605             :          * Same formula here as above.  It's even more important in this
    1606             :          * instance because the non-partial paths won't contribute anything to
    1607             :          * the planned number of parallel workers.
    1608             :          */
    1609        1674 :         parallel_workers = Max(parallel_workers,
    1610             :                                fls(list_length(live_childrels)));
    1611        1674 :         parallel_workers = Min(parallel_workers,
    1612             :                                max_parallel_workers_per_gather);
    1613             :         Assert(parallel_workers > 0);
    1614             : 
    1615        1674 :         appendpath = create_append_path(root, rel, pa_nonpartial_subpaths,
    1616             :                                         pa_partial_subpaths,
    1617             :                                         NIL, NULL, parallel_workers, true,
    1618             :                                         partitioned_rels, partial_rows);
    1619        1674 :         add_partial_path(rel, (Path *) appendpath);
    1620             :     }
    1621             : 
    1622             :     /*
    1623             :      * Also build unparameterized ordered append paths based on the collected
    1624             :      * list of child pathkeys.
    1625             :      */
    1626       14802 :     if (subpaths_valid)
    1627       14670 :         generate_orderedappend_paths(root, rel, live_childrels,
    1628             :                                      all_child_pathkeys,
    1629             :                                      partitioned_rels);
    1630             : 
    1631             :     /*
    1632             :      * Build Append paths for each parameterization seen among the child rels.
    1633             :      * (This may look pretty expensive, but in most cases of practical
    1634             :      * interest, the child rels will expose mostly the same parameterizations,
    1635             :      * so that not that many cases actually get considered here.)
    1636             :      *
    1637             :      * The Append node itself cannot enforce quals, so all qual checking must
    1638             :      * be done in the child paths.  This means that to have a parameterized
    1639             :      * Append path, we must have the exact same parameterization for each
    1640             :      * child path; otherwise some children might be failing to check the
    1641             :      * moved-down quals.  To make them match up, we can try to increase the
    1642             :      * parameterization of lesser-parameterized paths.
    1643             :      */
    1644       15892 :     foreach(l, all_child_outers)
    1645             :     {
    1646        1090 :         Relids      required_outer = (Relids) lfirst(l);
    1647             :         ListCell   *lcr;
    1648             : 
    1649             :         /* Select the child paths for an Append with this parameterization */
    1650        1090 :         subpaths = NIL;
    1651        1090 :         subpaths_valid = true;
    1652        3980 :         foreach(lcr, live_childrels)
    1653             :         {
    1654        2902 :             RelOptInfo *childrel = (RelOptInfo *) lfirst(lcr);
    1655             :             Path       *subpath;
    1656             : 
    1657        2902 :             if (childrel->pathlist == NIL)
    1658             :             {
    1659             :                 /* failed to make a suitable path for this child */
    1660           0 :                 subpaths_valid = false;
    1661           0 :                 break;
    1662             :             }
    1663             : 
    1664        2902 :             subpath = get_cheapest_parameterized_child_path(root,
    1665             :                                                             childrel,
    1666             :                                                             required_outer);
    1667        2902 :             if (subpath == NULL)
    1668             :             {
    1669             :                 /* failed to make a suitable path for this child */
    1670          12 :                 subpaths_valid = false;
    1671          12 :                 break;
    1672             :             }
    1673        2890 :             accumulate_append_subpath(subpath, &subpaths, NULL);
    1674             :         }
    1675             : 
    1676        1090 :         if (subpaths_valid)
    1677        2156 :             add_path(rel, (Path *)
    1678        1078 :                      create_append_path(root, rel, subpaths, NIL,
    1679             :                                         NIL, required_outer, 0, false,
    1680             :                                         partitioned_rels, -1));
    1681             :     }
    1682             : 
    1683             :     /*
    1684             :      * When there is only a single child relation, the Append path can inherit
    1685             :      * any ordering available for the child rel's path, so that it's useful to
    1686             :      * consider ordered partial paths.  Above we only considered the cheapest
    1687             :      * partial path for each child, but let's also make paths using any
    1688             :      * partial paths that have pathkeys.
    1689             :      */
    1690       14802 :     if (list_length(live_childrels) == 1)
    1691             :     {
    1692        3308 :         RelOptInfo *childrel = (RelOptInfo *) linitial(live_childrels);
    1693             : 
    1694        4740 :         foreach(l, childrel->partial_pathlist)
    1695             :         {
    1696        1432 :             Path       *path = (Path *) lfirst(l);
    1697             :             AppendPath *appendpath;
    1698             : 
    1699             :             /*
    1700             :              * Skip paths with no pathkeys.  Also skip the cheapest partial
    1701             :              * path, since we already used that above.
    1702             :              */
    1703        1504 :             if (path->pathkeys == NIL ||
    1704          72 :                 path == linitial(childrel->partial_pathlist))
    1705        1360 :                 continue;
    1706             : 
    1707          72 :             appendpath = create_append_path(root, rel, NIL, list_make1(path),
    1708             :                                             NIL, NULL,
    1709             :                                             path->parallel_workers, true,
    1710             :                                             partitioned_rels, partial_rows);
    1711          72 :             add_partial_path(rel, (Path *) appendpath);
    1712             :         }
    1713             :     }
    1714       14802 : }
    1715             : 
    1716             : /*
    1717             :  * generate_orderedappend_paths
    1718             :  *      Generate ordered append paths for an append relation
    1719             :  *
    1720             :  * Usually we generate MergeAppend paths here, but there are some special
    1721             :  * cases where we can generate simple Append paths, because the subpaths
    1722             :  * can provide tuples in the required order already.
    1723             :  *
    1724             :  * We generate a path for each ordering (pathkey list) appearing in
    1725             :  * all_child_pathkeys.
    1726             :  *
    1727             :  * We consider both cheapest-startup and cheapest-total cases, ie, for each
    1728             :  * interesting ordering, collect all the cheapest startup subpaths and all the
    1729             :  * cheapest total paths, and build a suitable path for each case.
    1730             :  *
    1731             :  * We don't currently generate any parameterized ordered paths here.  While
    1732             :  * it would not take much more code here to do so, it's very unclear that it
    1733             :  * is worth the planning cycles to investigate such paths: there's little
    1734             :  * use for an ordered path on the inside of a nestloop.  In fact, it's likely
    1735             :  * that the current coding of add_path would reject such paths out of hand,
    1736             :  * because add_path gives no credit for sort ordering of parameterized paths,
    1737             :  * and a parameterized MergeAppend is going to be more expensive than the
    1738             :  * corresponding parameterized Append path.  If we ever try harder to support
    1739             :  * parameterized mergejoin plans, it might be worth adding support for
    1740             :  * parameterized paths here to feed such joins.  (See notes in
    1741             :  * optimizer/README for why that might not ever happen, though.)
    1742             :  */
    1743             : static void
    1744       14670 : generate_orderedappend_paths(PlannerInfo *root, RelOptInfo *rel,
    1745             :                              List *live_childrels,
    1746             :                              List *all_child_pathkeys,
    1747             :                              List *partitioned_rels)
    1748             : {
    1749             :     ListCell   *lcp;
    1750       14670 :     List       *partition_pathkeys = NIL;
    1751       14670 :     List       *partition_pathkeys_desc = NIL;
    1752       14670 :     bool        partition_pathkeys_partial = true;
    1753       14670 :     bool        partition_pathkeys_desc_partial = true;
    1754             : 
    1755             :     /*
    1756             :      * Some partitioned table setups may allow us to use an Append node
    1757             :      * instead of a MergeAppend.  This is possible in cases such as RANGE
    1758             :      * partitioned tables where it's guaranteed that an earlier partition must
    1759             :      * contain rows which come earlier in the sort order.  To detect whether
    1760             :      * this is relevant, build pathkey descriptions of the partition ordering,
    1761             :      * for both forward and reverse scans.
    1762             :      */
    1763       24584 :     if (rel->part_scheme != NULL && IS_SIMPLE_REL(rel) &&
    1764        9914 :         partitions_are_ordered(rel->boundinfo, rel->nparts))
    1765             :     {
    1766        7348 :         partition_pathkeys = build_partition_pathkeys(root, rel,
    1767             :                                                       ForwardScanDirection,
    1768             :                                                       &partition_pathkeys_partial);
    1769             : 
    1770        7348 :         partition_pathkeys_desc = build_partition_pathkeys(root, rel,
    1771             :                                                            BackwardScanDirection,
    1772             :                                                            &partition_pathkeys_desc_partial);
    1773             : 
    1774             :         /*
    1775             :          * You might think we should truncate_useless_pathkeys here, but
    1776             :          * allowing partition keys which are a subset of the query's pathkeys
    1777             :          * can often be useful.  For example, consider a table partitioned by
    1778             :          * RANGE (a, b), and a query with ORDER BY a, b, c.  If we have child
    1779             :          * paths that can produce the a, b, c ordering (perhaps via indexes on
    1780             :          * (a, b, c)) then it works to consider the appendrel output as
    1781             :          * ordered by a, b, c.
    1782             :          */
    1783             :     }
    1784             : 
    1785             :     /* Now consider each interesting sort ordering */
    1786       16918 :     foreach(lcp, all_child_pathkeys)
    1787             :     {
    1788        2248 :         List       *pathkeys = (List *) lfirst(lcp);
    1789        2248 :         List       *startup_subpaths = NIL;
    1790        2248 :         List       *total_subpaths = NIL;
    1791        2248 :         bool        startup_neq_total = false;
    1792             :         ListCell   *lcr;
    1793             :         bool        match_partition_order;
    1794             :         bool        match_partition_order_desc;
    1795             : 
    1796             :         /*
    1797             :          * Determine if this sort ordering matches any partition pathkeys we
    1798             :          * have, for both ascending and descending partition order.  If the
    1799             :          * partition pathkeys happen to be contained in pathkeys then it still
    1800             :          * works, as described above, providing that the partition pathkeys
    1801             :          * are complete and not just a prefix of the partition keys.  (In such
    1802             :          * cases we'll be relying on the child paths to have sorted the
    1803             :          * lower-order columns of the required pathkeys.)
    1804             :          */
    1805        2248 :         match_partition_order =
    1806        4524 :             pathkeys_contained_in(pathkeys, partition_pathkeys) ||
    1807        1464 :             (!partition_pathkeys_partial &&
    1808          68 :              pathkeys_contained_in(partition_pathkeys, pathkeys));
    1809             : 
    1810        3640 :         match_partition_order_desc = !match_partition_order &&
    1811        2720 :             (pathkeys_contained_in(pathkeys, partition_pathkeys_desc) ||
    1812        1376 :              (!partition_pathkeys_desc_partial &&
    1813          24 :               pathkeys_contained_in(partition_pathkeys_desc, pathkeys)));
    1814             : 
    1815             :         /* Select the child paths for this ordering... */
    1816        8276 :         foreach(lcr, live_childrels)
    1817             :         {
    1818        6028 :             RelOptInfo *childrel = (RelOptInfo *) lfirst(lcr);
    1819             :             Path       *cheapest_startup,
    1820             :                        *cheapest_total;
    1821             : 
    1822             :             /* Locate the right paths, if they are available. */
    1823        6028 :             cheapest_startup =
    1824        6028 :                 get_cheapest_path_for_pathkeys(childrel->pathlist,
    1825             :                                                pathkeys,
    1826             :                                                NULL,
    1827             :                                                STARTUP_COST,
    1828             :                                                false);
    1829        6028 :             cheapest_total =
    1830        6028 :                 get_cheapest_path_for_pathkeys(childrel->pathlist,
    1831             :                                                pathkeys,
    1832             :                                                NULL,
    1833             :                                                TOTAL_COST,
    1834             :                                                false);
    1835             : 
    1836             :             /*
    1837             :              * If we can't find any paths with the right order just use the
    1838             :              * cheapest-total path; we'll have to sort it later.
    1839             :              */
    1840        6028 :             if (cheapest_startup == NULL || cheapest_total == NULL)
    1841             :             {
    1842         148 :                 cheapest_startup = cheapest_total =
    1843             :                     childrel->cheapest_total_path;
    1844             :                 /* Assert we do have an unparameterized path for this child */
    1845             :                 Assert(cheapest_total->param_info == NULL);
    1846             :             }
    1847             : 
    1848             :             /*
    1849             :              * Notice whether we actually have different paths for the
    1850             :              * "cheapest" and "total" cases; frequently there will be no point
    1851             :              * in two create_merge_append_path() calls.
    1852             :              */
    1853        6028 :             if (cheapest_startup != cheapest_total)
    1854           0 :                 startup_neq_total = true;
    1855             : 
    1856             :             /*
    1857             :              * Collect the appropriate child paths.  The required logic varies
    1858             :              * for the Append and MergeAppend cases.
    1859             :              */
    1860        6028 :             if (match_partition_order)
    1861             :             {
    1862             :                 /*
    1863             :                  * We're going to make a plain Append path.  We don't need
    1864             :                  * most of what accumulate_append_subpath would do, but we do
    1865             :                  * want to cut out child Appends or MergeAppends if they have
    1866             :                  * just a single subpath (and hence aren't doing anything
    1867             :                  * useful).
    1868             :                  */
    1869        2276 :                 cheapest_startup = get_singleton_append_subpath(cheapest_startup);
    1870        2276 :                 cheapest_total = get_singleton_append_subpath(cheapest_total);
    1871             : 
    1872        2276 :                 startup_subpaths = lappend(startup_subpaths, cheapest_startup);
    1873        2276 :                 total_subpaths = lappend(total_subpaths, cheapest_total);
    1874             :             }
    1875        3752 :             else if (match_partition_order_desc)
    1876             :             {
    1877             :                 /*
    1878             :                  * As above, but we need to reverse the order of the children,
    1879             :                  * because nodeAppend.c doesn't know anything about reverse
    1880             :                  * ordering and will scan the children in the order presented.
    1881             :                  */
    1882          72 :                 cheapest_startup = get_singleton_append_subpath(cheapest_startup);
    1883          72 :                 cheapest_total = get_singleton_append_subpath(cheapest_total);
    1884             : 
    1885          72 :                 startup_subpaths = lcons(cheapest_startup, startup_subpaths);
    1886          72 :                 total_subpaths = lcons(cheapest_total, total_subpaths);
    1887             :             }
    1888             :             else
    1889             :             {
    1890             :                 /*
    1891             :                  * Otherwise, rely on accumulate_append_subpath to collect the
    1892             :                  * child paths for the MergeAppend.
    1893             :                  */
    1894        3680 :                 accumulate_append_subpath(cheapest_startup,
    1895             :                                           &startup_subpaths, NULL);
    1896        3680 :                 accumulate_append_subpath(cheapest_total,
    1897             :                                           &total_subpaths, NULL);
    1898             :             }
    1899             :         }
    1900             : 
    1901             :         /* ... and build the Append or MergeAppend paths */
    1902        2248 :         if (match_partition_order || match_partition_order_desc)
    1903             :         {
    1904             :             /* We only need Append */
    1905         904 :             add_path(rel, (Path *) create_append_path(root,
    1906             :                                                       rel,
    1907             :                                                       startup_subpaths,
    1908             :                                                       NIL,
    1909             :                                                       pathkeys,
    1910             :                                                       NULL,
    1911             :                                                       0,
    1912             :                                                       false,
    1913             :                                                       partitioned_rels,
    1914             :                                                       -1));
    1915        1808 :             if (startup_neq_total)
    1916           0 :                 add_path(rel, (Path *) create_append_path(root,
    1917             :                                                           rel,
    1918             :                                                           total_subpaths,
    1919             :                                                           NIL,
    1920             :                                                           pathkeys,
    1921             :                                                           NULL,
    1922             :                                                           0,
    1923             :                                                           false,
    1924             :                                                           partitioned_rels,
    1925             :                                                           -1));
    1926             :         }
    1927             :         else
    1928             :         {
    1929             :             /* We need MergeAppend */
    1930        1344 :             add_path(rel, (Path *) create_merge_append_path(root,
    1931             :                                                             rel,
    1932             :                                                             startup_subpaths,
    1933             :                                                             pathkeys,
    1934             :                                                             NULL,
    1935             :                                                             partitioned_rels));
    1936        1344 :             if (startup_neq_total)
    1937           0 :                 add_path(rel, (Path *) create_merge_append_path(root,
    1938             :                                                                 rel,
    1939             :                                                                 total_subpaths,
    1940             :                                                                 pathkeys,
    1941             :                                                                 NULL,
    1942             :                                                                 partitioned_rels));
    1943             :         }
    1944             :     }
    1945       14670 : }
    1946             : 
    1947             : /*
    1948             :  * get_cheapest_parameterized_child_path
    1949             :  *      Get cheapest path for this relation that has exactly the requested
    1950             :  *      parameterization.
    1951             :  *
    1952             :  * Returns NULL if unable to create such a path.
    1953             :  */
    1954             : static Path *
    1955        2902 : get_cheapest_parameterized_child_path(PlannerInfo *root, RelOptInfo *rel,
    1956             :                                       Relids required_outer)
    1957             : {
    1958             :     Path       *cheapest;
    1959             :     ListCell   *lc;
    1960             : 
    1961             :     /*
    1962             :      * Look up the cheapest existing path with no more than the needed
    1963             :      * parameterization.  If it has exactly the needed parameterization, we're
    1964             :      * done.
    1965             :      */
    1966        2902 :     cheapest = get_cheapest_path_for_pathkeys(rel->pathlist,
    1967             :                                               NIL,
    1968             :                                               required_outer,
    1969             :                                               TOTAL_COST,
    1970             :                                               false);
    1971             :     Assert(cheapest != NULL);
    1972        2902 :     if (bms_equal(PATH_REQ_OUTER(cheapest), required_outer))
    1973        2730 :         return cheapest;
    1974             : 
    1975             :     /*
    1976             :      * Otherwise, we can "reparameterize" an existing path to match the given
    1977             :      * parameterization, which effectively means pushing down additional
    1978             :      * joinquals to be checked within the path's scan.  However, some existing
    1979             :      * paths might check the available joinquals already while others don't;
    1980             :      * therefore, it's not clear which existing path will be cheapest after
    1981             :      * reparameterization.  We have to go through them all and find out.
    1982             :      */
    1983         172 :     cheapest = NULL;
    1984         588 :     foreach(lc, rel->pathlist)
    1985             :     {
    1986         416 :         Path       *path = (Path *) lfirst(lc);
    1987             : 
    1988             :         /* Can't use it if it needs more than requested parameterization */
    1989         416 :         if (!bms_is_subset(PATH_REQ_OUTER(path), required_outer))
    1990          16 :             continue;
    1991             : 
    1992             :         /*
    1993             :          * Reparameterization can only increase the path's cost, so if it's
    1994             :          * already more expensive than the current cheapest, forget it.
    1995             :          */
    1996         608 :         if (cheapest != NULL &&
    1997         208 :             compare_path_costs(cheapest, path, TOTAL_COST) <= 0)
    1998         160 :             continue;
    1999             : 
    2000             :         /* Reparameterize if needed, then recheck cost */
    2001         240 :         if (!bms_equal(PATH_REQ_OUTER(path), required_outer))
    2002             :         {
    2003         188 :             path = reparameterize_path(root, path, required_outer, 1.0);
    2004         188 :             if (path == NULL)
    2005          32 :                 continue;       /* failed to reparameterize this one */
    2006             :             Assert(bms_equal(PATH_REQ_OUTER(path), required_outer));
    2007             : 
    2008         156 :             if (cheapest != NULL &&
    2009           0 :                 compare_path_costs(cheapest, path, TOTAL_COST) <= 0)
    2010           0 :                 continue;
    2011             :         }
    2012             : 
    2013             :         /* We have a new best path */
    2014         208 :         cheapest = path;
    2015             :     }
    2016             : 
    2017             :     /* Return the best path, or NULL if we found no suitable candidate */
    2018         172 :     return cheapest;
    2019             : }
    2020             : 
    2021             : /*
    2022             :  * accumulate_append_subpath
    2023             :  *      Add a subpath to the list being built for an Append or MergeAppend.
    2024             :  *
    2025             :  * It's possible that the child is itself an Append or MergeAppend path, in
    2026             :  * which case we can "cut out the middleman" and just add its child paths to
    2027             :  * our own list.  (We don't try to do this earlier because we need to apply
    2028             :  * both levels of transformation to the quals.)
    2029             :  *
    2030             :  * Note that if we omit a child MergeAppend in this way, we are effectively
    2031             :  * omitting a sort step, which seems fine: if the parent is to be an Append,
    2032             :  * its result would be unsorted anyway, while if the parent is to be a
    2033             :  * MergeAppend, there's no point in a separate sort on a child.
    2034             :  *
    2035             :  * Normally, either path is a partial path and subpaths is a list of partial
    2036             :  * paths, or else path is a non-partial plan and subpaths is a list of those.
    2037             :  * However, if path is a parallel-aware Append, then we add its partial path
    2038             :  * children to subpaths and the rest to special_subpaths.  If the latter is
    2039             :  * NULL, we don't flatten the path at all (unless it contains only partial
    2040             :  * paths).
    2041             :  */
    2042             : static void
    2043       88598 : accumulate_append_subpath(Path *path, List **subpaths, List **special_subpaths)
    2044             : {
    2045       88598 :     if (IsA(path, AppendPath))
    2046             :     {
    2047       10496 :         AppendPath *apath = (AppendPath *) path;
    2048             : 
    2049       10496 :         if (!apath->path.parallel_aware || apath->first_partial_path == 0)
    2050             :         {
    2051             :             /* list_copy is important here to avoid sharing list substructure */
    2052       10384 :             *subpaths = list_concat(*subpaths, list_copy(apath->subpaths));
    2053       10384 :             return;
    2054             :         }
    2055         112 :         else if (special_subpaths != NULL)
    2056             :         {
    2057             :             List       *new_special_subpaths;
    2058             : 
    2059             :             /* Split Parallel Append into partial and non-partial subpaths */
    2060         112 :             *subpaths = list_concat(*subpaths,
    2061          56 :                                     list_copy_tail(apath->subpaths,
    2062             :                                                    apath->first_partial_path));
    2063          56 :             new_special_subpaths =
    2064          56 :                 list_truncate(list_copy(apath->subpaths),
    2065             :                               apath->first_partial_path);
    2066          56 :             *special_subpaths = list_concat(*special_subpaths,
    2067             :                                             new_special_subpaths);
    2068          56 :             return;
    2069             :         }
    2070             :     }
    2071       78102 :     else if (IsA(path, MergeAppendPath))
    2072             :     {
    2073         244 :         MergeAppendPath *mpath = (MergeAppendPath *) path;
    2074             : 
    2075             :         /* list_copy is important here to avoid sharing list substructure */
    2076         244 :         *subpaths = list_concat(*subpaths, list_copy(mpath->subpaths));
    2077         244 :         return;
    2078             :     }
    2079             : 
    2080       77914 :     *subpaths = lappend(*subpaths, path);
    2081             : }
    2082             : 
    2083             : /*
    2084             :  * get_singleton_append_subpath
    2085             :  *      Returns the single subpath of an Append/MergeAppend, or just
    2086             :  *      return 'path' if it's not a single sub-path Append/MergeAppend.
    2087             :  *
    2088             :  * Note: 'path' must not be a parallel-aware path.
    2089             :  */
    2090             : static Path *
    2091        4696 : get_singleton_append_subpath(Path *path)
    2092             : {
    2093             :     Assert(!path->parallel_aware);
    2094             : 
    2095        4696 :     if (IsA(path, AppendPath))
    2096             :     {
    2097         100 :         AppendPath *apath = (AppendPath *) path;
    2098             : 
    2099         100 :         if (list_length(apath->subpaths) == 1)
    2100          24 :             return (Path *) linitial(apath->subpaths);
    2101             :     }
    2102        4596 :     else if (IsA(path, MergeAppendPath))
    2103             :     {
    2104         136 :         MergeAppendPath *mpath = (MergeAppendPath *) path;
    2105             : 
    2106         136 :         if (list_length(mpath->subpaths) == 1)
    2107           0 :             return (Path *) linitial(mpath->subpaths);
    2108             :     }
    2109             : 
    2110        4672 :     return path;
    2111             : }
    2112             : 
    2113             : /*
    2114             :  * set_dummy_rel_pathlist
    2115             :  *    Build a dummy path for a relation that's been excluded by constraints
    2116             :  *
    2117             :  * Rather than inventing a special "dummy" path type, we represent this as an
    2118             :  * AppendPath with no members (see also IS_DUMMY_APPEND/IS_DUMMY_REL macros).
    2119             :  *
    2120             :  * (See also mark_dummy_rel, which does basically the same thing, but is
    2121             :  * typically used to change a rel into dummy state after we already made
    2122             :  * paths for it.)
    2123             :  */
    2124             : static void
    2125         552 : set_dummy_rel_pathlist(RelOptInfo *rel)
    2126             : {
    2127             :     /* Set dummy size estimates --- we leave attr_widths[] as zeroes */
    2128         552 :     rel->rows = 0;
    2129         552 :     rel->reltarget->width = 0;
    2130             : 
    2131             :     /* Discard any pre-existing paths; no further need for them */
    2132         552 :     rel->pathlist = NIL;
    2133         552 :     rel->partial_pathlist = NIL;
    2134             : 
    2135             :     /* Set up the dummy path */
    2136         552 :     add_path(rel, (Path *) create_append_path(NULL, rel, NIL, NIL,
    2137             :                                               NIL, rel->lateral_relids,
    2138             :                                               0, false, NIL, -1));
    2139             : 
    2140             :     /*
    2141             :      * We set the cheapest-path fields immediately, just in case they were
    2142             :      * pointing at some discarded path.  This is redundant when we're called
    2143             :      * from set_rel_size(), but not when called from elsewhere, and doing it
    2144             :      * twice is harmless anyway.
    2145             :      */
    2146         552 :     set_cheapest(rel);
    2147         552 : }
    2148             : 
    2149             : /* quick-and-dirty test to see if any joining is needed */
    2150             : static bool
    2151        2260 : has_multiple_baserels(PlannerInfo *root)
    2152             : {
    2153        2260 :     int         num_base_rels = 0;
    2154             :     Index       rti;
    2155             : 
    2156        6416 :     for (rti = 1; rti < root->simple_rel_array_size; rti++)
    2157             :     {
    2158        4796 :         RelOptInfo *brel = root->simple_rel_array[rti];
    2159             : 
    2160        4796 :         if (brel == NULL)
    2161        1716 :             continue;
    2162             : 
    2163             :         /* ignore RTEs that are "other rels" */
    2164        3080 :         if (brel->reloptkind == RELOPT_BASEREL)
    2165        2900 :             if (++num_base_rels > 1)
    2166         640 :                 return true;
    2167             :     }
    2168        1620 :     return false;
    2169             : }
    2170             : 
    2171             : /*
    2172             :  * set_subquery_pathlist
    2173             :  *      Generate SubqueryScan access paths for a subquery RTE
    2174             :  *
    2175             :  * We don't currently support generating parameterized paths for subqueries
    2176             :  * by pushing join clauses down into them; it seems too expensive to re-plan
    2177             :  * the subquery multiple times to consider different alternatives.
    2178             :  * (XXX that could stand to be reconsidered, now that we use Paths.)
    2179             :  * So the paths made here will be parameterized if the subquery contains
    2180             :  * LATERAL references, otherwise not.  As long as that's true, there's no need
    2181             :  * for a separate set_subquery_size phase: just make the paths right away.
    2182             :  */
    2183             : static void
    2184        5488 : set_subquery_pathlist(PlannerInfo *root, RelOptInfo *rel,
    2185             :                       Index rti, RangeTblEntry *rte)
    2186             : {
    2187        5488 :     Query      *parse = root->parse;
    2188        5488 :     Query      *subquery = rte->subquery;
    2189             :     Relids      required_outer;
    2190             :     pushdown_safety_info safetyInfo;
    2191             :     double      tuple_fraction;
    2192             :     RelOptInfo *sub_final_rel;
    2193             :     ListCell   *lc;
    2194             : 
    2195             :     /*
    2196             :      * Must copy the Query so that planning doesn't mess up the RTE contents
    2197             :      * (really really need to fix the planner to not scribble on its input,
    2198             :      * someday ... but see remove_unused_subquery_outputs to start with).
    2199             :      */
    2200        5488 :     subquery = copyObject(subquery);
    2201             : 
    2202             :     /*
    2203             :      * If it's a LATERAL subquery, it might contain some Vars of the current
    2204             :      * query level, requiring it to be treated as parameterized, even though
    2205             :      * we don't support pushing down join quals into subqueries.
    2206             :      */
    2207        5488 :     required_outer = rel->lateral_relids;
    2208             : 
    2209             :     /*
    2210             :      * Zero out result area for subquery_is_pushdown_safe, so that it can set
    2211             :      * flags as needed while recursing.  In particular, we need a workspace
    2212             :      * for keeping track of unsafe-to-reference columns.  unsafeColumns[i]
    2213             :      * will be set true if we find that output column i of the subquery is
    2214             :      * unsafe to use in a pushed-down qual.
    2215             :      */
    2216        5488 :     memset(&safetyInfo, 0, sizeof(safetyInfo));
    2217        5488 :     safetyInfo.unsafeColumns = (bool *)
    2218        5488 :         palloc0((list_length(subquery->targetList) + 1) * sizeof(bool));
    2219             : 
    2220             :     /*
    2221             :      * If the subquery has the "security_barrier" flag, it means the subquery
    2222             :      * originated from a view that must enforce row level security.  Then we
    2223             :      * must not push down quals that contain leaky functions.  (Ideally this
    2224             :      * would be checked inside subquery_is_pushdown_safe, but since we don't
    2225             :      * currently pass the RTE to that function, we must do it here.)
    2226             :      */
    2227        5488 :     safetyInfo.unsafeLeaky = rte->security_barrier;
    2228             : 
    2229             :     /*
    2230             :      * If there are any restriction clauses that have been attached to the
    2231             :      * subquery relation, consider pushing them down to become WHERE or HAVING
    2232             :      * quals of the subquery itself.  This transformation is useful because it
    2233             :      * may allow us to generate a better plan for the subquery than evaluating
    2234             :      * all the subquery output rows and then filtering them.
    2235             :      *
    2236             :      * There are several cases where we cannot push down clauses. Restrictions
    2237             :      * involving the subquery are checked by subquery_is_pushdown_safe().
    2238             :      * Restrictions on individual clauses are checked by
    2239             :      * qual_is_pushdown_safe().  Also, we don't want to push down
    2240             :      * pseudoconstant clauses; better to have the gating node above the
    2241             :      * subquery.
    2242             :      *
    2243             :      * Non-pushed-down clauses will get evaluated as qpquals of the
    2244             :      * SubqueryScan node.
    2245             :      *
    2246             :      * XXX Are there any cases where we want to make a policy decision not to
    2247             :      * push down a pushable qual, because it'd result in a worse plan?
    2248             :      */
    2249        6114 :     if (rel->baserestrictinfo != NIL &&
    2250         626 :         subquery_is_pushdown_safe(subquery, subquery, &safetyInfo))
    2251             :     {
    2252             :         /* OK to consider pushing down individual quals */
    2253         564 :         List       *upperrestrictlist = NIL;
    2254             :         ListCell   *l;
    2255             : 
    2256        1384 :         foreach(l, rel->baserestrictinfo)
    2257             :         {
    2258         820 :             RestrictInfo *rinfo = (RestrictInfo *) lfirst(l);
    2259         820 :             Node       *clause = (Node *) rinfo->clause;
    2260             : 
    2261        1640 :             if (!rinfo->pseudoconstant &&
    2262         820 :                 qual_is_pushdown_safe(subquery, rti, clause, &safetyInfo))
    2263             :             {
    2264             :                 /* Push it down */
    2265         552 :                 subquery_push_qual(subquery, rte, rti, clause);
    2266             :             }
    2267             :             else
    2268             :             {
    2269             :                 /* Keep it in the upper query */
    2270         268 :                 upperrestrictlist = lappend(upperrestrictlist, rinfo);
    2271             :             }
    2272             :         }
    2273         564 :         rel->baserestrictinfo = upperrestrictlist;
    2274             :         /* We don't bother recomputing baserestrict_min_security */
    2275             :     }
    2276             : 
    2277        5488 :     pfree(safetyInfo.unsafeColumns);
    2278             : 
    2279             :     /*
    2280             :      * The upper query might not use all the subquery's output columns; if
    2281             :      * not, we can simplify.
    2282             :      */
    2283        5488 :     remove_unused_subquery_outputs(subquery, rel);
    2284             : 
    2285             :     /*
    2286             :      * We can safely pass the outer tuple_fraction down to the subquery if the
    2287             :      * outer level has no joining, aggregation, or sorting to do. Otherwise
    2288             :      * we'd better tell the subquery to plan for full retrieval. (XXX This
    2289             :      * could probably be made more intelligent ...)
    2290             :      */
    2291       10498 :     if (parse->hasAggs ||
    2292       10016 :         parse->groupClause ||
    2293       10012 :         parse->groupingSets ||
    2294       10012 :         parse->havingQual ||
    2295        9972 :         parse->distinctClause ||
    2296        7226 :         parse->sortClause ||
    2297        2260 :         has_multiple_baserels(root))
    2298        3868 :         tuple_fraction = 0.0;   /* default case */
    2299             :     else
    2300        1620 :         tuple_fraction = root->tuple_fraction;
    2301             : 
    2302             :     /* plan_params should not be in use in current query level */
    2303             :     Assert(root->plan_params == NIL);
    2304             : 
    2305             :     /* Generate a subroot and Paths for the subquery */
    2306        5488 :     rel->subroot = subquery_planner(root->glob, subquery,
    2307             :                                     root,
    2308             :                                     false, tuple_fraction);
    2309             : 
    2310             :     /* Isolate the params needed by this specific subplan */
    2311        5488 :     rel->subplan_params = root->plan_params;
    2312        5488 :     root->plan_params = NIL;
    2313             : 
    2314             :     /*
    2315             :      * It's possible that constraint exclusion proved the subquery empty. If
    2316             :      * so, it's desirable to produce an unadorned dummy path so that we will
    2317             :      * recognize appropriate optimizations at this query level.
    2318             :      */
    2319        5488 :     sub_final_rel = fetch_upper_rel(rel->subroot, UPPERREL_FINAL, NULL);
    2320             : 
    2321        5488 :     if (IS_DUMMY_REL(sub_final_rel))
    2322             :     {
    2323          68 :         set_dummy_rel_pathlist(rel);
    2324          68 :         return;
    2325             :     }
    2326             : 
    2327             :     /*
    2328             :      * Mark rel with estimated output rows, width, etc.  Note that we have to
    2329             :      * do this before generating outer-query paths, else cost_subqueryscan is
    2330             :      * not happy.
    2331             :      */
    2332        5420 :     set_subquery_size_estimates(root, rel);
    2333             : 
    2334             :     /*
    2335             :      * For each Path that subquery_planner produced, make a SubqueryScanPath
    2336             :      * in the outer query.
    2337             :      */
    2338       11054 :     foreach(lc, sub_final_rel->pathlist)
    2339             :     {
    2340        5634 :         Path       *subpath = (Path *) lfirst(lc);
    2341             :         List       *pathkeys;
    2342             : 
    2343             :         /* Convert subpath's pathkeys to outer representation */
    2344        5634 :         pathkeys = convert_subquery_pathkeys(root,
    2345             :                                              rel,
    2346             :                                              subpath->pathkeys,
    2347             :                                              make_tlist_from_pathtarget(subpath->pathtarget));
    2348             : 
    2349             :         /* Generate outer path using this subpath */
    2350        5634 :         add_path(rel, (Path *)
    2351        5634 :                  create_subqueryscan_path(root, rel, subpath,
    2352             :                                           pathkeys, required_outer));
    2353             :     }
    2354             : 
    2355             :     /* If outer rel allows parallelism, do same for partial paths. */
    2356        5420 :     if (rel->consider_parallel && bms_is_empty(required_outer))
    2357             :     {
    2358             :         /* If consider_parallel is false, there should be no partial paths. */
    2359             :         Assert(sub_final_rel->consider_parallel ||
    2360             :                sub_final_rel->partial_pathlist == NIL);
    2361             : 
    2362             :         /* Same for partial paths. */
    2363        3202 :         foreach(lc, sub_final_rel->partial_pathlist)
    2364             :         {
    2365          20 :             Path       *subpath = (Path *) lfirst(lc);
    2366             :             List       *pathkeys;
    2367             : 
    2368             :             /* Convert subpath's pathkeys to outer representation */
    2369          20 :             pathkeys = convert_subquery_pathkeys(root,
    2370             :                                                  rel,
    2371             :                                                  subpath->pathkeys,
    2372             :                                                  make_tlist_from_pathtarget(subpath->pathtarget));
    2373             : 
    2374             :             /* Generate outer path using this subpath */
    2375          20 :             add_partial_path(rel, (Path *)
    2376          20 :                              create_subqueryscan_path(root, rel, subpath,
    2377             :                                                       pathkeys,
    2378             :                                                       required_outer));
    2379             :         }
    2380             :     }
    2381             : }
    2382             : 
    2383             : /*
    2384             :  * set_function_pathlist
    2385             :  *      Build the (single) access path for a function RTE
    2386             :  */
    2387             : static void
    2388       28740 : set_function_pathlist(PlannerInfo *root, RelOptInfo *rel, RangeTblEntry *rte)
    2389             : {
    2390             :     Relids      required_outer;
    2391       28740 :     List       *pathkeys = NIL;
    2392             : 
    2393             :     /*
    2394             :      * We don't support pushing join clauses into the quals of a function
    2395             :      * scan, but it could still have required parameterization due to LATERAL
    2396             :      * refs in the function expression.
    2397             :      */
    2398       28740 :     required_outer = rel->lateral_relids;
    2399             : 
    2400             :     /*
    2401             :      * The result is considered unordered unless ORDINALITY was used, in which
    2402             :      * case it is ordered by the ordinal column (the last one).  See if we
    2403             :      * care, by checking for uses of that Var in equivalence classes.
    2404             :      */
    2405       28740 :     if (rte->funcordinality)
    2406             :     {
    2407        6318 :         AttrNumber  ordattno = rel->max_attr;
    2408        6318 :         Var        *var = NULL;
    2409             :         ListCell   *lc;
    2410             : 
    2411             :         /*
    2412             :          * Is there a Var for it in rel's targetlist?  If not, the query did
    2413             :          * not reference the ordinality column, or at least not in any way
    2414             :          * that would be interesting for sorting.
    2415             :          */
    2416       13132 :         foreach(lc, rel->reltarget->exprs)
    2417             :         {
    2418       12868 :             Var        *node = (Var *) lfirst(lc);
    2419             : 
    2420             :             /* checking varno/varlevelsup is just paranoia */
    2421       25736 :             if (IsA(node, Var) &&
    2422       18922 :                 node->varattno == ordattno &&
    2423       12108 :                 node->varno == rel->relid &&
    2424        6054 :                 node->varlevelsup == 0)
    2425             :             {
    2426        6054 :                 var = node;
    2427        6054 :                 break;
    2428             :             }
    2429             :         }
    2430             : 
    2431             :         /*
    2432             :          * Try to build pathkeys for this Var with int8 sorting.  We tell
    2433             :          * build_expression_pathkey not to build any new equivalence class; if
    2434             :          * the Var isn't already mentioned in some EC, it means that nothing
    2435             :          * cares about the ordering.
    2436             :          */
    2437        6318 :         if (var)
    2438        6054 :             pathkeys = build_expression_pathkey(root,
    2439             :                                                 (Expr *) var,
    2440             :                                                 NULL,   /* below outer joins */
    2441             :                                                 Int8LessOperator,
    2442             :                                                 rel->relids,
    2443             :                                                 false);
    2444             :     }
    2445             : 
    2446             :     /* Generate appropriate path */
    2447       28740 :     add_path(rel, create_functionscan_path(root, rel,
    2448             :                                            pathkeys, required_outer));
    2449       28740 : }
    2450             : 
    2451             : /*
    2452             :  * set_values_pathlist
    2453             :  *      Build the (single) access path for a VALUES RTE
    2454             :  */
    2455             : static void
    2456        3774 : set_values_pathlist(PlannerInfo *root, RelOptInfo *rel, RangeTblEntry *rte)
    2457             : {
    2458             :     Relids      required_outer;
    2459             : 
    2460             :     /*
    2461             :      * We don't support pushing join clauses into the quals of a values scan,
    2462             :      * but it could still have required parameterization due to LATERAL refs
    2463             :      * in the values expressions.
    2464             :      */
    2465        3774 :     required_outer = rel->lateral_relids;
    2466             : 
    2467             :     /* Generate appropriate path */
    2468        3774 :     add_path(rel, create_valuesscan_path(root, rel, required_outer));
    2469        3774 : }
    2470             : 
    2471             : /*
    2472             :  * set_tablefunc_pathlist
    2473             :  *      Build the (single) access path for a table func RTE
    2474             :  */
    2475             : static void
    2476         140 : set_tablefunc_pathlist(PlannerInfo *root, RelOptInfo *rel, RangeTblEntry *rte)
    2477             : {
    2478             :     Relids      required_outer;
    2479             : 
    2480             :     /*
    2481             :      * We don't support pushing join clauses into the quals of a tablefunc
    2482             :      * scan, but it could still have required parameterization due to LATERAL
    2483             :      * refs in the function expression.
    2484             :      */
    2485         140 :     required_outer = rel->lateral_relids;
    2486             : 
    2487             :     /* Generate appropriate path */
    2488         140 :     add_path(rel, create_tablefuncscan_path(root, rel,
    2489             :                                             required_outer));
    2490         140 : }
    2491             : 
    2492             : /*
    2493             :  * set_cte_pathlist
    2494             :  *      Build the (single) access path for a non-self-reference CTE RTE
    2495             :  *
    2496             :  * There's no need for a separate set_cte_size phase, since we don't
    2497             :  * support join-qual-parameterized paths for CTEs.
    2498             :  */
    2499             : static void
    2500         894 : set_cte_pathlist(PlannerInfo *root, RelOptInfo *rel, RangeTblEntry *rte)
    2501             : {
    2502             :     Plan       *cteplan;
    2503             :     PlannerInfo *cteroot;
    2504             :     Index       levelsup;
    2505             :     int         ndx;
    2506             :     ListCell   *lc;
    2507             :     int         plan_id;
    2508             :     Relids      required_outer;
    2509             : 
    2510             :     /*
    2511             :      * Find the referenced CTE, and locate the plan previously made for it.
    2512             :      */
    2513         894 :     levelsup = rte->ctelevelsup;
    2514         894 :     cteroot = root;
    2515        2060 :     while (levelsup-- > 0)
    2516             :     {
    2517         272 :         cteroot = cteroot->parent_root;
    2518         272 :         if (!cteroot)           /* shouldn't happen */
    2519           0 :             elog(ERROR, "bad levelsup for CTE \"%s\"", rte->ctename);
    2520             :     }
    2521             : 
    2522             :     /*
    2523             :      * Note: cte_plan_ids can be shorter than cteList, if we are still working
    2524             :      * on planning the CTEs (ie, this is a side-reference from another CTE).
    2525             :      * So we mustn't use forboth here.
    2526             :      */
    2527         894 :     ndx = 0;
    2528        1016 :     foreach(lc, cteroot->parse->cteList)
    2529             :     {
    2530        1016 :         CommonTableExpr *cte = (CommonTableExpr *) lfirst(lc);
    2531             : 
    2532        1016 :         if (strcmp(cte->ctename, rte->ctename) == 0)
    2533         894 :             break;
    2534         122 :         ndx++;
    2535             :     }
    2536         894 :     if (lc == NULL)             /* shouldn't happen */
    2537           0 :         elog(ERROR, "could not find CTE \"%s\"", rte->ctename);
    2538         894 :     if (ndx >= list_length(cteroot->cte_plan_ids))
    2539           0 :         elog(ERROR, "could not find plan for CTE \"%s\"", rte->ctename);
    2540         894 :     plan_id = list_nth_int(cteroot->cte_plan_ids, ndx);
    2541             :     Assert(plan_id > 0);
    2542         894 :     cteplan = (Plan *) list_nth(root->glob->subplans, plan_id - 1);
    2543             : 
    2544             :     /* Mark rel with estimated output rows, width, etc */
    2545         894 :     set_cte_size_estimates(root, rel, cteplan->plan_rows);
    2546             : 
    2547             :     /*
    2548             :      * We don't support pushing join clauses into the quals of a CTE scan, but
    2549             :      * it could still have required parameterization due to LATERAL refs in
    2550             :      * its tlist.
    2551             :      */
    2552         894 :     required_outer = rel->lateral_relids;
    2553             : 
    2554             :     /* Generate appropriate path */
    2555         894 :     add_path(rel, create_ctescan_path(root, rel, required_outer));
    2556         894 : }
    2557             : 
    2558             : /*
    2559             :  * set_namedtuplestore_pathlist
    2560             :  *      Build the (single) access path for a named tuplestore RTE
    2561             :  *
    2562             :  * There's no need for a separate set_namedtuplestore_size phase, since we
    2563             :  * don't support join-qual-parameterized paths for tuplestores.
    2564             :  */
    2565             : static void
    2566         256 : set_namedtuplestore_pathlist(PlannerInfo *root, RelOptInfo *rel,
    2567             :                              RangeTblEntry *rte)
    2568             : {
    2569             :     Relids      required_outer;
    2570             : 
    2571             :     /* Mark rel with estimated output rows, width, etc */
    2572         256 :     set_namedtuplestore_size_estimates(root, rel);
    2573             : 
    2574             :     /*
    2575             :      * We don't support pushing join clauses into the quals of a tuplestore
    2576             :      * scan, but it could still have required parameterization due to LATERAL
    2577             :      * refs in its tlist.
    2578             :      */
    2579         256 :     required_outer = rel->lateral_relids;
    2580             : 
    2581             :     /* Generate appropriate path */
    2582         256 :     add_path(rel, create_namedtuplestorescan_path(root, rel, required_outer));
    2583             : 
    2584             :     /* Select cheapest path (pretty easy in this case...) */
    2585         256 :     set_cheapest(rel);
    2586         256 : }
    2587             : 
    2588             : /*
    2589             :  * set_result_pathlist
    2590             :  *      Build the (single) access path for an RTE_RESULT RTE
    2591             :  *
    2592             :  * There's no need for a separate set_result_size phase, since we
    2593             :  * don't support join-qual-parameterized paths for these RTEs.
    2594             :  */
    2595             : static void
    2596         566 : set_result_pathlist(PlannerInfo *root, RelOptInfo *rel,
    2597             :                     RangeTblEntry *rte)
    2598             : {
    2599             :     Relids      required_outer;
    2600             : 
    2601             :     /* Mark rel with estimated output rows, width, etc */
    2602         566 :     set_result_size_estimates(root, rel);
    2603             : 
    2604             :     /*
    2605             :      * We don't support pushing join clauses into the quals of a Result scan,
    2606             :      * but it could still have required parameterization due to LATERAL refs
    2607             :      * in its tlist.
    2608             :      */
    2609         566 :     required_outer = rel->lateral_relids;
    2610             : 
    2611             :     /* Generate appropriate path */
    2612         566 :     add_path(rel, create_resultscan_path(root, rel, required_outer));
    2613             : 
    2614             :     /* Select cheapest path (pretty easy in this case...) */
    2615         566 :     set_cheapest(rel);
    2616         566 : }
    2617             : 
    2618             : /*
    2619             :  * set_worktable_pathlist
    2620             :  *      Build the (single) access path for a self-reference CTE RTE
    2621             :  *
    2622             :  * There's no need for a separate set_worktable_size phase, since we don't
    2623             :  * support join-qual-parameterized paths for CTEs.
    2624             :  */
    2625             : static void
    2626         326 : set_worktable_pathlist(PlannerInfo *root, RelOptInfo *rel, RangeTblEntry *rte)
    2627             : {
    2628             :     Path       *ctepath;
    2629             :     PlannerInfo *cteroot;
    2630             :     Index       levelsup;
    2631             :     Relids      required_outer;
    2632             : 
    2633             :     /*
    2634             :      * We need to find the non-recursive term's path, which is in the plan
    2635             :      * level that's processing the recursive UNION, which is one level *below*
    2636             :      * where the CTE comes from.
    2637             :      */
    2638         326 :     levelsup = rte->ctelevelsup;
    2639         326 :     if (levelsup == 0)          /* shouldn't happen */
    2640           0 :         elog(ERROR, "bad levelsup for CTE \"%s\"", rte->ctename);
    2641         326 :     levelsup--;
    2642         326 :     cteroot = root;
    2643        1014 :     while (levelsup-- > 0)
    2644             :     {
    2645         362 :         cteroot = cteroot->parent_root;
    2646         362 :         if (!cteroot)           /* shouldn't happen */
    2647           0 :             elog(ERROR, "bad levelsup for CTE \"%s\"", rte->ctename);
    2648             :     }
    2649         326 :     ctepath = cteroot->non_recursive_path;
    2650         326 :     if (!ctepath)               /* shouldn't happen */
    2651           0 :         elog(ERROR, "could not find path for CTE \"%s\"", rte->ctename);
    2652             : 
    2653             :     /* Mark rel with estimated output rows, width, etc */
    2654         326 :     set_cte_size_estimates(root, rel, ctepath->rows);
    2655             : 
    2656             :     /*
    2657             :      * We don't support pushing join clauses into the quals of a worktable
    2658             :      * scan, but it could still have required parameterization due to LATERAL
    2659             :      * refs in its tlist.  (I'm not sure this is actually possible given the
    2660             :      * restrictions on recursive references, but it's easy enough to support.)
    2661             :      */
    2662         326 :     required_outer = rel->lateral_relids;
    2663             : 
    2664             :     /* Generate appropriate path */
    2665         326 :     add_path(rel, create_worktablescan_path(root, rel, required_outer));
    2666         326 : }
    2667             : 
    2668             : /*
    2669             :  * generate_gather_paths
    2670             :  *      Generate parallel access paths for a relation by pushing a Gather or
    2671             :  *      Gather Merge on top of a partial path.
    2672             :  *
    2673             :  * This must not be called until after we're done creating all partial paths
    2674             :  * for the specified relation.  (Otherwise, add_partial_path might delete a
    2675             :  * path that some GatherPath or GatherMergePath has a reference to.)
    2676             :  *
    2677             :  * If we're generating paths for a scan or join relation, override_rows will
    2678             :  * be false, and we'll just use the relation's size estimate.  When we're
    2679             :  * being called for a partially-grouped path, though, we need to override
    2680             :  * the rowcount estimate.  (It's not clear that the particular value we're
    2681             :  * using here is actually best, but the underlying rel has no estimate so
    2682             :  * we must do something.)
    2683             :  */
    2684             : void
    2685      292732 : generate_gather_paths(PlannerInfo *root, RelOptInfo *rel, bool override_rows)
    2686             : {
    2687             :     Path       *cheapest_partial_path;
    2688             :     Path       *simple_gather_path;
    2689             :     ListCell   *lc;
    2690             :     double      rows;
    2691      292732 :     double     *rowsp = NULL;
    2692             : 
    2693             :     /* If there are no partial paths, there's nothing to do here. */
    2694      292732 :     if (rel->partial_pathlist == NIL)
    2695      285012 :         return;
    2696             : 
    2697             :     /* Should we override the rel's rowcount estimate? */
    2698        7720 :     if (override_rows)
    2699         966 :         rowsp = &rows;
    2700             : 
    2701             :     /*
    2702             :      * The output of Gather is always unsorted, so there's only one partial
    2703             :      * path of interest: the cheapest one.  That will be the one at the front
    2704             :      * of partial_pathlist because of the way add_partial_path works.
    2705             :      */
    2706        7720 :     cheapest_partial_path = linitial(rel->partial_pathlist);
    2707        7720 :     rows =
    2708        7720 :         cheapest_partial_path->rows * cheapest_partial_path->parallel_workers;
    2709        7720 :     simple_gather_path = (Path *)
    2710        7720 :         create_gather_path(root, rel, cheapest_partial_path, rel->reltarget,
    2711             :                            NULL, rowsp);
    2712        7720 :     add_path(rel, simple_gather_path);
    2713             : 
    2714             :     /*
    2715             :      * For each useful ordering, we can consider an order-preserving Gather
    2716             :      * Merge.
    2717             :      */
    2718       15982 :     foreach(lc, rel->partial_pathlist)
    2719             :     {
    2720        8262 :         Path       *subpath = (Path *) lfirst(lc);
    2721             :         GatherMergePath *path;
    2722             : 
    2723        8262 :         if (subpath->pathkeys == NIL)
    2724        7658 :             continue;
    2725             : 
    2726         604 :         rows = subpath->rows * subpath->parallel_workers;
    2727         604 :         path = create_gather_merge_path(root, rel, subpath, rel->reltarget,
    2728             :                                         subpath->pathkeys, NULL, rowsp);
    2729         604 :         add_path(rel, &path->path);
    2730             :     }
    2731             : }
    2732             : 
    2733             : /*
    2734             :  * make_rel_from_joinlist
    2735             :  *    Build access paths using a "joinlist" to guide the join path search.
    2736             :  *
    2737             :  * See comments for deconstruct_jointree() for definition of the joinlist
    2738             :  * data structure.
    2739             :  */
    2740             : static RelOptInfo *
    2741      188194 : make_rel_from_joinlist(PlannerInfo *root, List *joinlist)
    2742             : {
    2743             :     int         levels_needed;
    2744             :     List       *initial_rels;
    2745             :     ListCell   *jl;
    2746             : 
    2747             :     /*
    2748             :      * Count the number of child joinlist nodes.  This is the depth of the
    2749             :      * dynamic-programming algorithm we must employ to consider all ways of
    2750             :      * joining the child nodes.
    2751             :      */
    2752      188194 :     levels_needed = list_length(joinlist);
    2753             : 
    2754      188194 :     if (levels_needed <= 0)
    2755           0 :         return NULL;            /* nothing to do? */
    2756             : 
    2757             :     /*
    2758             :      * Construct a list of rels corresponding to the child joinlist nodes.
    2759             :      * This may contain both base rels and rels constructed according to
    2760             :      * sub-joinlists.
    2761             :      */
    2762      188194 :     initial_rels = NIL;
    2763      436040 :     foreach(jl, joinlist)
    2764             :     {
    2765      247846 :         Node       *jlnode = (Node *) lfirst(jl);
    2766             :         RelOptInfo *thisrel;
    2767             : 
    2768      247846 :         if (IsA(jlnode, RangeTblRef))
    2769             :         {
    2770      246320 :             int         varno = ((RangeTblRef *) jlnode)->rtindex;
    2771             : 
    2772      246320 :             thisrel = find_base_rel(root, varno);
    2773             :         }
    2774        1526 :         else if (IsA(jlnode, List))
    2775             :         {
    2776             :             /* Recurse to handle subproblem */
    2777        1526 :             thisrel = make_rel_from_joinlist(root, (List *) jlnode);
    2778             :         }
    2779             :         else
    2780             :         {
    2781           0 :             elog(ERROR, "unrecognized joinlist node type: %d",
    2782             :                  (int) nodeTag(jlnode));
    2783             :             thisrel = NULL;     /* keep compiler quiet */
    2784             :         }
    2785             : 
    2786      247846 :         initial_rels = lappend(initial_rels, thisrel);
    2787             :     }
    2788             : 
    2789      188194 :     if (levels_needed == 1)
    2790             :     {
    2791             :         /*
    2792             :          * Single joinlist node, so we're done.
    2793             :          */
    2794      141462 :         return (RelOptInfo *) linitial(initial_rels);
    2795             :     }
    2796             :     else
    2797             :     {
    2798             :         /*
    2799             :          * Consider the different orders in which we could join the rels,
    2800             :          * using a plugin, GEQO, or the regular join search code.
    2801             :          *
    2802             :          * We put the initial_rels list into a PlannerInfo field because
    2803             :          * has_legal_joinclause() needs to look at it (ugly :-().
    2804             :          */
    2805       46732 :         root->initial_rels = initial_rels;
    2806             : 
    2807       46732 :         if (join_search_hook)
    2808           0 :             return (*join_search_hook) (root, levels_needed, initial_rels);
    2809       46732 :         else if (enable_geqo && levels_needed >= geqo_threshold)
    2810           4 :             return geqo(root, levels_needed, initial_rels);
    2811             :         else
    2812       46728 :             return standard_join_search(root, levels_needed, initial_rels);
    2813             :     }
    2814             : }
    2815             : 
    2816             : /*
    2817             :  * standard_join_search
    2818             :  *    Find possible joinpaths for a query by successively finding ways
    2819             :  *    to join component relations into join relations.
    2820             :  *
    2821             :  * 'levels_needed' is the number of iterations needed, ie, the number of
    2822             :  *      independent jointree items in the query.  This is > 1.
    2823             :  *
    2824             :  * 'initial_rels' is a list of RelOptInfo nodes for each independent
    2825             :  *      jointree item.  These are the components to be joined together.
    2826             :  *      Note that levels_needed == list_length(initial_rels).
    2827             :  *
    2828             :  * Returns the final level of join relations, i.e., the relation that is
    2829             :  * the result of joining all the original relations together.
    2830             :  * At least one implementation path must be provided for this relation and
    2831             :  * all required sub-relations.
    2832             :  *
    2833             :  * To support loadable plugins that modify planner behavior by changing the
    2834             :  * join searching algorithm, we provide a hook variable that lets a plugin
    2835             :  * replace or supplement this function.  Any such hook must return the same
    2836             :  * final join relation as the standard code would, but it might have a
    2837             :  * different set of implementation paths attached, and only the sub-joinrels
    2838             :  * needed for these paths need have been instantiated.
    2839             :  *
    2840             :  * Note to plugin authors: the functions invoked during standard_join_search()
    2841             :  * modify root->join_rel_list and root->join_rel_hash.  If you want to do more
    2842             :  * than one join-order search, you'll probably need to save and restore the
    2843             :  * original states of those data structures.  See geqo_eval() for an example.
    2844             :  */
    2845             : RelOptInfo *
    2846       46728 : standard_join_search(PlannerInfo *root, int levels_needed, List *initial_rels)
    2847             : {
    2848             :     int         lev;
    2849             :     RelOptInfo *rel;
    2850             : 
    2851             :     /*
    2852             :      * This function cannot be invoked recursively within any one planning
    2853             :      * problem, so join_rel_level[] can't be in use already.
    2854             :      */
    2855             :     Assert(root->join_rel_level == NULL);
    2856             : 
    2857             :     /*
    2858             :      * We employ a simple "dynamic programming" algorithm: we first find all
    2859             :      * ways to build joins of two jointree items, then all ways to build joins
    2860             :      * of three items (from two-item joins and single items), then four-item
    2861             :      * joins, and so on until we have considered all ways to join all the
    2862             :      * items into one rel.
    2863             :      *
    2864             :      * root->join_rel_level[j] is a list of all the j-item rels.  Initially we
    2865             :      * set root->join_rel_level[1] to represent all the single-jointree-item
    2866             :      * relations.
    2867             :      */
    2868       46728 :     root->join_rel_level = (List **) palloc0((levels_needed + 1) * sizeof(List *));
    2869             : 
    2870       46728 :     root->join_rel_level[1] = initial_rels;
    2871             : 
    2872      106364 :     for (lev = 2; lev <= levels_needed; lev++)
    2873             :     {
    2874             :         ListCell   *lc;
    2875             : 
    2876             :         /*
    2877             :          * Determine all possible pairs of relations to be joined at this
    2878             :          * level, and build paths for making each one from every available
    2879             :          * pair of lower-level relations.
    2880             :          */
    2881       59636 :         join_search_one_level(root, lev);
    2882             : 
    2883             :         /*
    2884             :          * Run generate_partitionwise_join_paths() and generate_gather_paths()
    2885             :          * for each just-processed joinrel.  We could not do this earlier
    2886             :          * because both regular and partial paths can get added to a
    2887             :          * particular joinrel at multiple times within join_search_one_level.
    2888             :          *
    2889             :          * After that, we're done creating paths for the joinrel, so run
    2890             :          * set_cheapest().
    2891             :          */
    2892      150638 :         foreach(lc, root->join_rel_level[lev])
    2893             :         {
    2894       91002 :             rel = (RelOptInfo *) lfirst(lc);
    2895             : 
    2896             :             /* Create paths for partitionwise joins. */
    2897       91002 :             generate_partitionwise_join_paths(root, rel);
    2898             : 
    2899             :             /*
    2900             :              * Except for the topmost scan/join rel, consider gathering
    2901             :              * partial paths.  We'll do the same for the topmost scan/join rel
    2902             :              * once we know the final targetlist (see grouping_planner).
    2903             :              */
    2904       91002 :             if (lev < levels_needed)
    2905       44274 :                 generate_gather_paths(root, rel, false);
    2906             : 
    2907             :             /* Find and save the cheapest paths for this rel */
    2908       91002 :             set_cheapest(rel);
    2909             : 
    2910             : #ifdef OPTIMIZER_DEBUG
    2911             :             debug_print_rel(root, rel);
    2912             : #endif
    2913             :         }
    2914             :     }
    2915             : 
    2916             :     /*
    2917             :      * We should have a single rel at the final level.
    2918             :      */
    2919       46728 :     if (root->join_rel_level[levels_needed] == NIL)
    2920           0 :         elog(ERROR, "failed to build any %d-way joins", levels_needed);
    2921             :     Assert(list_length(root->join_rel_level[levels_needed]) == 1);
    2922             : 
    2923       46728 :     rel = (RelOptInfo *) linitial(root->join_rel_level[levels_needed]);
    2924             : 
    2925       46728 :     root->join_rel_level = NULL;
    2926             : 
    2927       46728 :     return rel;
    2928             : }
    2929             : 
    2930             : /*****************************************************************************
    2931             :  *          PUSHING QUALS DOWN INTO SUBQUERIES
    2932             :  *****************************************************************************/
    2933             : 
    2934             : /*
    2935             :  * subquery_is_pushdown_safe - is a subquery safe for pushing down quals?
    2936             :  *
    2937             :  * subquery is the particular component query being checked.  topquery
    2938             :  * is the top component of a set-operations tree (the same Query if no
    2939             :  * set-op is involved).
    2940             :  *
    2941             :  * Conditions checked here:
    2942             :  *
    2943             :  * 1. If the subquery has a LIMIT clause, we must not push down any quals,
    2944             :  * since that could change the set of rows returned.
    2945             :  *
    2946             :  * 2. If the subquery contains EXCEPT or EXCEPT ALL set ops we cannot push
    2947             :  * quals into it, because that could change the results.
    2948             :  *
    2949             :  * 3. If the subquery uses DISTINCT, we cannot push volatile quals into it.
    2950             :  * This is because upper-level quals should semantically be evaluated only
    2951             :  * once per distinct row, not once per original row, and if the qual is
    2952             :  * volatile then extra evaluations could change the results.  (This issue
    2953             :  * does not apply to other forms of aggregation such as GROUP BY, because
    2954             :  * when those are present we push into HAVING not WHERE, so that the quals
    2955             :  * are still applied after aggregation.)
    2956             :  *
    2957             :  * 4. If the subquery contains window functions, we cannot push volatile quals
    2958             :  * into it.  The issue here is a bit different from DISTINCT: a volatile qual
    2959             :  * might succeed for some rows of a window partition and fail for others,
    2960             :  * thereby changing the partition contents and thus the window functions'
    2961             :  * results for rows that remain.
    2962             :  *
    2963             :  * 5. If the subquery contains any set-returning functions in its targetlist,
    2964             :  * we cannot push volatile quals into it.  That would push them below the SRFs
    2965             :  * and thereby change the number of times they are evaluated.  Also, a
    2966             :  * volatile qual could succeed for some SRF output rows and fail for others,
    2967             :  * a behavior that cannot occur if it's evaluated before SRF expansion.
    2968             :  *
    2969             :  * In addition, we make several checks on the subquery's output columns to see
    2970             :  * if it is safe to reference them in pushed-down quals.  If output column k
    2971             :  * is found to be unsafe to reference, we set safetyInfo->unsafeColumns[k]
    2972             :  * to true, but we don't reject the subquery overall since column k might not
    2973             :  * be referenced by some/all quals.  The unsafeColumns[] array will be
    2974             :  * consulted later by qual_is_pushdown_safe().  It's better to do it this way
    2975             :  * than to make the checks directly in qual_is_pushdown_safe(), because when
    2976             :  * the subquery involves set operations we have to check the output
    2977             :  * expressions in each arm of the set op.
    2978             :  *
    2979             :  * Note: pushing quals into a DISTINCT subquery is theoretically dubious:
    2980             :  * we're effectively assuming that the quals cannot distinguish values that
    2981             :  * the DISTINCT's equality operator sees as equal, yet there are many
    2982             :  * counterexamples to that assumption.  However use of such a qual with a
    2983             :  * DISTINCT subquery would be unsafe anyway, since there's no guarantee which
    2984             :  * "equal" value will be chosen as the output value by the DISTINCT operation.
    2985             :  * So we don't worry too much about that.  Another objection is that if the
    2986             :  * qual is expensive to evaluate, running it for each original row might cost
    2987             :  * more than we save by eliminating rows before the DISTINCT step.  But it
    2988             :  * would be very hard to estimate that at this stage, and in practice pushdown
    2989             :  * seldom seems to make things worse, so we ignore that problem too.
    2990             :  *
    2991             :  * Note: likewise, pushing quals into a subquery with window functions is a
    2992             :  * bit dubious: the quals might remove some rows of a window partition while
    2993             :  * leaving others, causing changes in the window functions' results for the
    2994             :  * surviving rows.  We insist that such a qual reference only partitioning
    2995             :  * columns, but again that only protects us if the qual does not distinguish
    2996             :  * values that the partitioning equality operator sees as equal.  The risks
    2997             :  * here are perhaps larger than for DISTINCT, since no de-duplication of rows
    2998             :  * occurs and thus there is no theoretical problem with such a qual.  But
    2999             :  * we'll do this anyway because the potential performance benefits are very
    3000             :  * large, and we've seen no field complaints about the longstanding comparable
    3001             :  * behavior with DISTINCT.
    3002             :  */
    3003             : static bool
    3004         690 : subquery_is_pushdown_safe(Query *subquery, Query *topquery,
    3005             :                           pushdown_safety_info *safetyInfo)
    3006             : {
    3007             :     SetOperationStmt *topop;
    3008             : 
    3009             :     /* Check point 1 */
    3010         690 :     if (subquery->limitOffset != NULL || subquery->limitCount != NULL)
    3011          62 :         return false;
    3012             : 
    3013             :     /* Check points 3, 4, and 5 */
    3014        1220 :     if (subquery->distinctClause ||
    3015        1140 :         subquery->hasWindowFuncs ||
    3016         548 :         subquery->hasTargetSRFs)
    3017         180 :         safetyInfo->unsafeVolatile = true;
    3018             : 
    3019             :     /*
    3020             :      * If we're at a leaf query, check for unsafe expressions in its target
    3021             :      * list, and mark any unsafe ones in unsafeColumns[].  (Non-leaf nodes in
    3022             :      * setop trees have only simple Vars in their tlists, so no need to check
    3023             :      * them.)
    3024             :      */
    3025         628 :     if (subquery->setOperations == NULL)
    3026         596 :         check_output_expressions(subquery, safetyInfo);
    3027             : 
    3028             :     /* Are we at top level, or looking at a setop component? */
    3029         628 :     if (subquery == topquery)
    3030             :     {
    3031             :         /* Top level, so check any component queries */
    3032         564 :         if (subquery->setOperations != NULL)
    3033          32 :             if (!recurse_pushdown_safe(subquery->setOperations, topquery,
    3034             :                                        safetyInfo))
    3035           0 :                 return false;
    3036             :     }
    3037             :     else
    3038             :     {
    3039             :         /* Setop component must not have more components (too weird) */
    3040          64 :         if (subquery->setOperations != NULL)
    3041           0 :             return false;
    3042             :         /* Check whether setop component output types match top level */
    3043          64 :         topop = castNode(SetOperationStmt, topquery->setOperations);
    3044             :         Assert(topop);
    3045          64 :         compare_tlist_datatypes(subquery->targetList,
    3046             :                                 topop->colTypes,
    3047             :                                 safetyInfo);
    3048             :     }
    3049         628 :     return true;
    3050             : }
    3051             : 
    3052             : /*
    3053             :  * Helper routine to recurse through setOperations tree
    3054             :  */
    3055             : static bool
    3056          96 : recurse_pushdown_safe(Node *setOp, Query *topquery,
    3057             :                       pushdown_safety_info *safetyInfo)
    3058             : {
    3059          96 :     if (IsA(setOp, RangeTblRef))
    3060             :     {
    3061          64 :         RangeTblRef *rtr = (RangeTblRef *) setOp;
    3062          64 :         RangeTblEntry *rte = rt_fetch(rtr->rtindex, topquery->rtable);
    3063          64 :         Query      *subquery = rte->subquery;
    3064             : 
    3065             :         Assert(subquery != NULL);
    3066          64 :         return subquery_is_pushdown_safe(subquery, topquery, safetyInfo);
    3067             :     }
    3068          32 :     else if (IsA(setOp, SetOperationStmt))
    3069             :     {
    3070          32 :         SetOperationStmt *op = (SetOperationStmt *) setOp;
    3071             : 
    3072             :         /* EXCEPT is no good (point 2 for subquery_is_pushdown_safe) */
    3073          32 :         if (op->op == SETOP_EXCEPT)
    3074           0 :             return false;
    3075             :         /* Else recurse */
    3076          32 :         if (!recurse_pushdown_safe(op->larg, topquery, safetyInfo))
    3077           0 :             return false;
    3078          32 :         if (!recurse_pushdown_safe(op->rarg, topquery, safetyInfo))
    3079           0 :             return false;
    3080             :     }
    3081             :     else
    3082             :     {
    3083           0 :         elog(ERROR, "unrecognized node type: %d",
    3084             :              (int) nodeTag(setOp));
    3085             :     }
    3086          32 :     return true;
    3087             : }
    3088             : 
    3089             : /*
    3090             :  * check_output_expressions - check subquery's output expressions for safety
    3091             :  *
    3092             :  * There are several cases in which it's unsafe to push down an upper-level
    3093             :  * qual if it references a particular output column of a subquery.  We check
    3094             :  * each output column of the subquery and set unsafeColumns[k] to true if
    3095             :  * that column is unsafe for a pushed-down qual to reference.  The conditions
    3096             :  * checked here are:
    3097             :  *
    3098             :  * 1. We must not push down any quals that refer to subselect outputs that
    3099             :  * return sets, else we'd introduce functions-returning-sets into the
    3100             :  * subquery's WHERE/HAVING quals.
    3101             :  *
    3102             :  * 2. We must not push down any quals that refer to subselect outputs that
    3103             :  * contain volatile functions, for fear of introducing strange results due
    3104             :  * to multiple evaluation of a volatile function.
    3105             :  *
    3106             :  * 3. If the subquery uses DISTINCT ON, we must not push down any quals that
    3107             :  * refer to non-DISTINCT output columns, because that could change the set
    3108             :  * of rows returned.  (This condition is vacuous for DISTINCT, because then
    3109             :  * there are no non-DISTINCT output columns, so we needn't check.  Note that
    3110             :  * subquery_is_pushdown_safe already reported that we can't use volatile
    3111             :  * quals if there's DISTINCT or DISTINCT ON.)
    3112             :  *
    3113             :  * 4. If the subquery has any window functions, we must not push down quals
    3114             :  * that reference any output columns that are not listed in all the subquery's
    3115             :  * window PARTITION BY clauses.  We can push down quals that use only
    3116             :  * partitioning columns because they should succeed or fail identically for
    3117             :  * every row of any one window partition, and totally excluding some
    3118             :  * partitions will not change a window function's results for remaining
    3119             :  * partitions.  (Again, this also requires nonvolatile quals, but
    3120             :  * subquery_is_pushdown_safe handles that.)
    3121             :  */
    3122             : static void
    3123         596 : check_output_expressions(Query *subquery, pushdown_safety_info *safetyInfo)
    3124             : {
    3125             :     ListCell   *lc;
    3126             : 
    3127        4080 :     foreach(lc, subquery->targetList)
    3128             :     {
    3129        3484 :         TargetEntry *tle = (TargetEntry *) lfirst(lc);
    3130             : 
    3131        3484 :         if (tle->resjunk)
    3132         116 :             continue;           /* ignore resjunk columns */
    3133             : 
    3134             :         /* We need not check further if output col is already known unsafe */
    3135        3368 :         if (safetyInfo->unsafeColumns[tle->resno])
    3136          16 :             continue;
    3137             : 
    3138             :         /* Functions returning sets are unsafe (point 1) */
    3139        3708 :         if (subquery->hasTargetSRFs &&
    3140         356 :             expression_returns_set((Node *) tle->expr))
    3141             :         {
    3142         200 :             safetyInfo->unsafeColumns[tle->resno] = true;
    3143         200 :             continue;
    3144             :         }
    3145             : 
    3146             :         /* Volatile functions are unsafe (point 2) */
    3147        3152 :         if (contain_volatile_functions((Node *) tle->expr))
    3148             :         {
    3149          40 :             safetyInfo->unsafeColumns[tle->resno] = true;
    3150          40 :             continue;
    3151             :         }
    3152             : 
    3153             :         /* If subquery uses DISTINCT ON, check point 3 */
    3154        3112 :         if (subquery->hasDistinctOn &&
    3155           0 :             !targetIsInSortList(tle, InvalidOid, subquery->distinctClause))
    3156             :         {
    3157             :             /* non-DISTINCT column, so mark it unsafe */
    3158           0 :             safetyInfo->unsafeColumns[tle->resno] = true;
    3159           0 :             continue;
    3160             :         }
    3161             : 
    3162             :         /* If subquery uses window functions, check point 4 */
    3163        3428 :         if (subquery->hasWindowFuncs &&
    3164         316 :             !targetIsInAllPartitionLists(tle, subquery))
    3165             :         {
    3166             :             /* not present in all PARTITION BY clauses, so mark it unsafe */
    3167         304 :             safetyInfo->unsafeColumns[tle->resno] = true;
    3168         304 :             continue;
    3169             :         }
    3170             :     }
    3171         596 : }
    3172             : 
    3173             : /*
    3174             :  * For subqueries using UNION/UNION ALL/INTERSECT/INTERSECT ALL, we can
    3175             :  * push quals into each component query, but the quals can only reference
    3176             :  * subquery columns that suffer no type coercions in the set operation.
    3177             :  * Otherwise there are possible semantic gotchas.  So, we check the
    3178             :  * component queries to see if any of them have output types different from
    3179             :  * the top-level setop outputs.  unsafeColumns[k] is set true if column k
    3180             :  * has different type in any component.
    3181             :  *
    3182             :  * We don't have to care about typmods here: the only allowed difference
    3183             :  * between set-op input and output typmods is input is a specific typmod
    3184             :  * and output is -1, and that does not require a coercion.
    3185             :  *
    3186             :  * tlist is a subquery tlist.
    3187             :  * colTypes is an OID list of the top-level setop's output column types.
    3188             :  * safetyInfo->unsafeColumns[] is the result array.
    3189             :  */
    3190             : static void
    3191          64 : compare_tlist_datatypes(List *tlist, List *colTypes,
    3192             :                         pushdown_safety_info *safetyInfo)
    3193             : {
    3194             :     ListCell   *l;
    3195          64 :     ListCell   *colType = list_head(colTypes);
    3196             : 
    3197         232 :     foreach(l, tlist)
    3198             :     {
    3199         168 :         TargetEntry *tle = (TargetEntry *) lfirst(l);
    3200             : 
    3201         168 :         if (tle->resjunk)
    3202           0 :             continue;           /* ignore resjunk columns */
    3203         168 :         if (colType == NULL)
    3204           0 :             elog(ERROR, "wrong number of tlist entries");
    3205         168 :         if (exprType((Node *) tle->expr) != lfirst_oid(colType))
    3206           0 :             safetyInfo->unsafeColumns[tle->resno] = true;
    3207         168 :         colType = lnext(colType);
    3208             :     }
    3209          64 :     if (colType != NULL)
    3210           0 :         elog(ERROR, "wrong number of tlist entries");
    3211          64 : }
    3212             : 
    3213             : /*
    3214             :  * targetIsInAllPartitionLists
    3215             :  *      True if the TargetEntry is listed in the PARTITION BY clause
    3216             :  *      of every window defined in the query.
    3217             :  *
    3218             :  * It would be safe to ignore windows not actually used by any window
    3219             :  * function, but it's not easy to get that info at this stage; and it's
    3220             :  * unlikely to be useful to spend any extra cycles getting it, since
    3221             :  * unreferenced window definitions are probably infrequent in practice.
    3222             :  */
    3223             : static bool
    3224         316 : targetIsInAllPartitionLists(TargetEntry *tle, Query *query)
    3225             : {
    3226             :     ListCell   *lc;
    3227             : 
    3228         336 :     foreach(lc, query->windowClause)
    3229             :     {
    3230         324 :         WindowClause *wc = (WindowClause *) lfirst(lc);
    3231             : 
    3232         324 :         if (!targetIsInSortList(tle, InvalidOid, wc->partitionClause))
    3233         304 :             return false;
    3234             :     }
    3235          12 :     return true;
    3236             : }
    3237             : 
    3238             : /*
    3239             :  * qual_is_pushdown_safe - is a particular qual safe to push down?
    3240             :  *
    3241             :  * qual is a restriction clause applying to the given subquery (whose RTE
    3242             :  * has index rti in the parent query).
    3243             :  *
    3244             :  * Conditions checked here:
    3245             :  *
    3246             :  * 1. The qual must not contain any SubPlans (mainly because I'm not sure
    3247             :  * it will work correctly: SubLinks will already have been transformed into
    3248             :  * SubPlans in the qual, but not in the subquery).  Note that SubLinks that
    3249             :  * transform to initplans are safe, and will be accepted here because what
    3250             :  * we'll see in the qual is just a Param referencing the initplan output.
    3251             :  *
    3252             :  * 2. If unsafeVolatile is set, the qual must not contain any volatile
    3253             :  * functions.
    3254             :  *
    3255             :  * 3. If unsafeLeaky is set, the qual must not contain any leaky functions
    3256             :  * that are passed Var nodes, and therefore might reveal values from the
    3257             :  * subquery as side effects.
    3258             :  *
    3259             :  * 4. The qual must not refer to the whole-row output of the subquery
    3260             :  * (since there is no easy way to name that within the subquery itself).
    3261             :  *
    3262             :  * 5. The qual must not refer to any subquery output columns that were
    3263             :  * found to be unsafe to reference by subquery_is_pushdown_safe().
    3264             :  */
    3265             : static bool
    3266         820 : qual_is_pushdown_safe(Query *subquery, Index rti, Node *qual,
    3267             :                       pushdown_safety_info *safetyInfo)
    3268             : {
    3269         820 :     bool        safe = true;
    3270             :     List       *vars;
    3271             :     ListCell   *vl;
    3272             : 
    3273             :     /* Refuse subselects (point 1) */
    3274         820 :     if (contain_subplans(qual))
    3275          44 :         return false;
    3276             : 
    3277             :     /* Refuse volatile quals if we found they'd be unsafe (point 2) */
    3278         992 :     if (safetyInfo->unsafeVolatile &&
    3279         216 :         contain_volatile_functions(qual))
    3280          12 :         return false;
    3281             : 
    3282             :     /* Refuse leaky quals if told to (point 3) */
    3283         928 :     if (safetyInfo->unsafeLeaky &&
    3284         164 :         contain_leaked_vars(qual))
    3285          84 :         return false;
    3286             : 
    3287             :     /*
    3288             :      * It would be unsafe to push down window function calls, but at least for
    3289             :      * the moment we could never see any in a qual anyhow.  (The same applies
    3290             :      * to aggregates, which we check for in pull_var_clause below.)
    3291             :      */
    3292             :     Assert(!contain_window_function(qual));
    3293             : 
    3294             :     /*
    3295             :      * Examine all Vars used in clause; since it's a restriction clause, all
    3296             :      * such Vars must refer to subselect output columns.
    3297             :      */
    3298         680 :     vars = pull_var_clause(qual, PVC_INCLUDE_PLACEHOLDERS);
    3299        1256 :     foreach(vl, vars)
    3300             :     {
    3301         704 :         Var        *var = (Var *) lfirst(vl);
    3302             : 
    3303             :         /*
    3304             :          * XXX Punt if we find any PlaceHolderVars in the restriction clause.
    3305             :          * It's not clear whether a PHV could safely be pushed down, and even
    3306             :          * less clear whether such a situation could arise in any cases of
    3307             :          * practical interest anyway.  So for the moment, just refuse to push
    3308             :          * down.
    3309             :          */
    3310         704 :         if (!IsA(var, Var))
    3311             :         {
    3312           0 :             safe = false;
    3313           0 :             break;
    3314             :         }
    3315             : 
    3316             :         Assert(var->varno == rti);
    3317             :         Assert(var->varattno >= 0);
    3318             : 
    3319             :         /* Check point 4 */
    3320         704 :         if (var->varattno == 0)
    3321             :         {
    3322           0 :             safe = false;
    3323           0 :             break;
    3324             :         }
    3325             : 
    3326             :         /* Check point 5 */
    3327         704 :         if (safetyInfo->unsafeColumns[var->varattno])
    3328             :         {
    3329         128 :             safe = false;
    3330         128 :             break;
    3331             :         }
    3332             :     }
    3333             : 
    3334         680 :     list_free(vars);
    3335             : 
    3336         680 :     return safe;
    3337             : }
    3338             : 
    3339             : /*
    3340             :  * subquery_push_qual - push down a qual that we have determined is safe
    3341             :  */
    3342             : static void
    3343         584 : subquery_push_qual(Query *subquery, RangeTblEntry *rte, Index rti, Node *qual)
    3344             : {
    3345         584 :     if (subquery->setOperations != NULL)
    3346             :     {
    3347             :         /* Recurse to push it separately to each component query */
    3348          16 :         recurse_push_qual(subquery->setOperations, subquery,
    3349             :                           rte, rti, qual);
    3350             :     }
    3351             :     else
    3352             :     {
    3353             :         /*
    3354             :          * We need to replace Vars in the qual (which must refer to outputs of
    3355             :          * the subquery) with copies of the subquery's targetlist expressions.
    3356             :          * Note that at this point, any uplevel Vars in the qual should have
    3357             :          * been replaced with Params, so they need no work.
    3358             :          *
    3359             :          * This step also ensures that when we are pushing into a setop tree,
    3360             :          * each component query gets its own copy of the qual.
    3361             :          */
    3362         568 :         qual = ReplaceVarsFromTargetList(qual, rti, 0, rte,
    3363             :                                          subquery->targetList,
    3364             :                                          REPLACEVARS_REPORT_ERROR, 0,
    3365             :                                          &subquery->hasSubLinks);
    3366             : 
    3367             :         /*
    3368             :          * Now attach the qual to the proper place: normally WHERE, but if the
    3369             :          * subquery uses grouping or aggregation, put it in HAVING (since the
    3370             :          * qual really refers to the group-result rows).
    3371             :          */
    3372         568 :         if (subquery->hasAggs || subquery->groupClause || subquery->groupingSets || subquery->havingQual)
    3373         108 :             subquery->havingQual = make_and_qual(subquery->havingQual, qual);
    3374             :         else
    3375         920 :             subquery->jointree->quals =
    3376         460 :                 make_and_qual(subquery->jointree->quals, qual);
    3377             : 
    3378             :         /*
    3379             :          * We need not change the subquery's hasAggs or hasSubLinks flags,
    3380             :          * since we can't be pushing down any aggregates that weren't there
    3381             :          * before, and we don't push down subselects at all.
    3382             :          */
    3383             :     }
    3384         584 : }
    3385             : 
    3386             : /*
    3387             :  * Helper routine to recurse through setOperations tree
    3388             :  */
    3389             : static void
    3390          48 : recurse_push_qual(Node *setOp, Query *topquery,
    3391             :                   RangeTblEntry *rte, Index rti, Node *qual)
    3392             : {
    3393          48 :     if (IsA(setOp, RangeTblRef))
    3394             :     {
    3395          32 :         RangeTblRef *rtr = (RangeTblRef *) setOp;
    3396          32 :         RangeTblEntry *subrte = rt_fetch(rtr->rtindex, topquery->rtable);
    3397          32 :         Query      *subquery = subrte->subquery;
    3398             : 
    3399             :         Assert(subquery != NULL);
    3400          32 :         subquery_push_qual(subquery, rte, rti, qual);
    3401             :     }
    3402          16 :     else if (IsA(setOp, SetOperationStmt))
    3403             :     {
    3404          16 :         SetOperationStmt *op = (SetOperationStmt *) setOp;
    3405             : 
    3406          16 :         recurse_push_qual(op->larg, topquery, rte, rti, qual);
    3407          16 :         recurse_push_qual(op->rarg, topquery, rte, rti, qual);
    3408             :     }
    3409             :     else
    3410             :     {
    3411           0 :         elog(ERROR, "unrecognized node type: %d",
    3412             :              (int) nodeTag(setOp));
    3413             :     }
    3414          48 : }
    3415             : 
    3416             : /*****************************************************************************
    3417             :  *          SIMPLIFYING SUBQUERY TARGETLISTS
    3418             :  *****************************************************************************/
    3419             : 
    3420             : /*
    3421             :  * remove_unused_subquery_outputs
    3422             :  *      Remove subquery targetlist items we don't need
    3423             :  *
    3424             :  * It's possible, even likely, that the upper query does not read all the
    3425             :  * output columns of the subquery.  We can remove any such outputs that are
    3426             :  * not needed by the subquery itself (e.g., as sort/group columns) and do not
    3427             :  * affect semantics otherwise (e.g., volatile functions can't be removed).
    3428             :  * This is useful not only because we might be able to remove expensive-to-
    3429             :  * compute expressions, but because deletion of output columns might allow
    3430             :  * optimizations such as join removal to occur within the subquery.
    3431             :  *
    3432             :  * To avoid affecting column numbering in the targetlist, we don't physically
    3433             :  * remove unused tlist entries, but rather replace their expressions with NULL
    3434             :  * constants.  This is implemented by modifying subquery->targetList.
    3435             :  */
    3436             : static void
    3437        5488 : remove_unused_subquery_outputs(Query *subquery, RelOptInfo *rel)
    3438             : {
    3439        5488 :     Bitmapset  *attrs_used = NULL;
    3440             :     ListCell   *lc;
    3441             : 
    3442             :     /*
    3443             :      * Do nothing if subquery has UNION/INTERSECT/EXCEPT: in principle we
    3444             :      * could update all the child SELECTs' tlists, but it seems not worth the
    3445             :      * trouble presently.
    3446             :      */
    3447        5488 :     if (subquery->setOperations)
    3448        1132 :         return;
    3449             : 
    3450             :     /*
    3451             :      * If subquery has regular DISTINCT (not DISTINCT ON), we're wasting our
    3452             :      * time: all its output columns must be used in the distinctClause.
    3453             :      */
    3454        5086 :     if (subquery->distinctClause && !subquery->hasDistinctOn)
    3455          96 :         return;
    3456             : 
    3457             :     /*
    3458             :      * Collect a bitmap of all the output column numbers used by the upper
    3459             :      * query.
    3460             :      *
    3461             :      * Add all the attributes needed for joins or final output.  Note: we must
    3462             :      * look at rel's targetlist, not the attr_needed data, because attr_needed
    3463             :      * isn't computed for inheritance child rels, cf set_append_rel_size().
    3464             :      * (XXX might be worth changing that sometime.)
    3465             :      */
    3466        4990 :     pull_varattnos((Node *) rel->reltarget->exprs, rel->relid, &attrs_used);
    3467             : 
    3468             :     /* Add all the attributes used by un-pushed-down restriction clauses. */
    3469        5328 :     foreach(lc, rel->baserestrictinfo)
    3470             :     {
    3471         338 :         RestrictInfo *rinfo = (RestrictInfo *) lfirst(lc);
    3472             : 
    3473         338 :         pull_varattnos((Node *) rinfo->clause, rel->relid, &attrs_used);
    3474             :     }
    3475             : 
    3476             :     /*
    3477             :      * If there's a whole-row reference to the subquery, we can't remove
    3478             :      * anything.
    3479             :      */
    3480        4990 :     if (bms_is_member(0 - FirstLowInvalidHeapAttributeNumber, attrs_used))
    3481         232 :         return;
    3482             : 
    3483             :     /*
    3484             :      * Run through the tlist and zap entries we don't need.  It's okay to
    3485             :      * modify the tlist items in-place because set_subquery_pathlist made a
    3486             :      * copy of the subquery.
    3487             :      */
    3488       17718 :     foreach(lc, subquery->targetList)
    3489             :     {
    3490       12960 :         TargetEntry *tle = (TargetEntry *) lfirst(lc);
    3491       12960 :         Node       *texpr = (Node *) tle->expr;
    3492             : 
    3493             :         /*
    3494             :          * If it has a sortgroupref number, it's used in some sort/group
    3495             :          * clause so we'd better not remove it.  Also, don't remove any
    3496             :          * resjunk columns, since their reason for being has nothing to do
    3497             :          * with anybody reading the subquery's output.  (It's likely that
    3498             :          * resjunk columns in a sub-SELECT would always have ressortgroupref
    3499             :          * set, but even if they don't, it seems imprudent to remove them.)
    3500             :          */
    3501       12960 :         if (tle->ressortgroupref || tle->resjunk)
    3502        1384 :             continue;
    3503             : 
    3504             :         /*
    3505             :          * If it's used by the upper query, we can't remove it.
    3506             :          */
    3507       11576 :         if (bms_is_member(tle->resno - FirstLowInvalidHeapAttributeNumber,
    3508             :                           attrs_used))
    3509        7198 :             continue;
    3510             : 
    3511             :         /*
    3512             :          * If it contains a set-returning function, we can't remove it since
    3513             :          * that could change the number of rows returned by the subquery.
    3514             :          */
    3515        4676 :         if (subquery->hasTargetSRFs &&
    3516         298 :             expression_returns_set(texpr))
    3517         106 :             continue;
    3518             : 
    3519             :         /*
    3520             :          * If it contains volatile functions, we daren't remove it for fear
    3521             :          * that the user is expecting their side-effects to happen.
    3522             :          */
    3523        4272 :         if (contain_volatile_functions(texpr))
    3524          10 :             continue;
    3525             : 
    3526             :         /*
    3527             :          * OK, we don't need it.  Replace the expression with a NULL constant.
    3528             :          * Preserve the exposed type of the expression, in case something
    3529             :          * looks at the rowtype of the subquery's result.
    3530             :          */
    3531        4262 :         tle->expr = (Expr *) makeNullConst(exprType(texpr),
    3532             :                                            exprTypmod(texpr),
    3533             :                                            exprCollation(texpr));
    3534             :     }
    3535             : }
    3536             : 
    3537             : /*
    3538             :  * create_partial_bitmap_paths
    3539             :  *    Build partial bitmap heap path for the relation
    3540             :  */
    3541             : void
    3542       73104 : create_partial_bitmap_paths(PlannerInfo *root, RelOptInfo *rel,
    3543             :                             Path *bitmapqual)
    3544             : {
    3545             :     int         parallel_workers;
    3546             :     double      pages_fetched;
    3547             : 
    3548             :     /* Compute heap pages for bitmap heap scan */
    3549       73104 :     pages_fetched = compute_bitmap_pages(root, rel, bitmapqual, 1.0,
    3550             :                                          NULL, NULL);
    3551             : 
    3552       73104 :     parallel_workers = compute_parallel_worker(rel, pages_fetched, -1,
    3553             :                                                max_parallel_workers_per_gather);
    3554             : 
    3555       73104 :     if (parallel_workers <= 0)
    3556       72204 :         return;
    3557             : 
    3558         900 :     add_partial_path(rel, (Path *) create_bitmap_heap_path(root, rel,
    3559             :                                                            bitmapqual, rel->lateral_relids, 1.0, parallel_workers));
    3560             : }
    3561             : 
    3562             : /*
    3563             :  * Compute the number of parallel workers that should be used to scan a
    3564             :  * relation.  We compute the parallel workers based on the size of the heap to
    3565             :  * be scanned and the size of the index to be scanned, then choose a minimum
    3566             :  * of those.
    3567             :  *
    3568             :  * "heap_pages" is the number of pages from the table that we expect to scan, or
    3569             :  * -1 if we don't expect to scan any.
    3570             :  *
    3571             :  * "index_pages" is the number of pages from the index that we expect to scan, or
    3572             :  * -1 if we don't expect to scan any.
    3573             :  *
    3574             :  * "max_workers" is caller's limit on the number of workers.  This typically
    3575             :  * comes from a GUC.
    3576             :  */
    3577             : int
    3578      355904 : compute_parallel_worker(RelOptInfo *rel, double heap_pages, double index_pages,
    3579             :                         int max_workers)
    3580             : {
    3581      355904 :     int         parallel_workers = 0;
    3582             : 
    3583             :     /*
    3584             :      * If the user has set the parallel_workers reloption, use that; otherwise
    3585             :      * select a default number of workers.
    3586             :      */
    3587      355904 :     if (rel->rel_parallel_workers != -1)
    3588        1050 :         parallel_workers = rel->rel_parallel_workers;
    3589             :     else
    3590             :     {
    3591             :         /*
    3592             :          * If the number of pages being scanned is insufficient to justify a
    3593             :          * parallel scan, just return zero ... unless it's an inheritance
    3594             :          * child. In that case, we want to generate a parallel path here
    3595             :          * anyway.  It might not be worthwhile just for this relation, but
    3596             :          * when combined with all of its inheritance siblings it may well pay
    3597             :          * off.
    3598             :          */
    3599      354854 :         if (rel->reloptkind == RELOPT_BASEREL &&
    3600      331244 :             ((heap_pages >= 0 && heap_pages < min_parallel_table_scan_size) ||
    3601        9510 :              (index_pages >= 0 && index_pages < min_parallel_index_scan_size)))
    3602      339516 :             return 0;
    3603             : 
    3604       15338 :         if (heap_pages >= 0)
    3605             :         {
    3606             :             int         heap_parallel_threshold;
    3607       14534 :             int         heap_parallel_workers = 1;
    3608             : 
    3609             :             /*
    3610             :              * Select the number of workers based on the log of the size of
    3611             :              * the relation.  This probably needs to be a good deal more
    3612             :              * sophisticated, but we need something here for now.  Note that
    3613             :              * the upper limit of the min_parallel_table_scan_size GUC is
    3614             :              * chosen to prevent overflow here.
    3615             :              */
    3616       14534 :             heap_parallel_threshold = Max(min_parallel_table_scan_size, 1);
    3617       31832 :             while (heap_pages >= (BlockNumber) (heap_parallel_threshold * 3))
    3618             :             {
    3619        2764 :                 heap_parallel_workers++;
    3620        2764 :                 heap_parallel_threshold *= 3;
    3621        2764 :                 if (heap_parallel_threshold > INT_MAX / 3)
    3622           0 :                     break;      /* avoid overflow */
    3623             :             }
    3624             : 
    3625       14534 :             parallel_workers = heap_parallel_workers;
    3626             :         }
    3627             : 
    3628       15338 :         if (index_pages >= 0)
    3629             :         {
    3630        3060 :             int         index_parallel_workers = 1;
    3631             :             int         index_parallel_threshold;
    3632             : 
    3633             :             /* same calculation as for heap_pages above */
    3634        3060 :             index_parallel_threshold = Max(min_parallel_index_scan_size, 1);
    3635        6120 :             while (index_pages >= (BlockNumber) (index_parallel_threshold * 3))
    3636             :             {
    3637           0 :                 index_parallel_workers++;
    3638           0 :                 index_parallel_threshold *= 3;
    3639           0 :                 if (index_parallel_threshold > INT_MAX / 3)
    3640           0 :                     break;      /* avoid overflow */
    3641             :             }
    3642             : 
    3643        3060 :             if (parallel_workers > 0)
    3644        2256 :                 parallel_workers = Min(parallel_workers, index_parallel_workers);
    3645             :             else
    3646         804 :                 parallel_workers = index_parallel_workers;
    3647             :         }
    3648             :     }
    3649             : 
    3650             :     /* In no case use more than caller supplied maximum number of workers */
    3651       16388 :     parallel_workers = Min(parallel_workers, max_workers);
    3652             : 
    3653       16388 :     return parallel_workers;
    3654             : }
    3655             : 
    3656             : /*
    3657             :  * generate_partitionwise_join_paths
    3658             :  *      Create paths representing partitionwise join for given partitioned
    3659             :  *      join relation.
    3660             :  *
    3661             :  * This must not be called until after we are done adding paths for all
    3662             :  * child-joins. Otherwise, add_path might delete a path to which some path
    3663             :  * generated here has a reference.
    3664             :  */
    3665             : void
    3666       94466 : generate_partitionwise_join_paths(PlannerInfo *root, RelOptInfo *rel)
    3667             : {
    3668       94466 :     List       *live_children = NIL;
    3669             :     int         cnt_parts;
    3670             :     int         num_parts;
    3671             :     RelOptInfo **part_rels;
    3672             : 
    3673             :     /* Handle only join relations here. */
    3674       94466 :     if (!IS_JOIN_REL(rel))
    3675           0 :         return;
    3676             : 
    3677             :     /* We've nothing to do if the relation is not partitioned. */
    3678       94466 :     if (!IS_PARTITIONED_REL(rel))
    3679       93970 :         return;
    3680             : 
    3681             :     /* The relation should have consider_partitionwise_join set. */
    3682             :     Assert(rel->consider_partitionwise_join);
    3683             : 
    3684             :     /* Guard against stack overflow due to overly deep partition hierarchy. */
    3685         496 :     check_stack_depth();
    3686             : 
    3687         496 :     num_parts = rel->nparts;
    3688         496 :     part_rels = rel->part_rels;
    3689             : 
    3690             :     /* Collect non-dummy child-joins. */
    3691        1916 :     for (cnt_parts = 0; cnt_parts < num_parts; cnt_parts++)
    3692             :     {
    3693        1420 :         RelOptInfo *child_rel = part_rels[cnt_parts];
    3694             : 
    3695             :         /* If it's been pruned entirely, it's certainly dummy. */
    3696        1420 :         if (child_rel == NULL)
    3697          20 :             continue;
    3698             : 
    3699             :         /* Add partitionwise join paths for partitioned child-joins. */
    3700        1400 :         generate_partitionwise_join_paths(root, child_rel);
    3701             : 
    3702        1400 :         set_cheapest(child_rel);
    3703             : 
    3704             :         /* Dummy children will not be scanned, so ignore those. */
    3705        1400 :         if (IS_DUMMY_REL(child_rel))
    3706           0 :             continue;
    3707             : 
    3708             : #ifdef OPTIMIZER_DEBUG
    3709             :         debug_print_rel(root, child_rel);
    3710             : #endif
    3711             : 
    3712        1400 :         live_children = lappend(live_children, child_rel);
    3713             :     }
    3714             : 
    3715             :     /* If all child-joins are dummy, parent join is also dummy. */
    3716         496 :     if (!live_children)
    3717             :     {
    3718           0 :         mark_dummy_rel(rel);
    3719           0 :         return;
    3720             :     }
    3721             : 
    3722             :     /* Build additional paths for this rel from child-join paths. */
    3723         496 :     add_paths_to_append_rel(root, rel, live_children);
    3724         496 :     list_free(live_children);
    3725             : }
    3726             : 
    3727             : 
    3728             : /*****************************************************************************
    3729             :  *          DEBUG SUPPORT
    3730             :  *****************************************************************************/
    3731             : 
    3732             : #ifdef OPTIMIZER_DEBUG
    3733             : 
    3734             : static void
    3735             : print_relids(PlannerInfo *root, Relids relids)
    3736             : {
    3737             :     int         x;
    3738             :     bool        first = true;
    3739             : 
    3740             :     x = -1;
    3741             :     while ((x = bms_next_member(relids, x)) >= 0)
    3742             :     {
    3743             :         if (!first)
    3744             :             printf(" ");
    3745             :         if (x < root->simple_rel_array_size &&
    3746             :             root->simple_rte_array[x])
    3747             :             printf("%s", root->simple_rte_array[x]->eref->aliasname);
    3748             :         else
    3749             :             printf("%d", x);
    3750             :         first = false;
    3751             :     }
    3752             : }
    3753             : 
    3754             : static void
    3755             : print_restrictclauses(PlannerInfo *root, List *clauses)
    3756             : {
    3757             :     ListCell   *l;
    3758             : 
    3759             :     foreach(l, clauses)
    3760             :     {
    3761             :         RestrictInfo *c = lfirst(l);
    3762             : 
    3763             :         print_expr((Node *) c->clause, root->parse->rtable);
    3764             :         if (lnext(l))
    3765             :             printf(", ");
    3766             :     }
    3767             : }
    3768             : 
    3769             : static void
    3770             : print_path(PlannerInfo *root, Path *path, int indent)
    3771             : {
    3772             :     const char *ptype;
    3773             :     bool        join = false;
    3774             :     Path       *subpath = NULL;
    3775             :     int         i;
    3776             : 
    3777             :     switch (nodeTag(path))
    3778             :     {
    3779             :         case T_Path:
    3780             :             switch (path->pathtype)
    3781             :             {
    3782             :                 case T_SeqScan:
    3783             :                     ptype = "SeqScan";
    3784             :                     break;
    3785             :                 case T_SampleScan:
    3786             :                     ptype = "SampleScan";
    3787             :                     break;
    3788             :                 case T_FunctionScan:
    3789             :                     ptype = "FunctionScan";
    3790             :                     break;
    3791             :                 case T_TableFuncScan:
    3792             :                     ptype = "TableFuncScan";
    3793             :                     break;
    3794             :                 case T_ValuesScan:
    3795             :                     ptype = "ValuesScan";
    3796             :                     break;
    3797             :                 case T_CteScan:
    3798             :                     ptype = "CteScan";
    3799             :                     break;
    3800             :                 case T_NamedTuplestoreScan:
    3801             :                     ptype = "NamedTuplestoreScan";
    3802             :                     break;
    3803             :                 case T_Result:
    3804             :                     ptype = "Result";
    3805             :                     break;
    3806             :                 case T_WorkTableScan:
    3807             :                     ptype = "WorkTableScan";
    3808             :                     break;
    3809             :                 default:
    3810             :                     ptype = "???Path";
    3811             :                     break;
    3812             :             }
    3813             :             break;
    3814             :         case T_IndexPath:
    3815             :             ptype = "IdxScan";
    3816             :             break;
    3817             :         case T_BitmapHeapPath:
    3818             :             ptype = "BitmapHeapScan";
    3819             :             break;
    3820             :         case T_BitmapAndPath:
    3821             :             ptype = "BitmapAndPath";
    3822             :             break;
    3823             :         case T_BitmapOrPath:
    3824             :             ptype = "BitmapOrPath";
    3825             :             break;
    3826             :         case T_TidPath:
    3827             :             ptype = "TidScan";
    3828             :             break;
    3829             :         case T_SubqueryScanPath:
    3830             :             ptype = "SubqueryScan";
    3831             :             break;
    3832             :         case T_ForeignPath:
    3833             :             ptype = "ForeignScan";
    3834             :             break;
    3835             :         case T_CustomPath:
    3836             :             ptype = "CustomScan";
    3837             :             break;
    3838             :         case T_NestPath:
    3839             :             ptype = "NestLoop";
    3840             :             join = true;
    3841             :             break;
    3842             :         case T_MergePath:
    3843             :             ptype = "MergeJoin";
    3844             :             join = true;
    3845             :             break;
    3846             :         case T_HashPath:
    3847             :             ptype = "HashJoin";
    3848             :             join = true;
    3849             :             break;
    3850             :         case T_AppendPath:
    3851             :             ptype = "Append";
    3852             :             break;
    3853             :         case T_MergeAppendPath:
    3854             :             ptype = "MergeAppend";
    3855             :             break;
    3856             :         case T_GroupResultPath:
    3857             :             ptype = "GroupResult";
    3858             :             break;
    3859             :         case T_MaterialPath:
    3860             :             ptype = "Material";
    3861             :             subpath = ((MaterialPath *) path)->subpath;
    3862             :             break;
    3863             :         case T_UniquePath:
    3864             :             ptype = "Unique";
    3865             :             subpath = ((UniquePath *) path)->subpath;
    3866             :             break;
    3867             :         case T_GatherPath:
    3868             :             ptype = "Gather";
    3869             :             subpath = ((GatherPath *) path)->subpath;
    3870             :             break;
    3871             :         case T_GatherMergePath:
    3872             :             ptype = "GatherMerge";
    3873             :             subpath = ((GatherMergePath *) path)->subpath;
    3874             :             break;
    3875             :         case T_ProjectionPath:
    3876             :             ptype = "Projection";
    3877             :             subpath = ((ProjectionPath *) path)->subpath;
    3878             :             break;
    3879             :         case T_ProjectSetPath:
    3880             :             ptype = "ProjectSet";
    3881             :             subpath = ((ProjectSetPath *) path)->subpath;
    3882             :             break;
    3883             :         case T_SortPath:
    3884             :             ptype = "Sort";
    3885             :             subpath = ((SortPath *) path)->subpath;
    3886             :             break;
    3887             :         case T_GroupPath:
    3888             :             ptype = "Group";
    3889             :             subpath = ((GroupPath *) path)->subpath;
    3890             :             break;
    3891             :         case T_UpperUniquePath:
    3892             :             ptype = "UpperUnique";
    3893             :             subpath = ((UpperUniquePath *) path)->subpath;
    3894             :             break;
    3895             :         case T_AggPath:
    3896             :             ptype = "Agg";
    3897             :             subpath = ((AggPath *) path)->subpath;
    3898             :             break;
    3899             :         case T_GroupingSetsPath:
    3900             :             ptype = "GroupingSets";
    3901             :             subpath = ((GroupingSetsPath *) path)->subpath;
    3902             :             break;
    3903             :         case T_MinMaxAggPath:
    3904             :             ptype = "MinMaxAgg";
    3905             :             break;
    3906             :         case T_WindowAggPath:
    3907             :             ptype = "WindowAgg";
    3908             :             subpath = ((WindowAggPath *) path)->subpath;
    3909             :             break;
    3910             :         case T_SetOpPath:
    3911             :             ptype = "SetOp";
    3912             :             subpath = ((SetOpPath *) path)->subpath;
    3913             :             break;
    3914             :         case T_RecursiveUnionPath:
    3915             :             ptype = "RecursiveUnion";
    3916             :             break;
    3917             :         case T_LockRowsPath:
    3918             :             ptype = "LockRows";
    3919             :             subpath = ((LockRowsPath *) path)->subpath;
    3920             :             break;
    3921             :         case T_ModifyTablePath:
    3922             :             ptype = "ModifyTable";
    3923             :             break;
    3924             :         case T_LimitPath:
    3925             :             ptype = "Limit";
    3926             :             subpath = ((LimitPath *) path)->subpath;
    3927             :             break;
    3928             :         default:
    3929             :             ptype = "???Path";
    3930             :             break;
    3931             :     }
    3932             : 
    3933             :     for (i = 0; i < indent; i++)
    3934             :         printf("\t");
    3935             :     printf("%s", ptype);
    3936             : 
    3937             :     if (path->parent)
    3938             :     {
    3939             :         printf("(");
    3940             :         print_relids(root, path->parent->relids);
    3941             :         printf(")");
    3942             :     }
    3943             :     if (path->param_info)
    3944             :     {
    3945             :         printf(" required_outer (");
    3946             :         print_relids(root, path->param_info->ppi_req_outer);
    3947             :         printf(")");
    3948             :     }
    3949             :     printf(" rows=%.0f cost=%.2f..%.2f\n",
    3950             :            path->rows, path->startup_cost, path->total_cost);
    3951             : 
    3952             :     if (path->pathkeys)
    3953             :     {
    3954             :         for (i = 0; i < indent; i++)
    3955             :             printf("\t");
    3956             :         printf("  pathkeys: ");
    3957             :         print_pathkeys(path->pathkeys, root->parse->rtable);
    3958             :     }
    3959             : 
    3960             :     if (join)
    3961             :     {
    3962             :         JoinPath   *jp = (JoinPath *) path;
    3963             : 
    3964             :         for (i = 0; i < indent; i++)
    3965             :             printf("\t");
    3966             :         printf("  clauses: ");
    3967             :         print_restrictclauses(root, jp->joinrestrictinfo);
    3968             :         printf("\n");
    3969             : 
    3970             :         if (IsA(path, MergePath))
    3971             :         {
    3972             :             MergePath  *mp = (MergePath *) path;
    3973             : 
    3974             :             for (i = 0; i < indent; i++)
    3975             :                 printf("\t");
    3976             :             printf("  sortouter=%d sortinner=%d materializeinner=%d\n",
    3977             :                    ((mp->outersortkeys) ? 1 : 0),
    3978             :                    ((mp->innersortkeys) ? 1 : 0),
    3979             :                    ((mp->materialize_inner) ? 1 : 0));
    3980             :         }
    3981             : 
    3982             :         print_path(root, jp->outerjoinpath, indent + 1);
    3983             :         print_path(root, jp->innerjoinpath, indent + 1);
    3984             :     }
    3985             : 
    3986             :     if (subpath)
    3987             :         print_path(root, subpath, indent + 1);
    3988             : }
    3989             : 
    3990             : void
    3991             : debug_print_rel(PlannerInfo *root, RelOptInfo *rel)
    3992             : {
    3993             :     ListCell   *l;
    3994             : 
    3995             :     printf("RELOPTINFO (");
    3996             :     print_relids(root, rel->relids);
    3997             :     printf("): rows=%.0f width=%d\n", rel->rows, rel->reltarget->width);
    3998             : 
    3999             :     if (rel->baserestrictinfo)
    4000             :     {
    4001             :         printf("\tbaserestrictinfo: ");
    4002             :         print_restrictclauses(root, rel->baserestrictinfo);
    4003             :         printf("\n");
    4004             :     }
    4005             : 
    4006             :     if (rel->joininfo)
    4007             :     {
    4008             :         printf("\tjoininfo: ");
    4009             :         print_restrictclauses(root, rel->joininfo);
    4010             :         printf("\n");
    4011             :     }
    4012             : 
    4013             :     printf("\tpath list:\n");
    4014             :     foreach(l, rel->pathlist)
    4015             :         print_path(root, lfirst(l), 1);
    4016             :     if (rel->cheapest_parameterized_paths)
    4017             :     {
    4018             :         printf("\n\tcheapest parameterized paths:\n");
    4019             :         foreach(l, rel->cheapest_parameterized_paths)
    4020             :             print_path(root, lfirst(l), 1);
    4021             :     }
    4022             :     if (rel->cheapest_startup_path)
    4023             :     {
    4024             :         printf("\n\tcheapest startup path:\n");
    4025             :         print_path(root, rel->cheapest_startup_path, 1);
    4026             :     }
    4027             :     if (rel->cheapest_total_path)
    4028             :     {
    4029             :         printf("\n\tcheapest total path:\n");
    4030             :         print_path(root, rel->cheapest_total_path, 1);
    4031             :     }
    4032             :     printf("\n");
    4033             :     fflush(stdout);
    4034             : }
    4035             : 
    4036             : #endif                          /* OPTIMIZER_DEBUG */

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