LCOV - code coverage report
Current view: top level - src/backend/optimizer/path - joinrels.c (source / functions) Hit Total Coverage
Test: PostgreSQL 17beta1 Lines: 518 547 94.7 %
Date: 2024-06-14 18:11:26 Functions: 20 20 100.0 %
Legend: Lines: hit not hit

          Line data    Source code
       1             : /*-------------------------------------------------------------------------
       2             :  *
       3             :  * joinrels.c
       4             :  *    Routines to determine which relations should be joined
       5             :  *
       6             :  * Portions Copyright (c) 1996-2024, PostgreSQL Global Development Group
       7             :  * Portions Copyright (c) 1994, Regents of the University of California
       8             :  *
       9             :  *
      10             :  * IDENTIFICATION
      11             :  *    src/backend/optimizer/path/joinrels.c
      12             :  *
      13             :  *-------------------------------------------------------------------------
      14             :  */
      15             : #include "postgres.h"
      16             : 
      17             : #include "miscadmin.h"
      18             : #include "optimizer/appendinfo.h"
      19             : #include "optimizer/joininfo.h"
      20             : #include "optimizer/pathnode.h"
      21             : #include "optimizer/paths.h"
      22             : #include "partitioning/partbounds.h"
      23             : #include "utils/memutils.h"
      24             : 
      25             : 
      26             : static void make_rels_by_clause_joins(PlannerInfo *root,
      27             :                                       RelOptInfo *old_rel,
      28             :                                       List *other_rels,
      29             :                                       int first_rel_idx);
      30             : static void make_rels_by_clauseless_joins(PlannerInfo *root,
      31             :                                           RelOptInfo *old_rel,
      32             :                                           List *other_rels);
      33             : static bool has_join_restriction(PlannerInfo *root, RelOptInfo *rel);
      34             : static bool has_legal_joinclause(PlannerInfo *root, RelOptInfo *rel);
      35             : static bool restriction_is_constant_false(List *restrictlist,
      36             :                                           RelOptInfo *joinrel,
      37             :                                           bool only_pushed_down);
      38             : static void populate_joinrel_with_paths(PlannerInfo *root, RelOptInfo *rel1,
      39             :                                         RelOptInfo *rel2, RelOptInfo *joinrel,
      40             :                                         SpecialJoinInfo *sjinfo, List *restrictlist);
      41             : static void try_partitionwise_join(PlannerInfo *root, RelOptInfo *rel1,
      42             :                                    RelOptInfo *rel2, RelOptInfo *joinrel,
      43             :                                    SpecialJoinInfo *parent_sjinfo,
      44             :                                    List *parent_restrictlist);
      45             : static SpecialJoinInfo *build_child_join_sjinfo(PlannerInfo *root,
      46             :                                                 SpecialJoinInfo *parent_sjinfo,
      47             :                                                 Relids left_relids, Relids right_relids);
      48             : static void free_child_join_sjinfo(SpecialJoinInfo *sjinfo);
      49             : static void compute_partition_bounds(PlannerInfo *root, RelOptInfo *rel1,
      50             :                                      RelOptInfo *rel2, RelOptInfo *joinrel,
      51             :                                      SpecialJoinInfo *parent_sjinfo,
      52             :                                      List **parts1, List **parts2);
      53             : static void get_matching_part_pairs(PlannerInfo *root, RelOptInfo *joinrel,
      54             :                                     RelOptInfo *rel1, RelOptInfo *rel2,
      55             :                                     List **parts1, List **parts2);
      56             : 
      57             : 
      58             : /*
      59             :  * join_search_one_level
      60             :  *    Consider ways to produce join relations containing exactly 'level'
      61             :  *    jointree items.  (This is one step of the dynamic-programming method
      62             :  *    embodied in standard_join_search.)  Join rel nodes for each feasible
      63             :  *    combination of lower-level rels are created and returned in a list.
      64             :  *    Implementation paths are created for each such joinrel, too.
      65             :  *
      66             :  * level: level of rels we want to make this time
      67             :  * root->join_rel_level[j], 1 <= j < level, is a list of rels containing j items
      68             :  *
      69             :  * The result is returned in root->join_rel_level[level].
      70             :  */
      71             : void
      72      107218 : join_search_one_level(PlannerInfo *root, int level)
      73             : {
      74      107218 :     List      **joinrels = root->join_rel_level;
      75             :     ListCell   *r;
      76             :     int         k;
      77             : 
      78             :     Assert(joinrels[level] == NIL);
      79             : 
      80             :     /* Set join_cur_level so that new joinrels are added to proper list */
      81      107218 :     root->join_cur_level = level;
      82             : 
      83             :     /*
      84             :      * First, consider left-sided and right-sided plans, in which rels of
      85             :      * exactly level-1 member relations are joined against initial relations.
      86             :      * We prefer to join using join clauses, but if we find a rel of level-1
      87             :      * members that has no join clauses, we will generate Cartesian-product
      88             :      * joins against all initial rels not already contained in it.
      89             :      */
      90      378548 :     foreach(r, joinrels[level - 1])
      91             :     {
      92      271330 :         RelOptInfo *old_rel = (RelOptInfo *) lfirst(r);
      93             : 
      94      299548 :         if (old_rel->joininfo != NIL || old_rel->has_eclass_joins ||
      95       28218 :             has_join_restriction(root, old_rel))
      96      262086 :         {
      97             :             int         first_rel;
      98             : 
      99             :             /*
     100             :              * There are join clauses or join order restrictions relevant to
     101             :              * this rel, so consider joins between this rel and (only) those
     102             :              * initial rels it is linked to by a clause or restriction.
     103             :              *
     104             :              * At level 2 this condition is symmetric, so there is no need to
     105             :              * look at initial rels before this one in the list; we already
     106             :              * considered such joins when we were at the earlier rel.  (The
     107             :              * mirror-image joins are handled automatically by make_join_rel.)
     108             :              * In later passes (level > 2), we join rels of the previous level
     109             :              * to each initial rel they don't already include but have a join
     110             :              * clause or restriction with.
     111             :              */
     112      262086 :             if (level == 2)     /* consider remaining initial rels */
     113      176688 :                 first_rel = foreach_current_index(r) + 1;
     114             :             else
     115       85398 :                 first_rel = 0;
     116             : 
     117      262086 :             make_rels_by_clause_joins(root, old_rel, joinrels[1], first_rel);
     118             :         }
     119             :         else
     120             :         {
     121             :             /*
     122             :              * Oops, we have a relation that is not joined to any other
     123             :              * relation, either directly or by join-order restrictions.
     124             :              * Cartesian product time.
     125             :              *
     126             :              * We consider a cartesian product with each not-already-included
     127             :              * initial rel, whether it has other join clauses or not.  At
     128             :              * level 2, if there are two or more clauseless initial rels, we
     129             :              * will redundantly consider joining them in both directions; but
     130             :              * such cases aren't common enough to justify adding complexity to
     131             :              * avoid the duplicated effort.
     132             :              */
     133        9244 :             make_rels_by_clauseless_joins(root,
     134             :                                           old_rel,
     135        9244 :                                           joinrels[1]);
     136             :         }
     137             :     }
     138             : 
     139             :     /*
     140             :      * Now, consider "bushy plans" in which relations of k initial rels are
     141             :      * joined to relations of level-k initial rels, for 2 <= k <= level-2.
     142             :      *
     143             :      * We only consider bushy-plan joins for pairs of rels where there is a
     144             :      * suitable join clause (or join order restriction), in order to avoid
     145             :      * unreasonable growth of planning time.
     146             :      */
     147      107218 :     for (k = 2;; k++)
     148       10904 :     {
     149      118122 :         int         other_level = level - k;
     150             : 
     151             :         /*
     152             :          * Since make_join_rel(x, y) handles both x,y and y,x cases, we only
     153             :          * need to go as far as the halfway point.
     154             :          */
     155      118122 :         if (k > other_level)
     156      107218 :             break;
     157             : 
     158       55556 :         foreach(r, joinrels[k])
     159             :         {
     160       44652 :             RelOptInfo *old_rel = (RelOptInfo *) lfirst(r);
     161             :             int         first_rel;
     162             :             ListCell   *r2;
     163             : 
     164             :             /*
     165             :              * We can ignore relations without join clauses here, unless they
     166             :              * participate in join-order restrictions --- then we might have
     167             :              * to force a bushy join plan.
     168             :              */
     169       44652 :             if (old_rel->joininfo == NIL && !old_rel->has_eclass_joins &&
     170         508 :                 !has_join_restriction(root, old_rel))
     171         412 :                 continue;
     172             : 
     173       44240 :             if (k == other_level)   /* only consider remaining rels */
     174       31286 :                 first_rel = foreach_current_index(r) + 1;
     175             :             else
     176       12954 :                 first_rel = 0;
     177             : 
     178      188596 :             for_each_from(r2, joinrels[other_level], first_rel)
     179             :             {
     180      144356 :                 RelOptInfo *new_rel = (RelOptInfo *) lfirst(r2);
     181             : 
     182      144356 :                 if (!bms_overlap(old_rel->relids, new_rel->relids))
     183             :                 {
     184             :                     /*
     185             :                      * OK, we can build a rel of the right level from this
     186             :                      * pair of rels.  Do so if there is at least one relevant
     187             :                      * join clause or join order restriction.
     188             :                      */
     189       18802 :                     if (have_relevant_joinclause(root, old_rel, new_rel) ||
     190        1078 :                         have_join_order_restriction(root, old_rel, new_rel))
     191             :                     {
     192       16700 :                         (void) make_join_rel(root, old_rel, new_rel);
     193             :                     }
     194             :                 }
     195             :             }
     196             :         }
     197             :     }
     198             : 
     199             :     /*----------
     200             :      * Last-ditch effort: if we failed to find any usable joins so far, force
     201             :      * a set of cartesian-product joins to be generated.  This handles the
     202             :      * special case where all the available rels have join clauses but we
     203             :      * cannot use any of those clauses yet.  This can only happen when we are
     204             :      * considering a join sub-problem (a sub-joinlist) and all the rels in the
     205             :      * sub-problem have only join clauses with rels outside the sub-problem.
     206             :      * An example is
     207             :      *
     208             :      *      SELECT ... FROM a INNER JOIN b ON TRUE, c, d, ...
     209             :      *      WHERE a.w = c.x and b.y = d.z;
     210             :      *
     211             :      * If the "a INNER JOIN b" sub-problem does not get flattened into the
     212             :      * upper level, we must be willing to make a cartesian join of a and b;
     213             :      * but the code above will not have done so, because it thought that both
     214             :      * a and b have joinclauses.  We consider only left-sided and right-sided
     215             :      * cartesian joins in this case (no bushy).
     216             :      *----------
     217             :      */
     218      107218 :     if (joinrels[level] == NIL)
     219             :     {
     220             :         /*
     221             :          * This loop is just like the first one, except we always call
     222             :          * make_rels_by_clauseless_joins().
     223             :          */
     224          54 :         foreach(r, joinrels[level - 1])
     225             :         {
     226          36 :             RelOptInfo *old_rel = (RelOptInfo *) lfirst(r);
     227             : 
     228          36 :             make_rels_by_clauseless_joins(root,
     229             :                                           old_rel,
     230          36 :                                           joinrels[1]);
     231             :         }
     232             : 
     233             :         /*----------
     234             :          * When special joins are involved, there may be no legal way
     235             :          * to make an N-way join for some values of N.  For example consider
     236             :          *
     237             :          * SELECT ... FROM t1 WHERE
     238             :          *   x IN (SELECT ... FROM t2,t3 WHERE ...) AND
     239             :          *   y IN (SELECT ... FROM t4,t5 WHERE ...)
     240             :          *
     241             :          * We will flatten this query to a 5-way join problem, but there are
     242             :          * no 4-way joins that join_is_legal() will consider legal.  We have
     243             :          * to accept failure at level 4 and go on to discover a workable
     244             :          * bushy plan at level 5.
     245             :          *
     246             :          * However, if there are no special joins and no lateral references
     247             :          * then join_is_legal() should never fail, and so the following sanity
     248             :          * check is useful.
     249             :          *----------
     250             :          */
     251          18 :         if (joinrels[level] == NIL &&
     252           6 :             root->join_info_list == NIL &&
     253           0 :             !root->hasLateralRTEs)
     254           0 :             elog(ERROR, "failed to build any %d-way joins", level);
     255             :     }
     256      107218 : }
     257             : 
     258             : /*
     259             :  * make_rels_by_clause_joins
     260             :  *    Build joins between the given relation 'old_rel' and other relations
     261             :  *    that participate in join clauses that 'old_rel' also participates in
     262             :  *    (or participate in join-order restrictions with it).
     263             :  *    The join rels are returned in root->join_rel_level[join_cur_level].
     264             :  *
     265             :  * Note: at levels above 2 we will generate the same joined relation in
     266             :  * multiple ways --- for example (a join b) join c is the same RelOptInfo as
     267             :  * (b join c) join a, though the second case will add a different set of Paths
     268             :  * to it.  This is the reason for using the join_rel_level mechanism, which
     269             :  * automatically ensures that each new joinrel is only added to the list once.
     270             :  *
     271             :  * 'old_rel' is the relation entry for the relation to be joined
     272             :  * 'other_rels': a list containing the other rels to be considered for joining
     273             :  * 'first_rel_idx': the first rel to be considered in 'other_rels'
     274             :  *
     275             :  * Currently, this is only used with initial rels in other_rels, but it
     276             :  * will work for joining to joinrels too.
     277             :  */
     278             : static void
     279      262086 : make_rels_by_clause_joins(PlannerInfo *root,
     280             :                           RelOptInfo *old_rel,
     281             :                           List *other_rels,
     282             :                           int first_rel_idx)
     283             : {
     284             :     ListCell   *l;
     285             : 
     286      771228 :     for_each_from(l, other_rels, first_rel_idx)
     287             :     {
     288      509142 :         RelOptInfo *other_rel = (RelOptInfo *) lfirst(l);
     289             : 
     290      799730 :         if (!bms_overlap(old_rel->relids, other_rel->relids) &&
     291      355522 :             (have_relevant_joinclause(root, old_rel, other_rel) ||
     292       64934 :              have_join_order_restriction(root, old_rel, other_rel)))
     293             :         {
     294      236628 :             (void) make_join_rel(root, old_rel, other_rel);
     295             :         }
     296             :     }
     297      262086 : }
     298             : 
     299             : /*
     300             :  * make_rels_by_clauseless_joins
     301             :  *    Given a relation 'old_rel' and a list of other relations
     302             :  *    'other_rels', create a join relation between 'old_rel' and each
     303             :  *    member of 'other_rels' that isn't already included in 'old_rel'.
     304             :  *    The join rels are returned in root->join_rel_level[join_cur_level].
     305             :  *
     306             :  * 'old_rel' is the relation entry for the relation to be joined
     307             :  * 'other_rels': a list containing the other rels to be considered for joining
     308             :  *
     309             :  * Currently, this is only used with initial rels in other_rels, but it would
     310             :  * work for joining to joinrels too.
     311             :  */
     312             : static void
     313        9280 : make_rels_by_clauseless_joins(PlannerInfo *root,
     314             :                               RelOptInfo *old_rel,
     315             :                               List *other_rels)
     316             : {
     317             :     ListCell   *l;
     318             : 
     319       30516 :     foreach(l, other_rels)
     320             :     {
     321       21236 :         RelOptInfo *other_rel = (RelOptInfo *) lfirst(l);
     322             : 
     323       21236 :         if (!bms_overlap(other_rel->relids, old_rel->relids))
     324             :         {
     325       10476 :             (void) make_join_rel(root, old_rel, other_rel);
     326             :         }
     327             :     }
     328        9280 : }
     329             : 
     330             : 
     331             : /*
     332             :  * join_is_legal
     333             :  *     Determine whether a proposed join is legal given the query's
     334             :  *     join order constraints; and if it is, determine the join type.
     335             :  *
     336             :  * Caller must supply not only the two rels, but the union of their relids.
     337             :  * (We could simplify the API by computing joinrelids locally, but this
     338             :  * would be redundant work in the normal path through make_join_rel.
     339             :  * Note that this value does NOT include the RT index of any outer join that
     340             :  * might need to be performed here, so it's not the canonical identifier
     341             :  * of the join relation.)
     342             :  *
     343             :  * On success, *sjinfo_p is set to NULL if this is to be a plain inner join,
     344             :  * else it's set to point to the associated SpecialJoinInfo node.  Also,
     345             :  * *reversed_p is set true if the given relations need to be swapped to
     346             :  * match the SpecialJoinInfo node.
     347             :  */
     348             : static bool
     349      268874 : join_is_legal(PlannerInfo *root, RelOptInfo *rel1, RelOptInfo *rel2,
     350             :               Relids joinrelids,
     351             :               SpecialJoinInfo **sjinfo_p, bool *reversed_p)
     352             : {
     353             :     SpecialJoinInfo *match_sjinfo;
     354             :     bool        reversed;
     355             :     bool        unique_ified;
     356             :     bool        must_be_leftjoin;
     357             :     ListCell   *l;
     358             : 
     359             :     /*
     360             :      * Ensure output params are set on failure return.  This is just to
     361             :      * suppress uninitialized-variable warnings from overly anal compilers.
     362             :      */
     363      268874 :     *sjinfo_p = NULL;
     364      268874 :     *reversed_p = false;
     365             : 
     366             :     /*
     367             :      * If we have any special joins, the proposed join might be illegal; and
     368             :      * in any case we have to determine its join type.  Scan the join info
     369             :      * list for matches and conflicts.
     370             :      */
     371      268874 :     match_sjinfo = NULL;
     372      268874 :     reversed = false;
     373      268874 :     unique_ified = false;
     374      268874 :     must_be_leftjoin = false;
     375             : 
     376      579052 :     foreach(l, root->join_info_list)
     377             :     {
     378      318620 :         SpecialJoinInfo *sjinfo = (SpecialJoinInfo *) lfirst(l);
     379             : 
     380             :         /*
     381             :          * This special join is not relevant unless its RHS overlaps the
     382             :          * proposed join.  (Check this first as a fast path for dismissing
     383             :          * most irrelevant SJs quickly.)
     384             :          */
     385      318620 :         if (!bms_overlap(sjinfo->min_righthand, joinrelids))
     386      107364 :             continue;
     387             : 
     388             :         /*
     389             :          * Also, not relevant if proposed join is fully contained within RHS
     390             :          * (ie, we're still building up the RHS).
     391             :          */
     392      211256 :         if (bms_is_subset(joinrelids, sjinfo->min_righthand))
     393        4994 :             continue;
     394             : 
     395             :         /*
     396             :          * Also, not relevant if SJ is already done within either input.
     397             :          */
     398      385180 :         if (bms_is_subset(sjinfo->min_lefthand, rel1->relids) &&
     399      178918 :             bms_is_subset(sjinfo->min_righthand, rel1->relids))
     400       87082 :             continue;
     401      136768 :         if (bms_is_subset(sjinfo->min_lefthand, rel2->relids) &&
     402       17588 :             bms_is_subset(sjinfo->min_righthand, rel2->relids))
     403        9106 :             continue;
     404             : 
     405             :         /*
     406             :          * If it's a semijoin and we already joined the RHS to any other rels
     407             :          * within either input, then we must have unique-ified the RHS at that
     408             :          * point (see below).  Therefore the semijoin is no longer relevant in
     409             :          * this join path.
     410             :          */
     411      110074 :         if (sjinfo->jointype == JOIN_SEMI)
     412             :         {
     413        6942 :             if (bms_is_subset(sjinfo->syn_righthand, rel1->relids) &&
     414        1216 :                 !bms_equal(sjinfo->syn_righthand, rel1->relids))
     415         426 :                 continue;
     416        6516 :             if (bms_is_subset(sjinfo->syn_righthand, rel2->relids) &&
     417        3824 :                 !bms_equal(sjinfo->syn_righthand, rel2->relids))
     418          94 :                 continue;
     419             :         }
     420             : 
     421             :         /*
     422             :          * If one input contains min_lefthand and the other contains
     423             :          * min_righthand, then we can perform the SJ at this join.
     424             :          *
     425             :          * Reject if we get matches to more than one SJ; that implies we're
     426             :          * considering something that's not really valid.
     427             :          */
     428      201310 :         if (bms_is_subset(sjinfo->min_lefthand, rel1->relids) &&
     429       91756 :             bms_is_subset(sjinfo->min_righthand, rel2->relids))
     430             :         {
     431       85720 :             if (match_sjinfo)
     432        8442 :                 return false;   /* invalid join path */
     433       85720 :             match_sjinfo = sjinfo;
     434       85720 :             reversed = false;
     435             :         }
     436       32092 :         else if (bms_is_subset(sjinfo->min_lefthand, rel2->relids) &&
     437        8258 :                  bms_is_subset(sjinfo->min_righthand, rel1->relids))
     438             :         {
     439        7082 :             if (match_sjinfo)
     440           0 :                 return false;   /* invalid join path */
     441        7082 :             match_sjinfo = sjinfo;
     442        7082 :             reversed = true;
     443             :         }
     444       19400 :         else if (sjinfo->jointype == JOIN_SEMI &&
     445        3176 :                  bms_equal(sjinfo->syn_righthand, rel2->relids) &&
     446         528 :                  create_unique_path(root, rel2, rel2->cheapest_total_path,
     447             :                                     sjinfo) != NULL)
     448             :         {
     449             :             /*----------
     450             :              * For a semijoin, we can join the RHS to anything else by
     451             :              * unique-ifying the RHS (if the RHS can be unique-ified).
     452             :              * We will only get here if we have the full RHS but less
     453             :              * than min_lefthand on the LHS.
     454             :              *
     455             :              * The reason to consider such a join path is exemplified by
     456             :              *  SELECT ... FROM a,b WHERE (a.x,b.y) IN (SELECT c1,c2 FROM c)
     457             :              * If we insist on doing this as a semijoin we will first have
     458             :              * to form the cartesian product of A*B.  But if we unique-ify
     459             :              * C then the semijoin becomes a plain innerjoin and we can join
     460             :              * in any order, eg C to A and then to B.  When C is much smaller
     461             :              * than A and B this can be a huge win.  So we allow C to be
     462             :              * joined to just A or just B here, and then make_join_rel has
     463             :              * to handle the case properly.
     464             :              *
     465             :              * Note that actually we'll allow unique-ified C to be joined to
     466             :              * some other relation D here, too.  That is legal, if usually not
     467             :              * very sane, and this routine is only concerned with legality not
     468             :              * with whether the join is good strategy.
     469             :              *----------
     470             :              */
     471         522 :             if (match_sjinfo)
     472          78 :                 return false;   /* invalid join path */
     473         444 :             match_sjinfo = sjinfo;
     474         444 :             reversed = false;
     475         444 :             unique_ified = true;
     476             :         }
     477       18356 :         else if (sjinfo->jointype == JOIN_SEMI &&
     478        2344 :                  bms_equal(sjinfo->syn_righthand, rel1->relids) &&
     479         218 :                  create_unique_path(root, rel1, rel1->cheapest_total_path,
     480             :                                     sjinfo) != NULL)
     481             :         {
     482             :             /* Reversed semijoin case */
     483         218 :             if (match_sjinfo)
     484          78 :                 return false;   /* invalid join path */
     485         140 :             match_sjinfo = sjinfo;
     486         140 :             reversed = true;
     487         140 :             unique_ified = true;
     488             :         }
     489             :         else
     490             :         {
     491             :             /*
     492             :              * Otherwise, the proposed join overlaps the RHS but isn't a valid
     493             :              * implementation of this SJ.  But don't panic quite yet: the RHS
     494             :              * violation might have occurred previously, in one or both input
     495             :              * relations, in which case we must have previously decided that
     496             :              * it was OK to commute some other SJ with this one.  If we need
     497             :              * to perform this join to finish building up the RHS, rejecting
     498             :              * it could lead to not finding any plan at all.  (This can occur
     499             :              * because of the heuristics elsewhere in this file that postpone
     500             :              * clauseless joins: we might not consider doing a clauseless join
     501             :              * within the RHS until after we've performed other, validly
     502             :              * commutable SJs with one or both sides of the clauseless join.)
     503             :              * This consideration boils down to the rule that if both inputs
     504             :              * overlap the RHS, we can allow the join --- they are either
     505             :              * fully within the RHS, or represent previously-allowed joins to
     506             :              * rels outside it.
     507             :              */
     508       23550 :             if (bms_overlap(rel1->relids, sjinfo->min_righthand) &&
     509        7538 :                 bms_overlap(rel2->relids, sjinfo->min_righthand))
     510         174 :                 continue;       /* assume valid previous violation of RHS */
     511             : 
     512             :             /*
     513             :              * The proposed join could still be legal, but only if we're
     514             :              * allowed to associate it into the RHS of this SJ.  That means
     515             :              * this SJ must be a LEFT join (not SEMI or ANTI, and certainly
     516             :              * not FULL) and the proposed join must not overlap the LHS.
     517             :              */
     518       29636 :             if (sjinfo->jointype != JOIN_LEFT ||
     519       13798 :                 bms_overlap(joinrelids, sjinfo->min_lefthand))
     520        8286 :                 return false;   /* invalid join path */
     521             : 
     522             :             /*
     523             :              * To be valid, the proposed join must be a LEFT join; otherwise
     524             :              * it can't associate into this SJ's RHS.  But we may not yet have
     525             :              * found the SpecialJoinInfo matching the proposed join, so we
     526             :              * can't test that yet.  Remember the requirement for later.
     527             :              */
     528        7552 :             must_be_leftjoin = true;
     529             :         }
     530             :     }
     531             : 
     532             :     /*
     533             :      * Fail if violated any SJ's RHS and didn't match to a LEFT SJ: the
     534             :      * proposed join can't associate into an SJ's RHS.
     535             :      *
     536             :      * Also, fail if the proposed join's predicate isn't strict; we're
     537             :      * essentially checking to see if we can apply outer-join identity 3, and
     538             :      * that's a requirement.  (This check may be redundant with checks in
     539             :      * make_outerjoininfo, but I'm not quite sure, and it's cheap to test.)
     540             :      */
     541      260432 :     if (must_be_leftjoin &&
     542        4704 :         (match_sjinfo == NULL ||
     543        4704 :          match_sjinfo->jointype != JOIN_LEFT ||
     544        4704 :          !match_sjinfo->lhs_strict))
     545        1460 :         return false;           /* invalid join path */
     546             : 
     547             :     /*
     548             :      * We also have to check for constraints imposed by LATERAL references.
     549             :      */
     550      258972 :     if (root->hasLateralRTEs)
     551             :     {
     552             :         bool        lateral_fwd;
     553             :         bool        lateral_rev;
     554             :         Relids      join_lateral_rels;
     555             : 
     556             :         /*
     557             :          * The proposed rels could each contain lateral references to the
     558             :          * other, in which case the join is impossible.  If there are lateral
     559             :          * references in just one direction, then the join has to be done with
     560             :          * a nestloop with the lateral referencer on the inside.  If the join
     561             :          * matches an SJ that cannot be implemented by such a nestloop, the
     562             :          * join is impossible.
     563             :          *
     564             :          * Also, if the lateral reference is only indirect, we should reject
     565             :          * the join; whatever rel(s) the reference chain goes through must be
     566             :          * joined to first.
     567             :          *
     568             :          * Another case that might keep us from building a valid plan is the
     569             :          * implementation restriction described by have_dangerous_phv().
     570             :          */
     571       15918 :         lateral_fwd = bms_overlap(rel1->relids, rel2->lateral_relids);
     572       15918 :         lateral_rev = bms_overlap(rel2->relids, rel1->lateral_relids);
     573       15918 :         if (lateral_fwd && lateral_rev)
     574          18 :             return false;       /* have lateral refs in both directions */
     575       15900 :         if (lateral_fwd)
     576             :         {
     577             :             /* has to be implemented as nestloop with rel1 on left */
     578        9868 :             if (match_sjinfo &&
     579         354 :                 (reversed ||
     580         342 :                  unique_ified ||
     581         342 :                  match_sjinfo->jointype == JOIN_FULL))
     582          12 :                 return false;   /* not implementable as nestloop */
     583             :             /* check there is a direct reference from rel2 to rel1 */
     584        9856 :             if (!bms_overlap(rel1->relids, rel2->direct_lateral_relids))
     585          42 :                 return false;   /* only indirect refs, so reject */
     586             :             /* check we won't have a dangerous PHV */
     587        9814 :             if (have_dangerous_phv(root, rel1->relids, rel2->lateral_relids))
     588          72 :                 return false;   /* might be unable to handle required PHV */
     589             :         }
     590        6032 :         else if (lateral_rev)
     591             :         {
     592             :             /* has to be implemented as nestloop with rel2 on left */
     593        1122 :             if (match_sjinfo &&
     594          72 :                 (!reversed ||
     595          72 :                  unique_ified ||
     596          72 :                  match_sjinfo->jointype == JOIN_FULL))
     597           0 :                 return false;   /* not implementable as nestloop */
     598             :             /* check there is a direct reference from rel1 to rel2 */
     599        1122 :             if (!bms_overlap(rel2->relids, rel1->direct_lateral_relids))
     600           0 :                 return false;   /* only indirect refs, so reject */
     601             :             /* check we won't have a dangerous PHV */
     602        1122 :             if (have_dangerous_phv(root, rel2->relids, rel1->lateral_relids))
     603          84 :                 return false;   /* might be unable to handle required PHV */
     604             :         }
     605             : 
     606             :         /*
     607             :          * LATERAL references could also cause problems later on if we accept
     608             :          * this join: if the join's minimum parameterization includes any rels
     609             :          * that would have to be on the inside of an outer join with this join
     610             :          * rel, then it's never going to be possible to build the complete
     611             :          * query using this join.  We should reject this join not only because
     612             :          * it'll save work, but because if we don't, the clauseless-join
     613             :          * heuristics might think that legality of this join means that some
     614             :          * other join rel need not be formed, and that could lead to failure
     615             :          * to find any plan at all.  We have to consider not only rels that
     616             :          * are directly on the inner side of an OJ with the joinrel, but also
     617             :          * ones that are indirectly so, so search to find all such rels.
     618             :          */
     619       15690 :         join_lateral_rels = min_join_parameterization(root, joinrelids,
     620             :                                                       rel1, rel2);
     621       15690 :         if (join_lateral_rels)
     622             :         {
     623        1626 :             Relids      join_plus_rhs = bms_copy(joinrelids);
     624             :             bool        more;
     625             : 
     626             :             do
     627             :             {
     628        2010 :                 more = false;
     629        3864 :                 foreach(l, root->join_info_list)
     630             :                 {
     631        1854 :                     SpecialJoinInfo *sjinfo = (SpecialJoinInfo *) lfirst(l);
     632             : 
     633             :                     /* ignore full joins --- their ordering is predetermined */
     634        1854 :                     if (sjinfo->jointype == JOIN_FULL)
     635          18 :                         continue;
     636             : 
     637        1836 :                     if (bms_overlap(sjinfo->min_lefthand, join_plus_rhs) &&
     638        1566 :                         !bms_is_subset(sjinfo->min_righthand, join_plus_rhs))
     639             :                     {
     640         534 :                         join_plus_rhs = bms_add_members(join_plus_rhs,
     641         534 :                                                         sjinfo->min_righthand);
     642         534 :                         more = true;
     643             :                     }
     644             :                 }
     645        2010 :             } while (more);
     646        1626 :             if (bms_overlap(join_plus_rhs, join_lateral_rels))
     647         300 :                 return false;   /* will not be able to join to some RHS rel */
     648             :         }
     649             :     }
     650             : 
     651             :     /* Otherwise, it's a valid join */
     652      258444 :     *sjinfo_p = match_sjinfo;
     653      258444 :     *reversed_p = reversed;
     654      258444 :     return true;
     655             : }
     656             : 
     657             : /*
     658             :  * init_dummy_sjinfo
     659             :  *    Populate the given SpecialJoinInfo for a plain inner join between the
     660             :  *    left and right relations specified by left_relids and right_relids
     661             :  *    respectively.
     662             :  *
     663             :  * Normally, an inner join does not have a SpecialJoinInfo node associated with
     664             :  * it. But some functions involved in join planning require one containing at
     665             :  * least the information of which relations are being joined.  So we initialize
     666             :  * that information here.
     667             :  */
     668             : void
     669      686028 : init_dummy_sjinfo(SpecialJoinInfo *sjinfo, Relids left_relids,
     670             :                   Relids right_relids)
     671             : {
     672      686028 :     sjinfo->type = T_SpecialJoinInfo;
     673      686028 :     sjinfo->min_lefthand = left_relids;
     674      686028 :     sjinfo->min_righthand = right_relids;
     675      686028 :     sjinfo->syn_lefthand = left_relids;
     676      686028 :     sjinfo->syn_righthand = right_relids;
     677      686028 :     sjinfo->jointype = JOIN_INNER;
     678      686028 :     sjinfo->ojrelid = 0;
     679      686028 :     sjinfo->commute_above_l = NULL;
     680      686028 :     sjinfo->commute_above_r = NULL;
     681      686028 :     sjinfo->commute_below_l = NULL;
     682      686028 :     sjinfo->commute_below_r = NULL;
     683             :     /* we don't bother trying to make the remaining fields valid */
     684      686028 :     sjinfo->lhs_strict = false;
     685      686028 :     sjinfo->semi_can_btree = false;
     686      686028 :     sjinfo->semi_can_hash = false;
     687      686028 :     sjinfo->semi_operators = NIL;
     688      686028 :     sjinfo->semi_rhs_exprs = NIL;
     689      686028 : }
     690             : 
     691             : /*
     692             :  * make_join_rel
     693             :  *     Find or create a join RelOptInfo that represents the join of
     694             :  *     the two given rels, and add to it path information for paths
     695             :  *     created with the two rels as outer and inner rel.
     696             :  *     (The join rel may already contain paths generated from other
     697             :  *     pairs of rels that add up to the same set of base rels.)
     698             :  *
     699             :  * NB: will return NULL if attempted join is not valid.  This can happen
     700             :  * when working with outer joins, or with IN or EXISTS clauses that have been
     701             :  * turned into joins.
     702             :  */
     703             : RelOptInfo *
     704      268556 : make_join_rel(PlannerInfo *root, RelOptInfo *rel1, RelOptInfo *rel2)
     705             : {
     706             :     Relids      joinrelids;
     707             :     SpecialJoinInfo *sjinfo;
     708             :     bool        reversed;
     709      268556 :     List       *pushed_down_joins = NIL;
     710             :     SpecialJoinInfo sjinfo_data;
     711             :     RelOptInfo *joinrel;
     712             :     List       *restrictlist;
     713             : 
     714             :     /* We should never try to join two overlapping sets of rels. */
     715             :     Assert(!bms_overlap(rel1->relids, rel2->relids));
     716             : 
     717             :     /* Construct Relids set that identifies the joinrel (without OJ as yet). */
     718      268556 :     joinrelids = bms_union(rel1->relids, rel2->relids);
     719             : 
     720             :     /* Check validity and determine join type. */
     721      268556 :     if (!join_is_legal(root, rel1, rel2, joinrelids,
     722             :                        &sjinfo, &reversed))
     723             :     {
     724             :         /* invalid join path */
     725       10322 :         bms_free(joinrelids);
     726       10322 :         return NULL;
     727             :     }
     728             : 
     729             :     /*
     730             :      * Add outer join relid(s) to form the canonical relids.  Any added outer
     731             :      * joins besides sjinfo itself are appended to pushed_down_joins.
     732             :      */
     733      258234 :     joinrelids = add_outer_joins_to_relids(root, joinrelids, sjinfo,
     734             :                                            &pushed_down_joins);
     735             : 
     736             :     /* Swap rels if needed to match the join info. */
     737      258234 :     if (reversed)
     738             :     {
     739        7078 :         RelOptInfo *trel = rel1;
     740             : 
     741        7078 :         rel1 = rel2;
     742        7078 :         rel2 = trel;
     743             :     }
     744             : 
     745             :     /*
     746             :      * If it's a plain inner join, then we won't have found anything in
     747             :      * join_info_list.  Make up a SpecialJoinInfo so that selectivity
     748             :      * estimation functions will know what's being joined.
     749             :      */
     750      258234 :     if (sjinfo == NULL)
     751             :     {
     752      165362 :         sjinfo = &sjinfo_data;
     753      165362 :         init_dummy_sjinfo(sjinfo, rel1->relids, rel2->relids);
     754             :     }
     755             : 
     756             :     /*
     757             :      * Find or build the join RelOptInfo, and compute the restrictlist that
     758             :      * goes with this particular joining.
     759             :      */
     760      258234 :     joinrel = build_join_rel(root, joinrelids, rel1, rel2,
     761             :                              sjinfo, pushed_down_joins,
     762             :                              &restrictlist);
     763             : 
     764             :     /*
     765             :      * If we've already proven this join is empty, we needn't consider any
     766             :      * more paths for it.
     767             :      */
     768      258234 :     if (is_dummy_rel(joinrel))
     769             :     {
     770         456 :         bms_free(joinrelids);
     771         456 :         return joinrel;
     772             :     }
     773             : 
     774             :     /* Add paths to the join relation. */
     775      257778 :     populate_joinrel_with_paths(root, rel1, rel2, joinrel, sjinfo,
     776             :                                 restrictlist);
     777             : 
     778      257778 :     bms_free(joinrelids);
     779             : 
     780      257778 :     return joinrel;
     781             : }
     782             : 
     783             : /*
     784             :  * add_outer_joins_to_relids
     785             :  *    Add relids to input_relids to represent any outer joins that will be
     786             :  *    calculated at this join.
     787             :  *
     788             :  * input_relids is the union of the relid sets of the two input relations.
     789             :  * Note that we modify this in-place and return it; caller must bms_copy()
     790             :  * it first, if a separate value is desired.
     791             :  *
     792             :  * sjinfo represents the join being performed.
     793             :  *
     794             :  * If the current join completes the calculation of any outer joins that
     795             :  * have been pushed down per outer-join identity 3, those relids will be
     796             :  * added to the result along with sjinfo's own relid.  If pushed_down_joins
     797             :  * is not NULL, then also the SpecialJoinInfos for such added outer joins will
     798             :  * be appended to *pushed_down_joins (so caller must initialize it to NIL).
     799             :  */
     800             : Relids
     801      265066 : add_outer_joins_to_relids(PlannerInfo *root, Relids input_relids,
     802             :                           SpecialJoinInfo *sjinfo,
     803             :                           List **pushed_down_joins)
     804             : {
     805             :     /* Nothing to do if this isn't an outer join with an assigned relid. */
     806      265066 :     if (sjinfo == NULL || sjinfo->ojrelid == 0)
     807      179412 :         return input_relids;
     808             : 
     809             :     /*
     810             :      * If it's not a left join, we have no rules that would permit executing
     811             :      * it in non-syntactic order, so just form the syntactic relid set.  (This
     812             :      * is just a quick-exit test; we'd come to the same conclusion anyway,
     813             :      * since its commute_below_l and commute_above_l sets must be empty.)
     814             :      */
     815       85654 :     if (sjinfo->jointype != JOIN_LEFT)
     816        2034 :         return bms_add_member(input_relids, sjinfo->ojrelid);
     817             : 
     818             :     /*
     819             :      * We cannot add the OJ relid if this join has been pushed into the RHS of
     820             :      * a syntactically-lower left join per OJ identity 3.  (If it has, then we
     821             :      * cannot claim that its outputs represent the final state of its RHS.)
     822             :      * There will not be any other OJs that can be added either, so we're
     823             :      * done.
     824             :      */
     825       83620 :     if (!bms_is_subset(sjinfo->commute_below_l, input_relids))
     826        4440 :         return input_relids;
     827             : 
     828             :     /* OK to add OJ's own relid */
     829       79180 :     input_relids = bms_add_member(input_relids, sjinfo->ojrelid);
     830             : 
     831             :     /*
     832             :      * Contrariwise, if we are now forming the final result of such a commuted
     833             :      * pair of OJs, it's time to add the relid(s) of the pushed-down join(s).
     834             :      * We can skip this if this join was never a candidate to be pushed up.
     835             :      */
     836       79180 :     if (sjinfo->commute_above_l)
     837             :     {
     838       15760 :         Relids      commute_above_rels = bms_copy(sjinfo->commute_above_l);
     839             :         ListCell   *lc;
     840             : 
     841             :         /*
     842             :          * The current join could complete the nulling of more than one
     843             :          * pushed-down join, so we have to examine all the SpecialJoinInfos.
     844             :          * Because join_info_list was built in bottom-up order, it's
     845             :          * sufficient to traverse it once: an ojrelid we add in one loop
     846             :          * iteration would not have affected decisions of earlier iterations.
     847             :          */
     848       58188 :         foreach(lc, root->join_info_list)
     849             :         {
     850       42428 :             SpecialJoinInfo *othersj = (SpecialJoinInfo *) lfirst(lc);
     851             : 
     852       42428 :             if (othersj == sjinfo ||
     853       26668 :                 othersj->ojrelid == 0 || othersj->jointype != JOIN_LEFT)
     854       15772 :                 continue;       /* definitely not interesting */
     855             : 
     856       26656 :             if (!bms_is_member(othersj->ojrelid, commute_above_rels))
     857       10788 :                 continue;
     858             : 
     859             :             /* Add it if not already present but conditions now satisfied */
     860       31736 :             if (!bms_is_member(othersj->ojrelid, input_relids) &&
     861       31712 :                 bms_is_subset(othersj->min_lefthand, input_relids) &&
     862       23838 :                 bms_is_subset(othersj->min_righthand, input_relids) &&
     863        7994 :                 bms_is_subset(othersj->commute_below_l, input_relids))
     864             :             {
     865        7958 :                 input_relids = bms_add_member(input_relids, othersj->ojrelid);
     866             :                 /* report such pushed down outer joins, if asked */
     867        7958 :                 if (pushed_down_joins != NULL)
     868        7958 :                     *pushed_down_joins = lappend(*pushed_down_joins, othersj);
     869             : 
     870             :                 /*
     871             :                  * We must also check any joins that othersj potentially
     872             :                  * commutes with.  They likewise must appear later in
     873             :                  * join_info_list than othersj itself, so we can visit them
     874             :                  * later in this loop.
     875             :                  */
     876        7958 :                 commute_above_rels = bms_add_members(commute_above_rels,
     877        7958 :                                                      othersj->commute_above_l);
     878             :             }
     879             :         }
     880             :     }
     881             : 
     882       79180 :     return input_relids;
     883             : }
     884             : 
     885             : /*
     886             :  * populate_joinrel_with_paths
     887             :  *    Add paths to the given joinrel for given pair of joining relations. The
     888             :  *    SpecialJoinInfo provides details about the join and the restrictlist
     889             :  *    contains the join clauses and the other clauses applicable for given pair
     890             :  *    of the joining relations.
     891             :  */
     892             : static void
     893      262874 : populate_joinrel_with_paths(PlannerInfo *root, RelOptInfo *rel1,
     894             :                             RelOptInfo *rel2, RelOptInfo *joinrel,
     895             :                             SpecialJoinInfo *sjinfo, List *restrictlist)
     896             : {
     897             :     /*
     898             :      * Consider paths using each rel as both outer and inner.  Depending on
     899             :      * the join type, a provably empty outer or inner rel might mean the join
     900             :      * is provably empty too; in which case throw away any previously computed
     901             :      * paths and mark the join as dummy.  (We do it this way since it's
     902             :      * conceivable that dummy-ness of a multi-element join might only be
     903             :      * noticeable for certain construction paths.)
     904             :      *
     905             :      * Also, a provably constant-false join restriction typically means that
     906             :      * we can skip evaluating one or both sides of the join.  We do this by
     907             :      * marking the appropriate rel as dummy.  For outer joins, a
     908             :      * constant-false restriction that is pushed down still means the whole
     909             :      * join is dummy, while a non-pushed-down one means that no inner rows
     910             :      * will join so we can treat the inner rel as dummy.
     911             :      *
     912             :      * We need only consider the jointypes that appear in join_info_list, plus
     913             :      * JOIN_INNER.
     914             :      */
     915      262874 :     switch (sjinfo->jointype)
     916             :     {
     917      166978 :         case JOIN_INNER:
     918      333938 :             if (is_dummy_rel(rel1) || is_dummy_rel(rel2) ||
     919      166960 :                 restriction_is_constant_false(restrictlist, joinrel, false))
     920             :             {
     921         180 :                 mark_dummy_rel(joinrel);
     922         180 :                 break;
     923             :             }
     924      166798 :             add_paths_to_joinrel(root, joinrel, rel1, rel2,
     925             :                                  JOIN_INNER, sjinfo,
     926             :                                  restrictlist);
     927      166798 :             add_paths_to_joinrel(root, joinrel, rel2, rel1,
     928             :                                  JOIN_INNER, sjinfo,
     929             :                                  restrictlist);
     930      166798 :             break;
     931       85286 :         case JOIN_LEFT:
     932      170518 :             if (is_dummy_rel(rel1) ||
     933       85232 :                 restriction_is_constant_false(restrictlist, joinrel, true))
     934             :             {
     935          86 :                 mark_dummy_rel(joinrel);
     936          86 :                 break;
     937             :             }
     938       85380 :             if (restriction_is_constant_false(restrictlist, joinrel, false) &&
     939         180 :                 bms_is_subset(rel2->relids, sjinfo->syn_righthand))
     940         156 :                 mark_dummy_rel(rel2);
     941       85200 :             add_paths_to_joinrel(root, joinrel, rel1, rel2,
     942             :                                  JOIN_LEFT, sjinfo,
     943             :                                  restrictlist);
     944       85200 :             add_paths_to_joinrel(root, joinrel, rel2, rel1,
     945             :                                  JOIN_RIGHT, sjinfo,
     946             :                                  restrictlist);
     947       85200 :             break;
     948        1696 :         case JOIN_FULL:
     949        3392 :             if ((is_dummy_rel(rel1) && is_dummy_rel(rel2)) ||
     950        1696 :                 restriction_is_constant_false(restrictlist, joinrel, true))
     951             :             {
     952           0 :                 mark_dummy_rel(joinrel);
     953           0 :                 break;
     954             :             }
     955        1696 :             add_paths_to_joinrel(root, joinrel, rel1, rel2,
     956             :                                  JOIN_FULL, sjinfo,
     957             :                                  restrictlist);
     958        1696 :             add_paths_to_joinrel(root, joinrel, rel2, rel1,
     959             :                                  JOIN_FULL, sjinfo,
     960             :                                  restrictlist);
     961             : 
     962             :             /*
     963             :              * If there are join quals that aren't mergeable or hashable, we
     964             :              * may not be able to build any valid plan.  Complain here so that
     965             :              * we can give a somewhat-useful error message.  (Since we have no
     966             :              * flexibility of planning for a full join, there's no chance of
     967             :              * succeeding later with another pair of input rels.)
     968             :              */
     969        1696 :             if (joinrel->pathlist == NIL)
     970           0 :                 ereport(ERROR,
     971             :                         (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
     972             :                          errmsg("FULL JOIN is only supported with merge-joinable or hash-joinable join conditions")));
     973        1696 :             break;
     974        4396 :         case JOIN_SEMI:
     975             : 
     976             :             /*
     977             :              * We might have a normal semijoin, or a case where we don't have
     978             :              * enough rels to do the semijoin but can unique-ify the RHS and
     979             :              * then do an innerjoin (see comments in join_is_legal).  In the
     980             :              * latter case we can't apply JOIN_SEMI joining.
     981             :              */
     982        8566 :             if (bms_is_subset(sjinfo->min_lefthand, rel1->relids) &&
     983        4170 :                 bms_is_subset(sjinfo->min_righthand, rel2->relids))
     984             :             {
     985        8334 :                 if (is_dummy_rel(rel1) || is_dummy_rel(rel2) ||
     986        4164 :                     restriction_is_constant_false(restrictlist, joinrel, false))
     987             :                 {
     988          12 :                     mark_dummy_rel(joinrel);
     989          12 :                     break;
     990             :                 }
     991        4158 :                 add_paths_to_joinrel(root, joinrel, rel1, rel2,
     992             :                                      JOIN_SEMI, sjinfo,
     993             :                                      restrictlist);
     994             :             }
     995             : 
     996             :             /*
     997             :              * If we know how to unique-ify the RHS and one input rel is
     998             :              * exactly the RHS (not a superset) we can consider unique-ifying
     999             :              * it and then doing a regular join.  (The create_unique_path
    1000             :              * check here is probably redundant with what join_is_legal did,
    1001             :              * but if so the check is cheap because it's cached.  So test
    1002             :              * anyway to be sure.)
    1003             :              */
    1004        8768 :             if (bms_equal(sjinfo->syn_righthand, rel2->relids) &&
    1005        4384 :                 create_unique_path(root, rel2, rel2->cheapest_total_path,
    1006             :                                    sjinfo) != NULL)
    1007             :             {
    1008        8540 :                 if (is_dummy_rel(rel1) || is_dummy_rel(rel2) ||
    1009        4270 :                     restriction_is_constant_false(restrictlist, joinrel, false))
    1010             :                 {
    1011           0 :                     mark_dummy_rel(joinrel);
    1012           0 :                     break;
    1013             :                 }
    1014        4270 :                 add_paths_to_joinrel(root, joinrel, rel1, rel2,
    1015             :                                      JOIN_UNIQUE_INNER, sjinfo,
    1016             :                                      restrictlist);
    1017        4270 :                 add_paths_to_joinrel(root, joinrel, rel2, rel1,
    1018             :                                      JOIN_UNIQUE_OUTER, sjinfo,
    1019             :                                      restrictlist);
    1020             :             }
    1021        4384 :             break;
    1022        4518 :         case JOIN_ANTI:
    1023        9036 :             if (is_dummy_rel(rel1) ||
    1024        4518 :                 restriction_is_constant_false(restrictlist, joinrel, true))
    1025             :             {
    1026           0 :                 mark_dummy_rel(joinrel);
    1027           0 :                 break;
    1028             :             }
    1029        4518 :             if (restriction_is_constant_false(restrictlist, joinrel, false) &&
    1030           0 :                 bms_is_subset(rel2->relids, sjinfo->syn_righthand))
    1031           0 :                 mark_dummy_rel(rel2);
    1032        4518 :             add_paths_to_joinrel(root, joinrel, rel1, rel2,
    1033             :                                  JOIN_ANTI, sjinfo,
    1034             :                                  restrictlist);
    1035        4518 :             add_paths_to_joinrel(root, joinrel, rel2, rel1,
    1036             :                                  JOIN_RIGHT_ANTI, sjinfo,
    1037             :                                  restrictlist);
    1038        4518 :             break;
    1039           0 :         default:
    1040             :             /* other values not expected here */
    1041           0 :             elog(ERROR, "unrecognized join type: %d", (int) sjinfo->jointype);
    1042             :             break;
    1043             :     }
    1044             : 
    1045             :     /* Apply partitionwise join technique, if possible. */
    1046      262874 :     try_partitionwise_join(root, rel1, rel2, joinrel, sjinfo, restrictlist);
    1047      262874 : }
    1048             : 
    1049             : 
    1050             : /*
    1051             :  * have_join_order_restriction
    1052             :  *      Detect whether the two relations should be joined to satisfy
    1053             :  *      a join-order restriction arising from special or lateral joins.
    1054             :  *
    1055             :  * In practice this is always used with have_relevant_joinclause(), and so
    1056             :  * could be merged with that function, but it seems clearer to separate the
    1057             :  * two concerns.  We need this test because there are degenerate cases where
    1058             :  * a clauseless join must be performed to satisfy join-order restrictions.
    1059             :  * Also, if one rel has a lateral reference to the other, or both are needed
    1060             :  * to compute some PHV, we should consider joining them even if the join would
    1061             :  * be clauseless.
    1062             :  *
    1063             :  * Note: this is only a problem if one side of a degenerate outer join
    1064             :  * contains multiple rels, or a clauseless join is required within an
    1065             :  * IN/EXISTS RHS; else we will find a join path via the "last ditch" case in
    1066             :  * join_search_one_level().  We could dispense with this test if we were
    1067             :  * willing to try bushy plans in the "last ditch" case, but that seems much
    1068             :  * less efficient.
    1069             :  */
    1070             : bool
    1071       68292 : have_join_order_restriction(PlannerInfo *root,
    1072             :                             RelOptInfo *rel1, RelOptInfo *rel2)
    1073             : {
    1074       68292 :     bool        result = false;
    1075             :     ListCell   *l;
    1076             : 
    1077             :     /*
    1078             :      * If either side has a direct lateral reference to the other, attempt the
    1079             :      * join regardless of outer-join considerations.
    1080             :      */
    1081      127400 :     if (bms_overlap(rel1->relids, rel2->direct_lateral_relids) ||
    1082       59108 :         bms_overlap(rel2->relids, rel1->direct_lateral_relids))
    1083        9958 :         return true;
    1084             : 
    1085             :     /*
    1086             :      * Likewise, if both rels are needed to compute some PlaceHolderVar,
    1087             :      * attempt the join regardless of outer-join considerations.  (This is not
    1088             :      * very desirable, because a PHV with a large eval_at set will cause a lot
    1089             :      * of probably-useless joins to be considered, but failing to do this can
    1090             :      * cause us to fail to construct a plan at all.)
    1091             :      */
    1092       59886 :     foreach(l, root->placeholder_list)
    1093             :     {
    1094        1606 :         PlaceHolderInfo *phinfo = (PlaceHolderInfo *) lfirst(l);
    1095             : 
    1096        1978 :         if (bms_is_subset(rel1->relids, phinfo->ph_eval_at) &&
    1097         372 :             bms_is_subset(rel2->relids, phinfo->ph_eval_at))
    1098          54 :             return true;
    1099             :     }
    1100             : 
    1101             :     /*
    1102             :      * It's possible that the rels correspond to the left and right sides of a
    1103             :      * degenerate outer join, that is, one with no joinclause mentioning the
    1104             :      * non-nullable side; in which case we should force the join to occur.
    1105             :      *
    1106             :      * Also, the two rels could represent a clauseless join that has to be
    1107             :      * completed to build up the LHS or RHS of an outer join.
    1108             :      */
    1109      163208 :     foreach(l, root->join_info_list)
    1110             :     {
    1111      106154 :         SpecialJoinInfo *sjinfo = (SpecialJoinInfo *) lfirst(l);
    1112             : 
    1113             :         /* ignore full joins --- other mechanisms handle them */
    1114      106154 :         if (sjinfo->jointype == JOIN_FULL)
    1115          42 :             continue;
    1116             : 
    1117             :         /* Can we perform the SJ with these rels? */
    1118      133992 :         if (bms_is_subset(sjinfo->min_lefthand, rel1->relids) &&
    1119       27880 :             bms_is_subset(sjinfo->min_righthand, rel2->relids))
    1120             :         {
    1121         926 :             result = true;
    1122         926 :             break;
    1123             :         }
    1124      109694 :         if (bms_is_subset(sjinfo->min_lefthand, rel2->relids) &&
    1125        4508 :             bms_is_subset(sjinfo->min_righthand, rel1->relids))
    1126             :         {
    1127         162 :             result = true;
    1128         162 :             break;
    1129             :         }
    1130             : 
    1131             :         /*
    1132             :          * Might we need to join these rels to complete the RHS?  We have to
    1133             :          * use "overlap" tests since either rel might include a lower SJ that
    1134             :          * has been proven to commute with this one.
    1135             :          */
    1136      130458 :         if (bms_overlap(sjinfo->min_righthand, rel1->relids) &&
    1137       25434 :             bms_overlap(sjinfo->min_righthand, rel2->relids))
    1138             :         {
    1139         108 :             result = true;
    1140         108 :             break;
    1141             :         }
    1142             : 
    1143             :         /* Likewise for the LHS. */
    1144      134594 :         if (bms_overlap(sjinfo->min_lefthand, rel1->relids) &&
    1145       29678 :             bms_overlap(sjinfo->min_lefthand, rel2->relids))
    1146             :         {
    1147          30 :             result = true;
    1148          30 :             break;
    1149             :         }
    1150             :     }
    1151             : 
    1152             :     /*
    1153             :      * We do not force the join to occur if either input rel can legally be
    1154             :      * joined to anything else using joinclauses.  This essentially means that
    1155             :      * clauseless bushy joins are put off as long as possible. The reason is
    1156             :      * that when there is a join order restriction high up in the join tree
    1157             :      * (that is, with many rels inside the LHS or RHS), we would otherwise
    1158             :      * expend lots of effort considering very stupid join combinations within
    1159             :      * its LHS or RHS.
    1160             :      */
    1161       58280 :     if (result)
    1162             :     {
    1163        2356 :         if (has_legal_joinclause(root, rel1) ||
    1164        1130 :             has_legal_joinclause(root, rel2))
    1165         210 :             result = false;
    1166             :     }
    1167             : 
    1168       58280 :     return result;
    1169             : }
    1170             : 
    1171             : 
    1172             : /*
    1173             :  * has_join_restriction
    1174             :  *      Detect whether the specified relation has join-order restrictions,
    1175             :  *      due to being inside an outer join or an IN (sub-SELECT),
    1176             :  *      or participating in any LATERAL references or multi-rel PHVs.
    1177             :  *
    1178             :  * Essentially, this tests whether have_join_order_restriction() could
    1179             :  * succeed with this rel and some other one.  It's OK if we sometimes
    1180             :  * say "true" incorrectly.  (Therefore, we don't bother with the relatively
    1181             :  * expensive has_legal_joinclause test.)
    1182             :  */
    1183             : static bool
    1184       28726 : has_join_restriction(PlannerInfo *root, RelOptInfo *rel)
    1185             : {
    1186             :     ListCell   *l;
    1187             : 
    1188       28726 :     if (rel->lateral_relids != NULL || rel->lateral_referencers != NULL)
    1189       17218 :         return true;
    1190             : 
    1191       12138 :     foreach(l, root->placeholder_list)
    1192             :     {
    1193         666 :         PlaceHolderInfo *phinfo = (PlaceHolderInfo *) lfirst(l);
    1194             : 
    1195         666 :         if (bms_is_subset(rel->relids, phinfo->ph_eval_at) &&
    1196         144 :             !bms_equal(rel->relids, phinfo->ph_eval_at))
    1197          36 :             return true;
    1198             :     }
    1199             : 
    1200       12224 :     foreach(l, root->join_info_list)
    1201             :     {
    1202        2568 :         SpecialJoinInfo *sjinfo = (SpecialJoinInfo *) lfirst(l);
    1203             : 
    1204             :         /* ignore full joins --- other mechanisms preserve their ordering */
    1205        2568 :         if (sjinfo->jointype == JOIN_FULL)
    1206          86 :             continue;
    1207             : 
    1208             :         /* ignore if SJ is already contained in rel */
    1209        3846 :         if (bms_is_subset(sjinfo->min_lefthand, rel->relids) &&
    1210        1364 :             bms_is_subset(sjinfo->min_righthand, rel->relids))
    1211         354 :             continue;
    1212             : 
    1213             :         /* restricted if it overlaps LHS or RHS, but doesn't contain SJ */
    1214        3222 :         if (bms_overlap(sjinfo->min_lefthand, rel->relids) ||
    1215        1094 :             bms_overlap(sjinfo->min_righthand, rel->relids))
    1216        1816 :             return true;
    1217             :     }
    1218             : 
    1219        9656 :     return false;
    1220             : }
    1221             : 
    1222             : 
    1223             : /*
    1224             :  * has_legal_joinclause
    1225             :  *      Detect whether the specified relation can legally be joined
    1226             :  *      to any other rels using join clauses.
    1227             :  *
    1228             :  * We consider only joins to single other relations in the current
    1229             :  * initial_rels list.  This is sufficient to get a "true" result in most real
    1230             :  * queries, and an occasional erroneous "false" will only cost a bit more
    1231             :  * planning time.  The reason for this limitation is that considering joins to
    1232             :  * other joins would require proving that the other join rel can legally be
    1233             :  * formed, which seems like too much trouble for something that's only a
    1234             :  * heuristic to save planning time.  (Note: we must look at initial_rels
    1235             :  * and not all of the query, since when we are planning a sub-joinlist we
    1236             :  * may be forced to make clauseless joins within initial_rels even though
    1237             :  * there are join clauses linking to other parts of the query.)
    1238             :  */
    1239             : static bool
    1240        2356 : has_legal_joinclause(PlannerInfo *root, RelOptInfo *rel)
    1241             : {
    1242             :     ListCell   *lc;
    1243             : 
    1244        8676 :     foreach(lc, root->initial_rels)
    1245             :     {
    1246        6530 :         RelOptInfo *rel2 = (RelOptInfo *) lfirst(lc);
    1247             : 
    1248             :         /* ignore rels that are already in "rel" */
    1249        6530 :         if (bms_overlap(rel->relids, rel2->relids))
    1250        2788 :             continue;
    1251             : 
    1252        3742 :         if (have_relevant_joinclause(root, rel, rel2))
    1253             :         {
    1254             :             Relids      joinrelids;
    1255             :             SpecialJoinInfo *sjinfo;
    1256             :             bool        reversed;
    1257             : 
    1258             :             /* join_is_legal needs relids of the union */
    1259         318 :             joinrelids = bms_union(rel->relids, rel2->relids);
    1260             : 
    1261         318 :             if (join_is_legal(root, rel, rel2, joinrelids,
    1262             :                               &sjinfo, &reversed))
    1263             :             {
    1264             :                 /* Yes, this will work */
    1265         210 :                 bms_free(joinrelids);
    1266         210 :                 return true;
    1267             :             }
    1268             : 
    1269         108 :             bms_free(joinrelids);
    1270             :         }
    1271             :     }
    1272             : 
    1273        2146 :     return false;
    1274             : }
    1275             : 
    1276             : 
    1277             : /*
    1278             :  * There's a pitfall for creating parameterized nestloops: suppose the inner
    1279             :  * rel (call it A) has a parameter that is a PlaceHolderVar, and that PHV's
    1280             :  * minimum eval_at set includes the outer rel (B) and some third rel (C).
    1281             :  * We might think we could create a B/A nestloop join that's parameterized by
    1282             :  * C.  But we would end up with a plan in which the PHV's expression has to be
    1283             :  * evaluated as a nestloop parameter at the B/A join; and the executor is only
    1284             :  * set up to handle simple Vars as NestLoopParams.  Rather than add complexity
    1285             :  * and overhead to the executor for such corner cases, it seems better to
    1286             :  * forbid the join.  (Note that we can still make use of A's parameterized
    1287             :  * path with pre-joined B+C as the outer rel.  have_join_order_restriction()
    1288             :  * ensures that we will consider making such a join even if there are not
    1289             :  * other reasons to do so.)
    1290             :  *
    1291             :  * So we check whether any PHVs used in the query could pose such a hazard.
    1292             :  * We don't have any simple way of checking whether a risky PHV would actually
    1293             :  * be used in the inner plan, and the case is so unusual that it doesn't seem
    1294             :  * worth working very hard on it.
    1295             :  *
    1296             :  * This needs to be checked in two places.  If the inner rel's minimum
    1297             :  * parameterization would trigger the restriction, then join_is_legal() should
    1298             :  * reject the join altogether, because there will be no workable paths for it.
    1299             :  * But joinpath.c has to check again for every proposed nestloop path, because
    1300             :  * the inner path might have more than the minimum parameterization, causing
    1301             :  * some PHV to be dangerous for it that otherwise wouldn't be.
    1302             :  */
    1303             : bool
    1304       42600 : have_dangerous_phv(PlannerInfo *root,
    1305             :                    Relids outer_relids, Relids inner_params)
    1306             : {
    1307             :     ListCell   *lc;
    1308             : 
    1309       45414 :     foreach(lc, root->placeholder_list)
    1310             :     {
    1311        3066 :         PlaceHolderInfo *phinfo = (PlaceHolderInfo *) lfirst(lc);
    1312             : 
    1313        3066 :         if (!bms_is_subset(phinfo->ph_eval_at, inner_params))
    1314        2262 :             continue;           /* ignore, could not be a nestloop param */
    1315         804 :         if (!bms_overlap(phinfo->ph_eval_at, outer_relids))
    1316         192 :             continue;           /* ignore, not relevant to this join */
    1317         612 :         if (bms_is_subset(phinfo->ph_eval_at, outer_relids))
    1318         360 :             continue;           /* safe, it can be eval'd within outerrel */
    1319             :         /* Otherwise, it's potentially unsafe, so reject the join */
    1320         252 :         return true;
    1321             :     }
    1322             : 
    1323             :     /* OK to perform the join */
    1324       42348 :     return false;
    1325             : }
    1326             : 
    1327             : 
    1328             : /*
    1329             :  * is_dummy_rel --- has relation been proven empty?
    1330             :  */
    1331             : bool
    1332     2079504 : is_dummy_rel(RelOptInfo *rel)
    1333             : {
    1334             :     Path       *path;
    1335             : 
    1336             :     /*
    1337             :      * A rel that is known dummy will have just one path that is a childless
    1338             :      * Append.  (Even if somehow it has more paths, a childless Append will
    1339             :      * have cost zero and hence should be at the front of the pathlist.)
    1340             :      */
    1341     2079504 :     if (rel->pathlist == NIL)
    1342     1140162 :         return false;
    1343      939342 :     path = (Path *) linitial(rel->pathlist);
    1344             : 
    1345             :     /*
    1346             :      * Initially, a dummy path will just be a childless Append.  But in later
    1347             :      * planning stages we might stick a ProjectSetPath and/or ProjectionPath
    1348             :      * on top, since Append can't project.  Rather than make assumptions about
    1349             :      * which combinations can occur, just descend through whatever we find.
    1350             :      */
    1351             :     for (;;)
    1352             :     {
    1353      968730 :         if (IsA(path, ProjectionPath))
    1354       25816 :             path = ((ProjectionPath *) path)->subpath;
    1355      942914 :         else if (IsA(path, ProjectSetPath))
    1356        3572 :             path = ((ProjectSetPath *) path)->subpath;
    1357             :         else
    1358      939342 :             break;
    1359             :     }
    1360      939342 :     if (IS_DUMMY_APPEND(path))
    1361        3524 :         return true;
    1362      935818 :     return false;
    1363             : }
    1364             : 
    1365             : /*
    1366             :  * Mark a relation as proven empty.
    1367             :  *
    1368             :  * During GEQO planning, this can get invoked more than once on the same
    1369             :  * baserel struct, so it's worth checking to see if the rel is already marked
    1370             :  * dummy.
    1371             :  *
    1372             :  * Also, when called during GEQO join planning, we are in a short-lived
    1373             :  * memory context.  We must make sure that the dummy path attached to a
    1374             :  * baserel survives the GEQO cycle, else the baserel is trashed for future
    1375             :  * GEQO cycles.  On the other hand, when we are marking a joinrel during GEQO,
    1376             :  * we don't want the dummy path to clutter the main planning context.  Upshot
    1377             :  * is that the best solution is to explicitly make the dummy path in the same
    1378             :  * context the given RelOptInfo is in.
    1379             :  */
    1380             : void
    1381         524 : mark_dummy_rel(RelOptInfo *rel)
    1382             : {
    1383             :     MemoryContext oldcontext;
    1384             : 
    1385             :     /* Already marked? */
    1386         524 :     if (is_dummy_rel(rel))
    1387          12 :         return;
    1388             : 
    1389             :     /* No, so choose correct context to make the dummy path in */
    1390         512 :     oldcontext = MemoryContextSwitchTo(GetMemoryChunkContext(rel));
    1391             : 
    1392             :     /* Set dummy size estimate */
    1393         512 :     rel->rows = 0;
    1394             : 
    1395             :     /* Evict any previously chosen paths */
    1396         512 :     rel->pathlist = NIL;
    1397         512 :     rel->partial_pathlist = NIL;
    1398             : 
    1399             :     /* Set up the dummy path */
    1400         512 :     add_path(rel, (Path *) create_append_path(NULL, rel, NIL, NIL,
    1401             :                                               NIL, rel->lateral_relids,
    1402             :                                               0, false, -1));
    1403             : 
    1404             :     /* Set or update cheapest_total_path and related fields */
    1405         512 :     set_cheapest(rel);
    1406             : 
    1407         512 :     MemoryContextSwitchTo(oldcontext);
    1408             : }
    1409             : 
    1410             : 
    1411             : /*
    1412             :  * restriction_is_constant_false --- is a restrictlist just FALSE?
    1413             :  *
    1414             :  * In cases where a qual is provably constant FALSE, eval_const_expressions
    1415             :  * will generally have thrown away anything that's ANDed with it.  In outer
    1416             :  * join situations this will leave us computing cartesian products only to
    1417             :  * decide there's no match for an outer row, which is pretty stupid.  So,
    1418             :  * we need to detect the case.
    1419             :  *
    1420             :  * If only_pushed_down is true, then consider only quals that are pushed-down
    1421             :  * from the point of view of the joinrel.
    1422             :  */
    1423             : static bool
    1424      356558 : restriction_is_constant_false(List *restrictlist,
    1425             :                               RelOptInfo *joinrel,
    1426             :                               bool only_pushed_down)
    1427             : {
    1428             :     ListCell   *lc;
    1429             : 
    1430             :     /*
    1431             :      * Despite the above comment, the restriction list we see here might
    1432             :      * possibly have other members besides the FALSE constant, since other
    1433             :      * quals could get "pushed down" to the outer join level.  So we check
    1434             :      * each member of the list.
    1435             :      */
    1436      741408 :     foreach(lc, restrictlist)
    1437             :     {
    1438      385230 :         RestrictInfo *rinfo = lfirst_node(RestrictInfo, lc);
    1439             : 
    1440      385230 :         if (only_pushed_down && !RINFO_IS_PUSHED_DOWN(rinfo, joinrel->relids))
    1441      108858 :             continue;
    1442             : 
    1443      276372 :         if (rinfo->clause && IsA(rinfo->clause, Const))
    1444             :         {
    1445        4108 :             Const      *con = (Const *) rinfo->clause;
    1446             : 
    1447             :             /* constant NULL is as good as constant FALSE for our purposes */
    1448        4108 :             if (con->constisnull)
    1449         380 :                 return true;
    1450        4000 :             if (!DatumGetBool(con->constvalue))
    1451         272 :                 return true;
    1452             :         }
    1453             :     }
    1454      356178 :     return false;
    1455             : }
    1456             : 
    1457             : /*
    1458             :  * Assess whether join between given two partitioned relations can be broken
    1459             :  * down into joins between matching partitions; a technique called
    1460             :  * "partitionwise join"
    1461             :  *
    1462             :  * Partitionwise join is possible when a. Joining relations have same
    1463             :  * partitioning scheme b. There exists an equi-join between the partition keys
    1464             :  * of the two relations.
    1465             :  *
    1466             :  * Partitionwise join is planned as follows (details: optimizer/README.)
    1467             :  *
    1468             :  * 1. Create the RelOptInfos for joins between matching partitions i.e
    1469             :  * child-joins and add paths to them.
    1470             :  *
    1471             :  * 2. Construct Append or MergeAppend paths across the set of child joins.
    1472             :  * This second phase is implemented by generate_partitionwise_join_paths().
    1473             :  *
    1474             :  * The RelOptInfo, SpecialJoinInfo and restrictlist for each child join are
    1475             :  * obtained by translating the respective parent join structures.
    1476             :  */
    1477             : static void
    1478      262874 : try_partitionwise_join(PlannerInfo *root, RelOptInfo *rel1, RelOptInfo *rel2,
    1479             :                        RelOptInfo *joinrel, SpecialJoinInfo *parent_sjinfo,
    1480             :                        List *parent_restrictlist)
    1481             : {
    1482      262874 :     bool        rel1_is_simple = IS_SIMPLE_REL(rel1);
    1483      262874 :     bool        rel2_is_simple = IS_SIMPLE_REL(rel2);
    1484      262874 :     List       *parts1 = NIL;
    1485      262874 :     List       *parts2 = NIL;
    1486      262874 :     ListCell   *lcr1 = NULL;
    1487      262874 :     ListCell   *lcr2 = NULL;
    1488             :     int         cnt_parts;
    1489             : 
    1490             :     /* Guard against stack overflow due to overly deep partition hierarchy. */
    1491      262874 :     check_stack_depth();
    1492             : 
    1493             :     /* Nothing to do, if the join relation is not partitioned. */
    1494      262874 :     if (joinrel->part_scheme == NULL || joinrel->nparts == 0)
    1495      260940 :         return;
    1496             : 
    1497             :     /* The join relation should have consider_partitionwise_join set. */
    1498             :     Assert(joinrel->consider_partitionwise_join);
    1499             : 
    1500             :     /*
    1501             :      * We can not perform partitionwise join if either of the joining
    1502             :      * relations is not partitioned.
    1503             :      */
    1504        2072 :     if (!IS_PARTITIONED_REL(rel1) || !IS_PARTITIONED_REL(rel2))
    1505          18 :         return;
    1506             : 
    1507             :     Assert(REL_HAS_ALL_PART_PROPS(rel1) && REL_HAS_ALL_PART_PROPS(rel2));
    1508             : 
    1509             :     /* The joining relations should have consider_partitionwise_join set. */
    1510             :     Assert(rel1->consider_partitionwise_join &&
    1511             :            rel2->consider_partitionwise_join);
    1512             : 
    1513             :     /*
    1514             :      * The partition scheme of the join relation should match that of the
    1515             :      * joining relations.
    1516             :      */
    1517             :     Assert(joinrel->part_scheme == rel1->part_scheme &&
    1518             :            joinrel->part_scheme == rel2->part_scheme);
    1519             : 
    1520             :     Assert(!(joinrel->partbounds_merged && (joinrel->nparts <= 0)));
    1521             : 
    1522        2054 :     compute_partition_bounds(root, rel1, rel2, joinrel, parent_sjinfo,
    1523             :                              &parts1, &parts2);
    1524             : 
    1525        2054 :     if (joinrel->partbounds_merged)
    1526             :     {
    1527         768 :         lcr1 = list_head(parts1);
    1528         768 :         lcr2 = list_head(parts2);
    1529             :     }
    1530             : 
    1531             :     /*
    1532             :      * Create child-join relations for this partitioned join, if those don't
    1533             :      * exist. Add paths to child-joins for a pair of child relations
    1534             :      * corresponding to the given pair of parent relations.
    1535             :      */
    1536        7202 :     for (cnt_parts = 0; cnt_parts < joinrel->nparts; cnt_parts++)
    1537             :     {
    1538             :         RelOptInfo *child_rel1;
    1539             :         RelOptInfo *child_rel2;
    1540             :         bool        rel1_empty;
    1541             :         bool        rel2_empty;
    1542             :         SpecialJoinInfo *child_sjinfo;
    1543             :         List       *child_restrictlist;
    1544             :         RelOptInfo *child_joinrel;
    1545             :         AppendRelInfo **appinfos;
    1546             :         int         nappinfos;
    1547             : 
    1548        5268 :         if (joinrel->partbounds_merged)
    1549             :         {
    1550        2010 :             child_rel1 = lfirst_node(RelOptInfo, lcr1);
    1551        2010 :             child_rel2 = lfirst_node(RelOptInfo, lcr2);
    1552        2010 :             lcr1 = lnext(parts1, lcr1);
    1553        2010 :             lcr2 = lnext(parts2, lcr2);
    1554             :         }
    1555             :         else
    1556             :         {
    1557        3258 :             child_rel1 = rel1->part_rels[cnt_parts];
    1558        3258 :             child_rel2 = rel2->part_rels[cnt_parts];
    1559             :         }
    1560             : 
    1561        5268 :         rel1_empty = (child_rel1 == NULL || IS_DUMMY_REL(child_rel1));
    1562        5268 :         rel2_empty = (child_rel2 == NULL || IS_DUMMY_REL(child_rel2));
    1563             : 
    1564             :         /*
    1565             :          * Check for cases where we can prove that this segment of the join
    1566             :          * returns no rows, due to one or both inputs being empty (including
    1567             :          * inputs that have been pruned away entirely).  If so just ignore it.
    1568             :          * These rules are equivalent to populate_joinrel_with_paths's rules
    1569             :          * for dummy input relations.
    1570             :          */
    1571        5268 :         switch (parent_sjinfo->jointype)
    1572             :         {
    1573        2462 :             case JOIN_INNER:
    1574             :             case JOIN_SEMI:
    1575        2462 :                 if (rel1_empty || rel2_empty)
    1576          52 :                     continue;   /* ignore this join segment */
    1577        2438 :                 break;
    1578        2084 :             case JOIN_LEFT:
    1579             :             case JOIN_ANTI:
    1580        2084 :                 if (rel1_empty)
    1581          28 :                     continue;   /* ignore this join segment */
    1582        2056 :                 break;
    1583         722 :             case JOIN_FULL:
    1584         722 :                 if (rel1_empty && rel2_empty)
    1585           0 :                     continue;   /* ignore this join segment */
    1586         722 :                 break;
    1587           0 :             default:
    1588             :                 /* other values not expected here */
    1589           0 :                 elog(ERROR, "unrecognized join type: %d",
    1590             :                      (int) parent_sjinfo->jointype);
    1591             :                 break;
    1592             :         }
    1593             : 
    1594             :         /*
    1595             :          * If a child has been pruned entirely then we can't generate paths
    1596             :          * for it, so we have to reject partitionwise joining unless we were
    1597             :          * able to eliminate this partition above.
    1598             :          */
    1599        5216 :         if (child_rel1 == NULL || child_rel2 == NULL)
    1600             :         {
    1601             :             /*
    1602             :              * Mark the joinrel as unpartitioned so that later functions treat
    1603             :              * it correctly.
    1604             :              */
    1605         120 :             joinrel->nparts = 0;
    1606         120 :             return;
    1607             :         }
    1608             : 
    1609             :         /*
    1610             :          * If a leaf relation has consider_partitionwise_join=false, it means
    1611             :          * that it's a dummy relation for which we skipped setting up tlist
    1612             :          * expressions and adding EC members in set_append_rel_size(), so
    1613             :          * again we have to fail here.
    1614             :          */
    1615        5096 :         if (rel1_is_simple && !child_rel1->consider_partitionwise_join)
    1616             :         {
    1617             :             Assert(child_rel1->reloptkind == RELOPT_OTHER_MEMBER_REL);
    1618             :             Assert(IS_DUMMY_REL(child_rel1));
    1619           0 :             joinrel->nparts = 0;
    1620           0 :             return;
    1621             :         }
    1622        5096 :         if (rel2_is_simple && !child_rel2->consider_partitionwise_join)
    1623             :         {
    1624             :             Assert(child_rel2->reloptkind == RELOPT_OTHER_MEMBER_REL);
    1625             :             Assert(IS_DUMMY_REL(child_rel2));
    1626           0 :             joinrel->nparts = 0;
    1627           0 :             return;
    1628             :         }
    1629             : 
    1630             :         /* We should never try to join two overlapping sets of rels. */
    1631             :         Assert(!bms_overlap(child_rel1->relids, child_rel2->relids));
    1632             : 
    1633             :         /*
    1634             :          * Construct SpecialJoinInfo from parent join relations's
    1635             :          * SpecialJoinInfo.
    1636             :          */
    1637        5096 :         child_sjinfo = build_child_join_sjinfo(root, parent_sjinfo,
    1638             :                                                child_rel1->relids,
    1639             :                                                child_rel2->relids);
    1640             : 
    1641             :         /* Find the AppendRelInfo structures */
    1642        5096 :         appinfos = find_appinfos_by_relids(root,
    1643        5096 :                                            bms_union(child_rel1->relids,
    1644        5096 :                                                      child_rel2->relids),
    1645             :                                            &nappinfos);
    1646             : 
    1647             :         /*
    1648             :          * Construct restrictions applicable to the child join from those
    1649             :          * applicable to the parent join.
    1650             :          */
    1651             :         child_restrictlist =
    1652        5096 :             (List *) adjust_appendrel_attrs(root,
    1653             :                                             (Node *) parent_restrictlist,
    1654             :                                             nappinfos, appinfos);
    1655             : 
    1656             :         /* Find or construct the child join's RelOptInfo */
    1657        5096 :         child_joinrel = joinrel->part_rels[cnt_parts];
    1658        5096 :         if (!child_joinrel)
    1659             :         {
    1660        4624 :             child_joinrel = build_child_join_rel(root, child_rel1, child_rel2,
    1661             :                                                  joinrel, child_restrictlist,
    1662             :                                                  child_sjinfo);
    1663        4624 :             joinrel->part_rels[cnt_parts] = child_joinrel;
    1664        4624 :             joinrel->live_parts = bms_add_member(joinrel->live_parts, cnt_parts);
    1665        4624 :             joinrel->all_partrels = bms_add_members(joinrel->all_partrels,
    1666        4624 :                                                     child_joinrel->relids);
    1667             :         }
    1668             : 
    1669             :         /* Assert we got the right one */
    1670             :         Assert(bms_equal(child_joinrel->relids,
    1671             :                          adjust_child_relids(joinrel->relids,
    1672             :                                              nappinfos, appinfos)));
    1673             : 
    1674             :         /* And make paths for the child join */
    1675        5096 :         populate_joinrel_with_paths(root, child_rel1, child_rel2,
    1676             :                                     child_joinrel, child_sjinfo,
    1677             :                                     child_restrictlist);
    1678             : 
    1679        5096 :         pfree(appinfos);
    1680        5096 :         free_child_join_sjinfo(child_sjinfo);
    1681             :     }
    1682             : }
    1683             : 
    1684             : /*
    1685             :  * Construct the SpecialJoinInfo for a child-join by translating
    1686             :  * SpecialJoinInfo for the join between parents. left_relids and right_relids
    1687             :  * are the relids of left and right side of the join respectively.
    1688             :  *
    1689             :  * If translations are added to or removed from this function, consider
    1690             :  * updating free_child_join_sjinfo() accordingly.
    1691             :  */
    1692             : static SpecialJoinInfo *
    1693        5096 : build_child_join_sjinfo(PlannerInfo *root, SpecialJoinInfo *parent_sjinfo,
    1694             :                         Relids left_relids, Relids right_relids)
    1695             : {
    1696        5096 :     SpecialJoinInfo *sjinfo = makeNode(SpecialJoinInfo);
    1697             :     AppendRelInfo **left_appinfos;
    1698             :     int         left_nappinfos;
    1699             :     AppendRelInfo **right_appinfos;
    1700             :     int         right_nappinfos;
    1701             : 
    1702             :     /* Dummy SpecialJoinInfos can be created without any translation. */
    1703        5096 :     if (parent_sjinfo->jointype == JOIN_INNER)
    1704             :     {
    1705             :         Assert(parent_sjinfo->ojrelid == 0);
    1706        2042 :         init_dummy_sjinfo(sjinfo, left_relids, right_relids);
    1707        2042 :         return sjinfo;
    1708             :     }
    1709             : 
    1710        3054 :     memcpy(sjinfo, parent_sjinfo, sizeof(SpecialJoinInfo));
    1711        3054 :     left_appinfos = find_appinfos_by_relids(root, left_relids,
    1712             :                                             &left_nappinfos);
    1713        3054 :     right_appinfos = find_appinfos_by_relids(root, right_relids,
    1714             :                                              &right_nappinfos);
    1715             : 
    1716        3054 :     sjinfo->min_lefthand = adjust_child_relids(sjinfo->min_lefthand,
    1717             :                                                left_nappinfos, left_appinfos);
    1718        3054 :     sjinfo->min_righthand = adjust_child_relids(sjinfo->min_righthand,
    1719             :                                                 right_nappinfos,
    1720             :                                                 right_appinfos);
    1721        3054 :     sjinfo->syn_lefthand = adjust_child_relids(sjinfo->syn_lefthand,
    1722             :                                                left_nappinfos, left_appinfos);
    1723        3054 :     sjinfo->syn_righthand = adjust_child_relids(sjinfo->syn_righthand,
    1724             :                                                 right_nappinfos,
    1725             :                                                 right_appinfos);
    1726             :     /* outer-join relids need no adjustment */
    1727        6108 :     sjinfo->semi_rhs_exprs = (List *) adjust_appendrel_attrs(root,
    1728        3054 :                                                              (Node *) sjinfo->semi_rhs_exprs,
    1729             :                                                              right_nappinfos,
    1730             :                                                              right_appinfos);
    1731             : 
    1732        3054 :     pfree(left_appinfos);
    1733        3054 :     pfree(right_appinfos);
    1734             : 
    1735        3054 :     return sjinfo;
    1736             : }
    1737             : 
    1738             : /*
    1739             :  * free_child_join_sjinfo
    1740             :  *      Free memory consumed by a SpecialJoinInfo created by
    1741             :  *      build_child_join_sjinfo()
    1742             :  *
    1743             :  * Only members that are translated copies of their counterpart in the parent
    1744             :  * SpecialJoinInfo are freed here.
    1745             :  */
    1746             : static void
    1747        5096 : free_child_join_sjinfo(SpecialJoinInfo *sjinfo)
    1748             : {
    1749             :     /*
    1750             :      * Dummy SpecialJoinInfos of inner joins do not have any translated fields
    1751             :      * and hence no fields that to be freed.
    1752             :      */
    1753        5096 :     if (sjinfo->jointype != JOIN_INNER)
    1754             :     {
    1755        3054 :         bms_free(sjinfo->min_lefthand);
    1756        3054 :         bms_free(sjinfo->min_righthand);
    1757        3054 :         bms_free(sjinfo->syn_lefthand);
    1758        3054 :         bms_free(sjinfo->syn_righthand);
    1759             : 
    1760             :         /*
    1761             :          * semi_rhs_exprs may in principle be freed, but a simple pfree() does
    1762             :          * not suffice, so we leave it alone.
    1763             :          */
    1764             :     }
    1765             : 
    1766        5096 :     pfree(sjinfo);
    1767        5096 : }
    1768             : 
    1769             : /*
    1770             :  * compute_partition_bounds
    1771             :  *      Compute the partition bounds for a join rel from those for inputs
    1772             :  */
    1773             : static void
    1774        2054 : compute_partition_bounds(PlannerInfo *root, RelOptInfo *rel1,
    1775             :                          RelOptInfo *rel2, RelOptInfo *joinrel,
    1776             :                          SpecialJoinInfo *parent_sjinfo,
    1777             :                          List **parts1, List **parts2)
    1778             : {
    1779             :     /*
    1780             :      * If we don't have the partition bounds for the join rel yet, try to
    1781             :      * compute those along with pairs of partitions to be joined.
    1782             :      */
    1783        2054 :     if (joinrel->nparts == -1)
    1784             :     {
    1785        1890 :         PartitionScheme part_scheme = joinrel->part_scheme;
    1786        1890 :         PartitionBoundInfo boundinfo = NULL;
    1787        1890 :         int         nparts = 0;
    1788             : 
    1789             :         Assert(joinrel->boundinfo == NULL);
    1790             :         Assert(joinrel->part_rels == NULL);
    1791             : 
    1792             :         /*
    1793             :          * See if the partition bounds for inputs are exactly the same, in
    1794             :          * which case we don't need to work hard: the join rel will have the
    1795             :          * same partition bounds as inputs, and the partitions with the same
    1796             :          * cardinal positions will form the pairs.
    1797             :          *
    1798             :          * Note: even in cases where one or both inputs have merged bounds, it
    1799             :          * would be possible for both the bounds to be exactly the same, but
    1800             :          * it seems unlikely to be worth the cycles to check.
    1801             :          */
    1802        1890 :         if (!rel1->partbounds_merged &&
    1803        1830 :             !rel2->partbounds_merged &&
    1804        3402 :             rel1->nparts == rel2->nparts &&
    1805        1572 :             partition_bounds_equal(part_scheme->partnatts,
    1806             :                                    part_scheme->parttyplen,
    1807             :                                    part_scheme->parttypbyval,
    1808             :                                    rel1->boundinfo, rel2->boundinfo))
    1809             :         {
    1810        1044 :             boundinfo = rel1->boundinfo;
    1811        1044 :             nparts = rel1->nparts;
    1812             :         }
    1813             :         else
    1814             :         {
    1815             :             /* Try merging the partition bounds for inputs. */
    1816         846 :             boundinfo = partition_bounds_merge(part_scheme->partnatts,
    1817         846 :                                                part_scheme->partsupfunc,
    1818             :                                                part_scheme->partcollation,
    1819             :                                                rel1, rel2,
    1820             :                                                parent_sjinfo->jointype,
    1821             :                                                parts1, parts2);
    1822         846 :             if (boundinfo == NULL)
    1823             :             {
    1824         114 :                 joinrel->nparts = 0;
    1825         114 :                 return;
    1826             :             }
    1827         732 :             nparts = list_length(*parts1);
    1828         732 :             joinrel->partbounds_merged = true;
    1829             :         }
    1830             : 
    1831             :         Assert(nparts > 0);
    1832        1776 :         joinrel->boundinfo = boundinfo;
    1833        1776 :         joinrel->nparts = nparts;
    1834        1776 :         joinrel->part_rels =
    1835        1776 :             (RelOptInfo **) palloc0(sizeof(RelOptInfo *) * nparts);
    1836             :     }
    1837             :     else
    1838             :     {
    1839             :         Assert(joinrel->nparts > 0);
    1840             :         Assert(joinrel->boundinfo);
    1841             :         Assert(joinrel->part_rels);
    1842             : 
    1843             :         /*
    1844             :          * If the join rel's partbounds_merged flag is true, it means inputs
    1845             :          * are not guaranteed to have the same partition bounds, therefore we
    1846             :          * can't assume that the partitions at the same cardinal positions
    1847             :          * form the pairs; let get_matching_part_pairs() generate the pairs.
    1848             :          * Otherwise, nothing to do since we can assume that.
    1849             :          */
    1850         164 :         if (joinrel->partbounds_merged)
    1851             :         {
    1852          36 :             get_matching_part_pairs(root, joinrel, rel1, rel2,
    1853             :                                     parts1, parts2);
    1854             :             Assert(list_length(*parts1) == joinrel->nparts);
    1855             :             Assert(list_length(*parts2) == joinrel->nparts);
    1856             :         }
    1857             :     }
    1858             : }
    1859             : 
    1860             : /*
    1861             :  * get_matching_part_pairs
    1862             :  *      Generate pairs of partitions to be joined from inputs
    1863             :  */
    1864             : static void
    1865          36 : get_matching_part_pairs(PlannerInfo *root, RelOptInfo *joinrel,
    1866             :                         RelOptInfo *rel1, RelOptInfo *rel2,
    1867             :                         List **parts1, List **parts2)
    1868             : {
    1869          36 :     bool        rel1_is_simple = IS_SIMPLE_REL(rel1);
    1870          36 :     bool        rel2_is_simple = IS_SIMPLE_REL(rel2);
    1871             :     int         cnt_parts;
    1872             : 
    1873          36 :     *parts1 = NIL;
    1874          36 :     *parts2 = NIL;
    1875             : 
    1876         132 :     for (cnt_parts = 0; cnt_parts < joinrel->nparts; cnt_parts++)
    1877             :     {
    1878          96 :         RelOptInfo *child_joinrel = joinrel->part_rels[cnt_parts];
    1879             :         RelOptInfo *child_rel1;
    1880             :         RelOptInfo *child_rel2;
    1881             :         Relids      child_relids1;
    1882             :         Relids      child_relids2;
    1883             : 
    1884             :         /*
    1885             :          * If this segment of the join is empty, it means that this segment
    1886             :          * was ignored when previously creating child-join paths for it in
    1887             :          * try_partitionwise_join() as it would not contribute to the join
    1888             :          * result, due to one or both inputs being empty; add NULL to each of
    1889             :          * the given lists so that this segment will be ignored again in that
    1890             :          * function.
    1891             :          */
    1892          96 :         if (!child_joinrel)
    1893             :         {
    1894           0 :             *parts1 = lappend(*parts1, NULL);
    1895           0 :             *parts2 = lappend(*parts2, NULL);
    1896           0 :             continue;
    1897             :         }
    1898             : 
    1899             :         /*
    1900             :          * Get a relids set of partition(s) involved in this join segment that
    1901             :          * are from the rel1 side.
    1902             :          */
    1903          96 :         child_relids1 = bms_intersect(child_joinrel->relids,
    1904          96 :                                       rel1->all_partrels);
    1905             :         Assert(bms_num_members(child_relids1) == bms_num_members(rel1->relids));
    1906             : 
    1907             :         /*
    1908             :          * Get a child rel for rel1 with the relids.  Note that we should have
    1909             :          * the child rel even if rel1 is a join rel, because in that case the
    1910             :          * partitions specified in the relids would have matching/overlapping
    1911             :          * boundaries, so the specified partitions should be considered as
    1912             :          * ones to be joined when planning partitionwise joins of rel1,
    1913             :          * meaning that the child rel would have been built by the time we get
    1914             :          * here.
    1915             :          */
    1916          96 :         if (rel1_is_simple)
    1917             :         {
    1918           0 :             int         varno = bms_singleton_member(child_relids1);
    1919             : 
    1920           0 :             child_rel1 = find_base_rel(root, varno);
    1921             :         }
    1922             :         else
    1923          96 :             child_rel1 = find_join_rel(root, child_relids1);
    1924             :         Assert(child_rel1);
    1925             : 
    1926             :         /*
    1927             :          * Get a relids set of partition(s) involved in this join segment that
    1928             :          * are from the rel2 side.
    1929             :          */
    1930          96 :         child_relids2 = bms_intersect(child_joinrel->relids,
    1931          96 :                                       rel2->all_partrels);
    1932             :         Assert(bms_num_members(child_relids2) == bms_num_members(rel2->relids));
    1933             : 
    1934             :         /*
    1935             :          * Get a child rel for rel2 with the relids.  See above comments.
    1936             :          */
    1937          96 :         if (rel2_is_simple)
    1938             :         {
    1939          96 :             int         varno = bms_singleton_member(child_relids2);
    1940             : 
    1941          96 :             child_rel2 = find_base_rel(root, varno);
    1942             :         }
    1943             :         else
    1944           0 :             child_rel2 = find_join_rel(root, child_relids2);
    1945             :         Assert(child_rel2);
    1946             : 
    1947             :         /*
    1948             :          * The join of rel1 and rel2 is legal, so is the join of the child
    1949             :          * rels obtained above; add them to the given lists as a join pair
    1950             :          * producing this join segment.
    1951             :          */
    1952          96 :         *parts1 = lappend(*parts1, child_rel1);
    1953          96 :         *parts2 = lappend(*parts2, child_rel2);
    1954             :     }
    1955          36 : }

Generated by: LCOV version 1.14