LCOV - code coverage report
Current view: top level - src/backend/optimizer/util - pathnode.c (source / functions) Hit Total Coverage
Test: PostgreSQL 16beta1 Lines: 1350 1480 91.2 %
Date: 2023-05-30 23:12:14 Functions: 63 63 100.0 %
Legend: Lines: hit not hit

          Line data    Source code
       1             : /*-------------------------------------------------------------------------
       2             :  *
       3             :  * pathnode.c
       4             :  *    Routines to manipulate pathlists and create path nodes
       5             :  *
       6             :  * Portions Copyright (c) 1996-2023, PostgreSQL Global Development Group
       7             :  * Portions Copyright (c) 1994, Regents of the University of California
       8             :  *
       9             :  *
      10             :  * IDENTIFICATION
      11             :  *    src/backend/optimizer/util/pathnode.c
      12             :  *
      13             :  *-------------------------------------------------------------------------
      14             :  */
      15             : #include "postgres.h"
      16             : 
      17             : #include <math.h>
      18             : 
      19             : #include "foreign/fdwapi.h"
      20             : #include "miscadmin.h"
      21             : #include "nodes/extensible.h"
      22             : #include "nodes/nodeFuncs.h"
      23             : #include "optimizer/appendinfo.h"
      24             : #include "optimizer/clauses.h"
      25             : #include "optimizer/cost.h"
      26             : #include "optimizer/optimizer.h"
      27             : #include "optimizer/pathnode.h"
      28             : #include "optimizer/paths.h"
      29             : #include "optimizer/planmain.h"
      30             : #include "optimizer/prep.h"
      31             : #include "optimizer/restrictinfo.h"
      32             : #include "optimizer/tlist.h"
      33             : #include "parser/parsetree.h"
      34             : #include "utils/lsyscache.h"
      35             : #include "utils/memutils.h"
      36             : #include "utils/selfuncs.h"
      37             : 
      38             : typedef enum
      39             : {
      40             :     COSTS_EQUAL,                /* path costs are fuzzily equal */
      41             :     COSTS_BETTER1,              /* first path is cheaper than second */
      42             :     COSTS_BETTER2,              /* second path is cheaper than first */
      43             :     COSTS_DIFFERENT             /* neither path dominates the other on cost */
      44             : } PathCostComparison;
      45             : 
      46             : /*
      47             :  * STD_FUZZ_FACTOR is the normal fuzz factor for compare_path_costs_fuzzily.
      48             :  * XXX is it worth making this user-controllable?  It provides a tradeoff
      49             :  * between planner runtime and the accuracy of path cost comparisons.
      50             :  */
      51             : #define STD_FUZZ_FACTOR 1.01
      52             : 
      53             : static List *translate_sub_tlist(List *tlist, int relid);
      54             : static int  append_total_cost_compare(const ListCell *a, const ListCell *b);
      55             : static int  append_startup_cost_compare(const ListCell *a, const ListCell *b);
      56             : static List *reparameterize_pathlist_by_child(PlannerInfo *root,
      57             :                                               List *pathlist,
      58             :                                               RelOptInfo *child_rel);
      59             : 
      60             : 
      61             : /*****************************************************************************
      62             :  *      MISC. PATH UTILITIES
      63             :  *****************************************************************************/
      64             : 
      65             : /*
      66             :  * compare_path_costs
      67             :  *    Return -1, 0, or +1 according as path1 is cheaper, the same cost,
      68             :  *    or more expensive than path2 for the specified criterion.
      69             :  */
      70             : int
      71      587776 : compare_path_costs(Path *path1, Path *path2, CostSelector criterion)
      72             : {
      73      587776 :     if (criterion == STARTUP_COST)
      74             :     {
      75      301400 :         if (path1->startup_cost < path2->startup_cost)
      76      185860 :             return -1;
      77      115540 :         if (path1->startup_cost > path2->startup_cost)
      78       52452 :             return +1;
      79             : 
      80             :         /*
      81             :          * If paths have the same startup cost (not at all unlikely), order
      82             :          * them by total cost.
      83             :          */
      84       63088 :         if (path1->total_cost < path2->total_cost)
      85       25024 :             return -1;
      86       38064 :         if (path1->total_cost > path2->total_cost)
      87        3936 :             return +1;
      88             :     }
      89             :     else
      90             :     {
      91      286376 :         if (path1->total_cost < path2->total_cost)
      92      271842 :             return -1;
      93       14534 :         if (path1->total_cost > path2->total_cost)
      94        1002 :             return +1;
      95             : 
      96             :         /*
      97             :          * If paths have the same total cost, order them by startup cost.
      98             :          */
      99       13532 :         if (path1->startup_cost < path2->startup_cost)
     100          44 :             return -1;
     101       13488 :         if (path1->startup_cost > path2->startup_cost)
     102          76 :             return +1;
     103             :     }
     104       47540 :     return 0;
     105             : }
     106             : 
     107             : /*
     108             :  * compare_fractional_path_costs
     109             :  *    Return -1, 0, or +1 according as path1 is cheaper, the same cost,
     110             :  *    or more expensive than path2 for fetching the specified fraction
     111             :  *    of the total tuples.
     112             :  *
     113             :  * If fraction is <= 0 or > 1, we interpret it as 1, ie, we select the
     114             :  * path with the cheaper total_cost.
     115             :  */
     116             : int
     117        5848 : compare_fractional_path_costs(Path *path1, Path *path2,
     118             :                               double fraction)
     119             : {
     120             :     Cost        cost1,
     121             :                 cost2;
     122             : 
     123        5848 :     if (fraction <= 0.0 || fraction >= 1.0)
     124        4694 :         return compare_path_costs(path1, path2, TOTAL_COST);
     125        1154 :     cost1 = path1->startup_cost +
     126        1154 :         fraction * (path1->total_cost - path1->startup_cost);
     127        1154 :     cost2 = path2->startup_cost +
     128        1154 :         fraction * (path2->total_cost - path2->startup_cost);
     129        1154 :     if (cost1 < cost2)
     130         690 :         return -1;
     131         464 :     if (cost1 > cost2)
     132         464 :         return +1;
     133           0 :     return 0;
     134             : }
     135             : 
     136             : /*
     137             :  * compare_path_costs_fuzzily
     138             :  *    Compare the costs of two paths to see if either can be said to
     139             :  *    dominate the other.
     140             :  *
     141             :  * We use fuzzy comparisons so that add_path() can avoid keeping both of
     142             :  * a pair of paths that really have insignificantly different cost.
     143             :  *
     144             :  * The fuzz_factor argument must be 1.0 plus delta, where delta is the
     145             :  * fraction of the smaller cost that is considered to be a significant
     146             :  * difference.  For example, fuzz_factor = 1.01 makes the fuzziness limit
     147             :  * be 1% of the smaller cost.
     148             :  *
     149             :  * The two paths are said to have "equal" costs if both startup and total
     150             :  * costs are fuzzily the same.  Path1 is said to be better than path2 if
     151             :  * it has fuzzily better startup cost and fuzzily no worse total cost,
     152             :  * or if it has fuzzily better total cost and fuzzily no worse startup cost.
     153             :  * Path2 is better than path1 if the reverse holds.  Finally, if one path
     154             :  * is fuzzily better than the other on startup cost and fuzzily worse on
     155             :  * total cost, we just say that their costs are "different", since neither
     156             :  * dominates the other across the whole performance spectrum.
     157             :  *
     158             :  * This function also enforces a policy rule that paths for which the relevant
     159             :  * one of parent->consider_startup and parent->consider_param_startup is false
     160             :  * cannot survive comparisons solely on the grounds of good startup cost, so
     161             :  * we never return COSTS_DIFFERENT when that is true for the total-cost loser.
     162             :  * (But if total costs are fuzzily equal, we compare startup costs anyway,
     163             :  * in hopes of eliminating one path or the other.)
     164             :  */
     165             : static PathCostComparison
     166     2572548 : compare_path_costs_fuzzily(Path *path1, Path *path2, double fuzz_factor)
     167             : {
     168             : #define CONSIDER_PATH_STARTUP_COST(p)  \
     169             :     ((p)->param_info == NULL ? (p)->parent->consider_startup : (p)->parent->consider_param_startup)
     170             : 
     171             :     /*
     172             :      * Check total cost first since it's more likely to be different; many
     173             :      * paths have zero startup cost.
     174             :      */
     175     2572548 :     if (path1->total_cost > path2->total_cost * fuzz_factor)
     176             :     {
     177             :         /* path1 fuzzily worse on total cost */
     178     1301996 :         if (CONSIDER_PATH_STARTUP_COST(path1) &&
     179       44616 :             path2->startup_cost > path1->startup_cost * fuzz_factor)
     180             :         {
     181             :             /* ... but path2 fuzzily worse on startup, so DIFFERENT */
     182       21398 :             return COSTS_DIFFERENT;
     183             :         }
     184             :         /* else path2 dominates */
     185     1280598 :         return COSTS_BETTER2;
     186             :     }
     187     1270552 :     if (path2->total_cost > path1->total_cost * fuzz_factor)
     188             :     {
     189             :         /* path2 fuzzily worse on total cost */
     190      685256 :         if (CONSIDER_PATH_STARTUP_COST(path2) &&
     191       20970 :             path1->startup_cost > path2->startup_cost * fuzz_factor)
     192             :         {
     193             :             /* ... but path1 fuzzily worse on startup, so DIFFERENT */
     194       11882 :             return COSTS_DIFFERENT;
     195             :         }
     196             :         /* else path1 dominates */
     197      673374 :         return COSTS_BETTER1;
     198             :     }
     199             :     /* fuzzily the same on total cost ... */
     200      585296 :     if (path1->startup_cost > path2->startup_cost * fuzz_factor)
     201             :     {
     202             :         /* ... but path1 fuzzily worse on startup, so path2 wins */
     203      231382 :         return COSTS_BETTER2;
     204             :     }
     205      353914 :     if (path2->startup_cost > path1->startup_cost * fuzz_factor)
     206             :     {
     207             :         /* ... but path2 fuzzily worse on startup, so path1 wins */
     208       35276 :         return COSTS_BETTER1;
     209             :     }
     210             :     /* fuzzily the same on both costs */
     211      318638 :     return COSTS_EQUAL;
     212             : 
     213             : #undef CONSIDER_PATH_STARTUP_COST
     214             : }
     215             : 
     216             : /*
     217             :  * set_cheapest
     218             :  *    Find the minimum-cost paths from among a relation's paths,
     219             :  *    and save them in the rel's cheapest-path fields.
     220             :  *
     221             :  * cheapest_total_path is normally the cheapest-total-cost unparameterized
     222             :  * path; but if there are no unparameterized paths, we assign it to be the
     223             :  * best (cheapest least-parameterized) parameterized path.  However, only
     224             :  * unparameterized paths are considered candidates for cheapest_startup_path,
     225             :  * so that will be NULL if there are no unparameterized paths.
     226             :  *
     227             :  * The cheapest_parameterized_paths list collects all parameterized paths
     228             :  * that have survived the add_path() tournament for this relation.  (Since
     229             :  * add_path ignores pathkeys for a parameterized path, these will be paths
     230             :  * that have best cost or best row count for their parameterization.  We
     231             :  * may also have both a parallel-safe and a non-parallel-safe path in some
     232             :  * cases for the same parameterization in some cases, but this should be
     233             :  * relatively rare since, most typically, all paths for the same relation
     234             :  * will be parallel-safe or none of them will.)
     235             :  *
     236             :  * cheapest_parameterized_paths always includes the cheapest-total
     237             :  * unparameterized path, too, if there is one; the users of that list find
     238             :  * it more convenient if that's included.
     239             :  *
     240             :  * This is normally called only after we've finished constructing the path
     241             :  * list for the rel node.
     242             :  */
     243             : void
     244     1710536 : set_cheapest(RelOptInfo *parent_rel)
     245             : {
     246             :     Path       *cheapest_startup_path;
     247             :     Path       *cheapest_total_path;
     248             :     Path       *best_param_path;
     249             :     List       *parameterized_paths;
     250             :     ListCell   *p;
     251             : 
     252             :     Assert(IsA(parent_rel, RelOptInfo));
     253             : 
     254     1710536 :     if (parent_rel->pathlist == NIL)
     255           0 :         elog(ERROR, "could not devise a query plan for the given query");
     256             : 
     257     1710536 :     cheapest_startup_path = cheapest_total_path = best_param_path = NULL;
     258     1710536 :     parameterized_paths = NIL;
     259             : 
     260     3739094 :     foreach(p, parent_rel->pathlist)
     261             :     {
     262     2028558 :         Path       *path = (Path *) lfirst(p);
     263             :         int         cmp;
     264             : 
     265     2028558 :         if (path->param_info)
     266             :         {
     267             :             /* Parameterized path, so add it to parameterized_paths */
     268       94706 :             parameterized_paths = lappend(parameterized_paths, path);
     269             : 
     270             :             /*
     271             :              * If we have an unparameterized cheapest-total, we no longer care
     272             :              * about finding the best parameterized path, so move on.
     273             :              */
     274       94706 :             if (cheapest_total_path)
     275       16840 :                 continue;
     276             : 
     277             :             /*
     278             :              * Otherwise, track the best parameterized path, which is the one
     279             :              * with least total cost among those of the minimum
     280             :              * parameterization.
     281             :              */
     282       77866 :             if (best_param_path == NULL)
     283       72140 :                 best_param_path = path;
     284             :             else
     285             :             {
     286        5726 :                 switch (bms_subset_compare(PATH_REQ_OUTER(path),
     287        5726 :                                            PATH_REQ_OUTER(best_param_path)))
     288             :                 {
     289          54 :                     case BMS_EQUAL:
     290             :                         /* keep the cheaper one */
     291          54 :                         if (compare_path_costs(path, best_param_path,
     292             :                                                TOTAL_COST) < 0)
     293           0 :                             best_param_path = path;
     294          54 :                         break;
     295         328 :                     case BMS_SUBSET1:
     296             :                         /* new path is less-parameterized */
     297         328 :                         best_param_path = path;
     298         328 :                         break;
     299           4 :                     case BMS_SUBSET2:
     300             :                         /* old path is less-parameterized, keep it */
     301           4 :                         break;
     302        5340 :                     case BMS_DIFFERENT:
     303             : 
     304             :                         /*
     305             :                          * This means that neither path has the least possible
     306             :                          * parameterization for the rel.  We'll sit on the old
     307             :                          * path until something better comes along.
     308             :                          */
     309        5340 :                         break;
     310             :                 }
     311       77866 :             }
     312             :         }
     313             :         else
     314             :         {
     315             :             /* Unparameterized path, so consider it for cheapest slots */
     316     1933852 :             if (cheapest_total_path == NULL)
     317             :             {
     318     1702086 :                 cheapest_startup_path = cheapest_total_path = path;
     319     1702086 :                 continue;
     320             :             }
     321             : 
     322             :             /*
     323             :              * If we find two paths of identical costs, try to keep the
     324             :              * better-sorted one.  The paths might have unrelated sort
     325             :              * orderings, in which case we can only guess which might be
     326             :              * better to keep, but if one is superior then we definitely
     327             :              * should keep that one.
     328             :              */
     329      231766 :             cmp = compare_path_costs(cheapest_startup_path, path, STARTUP_COST);
     330      231766 :             if (cmp > 0 ||
     331         182 :                 (cmp == 0 &&
     332         182 :                  compare_pathkeys(cheapest_startup_path->pathkeys,
     333             :                                   path->pathkeys) == PATHKEYS_BETTER2))
     334       41722 :                 cheapest_startup_path = path;
     335             : 
     336      231766 :             cmp = compare_path_costs(cheapest_total_path, path, TOTAL_COST);
     337      231766 :             if (cmp > 0 ||
     338           0 :                 (cmp == 0 &&
     339           0 :                  compare_pathkeys(cheapest_total_path->pathkeys,
     340             :                                   path->pathkeys) == PATHKEYS_BETTER2))
     341           0 :                 cheapest_total_path = path;
     342             :         }
     343             :     }
     344             : 
     345             :     /* Add cheapest unparameterized path, if any, to parameterized_paths */
     346     1710536 :     if (cheapest_total_path)
     347     1702086 :         parameterized_paths = lcons(cheapest_total_path, parameterized_paths);
     348             : 
     349             :     /*
     350             :      * If there is no unparameterized path, use the best parameterized path as
     351             :      * cheapest_total_path (but not as cheapest_startup_path).
     352             :      */
     353     1710536 :     if (cheapest_total_path == NULL)
     354        8450 :         cheapest_total_path = best_param_path;
     355             :     Assert(cheapest_total_path != NULL);
     356             : 
     357     1710536 :     parent_rel->cheapest_startup_path = cheapest_startup_path;
     358     1710536 :     parent_rel->cheapest_total_path = cheapest_total_path;
     359     1710536 :     parent_rel->cheapest_unique_path = NULL; /* computed only if needed */
     360     1710536 :     parent_rel->cheapest_parameterized_paths = parameterized_paths;
     361     1710536 : }
     362             : 
     363             : /*
     364             :  * add_path
     365             :  *    Consider a potential implementation path for the specified parent rel,
     366             :  *    and add it to the rel's pathlist if it is worthy of consideration.
     367             :  *    A path is worthy if it has a better sort order (better pathkeys) or
     368             :  *    cheaper cost (on either dimension), or generates fewer rows, than any
     369             :  *    existing path that has the same or superset parameterization rels.
     370             :  *    We also consider parallel-safe paths more worthy than others.
     371             :  *
     372             :  *    We also remove from the rel's pathlist any old paths that are dominated
     373             :  *    by new_path --- that is, new_path is cheaper, at least as well ordered,
     374             :  *    generates no more rows, requires no outer rels not required by the old
     375             :  *    path, and is no less parallel-safe.
     376             :  *
     377             :  *    In most cases, a path with a superset parameterization will generate
     378             :  *    fewer rows (since it has more join clauses to apply), so that those two
     379             :  *    figures of merit move in opposite directions; this means that a path of
     380             :  *    one parameterization can seldom dominate a path of another.  But such
     381             :  *    cases do arise, so we make the full set of checks anyway.
     382             :  *
     383             :  *    There are two policy decisions embedded in this function, along with
     384             :  *    its sibling add_path_precheck.  First, we treat all parameterized paths
     385             :  *    as having NIL pathkeys, so that they cannot win comparisons on the
     386             :  *    basis of sort order.  This is to reduce the number of parameterized
     387             :  *    paths that are kept; see discussion in src/backend/optimizer/README.
     388             :  *
     389             :  *    Second, we only consider cheap startup cost to be interesting if
     390             :  *    parent_rel->consider_startup is true for an unparameterized path, or
     391             :  *    parent_rel->consider_param_startup is true for a parameterized one.
     392             :  *    Again, this allows discarding useless paths sooner.
     393             :  *
     394             :  *    The pathlist is kept sorted by total_cost, with cheaper paths
     395             :  *    at the front.  Within this routine, that's simply a speed hack:
     396             :  *    doing it that way makes it more likely that we will reject an inferior
     397             :  *    path after a few comparisons, rather than many comparisons.
     398             :  *    However, add_path_precheck relies on this ordering to exit early
     399             :  *    when possible.
     400             :  *
     401             :  *    NOTE: discarded Path objects are immediately pfree'd to reduce planner
     402             :  *    memory consumption.  We dare not try to free the substructure of a Path,
     403             :  *    since much of it may be shared with other Paths or the query tree itself;
     404             :  *    but just recycling discarded Path nodes is a very useful savings in
     405             :  *    a large join tree.  We can recycle the List nodes of pathlist, too.
     406             :  *
     407             :  *    As noted in optimizer/README, deleting a previously-accepted Path is
     408             :  *    safe because we know that Paths of this rel cannot yet be referenced
     409             :  *    from any other rel, such as a higher-level join.  However, in some cases
     410             :  *    it is possible that a Path is referenced by another Path for its own
     411             :  *    rel; we must not delete such a Path, even if it is dominated by the new
     412             :  *    Path.  Currently this occurs only for IndexPath objects, which may be
     413             :  *    referenced as children of BitmapHeapPaths as well as being paths in
     414             :  *    their own right.  Hence, we don't pfree IndexPaths when rejecting them.
     415             :  *
     416             :  * 'parent_rel' is the relation entry to which the path corresponds.
     417             :  * 'new_path' is a potential path for parent_rel.
     418             :  *
     419             :  * Returns nothing, but modifies parent_rel->pathlist.
     420             :  */
     421             : void
     422     3027318 : add_path(RelOptInfo *parent_rel, Path *new_path)
     423             : {
     424     3027318 :     bool        accept_new = true;  /* unless we find a superior old path */
     425     3027318 :     int         insert_at = 0;  /* where to insert new item */
     426             :     List       *new_path_pathkeys;
     427             :     ListCell   *p1;
     428             : 
     429             :     /*
     430             :      * This is a convenient place to check for query cancel --- no part of the
     431             :      * planner goes very long without calling add_path().
     432             :      */
     433     3027318 :     CHECK_FOR_INTERRUPTS();
     434             : 
     435             :     /* Pretend parameterized paths have no pathkeys, per comment above */
     436     3027318 :     new_path_pathkeys = new_path->param_info ? NIL : new_path->pathkeys;
     437             : 
     438             :     /*
     439             :      * Loop to check proposed new path against old paths.  Note it is possible
     440             :      * for more than one old path to be tossed out because new_path dominates
     441             :      * it.
     442             :      */
     443     4373950 :     foreach(p1, parent_rel->pathlist)
     444             :     {
     445     2363812 :         Path       *old_path = (Path *) lfirst(p1);
     446     2363812 :         bool        remove_old = false; /* unless new proves superior */
     447             :         PathCostComparison costcmp;
     448             :         PathKeysComparison keyscmp;
     449             :         BMS_Comparison outercmp;
     450             : 
     451             :         /*
     452             :          * Do a fuzzy cost comparison with standard fuzziness limit.
     453             :          */
     454     2363812 :         costcmp = compare_path_costs_fuzzily(new_path, old_path,
     455             :                                              STD_FUZZ_FACTOR);
     456             : 
     457             :         /*
     458             :          * If the two paths compare differently for startup and total cost,
     459             :          * then we want to keep both, and we can skip comparing pathkeys and
     460             :          * required_outer rels.  If they compare the same, proceed with the
     461             :          * other comparisons.  Row count is checked last.  (We make the tests
     462             :          * in this order because the cost comparison is most likely to turn
     463             :          * out "different", and the pathkeys comparison next most likely.  As
     464             :          * explained above, row count very seldom makes a difference, so even
     465             :          * though it's cheap to compare there's not much point in checking it
     466             :          * earlier.)
     467             :          */
     468     2363812 :         if (costcmp != COSTS_DIFFERENT)
     469             :         {
     470             :             /* Similarly check to see if either dominates on pathkeys */
     471             :             List       *old_path_pathkeys;
     472             : 
     473     2330540 :             old_path_pathkeys = old_path->param_info ? NIL : old_path->pathkeys;
     474     2330540 :             keyscmp = compare_pathkeys(new_path_pathkeys,
     475             :                                        old_path_pathkeys);
     476     2330540 :             if (keyscmp != PATHKEYS_DIFFERENT)
     477             :             {
     478     2233712 :                 switch (costcmp)
     479             :                 {
     480      223360 :                     case COSTS_EQUAL:
     481      223360 :                         outercmp = bms_subset_compare(PATH_REQ_OUTER(new_path),
     482      223360 :                                                       PATH_REQ_OUTER(old_path));
     483      223360 :                         if (keyscmp == PATHKEYS_BETTER1)
     484             :                         {
     485        1864 :                             if ((outercmp == BMS_EQUAL ||
     486        1864 :                                  outercmp == BMS_SUBSET1) &&
     487        1864 :                                 new_path->rows <= old_path->rows &&
     488        1856 :                                 new_path->parallel_safe >= old_path->parallel_safe)
     489        1856 :                                 remove_old = true;  /* new dominates old */
     490             :                         }
     491      221496 :                         else if (keyscmp == PATHKEYS_BETTER2)
     492             :                         {
     493        9476 :                             if ((outercmp == BMS_EQUAL ||
     494        9476 :                                  outercmp == BMS_SUBSET2) &&
     495        9476 :                                 new_path->rows >= old_path->rows &&
     496        9350 :                                 new_path->parallel_safe <= old_path->parallel_safe)
     497        9350 :                                 accept_new = false; /* old dominates new */
     498             :                         }
     499             :                         else    /* keyscmp == PATHKEYS_EQUAL */
     500             :                         {
     501      212020 :                             if (outercmp == BMS_EQUAL)
     502             :                             {
     503             :                                 /*
     504             :                                  * Same pathkeys and outer rels, and fuzzily
     505             :                                  * the same cost, so keep just one; to decide
     506             :                                  * which, first check parallel-safety, then
     507             :                                  * rows, then do a fuzzy cost comparison with
     508             :                                  * very small fuzz limit.  (We used to do an
     509             :                                  * exact cost comparison, but that results in
     510             :                                  * annoying platform-specific plan variations
     511             :                                  * due to roundoff in the cost estimates.)  If
     512             :                                  * things are still tied, arbitrarily keep
     513             :                                  * only the old path.  Notice that we will
     514             :                                  * keep only the old path even if the
     515             :                                  * less-fuzzy comparison decides the startup
     516             :                                  * and total costs compare differently.
     517             :                                  */
     518      208960 :                                 if (new_path->parallel_safe >
     519      208960 :                                     old_path->parallel_safe)
     520          48 :                                     remove_old = true;  /* new dominates old */
     521      208912 :                                 else if (new_path->parallel_safe <
     522      208912 :                                          old_path->parallel_safe)
     523         136 :                                     accept_new = false; /* old dominates new */
     524      208776 :                                 else if (new_path->rows < old_path->rows)
     525          28 :                                     remove_old = true;  /* new dominates old */
     526      208748 :                                 else if (new_path->rows > old_path->rows)
     527          12 :                                     accept_new = false; /* old dominates new */
     528      208736 :                                 else if (compare_path_costs_fuzzily(new_path,
     529             :                                                                     old_path,
     530             :                                                                     1.0000000001) == COSTS_BETTER1)
     531        8778 :                                     remove_old = true;  /* new dominates old */
     532             :                                 else
     533      199958 :                                     accept_new = false; /* old equals or
     534             :                                                          * dominates new */
     535             :                             }
     536        3060 :                             else if (outercmp == BMS_SUBSET1 &&
     537         528 :                                      new_path->rows <= old_path->rows &&
     538         512 :                                      new_path->parallel_safe >= old_path->parallel_safe)
     539         512 :                                 remove_old = true;  /* new dominates old */
     540        2548 :                             else if (outercmp == BMS_SUBSET2 &&
     541        2342 :                                      new_path->rows >= old_path->rows &&
     542        2326 :                                      new_path->parallel_safe <= old_path->parallel_safe)
     543        2326 :                                 accept_new = false; /* old dominates new */
     544             :                             /* else different parameterizations, keep both */
     545             :                         }
     546      223360 :                         break;
     547      685354 :                     case COSTS_BETTER1:
     548      685354 :                         if (keyscmp != PATHKEYS_BETTER2)
     549             :                         {
     550      488598 :                             outercmp = bms_subset_compare(PATH_REQ_OUTER(new_path),
     551      488598 :                                                           PATH_REQ_OUTER(old_path));
     552      488598 :                             if ((outercmp == BMS_EQUAL ||
     553      411290 :                                  outercmp == BMS_SUBSET1) &&
     554      411290 :                                 new_path->rows <= old_path->rows &&
     555      408628 :                                 new_path->parallel_safe >= old_path->parallel_safe)
     556      406104 :                                 remove_old = true;  /* new dominates old */
     557             :                         }
     558      685354 :                         break;
     559     1324998 :                     case COSTS_BETTER2:
     560     1324998 :                         if (keyscmp != PATHKEYS_BETTER1)
     561             :                         {
     562      915102 :                             outercmp = bms_subset_compare(PATH_REQ_OUTER(new_path),
     563      915102 :                                                           PATH_REQ_OUTER(old_path));
     564      915102 :                             if ((outercmp == BMS_EQUAL ||
     565      848936 :                                  outercmp == BMS_SUBSET2) &&
     566      848936 :                                 new_path->rows >= old_path->rows &&
     567      807440 :                                 new_path->parallel_safe <= old_path->parallel_safe)
     568      805398 :                                 accept_new = false; /* old dominates new */
     569             :                         }
     570     1324998 :                         break;
     571           0 :                     case COSTS_DIFFERENT:
     572             : 
     573             :                         /*
     574             :                          * can't get here, but keep this case to keep compiler
     575             :                          * quiet
     576             :                          */
     577           0 :                         break;
     578             :                 }
     579      130100 :             }
     580             :         }
     581             : 
     582             :         /*
     583             :          * Remove current element from pathlist if dominated by new.
     584             :          */
     585     2363812 :         if (remove_old)
     586             :         {
     587      417326 :             parent_rel->pathlist = foreach_delete_current(parent_rel->pathlist,
     588             :                                                           p1);
     589             : 
     590             :             /*
     591             :              * Delete the data pointed-to by the deleted cell, if possible
     592             :              */
     593      417326 :             if (!IsA(old_path, IndexPath))
     594      397054 :                 pfree(old_path);
     595             :         }
     596             :         else
     597             :         {
     598             :             /* new belongs after this old path if it has cost >= old's */
     599     1946486 :             if (new_path->total_cost >= old_path->total_cost)
     600     1607938 :                 insert_at = foreach_current_index(p1) + 1;
     601             :         }
     602             : 
     603             :         /*
     604             :          * If we found an old path that dominates new_path, we can quit
     605             :          * scanning the pathlist; we will not add new_path, and we assume
     606             :          * new_path cannot dominate any other elements of the pathlist.
     607             :          */
     608     2363812 :         if (!accept_new)
     609     1017180 :             break;
     610             :     }
     611             : 
     612     3027318 :     if (accept_new)
     613             :     {
     614             :         /* Accept the new path: insert it at proper place in pathlist */
     615     2010138 :         parent_rel->pathlist =
     616     2010138 :             list_insert_nth(parent_rel->pathlist, insert_at, new_path);
     617             :     }
     618             :     else
     619             :     {
     620             :         /* Reject and recycle the new path */
     621     1017180 :         if (!IsA(new_path, IndexPath))
     622      956912 :             pfree(new_path);
     623             :     }
     624     3027318 : }
     625             : 
     626             : /*
     627             :  * add_path_precheck
     628             :  *    Check whether a proposed new path could possibly get accepted.
     629             :  *    We assume we know the path's pathkeys and parameterization accurately,
     630             :  *    and have lower bounds for its costs.
     631             :  *
     632             :  * Note that we do not know the path's rowcount, since getting an estimate for
     633             :  * that is too expensive to do before prechecking.  We assume here that paths
     634             :  * of a superset parameterization will generate fewer rows; if that holds,
     635             :  * then paths with different parameterizations cannot dominate each other
     636             :  * and so we can simply ignore existing paths of another parameterization.
     637             :  * (In the infrequent cases where that rule of thumb fails, add_path will
     638             :  * get rid of the inferior path.)
     639             :  *
     640             :  * At the time this is called, we haven't actually built a Path structure,
     641             :  * so the required information has to be passed piecemeal.
     642             :  */
     643             : bool
     644     2991262 : add_path_precheck(RelOptInfo *parent_rel,
     645             :                   Cost startup_cost, Cost total_cost,
     646             :                   List *pathkeys, Relids required_outer)
     647             : {
     648             :     List       *new_path_pathkeys;
     649             :     bool        consider_startup;
     650             :     ListCell   *p1;
     651             : 
     652             :     /* Pretend parameterized paths have no pathkeys, per add_path policy */
     653     2991262 :     new_path_pathkeys = required_outer ? NIL : pathkeys;
     654             : 
     655             :     /* Decide whether new path's startup cost is interesting */
     656     2991262 :     consider_startup = required_outer ? parent_rel->consider_param_startup : parent_rel->consider_startup;
     657             : 
     658     3716352 :     foreach(p1, parent_rel->pathlist)
     659             :     {
     660     3523652 :         Path       *old_path = (Path *) lfirst(p1);
     661             :         PathKeysComparison keyscmp;
     662             : 
     663             :         /*
     664             :          * We are looking for an old_path with the same parameterization (and
     665             :          * by assumption the same rowcount) that dominates the new path on
     666             :          * pathkeys as well as both cost metrics.  If we find one, we can
     667             :          * reject the new path.
     668             :          *
     669             :          * Cost comparisons here should match compare_path_costs_fuzzily.
     670             :          */
     671     3523652 :         if (total_cost > old_path->total_cost * STD_FUZZ_FACTOR)
     672             :         {
     673             :             /* new path can win on startup cost only if consider_startup */
     674     2481340 :             if (startup_cost > old_path->startup_cost * STD_FUZZ_FACTOR ||
     675     1101146 :                 !consider_startup)
     676             :             {
     677             :                 /* new path loses on cost, so check pathkeys... */
     678             :                 List       *old_path_pathkeys;
     679             : 
     680     2459402 :                 old_path_pathkeys = old_path->param_info ? NIL : old_path->pathkeys;
     681     2459402 :                 keyscmp = compare_pathkeys(new_path_pathkeys,
     682             :                                            old_path_pathkeys);
     683     2459402 :                 if (keyscmp == PATHKEYS_EQUAL ||
     684             :                     keyscmp == PATHKEYS_BETTER2)
     685             :                 {
     686             :                     /* new path does not win on pathkeys... */
     687     1816132 :                     if (bms_equal(required_outer, PATH_REQ_OUTER(old_path)))
     688             :                     {
     689             :                         /* Found an old path that dominates the new one */
     690     1756250 :                         return false;
     691             :                     }
     692             :                 }
     693             :             }
     694             :         }
     695             :         else
     696             :         {
     697             :             /*
     698             :              * Since the pathlist is sorted by total_cost, we can stop looking
     699             :              * once we reach a path with a total_cost larger than the new
     700             :              * path's.
     701             :              */
     702     1042312 :             break;
     703             :         }
     704             :     }
     705             : 
     706     1235012 :     return true;
     707             : }
     708             : 
     709             : /*
     710             :  * add_partial_path
     711             :  *    Like add_path, our goal here is to consider whether a path is worthy
     712             :  *    of being kept around, but the considerations here are a bit different.
     713             :  *    A partial path is one which can be executed in any number of workers in
     714             :  *    parallel such that each worker will generate a subset of the path's
     715             :  *    overall result.
     716             :  *
     717             :  *    As in add_path, the partial_pathlist is kept sorted with the cheapest
     718             :  *    total path in front.  This is depended on by multiple places, which
     719             :  *    just take the front entry as the cheapest path without searching.
     720             :  *
     721             :  *    We don't generate parameterized partial paths for several reasons.  Most
     722             :  *    importantly, they're not safe to execute, because there's nothing to
     723             :  *    make sure that a parallel scan within the parameterized portion of the
     724             :  *    plan is running with the same value in every worker at the same time.
     725             :  *    Fortunately, it seems unlikely to be worthwhile anyway, because having
     726             :  *    each worker scan the entire outer relation and a subset of the inner
     727             :  *    relation will generally be a terrible plan.  The inner (parameterized)
     728             :  *    side of the plan will be small anyway.  There could be rare cases where
     729             :  *    this wins big - e.g. if join order constraints put a 1-row relation on
     730             :  *    the outer side of the topmost join with a parameterized plan on the inner
     731             :  *    side - but we'll have to be content not to handle such cases until
     732             :  *    somebody builds an executor infrastructure that can cope with them.
     733             :  *
     734             :  *    Because we don't consider parameterized paths here, we also don't
     735             :  *    need to consider the row counts as a measure of quality: every path will
     736             :  *    produce the same number of rows.  Neither do we need to consider startup
     737             :  *    costs: parallelism is only used for plans that will be run to completion.
     738             :  *    Therefore, this routine is much simpler than add_path: it needs to
     739             :  *    consider only pathkeys and total cost.
     740             :  *
     741             :  *    As with add_path, we pfree paths that are found to be dominated by
     742             :  *    another partial path; this requires that there be no other references to
     743             :  *    such paths yet.  Hence, GatherPaths must not be created for a rel until
     744             :  *    we're done creating all partial paths for it.  Unlike add_path, we don't
     745             :  *    take an exception for IndexPaths as partial index paths won't be
     746             :  *    referenced by partial BitmapHeapPaths.
     747             :  */
     748             : void
     749       88326 : add_partial_path(RelOptInfo *parent_rel, Path *new_path)
     750             : {
     751       88326 :     bool        accept_new = true;  /* unless we find a superior old path */
     752       88326 :     int         insert_at = 0;  /* where to insert new item */
     753             :     ListCell   *p1;
     754             : 
     755             :     /* Check for query cancel. */
     756       88326 :     CHECK_FOR_INTERRUPTS();
     757             : 
     758             :     /* Path to be added must be parallel safe. */
     759             :     Assert(new_path->parallel_safe);
     760             : 
     761             :     /* Relation should be OK for parallelism, too. */
     762             :     Assert(parent_rel->consider_parallel);
     763             : 
     764             :     /*
     765             :      * As in add_path, throw out any paths which are dominated by the new
     766             :      * path, but throw out the new path if some existing path dominates it.
     767             :      */
     768      119840 :     foreach(p1, parent_rel->partial_pathlist)
     769             :     {
     770       45764 :         Path       *old_path = (Path *) lfirst(p1);
     771       45764 :         bool        remove_old = false; /* unless new proves superior */
     772             :         PathKeysComparison keyscmp;
     773             : 
     774             :         /* Compare pathkeys. */
     775       45764 :         keyscmp = compare_pathkeys(new_path->pathkeys, old_path->pathkeys);
     776             : 
     777             :         /* Unless pathkeys are incompatible, keep just one of the two paths. */
     778       45764 :         if (keyscmp != PATHKEYS_DIFFERENT)
     779             :         {
     780       45566 :             if (new_path->total_cost > old_path->total_cost * STD_FUZZ_FACTOR)
     781             :             {
     782             :                 /* New path costs more; keep it only if pathkeys are better. */
     783       14664 :                 if (keyscmp != PATHKEYS_BETTER1)
     784        6436 :                     accept_new = false;
     785             :             }
     786       30902 :             else if (old_path->total_cost > new_path->total_cost
     787       30902 :                      * STD_FUZZ_FACTOR)
     788             :             {
     789             :                 /* Old path costs more; keep it only if pathkeys are better. */
     790       22746 :                 if (keyscmp != PATHKEYS_BETTER2)
     791       11698 :                     remove_old = true;
     792             :             }
     793        8156 :             else if (keyscmp == PATHKEYS_BETTER1)
     794             :             {
     795             :                 /* Costs are about the same, new path has better pathkeys. */
     796           0 :                 remove_old = true;
     797             :             }
     798        8156 :             else if (keyscmp == PATHKEYS_BETTER2)
     799             :             {
     800             :                 /* Costs are about the same, old path has better pathkeys. */
     801        1662 :                 accept_new = false;
     802             :             }
     803        6494 :             else if (old_path->total_cost > new_path->total_cost * 1.0000000001)
     804             :             {
     805             :                 /* Pathkeys are the same, and the old path costs more. */
     806         342 :                 remove_old = true;
     807             :             }
     808             :             else
     809             :             {
     810             :                 /*
     811             :                  * Pathkeys are the same, and new path isn't materially
     812             :                  * cheaper.
     813             :                  */
     814        6152 :                 accept_new = false;
     815             :             }
     816             :         }
     817             : 
     818             :         /*
     819             :          * Remove current element from partial_pathlist if dominated by new.
     820             :          */
     821       45764 :         if (remove_old)
     822             :         {
     823       12040 :             parent_rel->partial_pathlist =
     824       12040 :                 foreach_delete_current(parent_rel->partial_pathlist, p1);
     825       12040 :             pfree(old_path);
     826             :         }
     827             :         else
     828             :         {
     829             :             /* new belongs after this old path if it has cost >= old's */
     830       33724 :             if (new_path->total_cost >= old_path->total_cost)
     831       22274 :                 insert_at = foreach_current_index(p1) + 1;
     832             :         }
     833             : 
     834             :         /*
     835             :          * If we found an old path that dominates new_path, we can quit
     836             :          * scanning the partial_pathlist; we will not add new_path, and we
     837             :          * assume new_path cannot dominate any later path.
     838             :          */
     839       45764 :         if (!accept_new)
     840       14250 :             break;
     841             :     }
     842             : 
     843       88326 :     if (accept_new)
     844             :     {
     845             :         /* Accept the new path: insert it at proper place */
     846       74076 :         parent_rel->partial_pathlist =
     847       74076 :             list_insert_nth(parent_rel->partial_pathlist, insert_at, new_path);
     848             :     }
     849             :     else
     850             :     {
     851             :         /* Reject and recycle the new path */
     852       14250 :         pfree(new_path);
     853             :     }
     854       88326 : }
     855             : 
     856             : /*
     857             :  * add_partial_path_precheck
     858             :  *    Check whether a proposed new partial path could possibly get accepted.
     859             :  *
     860             :  * Unlike add_path_precheck, we can ignore startup cost and parameterization,
     861             :  * since they don't matter for partial paths (see add_partial_path).  But
     862             :  * we do want to make sure we don't add a partial path if there's already
     863             :  * a complete path that dominates it, since in that case the proposed path
     864             :  * is surely a loser.
     865             :  */
     866             : bool
     867       60798 : add_partial_path_precheck(RelOptInfo *parent_rel, Cost total_cost,
     868             :                           List *pathkeys)
     869             : {
     870             :     ListCell   *p1;
     871             : 
     872             :     /*
     873             :      * Our goal here is twofold.  First, we want to find out whether this path
     874             :      * is clearly inferior to some existing partial path.  If so, we want to
     875             :      * reject it immediately.  Second, we want to find out whether this path
     876             :      * is clearly superior to some existing partial path -- at least, modulo
     877             :      * final cost computations.  If so, we definitely want to consider it.
     878             :      *
     879             :      * Unlike add_path(), we always compare pathkeys here.  This is because we
     880             :      * expect partial_pathlist to be very short, and getting a definitive
     881             :      * answer at this stage avoids the need to call add_path_precheck.
     882             :      */
     883       85848 :     foreach(p1, parent_rel->partial_pathlist)
     884             :     {
     885       68582 :         Path       *old_path = (Path *) lfirst(p1);
     886             :         PathKeysComparison keyscmp;
     887             : 
     888       68582 :         keyscmp = compare_pathkeys(pathkeys, old_path->pathkeys);
     889       68582 :         if (keyscmp != PATHKEYS_DIFFERENT)
     890             :         {
     891       68390 :             if (total_cost > old_path->total_cost * STD_FUZZ_FACTOR &&
     892             :                 keyscmp != PATHKEYS_BETTER1)
     893       43532 :                 return false;
     894       34816 :             if (old_path->total_cost > total_cost * STD_FUZZ_FACTOR &&
     895             :                 keyscmp != PATHKEYS_BETTER2)
     896        9958 :                 return true;
     897             :         }
     898             :     }
     899             : 
     900             :     /*
     901             :      * This path is neither clearly inferior to an existing partial path nor
     902             :      * clearly good enough that it might replace one.  Compare it to
     903             :      * non-parallel plans.  If it loses even before accounting for the cost of
     904             :      * the Gather node, we should definitely reject it.
     905             :      *
     906             :      * Note that we pass the total_cost to add_path_precheck twice.  This is
     907             :      * because it's never advantageous to consider the startup cost of a
     908             :      * partial path; the resulting plans, if run in parallel, will be run to
     909             :      * completion.
     910             :      */
     911       17266 :     if (!add_path_precheck(parent_rel, total_cost, total_cost, pathkeys,
     912             :                            NULL))
     913         784 :         return false;
     914             : 
     915       16482 :     return true;
     916             : }
     917             : 
     918             : 
     919             : /*****************************************************************************
     920             :  *      PATH NODE CREATION ROUTINES
     921             :  *****************************************************************************/
     922             : 
     923             : /*
     924             :  * create_seqscan_path
     925             :  *    Creates a path corresponding to a sequential scan, returning the
     926             :  *    pathnode.
     927             :  */
     928             : Path *
     929      335958 : create_seqscan_path(PlannerInfo *root, RelOptInfo *rel,
     930             :                     Relids required_outer, int parallel_workers)
     931             : {
     932      335958 :     Path       *pathnode = makeNode(Path);
     933             : 
     934      335958 :     pathnode->pathtype = T_SeqScan;
     935      335958 :     pathnode->parent = rel;
     936      335958 :     pathnode->pathtarget = rel->reltarget;
     937      335958 :     pathnode->param_info = get_baserel_parampathinfo(root, rel,
     938             :                                                      required_outer);
     939      335958 :     pathnode->parallel_aware = (parallel_workers > 0);
     940      335958 :     pathnode->parallel_safe = rel->consider_parallel;
     941      335958 :     pathnode->parallel_workers = parallel_workers;
     942      335958 :     pathnode->pathkeys = NIL;    /* seqscan has unordered result */
     943             : 
     944      335958 :     cost_seqscan(pathnode, root, rel, pathnode->param_info);
     945             : 
     946      335958 :     return pathnode;
     947             : }
     948             : 
     949             : /*
     950             :  * create_samplescan_path
     951             :  *    Creates a path node for a sampled table scan.
     952             :  */
     953             : Path *
     954         252 : create_samplescan_path(PlannerInfo *root, RelOptInfo *rel, Relids required_outer)
     955             : {
     956         252 :     Path       *pathnode = makeNode(Path);
     957             : 
     958         252 :     pathnode->pathtype = T_SampleScan;
     959         252 :     pathnode->parent = rel;
     960         252 :     pathnode->pathtarget = rel->reltarget;
     961         252 :     pathnode->param_info = get_baserel_parampathinfo(root, rel,
     962             :                                                      required_outer);
     963         252 :     pathnode->parallel_aware = false;
     964         252 :     pathnode->parallel_safe = rel->consider_parallel;
     965         252 :     pathnode->parallel_workers = 0;
     966         252 :     pathnode->pathkeys = NIL;    /* samplescan has unordered result */
     967             : 
     968         252 :     cost_samplescan(pathnode, root, rel, pathnode->param_info);
     969             : 
     970         252 :     return pathnode;
     971             : }
     972             : 
     973             : /*
     974             :  * create_index_path
     975             :  *    Creates a path node for an index scan.
     976             :  *
     977             :  * 'index' is a usable index.
     978             :  * 'indexclauses' is a list of IndexClause nodes representing clauses
     979             :  *          to be enforced as qual conditions in the scan.
     980             :  * 'indexorderbys' is a list of bare expressions (no RestrictInfos)
     981             :  *          to be used as index ordering operators in the scan.
     982             :  * 'indexorderbycols' is an integer list of index column numbers (zero based)
     983             :  *          the ordering operators can be used with.
     984             :  * 'pathkeys' describes the ordering of the path.
     985             :  * 'indexscandir' is either ForwardScanDirection or BackwardScanDirection.
     986             :  * 'indexonly' is true if an index-only scan is wanted.
     987             :  * 'required_outer' is the set of outer relids for a parameterized path.
     988             :  * 'loop_count' is the number of repetitions of the indexscan to factor into
     989             :  *      estimates of caching behavior.
     990             :  * 'partial_path' is true if constructing a parallel index scan path.
     991             :  *
     992             :  * Returns the new path node.
     993             :  */
     994             : IndexPath *
     995      520860 : create_index_path(PlannerInfo *root,
     996             :                   IndexOptInfo *index,
     997             :                   List *indexclauses,
     998             :                   List *indexorderbys,
     999             :                   List *indexorderbycols,
    1000             :                   List *pathkeys,
    1001             :                   ScanDirection indexscandir,
    1002             :                   bool indexonly,
    1003             :                   Relids required_outer,
    1004             :                   double loop_count,
    1005             :                   bool partial_path)
    1006             : {
    1007      520860 :     IndexPath  *pathnode = makeNode(IndexPath);
    1008      520860 :     RelOptInfo *rel = index->rel;
    1009             : 
    1010      520860 :     pathnode->path.pathtype = indexonly ? T_IndexOnlyScan : T_IndexScan;
    1011      520860 :     pathnode->path.parent = rel;
    1012      520860 :     pathnode->path.pathtarget = rel->reltarget;
    1013      520860 :     pathnode->path.param_info = get_baserel_parampathinfo(root, rel,
    1014             :                                                           required_outer);
    1015      520860 :     pathnode->path.parallel_aware = false;
    1016      520860 :     pathnode->path.parallel_safe = rel->consider_parallel;
    1017      520860 :     pathnode->path.parallel_workers = 0;
    1018      520860 :     pathnode->path.pathkeys = pathkeys;
    1019             : 
    1020      520860 :     pathnode->indexinfo = index;
    1021      520860 :     pathnode->indexclauses = indexclauses;
    1022      520860 :     pathnode->indexorderbys = indexorderbys;
    1023      520860 :     pathnode->indexorderbycols = indexorderbycols;
    1024      520860 :     pathnode->indexscandir = indexscandir;
    1025             : 
    1026      520860 :     cost_index(pathnode, root, loop_count, partial_path);
    1027             : 
    1028      520860 :     return pathnode;
    1029             : }
    1030             : 
    1031             : /*
    1032             :  * create_bitmap_heap_path
    1033             :  *    Creates a path node for a bitmap scan.
    1034             :  *
    1035             :  * 'bitmapqual' is a tree of IndexPath, BitmapAndPath, and BitmapOrPath nodes.
    1036             :  * 'required_outer' is the set of outer relids for a parameterized path.
    1037             :  * 'loop_count' is the number of repetitions of the indexscan to factor into
    1038             :  *      estimates of caching behavior.
    1039             :  *
    1040             :  * loop_count should match the value used when creating the component
    1041             :  * IndexPaths.
    1042             :  */
    1043             : BitmapHeapPath *
    1044      248756 : create_bitmap_heap_path(PlannerInfo *root,
    1045             :                         RelOptInfo *rel,
    1046             :                         Path *bitmapqual,
    1047             :                         Relids required_outer,
    1048             :                         double loop_count,
    1049             :                         int parallel_degree)
    1050             : {
    1051      248756 :     BitmapHeapPath *pathnode = makeNode(BitmapHeapPath);
    1052             : 
    1053      248756 :     pathnode->path.pathtype = T_BitmapHeapScan;
    1054      248756 :     pathnode->path.parent = rel;
    1055      248756 :     pathnode->path.pathtarget = rel->reltarget;
    1056      248756 :     pathnode->path.param_info = get_baserel_parampathinfo(root, rel,
    1057             :                                                           required_outer);
    1058      248756 :     pathnode->path.parallel_aware = (parallel_degree > 0);
    1059      248756 :     pathnode->path.parallel_safe = rel->consider_parallel;
    1060      248756 :     pathnode->path.parallel_workers = parallel_degree;
    1061      248756 :     pathnode->path.pathkeys = NIL;   /* always unordered */
    1062             : 
    1063      248756 :     pathnode->bitmapqual = bitmapqual;
    1064             : 
    1065      248756 :     cost_bitmap_heap_scan(&pathnode->path, root, rel,
    1066             :                           pathnode->path.param_info,
    1067             :                           bitmapqual, loop_count);
    1068             : 
    1069      248756 :     return pathnode;
    1070             : }
    1071             : 
    1072             : /*
    1073             :  * create_bitmap_and_path
    1074             :  *    Creates a path node representing a BitmapAnd.
    1075             :  */
    1076             : BitmapAndPath *
    1077       24720 : create_bitmap_and_path(PlannerInfo *root,
    1078             :                        RelOptInfo *rel,
    1079             :                        List *bitmapquals)
    1080             : {
    1081       24720 :     BitmapAndPath *pathnode = makeNode(BitmapAndPath);
    1082       24720 :     Relids      required_outer = NULL;
    1083             :     ListCell   *lc;
    1084             : 
    1085       24720 :     pathnode->path.pathtype = T_BitmapAnd;
    1086       24720 :     pathnode->path.parent = rel;
    1087       24720 :     pathnode->path.pathtarget = rel->reltarget;
    1088             : 
    1089             :     /*
    1090             :      * Identify the required outer rels as the union of what the child paths
    1091             :      * depend on.  (Alternatively, we could insist that the caller pass this
    1092             :      * in, but it's more convenient and reliable to compute it here.)
    1093             :      */
    1094       74160 :     foreach(lc, bitmapquals)
    1095             :     {
    1096       49440 :         Path       *bitmapqual = (Path *) lfirst(lc);
    1097             : 
    1098       49440 :         required_outer = bms_add_members(required_outer,
    1099       49440 :                                          PATH_REQ_OUTER(bitmapqual));
    1100             :     }
    1101       24720 :     pathnode->path.param_info = get_baserel_parampathinfo(root, rel,
    1102             :                                                           required_outer);
    1103             : 
    1104             :     /*
    1105             :      * Currently, a BitmapHeapPath, BitmapAndPath, or BitmapOrPath will be
    1106             :      * parallel-safe if and only if rel->consider_parallel is set.  So, we can
    1107             :      * set the flag for this path based only on the relation-level flag,
    1108             :      * without actually iterating over the list of children.
    1109             :      */
    1110       24720 :     pathnode->path.parallel_aware = false;
    1111       24720 :     pathnode->path.parallel_safe = rel->consider_parallel;
    1112       24720 :     pathnode->path.parallel_workers = 0;
    1113             : 
    1114       24720 :     pathnode->path.pathkeys = NIL;   /* always unordered */
    1115             : 
    1116       24720 :     pathnode->bitmapquals = bitmapquals;
    1117             : 
    1118             :     /* this sets bitmapselectivity as well as the regular cost fields: */
    1119       24720 :     cost_bitmap_and_node(pathnode, root);
    1120             : 
    1121       24720 :     return pathnode;
    1122             : }
    1123             : 
    1124             : /*
    1125             :  * create_bitmap_or_path
    1126             :  *    Creates a path node representing a BitmapOr.
    1127             :  */
    1128             : BitmapOrPath *
    1129         712 : create_bitmap_or_path(PlannerInfo *root,
    1130             :                       RelOptInfo *rel,
    1131             :                       List *bitmapquals)
    1132             : {
    1133         712 :     BitmapOrPath *pathnode = makeNode(BitmapOrPath);
    1134         712 :     Relids      required_outer = NULL;
    1135             :     ListCell   *lc;
    1136             : 
    1137         712 :     pathnode->path.pathtype = T_BitmapOr;
    1138         712 :     pathnode->path.parent = rel;
    1139         712 :     pathnode->path.pathtarget = rel->reltarget;
    1140             : 
    1141             :     /*
    1142             :      * Identify the required outer rels as the union of what the child paths
    1143             :      * depend on.  (Alternatively, we could insist that the caller pass this
    1144             :      * in, but it's more convenient and reliable to compute it here.)
    1145             :      */
    1146        2196 :     foreach(lc, bitmapquals)
    1147             :     {
    1148        1484 :         Path       *bitmapqual = (Path *) lfirst(lc);
    1149             : 
    1150        1484 :         required_outer = bms_add_members(required_outer,
    1151        1484 :                                          PATH_REQ_OUTER(bitmapqual));
    1152             :     }
    1153         712 :     pathnode->path.param_info = get_baserel_parampathinfo(root, rel,
    1154             :                                                           required_outer);
    1155             : 
    1156             :     /*
    1157             :      * Currently, a BitmapHeapPath, BitmapAndPath, or BitmapOrPath will be
    1158             :      * parallel-safe if and only if rel->consider_parallel is set.  So, we can
    1159             :      * set the flag for this path based only on the relation-level flag,
    1160             :      * without actually iterating over the list of children.
    1161             :      */
    1162         712 :     pathnode->path.parallel_aware = false;
    1163         712 :     pathnode->path.parallel_safe = rel->consider_parallel;
    1164         712 :     pathnode->path.parallel_workers = 0;
    1165             : 
    1166         712 :     pathnode->path.pathkeys = NIL;   /* always unordered */
    1167             : 
    1168         712 :     pathnode->bitmapquals = bitmapquals;
    1169             : 
    1170             :     /* this sets bitmapselectivity as well as the regular cost fields: */
    1171         712 :     cost_bitmap_or_node(pathnode, root);
    1172             : 
    1173         712 :     return pathnode;
    1174             : }
    1175             : 
    1176             : /*
    1177             :  * create_tidscan_path
    1178             :  *    Creates a path corresponding to a scan by TID, returning the pathnode.
    1179             :  */
    1180             : TidPath *
    1181         756 : create_tidscan_path(PlannerInfo *root, RelOptInfo *rel, List *tidquals,
    1182             :                     Relids required_outer)
    1183             : {
    1184         756 :     TidPath    *pathnode = makeNode(TidPath);
    1185             : 
    1186         756 :     pathnode->path.pathtype = T_TidScan;
    1187         756 :     pathnode->path.parent = rel;
    1188         756 :     pathnode->path.pathtarget = rel->reltarget;
    1189         756 :     pathnode->path.param_info = get_baserel_parampathinfo(root, rel,
    1190             :                                                           required_outer);
    1191         756 :     pathnode->path.parallel_aware = false;
    1192         756 :     pathnode->path.parallel_safe = rel->consider_parallel;
    1193         756 :     pathnode->path.parallel_workers = 0;
    1194         756 :     pathnode->path.pathkeys = NIL;   /* always unordered */
    1195             : 
    1196         756 :     pathnode->tidquals = tidquals;
    1197             : 
    1198         756 :     cost_tidscan(&pathnode->path, root, rel, tidquals,
    1199             :                  pathnode->path.param_info);
    1200             : 
    1201         756 :     return pathnode;
    1202             : }
    1203             : 
    1204             : /*
    1205             :  * create_tidrangescan_path
    1206             :  *    Creates a path corresponding to a scan by a range of TIDs, returning
    1207             :  *    the pathnode.
    1208             :  */
    1209             : TidRangePath *
    1210         202 : create_tidrangescan_path(PlannerInfo *root, RelOptInfo *rel,
    1211             :                          List *tidrangequals, Relids required_outer)
    1212             : {
    1213         202 :     TidRangePath *pathnode = makeNode(TidRangePath);
    1214             : 
    1215         202 :     pathnode->path.pathtype = T_TidRangeScan;
    1216         202 :     pathnode->path.parent = rel;
    1217         202 :     pathnode->path.pathtarget = rel->reltarget;
    1218         202 :     pathnode->path.param_info = get_baserel_parampathinfo(root, rel,
    1219             :                                                           required_outer);
    1220         202 :     pathnode->path.parallel_aware = false;
    1221         202 :     pathnode->path.parallel_safe = rel->consider_parallel;
    1222         202 :     pathnode->path.parallel_workers = 0;
    1223         202 :     pathnode->path.pathkeys = NIL;   /* always unordered */
    1224             : 
    1225         202 :     pathnode->tidrangequals = tidrangequals;
    1226             : 
    1227         202 :     cost_tidrangescan(&pathnode->path, root, rel, tidrangequals,
    1228             :                       pathnode->path.param_info);
    1229             : 
    1230         202 :     return pathnode;
    1231             : }
    1232             : 
    1233             : /*
    1234             :  * create_append_path
    1235             :  *    Creates a path corresponding to an Append plan, returning the
    1236             :  *    pathnode.
    1237             :  *
    1238             :  * Note that we must handle subpaths = NIL, representing a dummy access path.
    1239             :  * Also, there are callers that pass root = NULL.
    1240             :  */
    1241             : AppendPath *
    1242       62696 : create_append_path(PlannerInfo *root,
    1243             :                    RelOptInfo *rel,
    1244             :                    List *subpaths, List *partial_subpaths,
    1245             :                    List *pathkeys, Relids required_outer,
    1246             :                    int parallel_workers, bool parallel_aware,
    1247             :                    double rows)
    1248             : {
    1249       62696 :     AppendPath *pathnode = makeNode(AppendPath);
    1250             :     ListCell   *l;
    1251             : 
    1252             :     Assert(!parallel_aware || parallel_workers > 0);
    1253             : 
    1254       62696 :     pathnode->path.pathtype = T_Append;
    1255       62696 :     pathnode->path.parent = rel;
    1256       62696 :     pathnode->path.pathtarget = rel->reltarget;
    1257             : 
    1258             :     /*
    1259             :      * If this is for a baserel (not a join or non-leaf partition), we prefer
    1260             :      * to apply get_baserel_parampathinfo to construct a full ParamPathInfo
    1261             :      * for the path.  This supports building a Memoize path atop this path,
    1262             :      * and if this is a partitioned table the info may be useful for run-time
    1263             :      * pruning (cf make_partition_pruneinfo()).
    1264             :      *
    1265             :      * However, if we don't have "root" then that won't work and we fall back
    1266             :      * on the simpler get_appendrel_parampathinfo.  There's no point in doing
    1267             :      * the more expensive thing for a dummy path, either.
    1268             :      */
    1269       62696 :     if (rel->reloptkind == RELOPT_BASEREL && root && subpaths != NIL)
    1270       27670 :         pathnode->path.param_info = get_baserel_parampathinfo(root,
    1271             :                                                               rel,
    1272             :                                                               required_outer);
    1273             :     else
    1274       35026 :         pathnode->path.param_info = get_appendrel_parampathinfo(rel,
    1275             :                                                                 required_outer);
    1276             : 
    1277       62696 :     pathnode->path.parallel_aware = parallel_aware;
    1278       62696 :     pathnode->path.parallel_safe = rel->consider_parallel;
    1279       62696 :     pathnode->path.parallel_workers = parallel_workers;
    1280       62696 :     pathnode->path.pathkeys = pathkeys;
    1281             : 
    1282             :     /*
    1283             :      * For parallel append, non-partial paths are sorted by descending total
    1284             :      * costs. That way, the total time to finish all non-partial paths is
    1285             :      * minimized.  Also, the partial paths are sorted by descending startup
    1286             :      * costs.  There may be some paths that require to do startup work by a
    1287             :      * single worker.  In such case, it's better for workers to choose the
    1288             :      * expensive ones first, whereas the leader should choose the cheapest
    1289             :      * startup plan.
    1290             :      */
    1291       62696 :     if (pathnode->path.parallel_aware)
    1292             :     {
    1293             :         /*
    1294             :          * We mustn't fiddle with the order of subpaths when the Append has
    1295             :          * pathkeys.  The order they're listed in is critical to keeping the
    1296             :          * pathkeys valid.
    1297             :          */
    1298             :         Assert(pathkeys == NIL);
    1299             : 
    1300       20890 :         list_sort(subpaths, append_total_cost_compare);
    1301       20890 :         list_sort(partial_subpaths, append_startup_cost_compare);
    1302             :     }
    1303       62696 :     pathnode->first_partial_path = list_length(subpaths);
    1304       62696 :     pathnode->subpaths = list_concat(subpaths, partial_subpaths);
    1305             : 
    1306             :     /*
    1307             :      * Apply query-wide LIMIT if known and path is for sole base relation.
    1308             :      * (Handling this at this low level is a bit klugy.)
    1309             :      */
    1310       62696 :     if (root != NULL && bms_equal(rel->relids, root->all_query_rels))
    1311       34520 :         pathnode->limit_tuples = root->limit_tuples;
    1312             :     else
    1313       28176 :         pathnode->limit_tuples = -1.0;
    1314             : 
    1315      207368 :     foreach(l, pathnode->subpaths)
    1316             :     {
    1317      144672 :         Path       *subpath = (Path *) lfirst(l);
    1318             : 
    1319      256480 :         pathnode->path.parallel_safe = pathnode->path.parallel_safe &&
    1320      111808 :             subpath->parallel_safe;
    1321             : 
    1322             :         /* All child paths must have same parameterization */
    1323             :         Assert(bms_equal(PATH_REQ_OUTER(subpath), required_outer));
    1324             :     }
    1325             : 
    1326             :     Assert(!parallel_aware || pathnode->path.parallel_safe);
    1327             : 
    1328             :     /*
    1329             :      * If there's exactly one child path then the output of the Append is
    1330             :      * necessarily ordered the same as the child's, so we can inherit the
    1331             :      * child's pathkeys if any, overriding whatever the caller might've said.
    1332             :      * Furthermore, if the child's parallel awareness matches the Append's,
    1333             :      * then the Append is a no-op and will be discarded later (in setrefs.c).
    1334             :      * Then we can inherit the child's size and cost too, effectively charging
    1335             :      * zero for the Append.  Otherwise, we must do the normal costsize
    1336             :      * calculation.
    1337             :      */
    1338       62696 :     if (list_length(pathnode->subpaths) == 1)
    1339             :     {
    1340       20086 :         Path       *child = (Path *) linitial(pathnode->subpaths);
    1341             : 
    1342       20086 :         if (child->parallel_aware == parallel_aware)
    1343             :         {
    1344       19876 :             pathnode->path.rows = child->rows;
    1345       19876 :             pathnode->path.startup_cost = child->startup_cost;
    1346       19876 :             pathnode->path.total_cost = child->total_cost;
    1347             :         }
    1348             :         else
    1349         210 :             cost_append(pathnode);
    1350             :         /* Must do this last, else cost_append complains */
    1351       20086 :         pathnode->path.pathkeys = child->pathkeys;
    1352             :     }
    1353             :     else
    1354       42610 :         cost_append(pathnode);
    1355             : 
    1356             :     /* If the caller provided a row estimate, override the computed value. */
    1357       62696 :     if (rows >= 0)
    1358         582 :         pathnode->path.rows = rows;
    1359             : 
    1360       62696 :     return pathnode;
    1361             : }
    1362             : 
    1363             : /*
    1364             :  * append_total_cost_compare
    1365             :  *    list_sort comparator for sorting append child paths
    1366             :  *    by total_cost descending
    1367             :  *
    1368             :  * For equal total costs, we fall back to comparing startup costs; if those
    1369             :  * are equal too, break ties using bms_compare on the paths' relids.
    1370             :  * (This is to avoid getting unpredictable results from list_sort.)
    1371             :  */
    1372             : static int
    1373        1480 : append_total_cost_compare(const ListCell *a, const ListCell *b)
    1374             : {
    1375        1480 :     Path       *path1 = (Path *) lfirst(a);
    1376        1480 :     Path       *path2 = (Path *) lfirst(b);
    1377             :     int         cmp;
    1378             : 
    1379        1480 :     cmp = compare_path_costs(path1, path2, TOTAL_COST);
    1380        1480 :     if (cmp != 0)
    1381        1210 :         return -cmp;
    1382         270 :     return bms_compare(path1->parent->relids, path2->parent->relids);
    1383             : }
    1384             : 
    1385             : /*
    1386             :  * append_startup_cost_compare
    1387             :  *    list_sort comparator for sorting append child paths
    1388             :  *    by startup_cost descending
    1389             :  *
    1390             :  * For equal startup costs, we fall back to comparing total costs; if those
    1391             :  * are equal too, break ties using bms_compare on the paths' relids.
    1392             :  * (This is to avoid getting unpredictable results from list_sort.)
    1393             :  */
    1394             : static int
    1395       31914 : append_startup_cost_compare(const ListCell *a, const ListCell *b)
    1396             : {
    1397       31914 :     Path       *path1 = (Path *) lfirst(a);
    1398       31914 :     Path       *path2 = (Path *) lfirst(b);
    1399             :     int         cmp;
    1400             : 
    1401       31914 :     cmp = compare_path_costs(path1, path2, STARTUP_COST);
    1402       31914 :     if (cmp != 0)
    1403       12360 :         return -cmp;
    1404       19554 :     return bms_compare(path1->parent->relids, path2->parent->relids);
    1405             : }
    1406             : 
    1407             : /*
    1408             :  * create_merge_append_path
    1409             :  *    Creates a path corresponding to a MergeAppend plan, returning the
    1410             :  *    pathnode.
    1411             :  */
    1412             : MergeAppendPath *
    1413        3680 : create_merge_append_path(PlannerInfo *root,
    1414             :                          RelOptInfo *rel,
    1415             :                          List *subpaths,
    1416             :                          List *pathkeys,
    1417             :                          Relids required_outer)
    1418             : {
    1419        3680 :     MergeAppendPath *pathnode = makeNode(MergeAppendPath);
    1420             :     Cost        input_startup_cost;
    1421             :     Cost        input_total_cost;
    1422             :     ListCell   *l;
    1423             : 
    1424        3680 :     pathnode->path.pathtype = T_MergeAppend;
    1425        3680 :     pathnode->path.parent = rel;
    1426        3680 :     pathnode->path.pathtarget = rel->reltarget;
    1427        3680 :     pathnode->path.param_info = get_appendrel_parampathinfo(rel,
    1428             :                                                             required_outer);
    1429        3680 :     pathnode->path.parallel_aware = false;
    1430        3680 :     pathnode->path.parallel_safe = rel->consider_parallel;
    1431        3680 :     pathnode->path.parallel_workers = 0;
    1432        3680 :     pathnode->path.pathkeys = pathkeys;
    1433        3680 :     pathnode->subpaths = subpaths;
    1434             : 
    1435             :     /*
    1436             :      * Apply query-wide LIMIT if known and path is for sole base relation.
    1437             :      * (Handling this at this low level is a bit klugy.)
    1438             :      */
    1439        3680 :     if (bms_equal(rel->relids, root->all_query_rels))
    1440        2018 :         pathnode->limit_tuples = root->limit_tuples;
    1441             :     else
    1442        1662 :         pathnode->limit_tuples = -1.0;
    1443             : 
    1444             :     /*
    1445             :      * Add up the sizes and costs of the input paths.
    1446             :      */
    1447        3680 :     pathnode->path.rows = 0;
    1448        3680 :     input_startup_cost = 0;
    1449        3680 :     input_total_cost = 0;
    1450       13902 :     foreach(l, subpaths)
    1451             :     {
    1452       10222 :         Path       *subpath = (Path *) lfirst(l);
    1453             : 
    1454       10222 :         pathnode->path.rows += subpath->rows;
    1455       18408 :         pathnode->path.parallel_safe = pathnode->path.parallel_safe &&
    1456        8186 :             subpath->parallel_safe;
    1457             : 
    1458       10222 :         if (pathkeys_contained_in(pathkeys, subpath->pathkeys))
    1459             :         {
    1460             :             /* Subpath is adequately ordered, we won't need to sort it */
    1461        9942 :             input_startup_cost += subpath->startup_cost;
    1462        9942 :             input_total_cost += subpath->total_cost;
    1463             :         }
    1464             :         else
    1465             :         {
    1466             :             /* We'll need to insert a Sort node, so include cost for that */
    1467             :             Path        sort_path;  /* dummy for result of cost_sort */
    1468             : 
    1469         280 :             cost_sort(&sort_path,
    1470             :                       root,
    1471             :                       pathkeys,
    1472             :                       subpath->total_cost,
    1473         280 :                       subpath->parent->tuples,
    1474         280 :                       subpath->pathtarget->width,
    1475             :                       0.0,
    1476             :                       work_mem,
    1477             :                       pathnode->limit_tuples);
    1478         280 :             input_startup_cost += sort_path.startup_cost;
    1479         280 :             input_total_cost += sort_path.total_cost;
    1480             :         }
    1481             : 
    1482             :         /* All child paths must have same parameterization */
    1483             :         Assert(bms_equal(PATH_REQ_OUTER(subpath), required_outer));
    1484             :     }
    1485             : 
    1486             :     /*
    1487             :      * Now we can compute total costs of the MergeAppend.  If there's exactly
    1488             :      * one child path and its parallel awareness matches that of the
    1489             :      * MergeAppend, then the MergeAppend is a no-op and will be discarded
    1490             :      * later (in setrefs.c); otherwise we do the normal cost calculation.
    1491             :      */
    1492        3680 :     if (list_length(subpaths) == 1 &&
    1493         110 :         ((Path *) linitial(subpaths))->parallel_aware ==
    1494         110 :         pathnode->path.parallel_aware)
    1495             :     {
    1496         110 :         pathnode->path.startup_cost = input_startup_cost;
    1497         110 :         pathnode->path.total_cost = input_total_cost;
    1498             :     }
    1499             :     else
    1500        3570 :         cost_merge_append(&pathnode->path, root,
    1501             :                           pathkeys, list_length(subpaths),
    1502             :                           input_startup_cost, input_total_cost,
    1503             :                           pathnode->path.rows);
    1504             : 
    1505        3680 :     return pathnode;
    1506             : }
    1507             : 
    1508             : /*
    1509             :  * create_group_result_path
    1510             :  *    Creates a path representing a Result-and-nothing-else plan.
    1511             :  *
    1512             :  * This is only used for degenerate grouping cases, in which we know we
    1513             :  * need to produce one result row, possibly filtered by a HAVING qual.
    1514             :  */
    1515             : GroupResultPath *
    1516      193730 : create_group_result_path(PlannerInfo *root, RelOptInfo *rel,
    1517             :                          PathTarget *target, List *havingqual)
    1518             : {
    1519      193730 :     GroupResultPath *pathnode = makeNode(GroupResultPath);
    1520             : 
    1521      193730 :     pathnode->path.pathtype = T_Result;
    1522      193730 :     pathnode->path.parent = rel;
    1523      193730 :     pathnode->path.pathtarget = target;
    1524      193730 :     pathnode->path.param_info = NULL;    /* there are no other rels... */
    1525      193730 :     pathnode->path.parallel_aware = false;
    1526      193730 :     pathnode->path.parallel_safe = rel->consider_parallel;
    1527      193730 :     pathnode->path.parallel_workers = 0;
    1528      193730 :     pathnode->path.pathkeys = NIL;
    1529      193730 :     pathnode->quals = havingqual;
    1530             : 
    1531             :     /*
    1532             :      * We can't quite use cost_resultscan() because the quals we want to
    1533             :      * account for are not baserestrict quals of the rel.  Might as well just
    1534             :      * hack it here.
    1535             :      */
    1536      193730 :     pathnode->path.rows = 1;
    1537      193730 :     pathnode->path.startup_cost = target->cost.startup;
    1538      193730 :     pathnode->path.total_cost = target->cost.startup +
    1539      193730 :         cpu_tuple_cost + target->cost.per_tuple;
    1540             : 
    1541             :     /*
    1542             :      * Add cost of qual, if any --- but we ignore its selectivity, since our
    1543             :      * rowcount estimate should be 1 no matter what the qual is.
    1544             :      */
    1545      193730 :     if (havingqual)
    1546             :     {
    1547             :         QualCost    qual_cost;
    1548             : 
    1549         486 :         cost_qual_eval(&qual_cost, havingqual, root);
    1550             :         /* havingqual is evaluated once at startup */
    1551         486 :         pathnode->path.startup_cost += qual_cost.startup + qual_cost.per_tuple;
    1552         486 :         pathnode->path.total_cost += qual_cost.startup + qual_cost.per_tuple;
    1553             :     }
    1554             : 
    1555      193730 :     return pathnode;
    1556             : }
    1557             : 
    1558             : /*
    1559             :  * create_material_path
    1560             :  *    Creates a path corresponding to a Material plan, returning the
    1561             :  *    pathnode.
    1562             :  */
    1563             : MaterialPath *
    1564      343604 : create_material_path(RelOptInfo *rel, Path *subpath)
    1565             : {
    1566      343604 :     MaterialPath *pathnode = makeNode(MaterialPath);
    1567             : 
    1568             :     Assert(subpath->parent == rel);
    1569             : 
    1570      343604 :     pathnode->path.pathtype = T_Material;
    1571      343604 :     pathnode->path.parent = rel;
    1572      343604 :     pathnode->path.pathtarget = rel->reltarget;
    1573      343604 :     pathnode->path.param_info = subpath->param_info;
    1574      343604 :     pathnode->path.parallel_aware = false;
    1575      639156 :     pathnode->path.parallel_safe = rel->consider_parallel &&
    1576      295552 :         subpath->parallel_safe;
    1577      343604 :     pathnode->path.parallel_workers = subpath->parallel_workers;
    1578      343604 :     pathnode->path.pathkeys = subpath->pathkeys;
    1579             : 
    1580      343604 :     pathnode->subpath = subpath;
    1581             : 
    1582      343604 :     cost_material(&pathnode->path,
    1583             :                   subpath->startup_cost,
    1584             :                   subpath->total_cost,
    1585             :                   subpath->rows,
    1586      343604 :                   subpath->pathtarget->width);
    1587             : 
    1588      343604 :     return pathnode;
    1589             : }
    1590             : 
    1591             : /*
    1592             :  * create_memoize_path
    1593             :  *    Creates a path corresponding to a Memoize plan, returning the pathnode.
    1594             :  */
    1595             : MemoizePath *
    1596      181632 : create_memoize_path(PlannerInfo *root, RelOptInfo *rel, Path *subpath,
    1597             :                     List *param_exprs, List *hash_operators,
    1598             :                     bool singlerow, bool binary_mode, double calls)
    1599             : {
    1600      181632 :     MemoizePath *pathnode = makeNode(MemoizePath);
    1601             : 
    1602             :     Assert(subpath->parent == rel);
    1603             : 
    1604      181632 :     pathnode->path.pathtype = T_Memoize;
    1605      181632 :     pathnode->path.parent = rel;
    1606      181632 :     pathnode->path.pathtarget = rel->reltarget;
    1607      181632 :     pathnode->path.param_info = subpath->param_info;
    1608      181632 :     pathnode->path.parallel_aware = false;
    1609      350284 :     pathnode->path.parallel_safe = rel->consider_parallel &&
    1610      168652 :         subpath->parallel_safe;
    1611      181632 :     pathnode->path.parallel_workers = subpath->parallel_workers;
    1612      181632 :     pathnode->path.pathkeys = subpath->pathkeys;
    1613             : 
    1614      181632 :     pathnode->subpath = subpath;
    1615      181632 :     pathnode->hash_operators = hash_operators;
    1616      181632 :     pathnode->param_exprs = param_exprs;
    1617      181632 :     pathnode->singlerow = singlerow;
    1618      181632 :     pathnode->binary_mode = binary_mode;
    1619      181632 :     pathnode->calls = calls;
    1620             : 
    1621             :     /*
    1622             :      * For now we set est_entries to 0.  cost_memoize_rescan() does all the
    1623             :      * hard work to determine how many cache entries there are likely to be,
    1624             :      * so it seems best to leave it up to that function to fill this field in.
    1625             :      * If left at 0, the executor will make a guess at a good value.
    1626             :      */
    1627      181632 :     pathnode->est_entries = 0;
    1628             : 
    1629             :     /*
    1630             :      * Add a small additional charge for caching the first entry.  All the
    1631             :      * harder calculations for rescans are performed in cost_memoize_rescan().
    1632             :      */
    1633      181632 :     pathnode->path.startup_cost = subpath->startup_cost + cpu_tuple_cost;
    1634      181632 :     pathnode->path.total_cost = subpath->total_cost + cpu_tuple_cost;
    1635      181632 :     pathnode->path.rows = subpath->rows;
    1636             : 
    1637      181632 :     return pathnode;
    1638             : }
    1639             : 
    1640             : /*
    1641             :  * create_unique_path
    1642             :  *    Creates a path representing elimination of distinct rows from the
    1643             :  *    input data.  Distinct-ness is defined according to the needs of the
    1644             :  *    semijoin represented by sjinfo.  If it is not possible to identify
    1645             :  *    how to make the data unique, NULL is returned.
    1646             :  *
    1647             :  * If used at all, this is likely to be called repeatedly on the same rel;
    1648             :  * and the input subpath should always be the same (the cheapest_total path
    1649             :  * for the rel).  So we cache the result.
    1650             :  */
    1651             : UniquePath *
    1652       21244 : create_unique_path(PlannerInfo *root, RelOptInfo *rel, Path *subpath,
    1653             :                    SpecialJoinInfo *sjinfo)
    1654             : {
    1655             :     UniquePath *pathnode;
    1656             :     Path        sort_path;      /* dummy for result of cost_sort */
    1657             :     Path        agg_path;       /* dummy for result of cost_agg */
    1658             :     MemoryContext oldcontext;
    1659             :     int         numCols;
    1660             : 
    1661             :     /* Caller made a mistake if subpath isn't cheapest_total ... */
    1662             :     Assert(subpath == rel->cheapest_total_path);
    1663             :     Assert(subpath->parent == rel);
    1664             :     /* ... or if SpecialJoinInfo is the wrong one */
    1665             :     Assert(sjinfo->jointype == JOIN_SEMI);
    1666             :     Assert(bms_equal(rel->relids, sjinfo->syn_righthand));
    1667             : 
    1668             :     /* If result already cached, return it */
    1669       21244 :     if (rel->cheapest_unique_path)
    1670       18108 :         return (UniquePath *) rel->cheapest_unique_path;
    1671             : 
    1672             :     /* If it's not possible to unique-ify, return NULL */
    1673        3136 :     if (!(sjinfo->semi_can_btree || sjinfo->semi_can_hash))
    1674         102 :         return NULL;
    1675             : 
    1676             :     /*
    1677             :      * When called during GEQO join planning, we are in a short-lived memory
    1678             :      * context.  We must make sure that the path and any subsidiary data
    1679             :      * structures created for a baserel survive the GEQO cycle, else the
    1680             :      * baserel is trashed for future GEQO cycles.  On the other hand, when we
    1681             :      * are creating those for a joinrel during GEQO, we don't want them to
    1682             :      * clutter the main planning context.  Upshot is that the best solution is
    1683             :      * to explicitly allocate memory in the same context the given RelOptInfo
    1684             :      * is in.
    1685             :      */
    1686        3034 :     oldcontext = MemoryContextSwitchTo(GetMemoryChunkContext(rel));
    1687             : 
    1688        3034 :     pathnode = makeNode(UniquePath);
    1689             : 
    1690        3034 :     pathnode->path.pathtype = T_Unique;
    1691        3034 :     pathnode->path.parent = rel;
    1692        3034 :     pathnode->path.pathtarget = rel->reltarget;
    1693        3034 :     pathnode->path.param_info = subpath->param_info;
    1694        3034 :     pathnode->path.parallel_aware = false;
    1695        5800 :     pathnode->path.parallel_safe = rel->consider_parallel &&
    1696        2766 :         subpath->parallel_safe;
    1697        3034 :     pathnode->path.parallel_workers = subpath->parallel_workers;
    1698             : 
    1699             :     /*
    1700             :      * Assume the output is unsorted, since we don't necessarily have pathkeys
    1701             :      * to represent it.  (This might get overridden below.)
    1702             :      */
    1703        3034 :     pathnode->path.pathkeys = NIL;
    1704             : 
    1705        3034 :     pathnode->subpath = subpath;
    1706        3034 :     pathnode->in_operators = sjinfo->semi_operators;
    1707        3034 :     pathnode->uniq_exprs = sjinfo->semi_rhs_exprs;
    1708             : 
    1709             :     /*
    1710             :      * If the input is a relation and it has a unique index that proves the
    1711             :      * semi_rhs_exprs are unique, then we don't need to do anything.  Note
    1712             :      * that relation_has_unique_index_for automatically considers restriction
    1713             :      * clauses for the rel, as well.
    1714             :      */
    1715        3702 :     if (rel->rtekind == RTE_RELATION && sjinfo->semi_can_btree &&
    1716         668 :         relation_has_unique_index_for(root, rel, NIL,
    1717             :                                       sjinfo->semi_rhs_exprs,
    1718             :                                       sjinfo->semi_operators))
    1719             :     {
    1720           0 :         pathnode->umethod = UNIQUE_PATH_NOOP;
    1721           0 :         pathnode->path.rows = rel->rows;
    1722           0 :         pathnode->path.startup_cost = subpath->startup_cost;
    1723           0 :         pathnode->path.total_cost = subpath->total_cost;
    1724           0 :         pathnode->path.pathkeys = subpath->pathkeys;
    1725             : 
    1726           0 :         rel->cheapest_unique_path = (Path *) pathnode;
    1727             : 
    1728           0 :         MemoryContextSwitchTo(oldcontext);
    1729             : 
    1730           0 :         return pathnode;
    1731             :     }
    1732             : 
    1733             :     /*
    1734             :      * If the input is a subquery whose output must be unique already, then we
    1735             :      * don't need to do anything.  The test for uniqueness has to consider
    1736             :      * exactly which columns we are extracting; for example "SELECT DISTINCT
    1737             :      * x,y" doesn't guarantee that x alone is distinct. So we cannot check for
    1738             :      * this optimization unless semi_rhs_exprs consists only of simple Vars
    1739             :      * referencing subquery outputs.  (Possibly we could do something with
    1740             :      * expressions in the subquery outputs, too, but for now keep it simple.)
    1741             :      */
    1742        3034 :     if (rel->rtekind == RTE_SUBQUERY)
    1743             :     {
    1744         512 :         RangeTblEntry *rte = planner_rt_fetch(rel->relid, root);
    1745             : 
    1746         512 :         if (query_supports_distinctness(rte->subquery))
    1747             :         {
    1748             :             List       *sub_tlist_colnos;
    1749             : 
    1750         476 :             sub_tlist_colnos = translate_sub_tlist(sjinfo->semi_rhs_exprs,
    1751         476 :                                                    rel->relid);
    1752             : 
    1753         538 :             if (sub_tlist_colnos &&
    1754          62 :                 query_is_distinct_for(rte->subquery,
    1755             :                                       sub_tlist_colnos,
    1756             :                                       sjinfo->semi_operators))
    1757             :             {
    1758           0 :                 pathnode->umethod = UNIQUE_PATH_NOOP;
    1759           0 :                 pathnode->path.rows = rel->rows;
    1760           0 :                 pathnode->path.startup_cost = subpath->startup_cost;
    1761           0 :                 pathnode->path.total_cost = subpath->total_cost;
    1762           0 :                 pathnode->path.pathkeys = subpath->pathkeys;
    1763             : 
    1764           0 :                 rel->cheapest_unique_path = (Path *) pathnode;
    1765             : 
    1766           0 :                 MemoryContextSwitchTo(oldcontext);
    1767             : 
    1768           0 :                 return pathnode;
    1769             :             }
    1770             :         }
    1771             :     }
    1772             : 
    1773             :     /* Estimate number of output rows */
    1774        3034 :     pathnode->path.rows = estimate_num_groups(root,
    1775             :                                               sjinfo->semi_rhs_exprs,
    1776             :                                               rel->rows,
    1777             :                                               NULL,
    1778             :                                               NULL);
    1779        3034 :     numCols = list_length(sjinfo->semi_rhs_exprs);
    1780             : 
    1781        3034 :     if (sjinfo->semi_can_btree)
    1782             :     {
    1783             :         /*
    1784             :          * Estimate cost for sort+unique implementation
    1785             :          */
    1786        3034 :         cost_sort(&sort_path, root, NIL,
    1787             :                   subpath->total_cost,
    1788             :                   rel->rows,
    1789        3034 :                   subpath->pathtarget->width,
    1790             :                   0.0,
    1791             :                   work_mem,
    1792             :                   -1.0);
    1793             : 
    1794             :         /*
    1795             :          * Charge one cpu_operator_cost per comparison per input tuple. We
    1796             :          * assume all columns get compared at most of the tuples. (XXX
    1797             :          * probably this is an overestimate.)  This should agree with
    1798             :          * create_upper_unique_path.
    1799             :          */
    1800        3034 :         sort_path.total_cost += cpu_operator_cost * rel->rows * numCols;
    1801             :     }
    1802             : 
    1803        3034 :     if (sjinfo->semi_can_hash)
    1804             :     {
    1805             :         /*
    1806             :          * Estimate the overhead per hashtable entry at 64 bytes (same as in
    1807             :          * planner.c).
    1808             :          */
    1809        3034 :         int         hashentrysize = subpath->pathtarget->width + 64;
    1810             : 
    1811        3034 :         if (hashentrysize * pathnode->path.rows > get_hash_memory_limit())
    1812             :         {
    1813             :             /*
    1814             :              * We should not try to hash.  Hack the SpecialJoinInfo to
    1815             :              * remember this, in case we come through here again.
    1816             :              */
    1817           0 :             sjinfo->semi_can_hash = false;
    1818             :         }
    1819             :         else
    1820        3034 :             cost_agg(&agg_path, root,
    1821             :                      AGG_HASHED, NULL,
    1822             :                      numCols, pathnode->path.rows,
    1823             :                      NIL,
    1824             :                      subpath->startup_cost,
    1825             :                      subpath->total_cost,
    1826             :                      rel->rows,
    1827        3034 :                      subpath->pathtarget->width);
    1828             :     }
    1829             : 
    1830        3034 :     if (sjinfo->semi_can_btree && sjinfo->semi_can_hash)
    1831             :     {
    1832        3034 :         if (agg_path.total_cost < sort_path.total_cost)
    1833        2958 :             pathnode->umethod = UNIQUE_PATH_HASH;
    1834             :         else
    1835          76 :             pathnode->umethod = UNIQUE_PATH_SORT;
    1836             :     }
    1837           0 :     else if (sjinfo->semi_can_btree)
    1838           0 :         pathnode->umethod = UNIQUE_PATH_SORT;
    1839           0 :     else if (sjinfo->semi_can_hash)
    1840           0 :         pathnode->umethod = UNIQUE_PATH_HASH;
    1841             :     else
    1842             :     {
    1843             :         /* we can get here only if we abandoned hashing above */
    1844           0 :         MemoryContextSwitchTo(oldcontext);
    1845           0 :         return NULL;
    1846             :     }
    1847             : 
    1848        3034 :     if (pathnode->umethod == UNIQUE_PATH_HASH)
    1849             :     {
    1850        2958 :         pathnode->path.startup_cost = agg_path.startup_cost;
    1851        2958 :         pathnode->path.total_cost = agg_path.total_cost;
    1852             :     }
    1853             :     else
    1854             :     {
    1855          76 :         pathnode->path.startup_cost = sort_path.startup_cost;
    1856          76 :         pathnode->path.total_cost = sort_path.total_cost;
    1857             :     }
    1858             : 
    1859        3034 :     rel->cheapest_unique_path = (Path *) pathnode;
    1860             : 
    1861        3034 :     MemoryContextSwitchTo(oldcontext);
    1862             : 
    1863        3034 :     return pathnode;
    1864             : }
    1865             : 
    1866             : /*
    1867             :  * create_gather_merge_path
    1868             :  *
    1869             :  *    Creates a path corresponding to a gather merge scan, returning
    1870             :  *    the pathnode.
    1871             :  */
    1872             : GatherMergePath *
    1873        9406 : create_gather_merge_path(PlannerInfo *root, RelOptInfo *rel, Path *subpath,
    1874             :                          PathTarget *target, List *pathkeys,
    1875             :                          Relids required_outer, double *rows)
    1876             : {
    1877        9406 :     GatherMergePath *pathnode = makeNode(GatherMergePath);
    1878        9406 :     Cost        input_startup_cost = 0;
    1879        9406 :     Cost        input_total_cost = 0;
    1880             : 
    1881             :     Assert(subpath->parallel_safe);
    1882             :     Assert(pathkeys);
    1883             : 
    1884        9406 :     pathnode->path.pathtype = T_GatherMerge;
    1885        9406 :     pathnode->path.parent = rel;
    1886        9406 :     pathnode->path.param_info = get_baserel_parampathinfo(root, rel,
    1887             :                                                           required_outer);
    1888        9406 :     pathnode->path.parallel_aware = false;
    1889             : 
    1890        9406 :     pathnode->subpath = subpath;
    1891        9406 :     pathnode->num_workers = subpath->parallel_workers;
    1892        9406 :     pathnode->path.pathkeys = pathkeys;
    1893        9406 :     pathnode->path.pathtarget = target ? target : rel->reltarget;
    1894        9406 :     pathnode->path.rows += subpath->rows;
    1895             : 
    1896        9406 :     if (pathkeys_contained_in(pathkeys, subpath->pathkeys))
    1897             :     {
    1898             :         /* Subpath is adequately ordered, we won't need to sort it */
    1899        9406 :         input_startup_cost += subpath->startup_cost;
    1900        9406 :         input_total_cost += subpath->total_cost;
    1901             :     }
    1902             :     else
    1903             :     {
    1904             :         /* We'll need to insert a Sort node, so include cost for that */
    1905             :         Path        sort_path;  /* dummy for result of cost_sort */
    1906             : 
    1907           0 :         cost_sort(&sort_path,
    1908             :                   root,
    1909             :                   pathkeys,
    1910             :                   subpath->total_cost,
    1911             :                   subpath->rows,
    1912           0 :                   subpath->pathtarget->width,
    1913             :                   0.0,
    1914             :                   work_mem,
    1915             :                   -1);
    1916           0 :         input_startup_cost += sort_path.startup_cost;
    1917           0 :         input_total_cost += sort_path.total_cost;
    1918             :     }
    1919             : 
    1920        9406 :     cost_gather_merge(pathnode, root, rel, pathnode->path.param_info,
    1921             :                       input_startup_cost, input_total_cost, rows);
    1922             : 
    1923        9406 :     return pathnode;
    1924             : }
    1925             : 
    1926             : /*
    1927             :  * translate_sub_tlist - get subquery column numbers represented by tlist
    1928             :  *
    1929             :  * The given targetlist usually contains only Vars referencing the given relid.
    1930             :  * Extract their varattnos (ie, the column numbers of the subquery) and return
    1931             :  * as an integer List.
    1932             :  *
    1933             :  * If any of the tlist items is not a simple Var, we cannot determine whether
    1934             :  * the subquery's uniqueness condition (if any) matches ours, so punt and
    1935             :  * return NIL.
    1936             :  */
    1937             : static List *
    1938         476 : translate_sub_tlist(List *tlist, int relid)
    1939             : {
    1940         476 :     List       *result = NIL;
    1941             :     ListCell   *l;
    1942             : 
    1943         538 :     foreach(l, tlist)
    1944             :     {
    1945         476 :         Var        *var = (Var *) lfirst(l);
    1946             : 
    1947         476 :         if (!var || !IsA(var, Var) ||
    1948          62 :             var->varno != relid)
    1949         414 :             return NIL;         /* punt */
    1950             : 
    1951          62 :         result = lappend_int(result, var->varattno);
    1952             :     }
    1953          62 :     return result;
    1954             : }
    1955             : 
    1956             : /*
    1957             :  * create_gather_path
    1958             :  *    Creates a path corresponding to a gather scan, returning the
    1959             :  *    pathnode.
    1960             :  *
    1961             :  * 'rows' may optionally be set to override row estimates from other sources.
    1962             :  */
    1963             : GatherPath *
    1964       14640 : create_gather_path(PlannerInfo *root, RelOptInfo *rel, Path *subpath,
    1965             :                    PathTarget *target, Relids required_outer, double *rows)
    1966             : {
    1967       14640 :     GatherPath *pathnode = makeNode(GatherPath);
    1968             : 
    1969             :     Assert(subpath->parallel_safe);
    1970             : 
    1971       14640 :     pathnode->path.pathtype = T_Gather;
    1972       14640 :     pathnode->path.parent = rel;
    1973       14640 :     pathnode->path.pathtarget = target;
    1974       14640 :     pathnode->path.param_info = get_baserel_parampathinfo(root, rel,
    1975             :                                                           required_outer);
    1976       14640 :     pathnode->path.parallel_aware = false;
    1977       14640 :     pathnode->path.parallel_safe = false;
    1978       14640 :     pathnode->path.parallel_workers = 0;
    1979       14640 :     pathnode->path.pathkeys = NIL;   /* Gather has unordered result */
    1980             : 
    1981       14640 :     pathnode->subpath = subpath;
    1982       14640 :     pathnode->num_workers = subpath->parallel_workers;
    1983       14640 :     pathnode->single_copy = false;
    1984             : 
    1985       14640 :     if (pathnode->num_workers == 0)
    1986             :     {
    1987           0 :         pathnode->path.pathkeys = subpath->pathkeys;
    1988           0 :         pathnode->num_workers = 1;
    1989           0 :         pathnode->single_copy = true;
    1990             :     }
    1991             : 
    1992       14640 :     cost_gather(pathnode, root, rel, pathnode->path.param_info, rows);
    1993             : 
    1994       14640 :     return pathnode;
    1995             : }
    1996             : 
    1997             : /*
    1998             :  * create_subqueryscan_path
    1999             :  *    Creates a path corresponding to a scan of a subquery,
    2000             :  *    returning the pathnode.
    2001             :  *
    2002             :  * Caller must pass trivial_pathtarget = true if it believes rel->reltarget to
    2003             :  * be trivial, ie just a fetch of all the subquery output columns in order.
    2004             :  * While we could determine that here, the caller can usually do it more
    2005             :  * efficiently (or at least amortize it over multiple calls).
    2006             :  */
    2007             : SubqueryScanPath *
    2008       20490 : create_subqueryscan_path(PlannerInfo *root, RelOptInfo *rel, Path *subpath,
    2009             :                          bool trivial_pathtarget,
    2010             :                          List *pathkeys, Relids required_outer)
    2011             : {
    2012       20490 :     SubqueryScanPath *pathnode = makeNode(SubqueryScanPath);
    2013             : 
    2014       20490 :     pathnode->path.pathtype = T_SubqueryScan;
    2015       20490 :     pathnode->path.parent = rel;
    2016       20490 :     pathnode->path.pathtarget = rel->reltarget;
    2017       20490 :     pathnode->path.param_info = get_baserel_parampathinfo(root, rel,
    2018             :                                                           required_outer);
    2019       20490 :     pathnode->path.parallel_aware = false;
    2020       31596 :     pathnode->path.parallel_safe = rel->consider_parallel &&
    2021       11106 :         subpath->parallel_safe;
    2022       20490 :     pathnode->path.parallel_workers = subpath->parallel_workers;
    2023       20490 :     pathnode->path.pathkeys = pathkeys;
    2024       20490 :     pathnode->subpath = subpath;
    2025             : 
    2026       20490 :     cost_subqueryscan(pathnode, root, rel, pathnode->path.param_info,
    2027             :                       trivial_pathtarget);
    2028             : 
    2029       20490 :     return pathnode;
    2030             : }
    2031             : 
    2032             : /*
    2033             :  * create_functionscan_path
    2034             :  *    Creates a path corresponding to a sequential scan of a function,
    2035             :  *    returning the pathnode.
    2036             :  */
    2037             : Path *
    2038       34858 : create_functionscan_path(PlannerInfo *root, RelOptInfo *rel,
    2039             :                          List *pathkeys, Relids required_outer)
    2040             : {
    2041       34858 :     Path       *pathnode = makeNode(Path);
    2042             : 
    2043       34858 :     pathnode->pathtype = T_FunctionScan;
    2044       34858 :     pathnode->parent = rel;
    2045       34858 :     pathnode->pathtarget = rel->reltarget;
    2046       34858 :     pathnode->param_info = get_baserel_parampathinfo(root, rel,
    2047             :                                                      required_outer);
    2048       34858 :     pathnode->parallel_aware = false;
    2049       34858 :     pathnode->parallel_safe = rel->consider_parallel;
    2050       34858 :     pathnode->parallel_workers = 0;
    2051       34858 :     pathnode->pathkeys = pathkeys;
    2052             : 
    2053       34858 :     cost_functionscan(pathnode, root, rel, pathnode->param_info);
    2054             : 
    2055       34858 :     return pathnode;
    2056             : }
    2057             : 
    2058             : /*
    2059             :  * create_tablefuncscan_path
    2060             :  *    Creates a path corresponding to a sequential scan of a table function,
    2061             :  *    returning the pathnode.
    2062             :  */
    2063             : Path *
    2064         216 : create_tablefuncscan_path(PlannerInfo *root, RelOptInfo *rel,
    2065             :                           Relids required_outer)
    2066             : {
    2067         216 :     Path       *pathnode = makeNode(Path);
    2068             : 
    2069         216 :     pathnode->pathtype = T_TableFuncScan;
    2070         216 :     pathnode->parent = rel;
    2071         216 :     pathnode->pathtarget = rel->reltarget;
    2072         216 :     pathnode->param_info = get_baserel_parampathinfo(root, rel,
    2073             :                                                      required_outer);
    2074         216 :     pathnode->parallel_aware = false;
    2075         216 :     pathnode->parallel_safe = rel->consider_parallel;
    2076         216 :     pathnode->parallel_workers = 0;
    2077         216 :     pathnode->pathkeys = NIL;    /* result is always unordered */
    2078             : 
    2079         216 :     cost_tablefuncscan(pathnode, root, rel, pathnode->param_info);
    2080             : 
    2081         216 :     return pathnode;
    2082             : }
    2083             : 
    2084             : /*
    2085             :  * create_valuesscan_path
    2086             :  *    Creates a path corresponding to a scan of a VALUES list,
    2087             :  *    returning the pathnode.
    2088             :  */
    2089             : Path *
    2090        7216 : create_valuesscan_path(PlannerInfo *root, RelOptInfo *rel,
    2091             :                        Relids required_outer)
    2092             : {
    2093        7216 :     Path       *pathnode = makeNode(Path);
    2094             : 
    2095        7216 :     pathnode->pathtype = T_ValuesScan;
    2096        7216 :     pathnode->parent = rel;
    2097        7216 :     pathnode->pathtarget = rel->reltarget;
    2098        7216 :     pathnode->param_info = get_baserel_parampathinfo(root, rel,
    2099             :                                                      required_outer);
    2100        7216 :     pathnode->parallel_aware = false;
    2101        7216 :     pathnode->parallel_safe = rel->consider_parallel;
    2102        7216 :     pathnode->parallel_workers = 0;
    2103        7216 :     pathnode->pathkeys = NIL;    /* result is always unordered */
    2104             : 
    2105        7216 :     cost_valuesscan(pathnode, root, rel, pathnode->param_info);
    2106             : 
    2107        7216 :     return pathnode;
    2108             : }
    2109             : 
    2110             : /*
    2111             :  * create_ctescan_path
    2112             :  *    Creates a path corresponding to a scan of a non-self-reference CTE,
    2113             :  *    returning the pathnode.
    2114             :  */
    2115             : Path *
    2116        2474 : create_ctescan_path(PlannerInfo *root, RelOptInfo *rel, Relids required_outer)
    2117             : {
    2118        2474 :     Path       *pathnode = makeNode(Path);
    2119             : 
    2120        2474 :     pathnode->pathtype = T_CteScan;
    2121        2474 :     pathnode->parent = rel;
    2122        2474 :     pathnode->pathtarget = rel->reltarget;
    2123        2474 :     pathnode->param_info = get_baserel_parampathinfo(root, rel,
    2124             :                                                      required_outer);
    2125        2474 :     pathnode->parallel_aware = false;
    2126        2474 :     pathnode->parallel_safe = rel->consider_parallel;
    2127        2474 :     pathnode->parallel_workers = 0;
    2128        2474 :     pathnode->pathkeys = NIL;    /* XXX for now, result is always unordered */
    2129             : 
    2130        2474 :     cost_ctescan(pathnode, root, rel, pathnode->param_info);
    2131             : 
    2132        2474 :     return pathnode;
    2133             : }
    2134             : 
    2135             : /*
    2136             :  * create_namedtuplestorescan_path
    2137             :  *    Creates a path corresponding to a scan of a named tuplestore, returning
    2138             :  *    the pathnode.
    2139             :  */
    2140             : Path *
    2141         438 : create_namedtuplestorescan_path(PlannerInfo *root, RelOptInfo *rel,
    2142             :                                 Relids required_outer)
    2143             : {
    2144         438 :     Path       *pathnode = makeNode(Path);
    2145             : 
    2146         438 :     pathnode->pathtype = T_NamedTuplestoreScan;
    2147         438 :     pathnode->parent = rel;
    2148         438 :     pathnode->pathtarget = rel->reltarget;
    2149         438 :     pathnode->param_info = get_baserel_parampathinfo(root, rel,
    2150             :                                                      required_outer);
    2151         438 :     pathnode->parallel_aware = false;
    2152         438 :     pathnode->parallel_safe = rel->consider_parallel;
    2153         438 :     pathnode->parallel_workers = 0;
    2154         438 :     pathnode->pathkeys = NIL;    /* result is always unordered */
    2155             : 
    2156         438 :     cost_namedtuplestorescan(pathnode, root, rel, pathnode->param_info);
    2157             : 
    2158         438 :     return pathnode;
    2159             : }
    2160             : 
    2161             : /*
    2162             :  * create_resultscan_path
    2163             :  *    Creates a path corresponding to a scan of an RTE_RESULT relation,
    2164             :  *    returning the pathnode.
    2165             :  */
    2166             : Path *
    2167        1370 : create_resultscan_path(PlannerInfo *root, RelOptInfo *rel,
    2168             :                        Relids required_outer)
    2169             : {
    2170        1370 :     Path       *pathnode = makeNode(Path);
    2171             : 
    2172        1370 :     pathnode->pathtype = T_Result;
    2173        1370 :     pathnode->parent = rel;
    2174        1370 :     pathnode->pathtarget = rel->reltarget;
    2175        1370 :     pathnode->param_info = get_baserel_parampathinfo(root, rel,
    2176             :                                                      required_outer);
    2177        1370 :     pathnode->parallel_aware = false;
    2178        1370 :     pathnode->parallel_safe = rel->consider_parallel;
    2179        1370 :     pathnode->parallel_workers = 0;
    2180        1370 :     pathnode->pathkeys = NIL;    /* result is always unordered */
    2181             : 
    2182        1370 :     cost_resultscan(pathnode, root, rel, pathnode->param_info);
    2183             : 
    2184        1370 :     return pathnode;
    2185             : }
    2186             : 
    2187             : /*
    2188             :  * create_worktablescan_path
    2189             :  *    Creates a path corresponding to a scan of a self-reference CTE,
    2190             :  *    returning the pathnode.
    2191             :  */
    2192             : Path *
    2193         708 : create_worktablescan_path(PlannerInfo *root, RelOptInfo *rel,
    2194             :                           Relids required_outer)
    2195             : {
    2196         708 :     Path       *pathnode = makeNode(Path);
    2197             : 
    2198         708 :     pathnode->pathtype = T_WorkTableScan;
    2199         708 :     pathnode->parent = rel;
    2200         708 :     pathnode->pathtarget = rel->reltarget;
    2201         708 :     pathnode->param_info = get_baserel_parampathinfo(root, rel,
    2202             :                                                      required_outer);
    2203         708 :     pathnode->parallel_aware = false;
    2204         708 :     pathnode->parallel_safe = rel->consider_parallel;
    2205         708 :     pathnode->parallel_workers = 0;
    2206         708 :     pathnode->pathkeys = NIL;    /* result is always unordered */
    2207             : 
    2208             :     /* Cost is the same as for a regular CTE scan */
    2209         708 :     cost_ctescan(pathnode, root, rel, pathnode->param_info);
    2210             : 
    2211         708 :     return pathnode;
    2212             : }
    2213             : 
    2214             : /*
    2215             :  * create_foreignscan_path
    2216             :  *    Creates a path corresponding to a scan of a foreign base table,
    2217             :  *    returning the pathnode.
    2218             :  *
    2219             :  * This function is never called from core Postgres; rather, it's expected
    2220             :  * to be called by the GetForeignPaths function of a foreign data wrapper.
    2221             :  * We make the FDW supply all fields of the path, since we do not have any way
    2222             :  * to calculate them in core.  However, there is a usually-sane default for
    2223             :  * the pathtarget (rel->reltarget), so we let a NULL for "target" select that.
    2224             :  */
    2225             : ForeignPath *
    2226        3204 : create_foreignscan_path(PlannerInfo *root, RelOptInfo *rel,
    2227             :                         PathTarget *target,
    2228             :                         double rows, Cost startup_cost, Cost total_cost,
    2229             :                         List *pathkeys,
    2230             :                         Relids required_outer,
    2231             :                         Path *fdw_outerpath,
    2232             :                         List *fdw_private)
    2233             : {
    2234        3204 :     ForeignPath *pathnode = makeNode(ForeignPath);
    2235             : 
    2236             :     /* Historically some FDWs were confused about when to use this */
    2237             :     Assert(IS_SIMPLE_REL(rel));
    2238             : 
    2239        3204 :     pathnode->path.pathtype = T_ForeignScan;
    2240        3204 :     pathnode->path.parent = rel;
    2241        3204 :     pathnode->path.pathtarget = target ? target : rel->reltarget;
    2242        3204 :     pathnode->path.param_info = get_baserel_parampathinfo(root, rel,
    2243             :                                                           required_outer);
    2244        3204 :     pathnode->path.parallel_aware = false;
    2245        3204 :     pathnode->path.parallel_safe = rel->consider_parallel;
    2246        3204 :     pathnode->path.parallel_workers = 0;
    2247        3204 :     pathnode->path.rows = rows;
    2248        3204 :     pathnode->path.startup_cost = startup_cost;
    2249        3204 :     pathnode->path.total_cost = total_cost;
    2250        3204 :     pathnode->path.pathkeys = pathkeys;
    2251             : 
    2252        3204 :     pathnode->fdw_outerpath = fdw_outerpath;
    2253        3204 :     pathnode->fdw_private = fdw_private;
    2254             : 
    2255        3204 :     return pathnode;
    2256             : }
    2257             : 
    2258             : /*
    2259             :  * create_foreign_join_path
    2260             :  *    Creates a path corresponding to a scan of a foreign join,
    2261             :  *    returning the pathnode.
    2262             :  *
    2263             :  * This function is never called from core Postgres; rather, it's expected
    2264             :  * to be called by the GetForeignJoinPaths function of a foreign data wrapper.
    2265             :  * We make the FDW supply all fields of the path, since we do not have any way
    2266             :  * to calculate them in core.  However, there is a usually-sane default for
    2267             :  * the pathtarget (rel->reltarget), so we let a NULL for "target" select that.
    2268             :  */
    2269             : ForeignPath *
    2270         738 : create_foreign_join_path(PlannerInfo *root, RelOptInfo *rel,
    2271             :                          PathTarget *target,
    2272             :                          double rows, Cost startup_cost, Cost total_cost,
    2273             :                          List *pathkeys,
    2274             :                          Relids required_outer,
    2275             :                          Path *fdw_outerpath,
    2276             :                          List *fdw_private)
    2277             : {
    2278         738 :     ForeignPath *pathnode = makeNode(ForeignPath);
    2279             : 
    2280             :     /*
    2281             :      * We should use get_joinrel_parampathinfo to handle parameterized paths,
    2282             :      * but the API of this function doesn't support it, and existing
    2283             :      * extensions aren't yet trying to build such paths anyway.  For the
    2284             :      * moment just throw an error if someone tries it; eventually we should
    2285             :      * revisit this.
    2286             :      */
    2287         738 :     if (!bms_is_empty(required_outer) || !bms_is_empty(rel->lateral_relids))
    2288           0 :         elog(ERROR, "parameterized foreign joins are not supported yet");
    2289             : 
    2290         738 :     pathnode->path.pathtype = T_ForeignScan;
    2291         738 :     pathnode->path.parent = rel;
    2292         738 :     pathnode->path.pathtarget = target ? target : rel->reltarget;
    2293         738 :     pathnode->path.param_info = NULL;    /* XXX see above */
    2294         738 :     pathnode->path.parallel_aware = false;
    2295         738 :     pathnode->path.parallel_safe = rel->consider_parallel;
    2296         738 :     pathnode->path.parallel_workers = 0;
    2297         738 :     pathnode->path.rows = rows;
    2298         738 :     pathnode->path.startup_cost = startup_cost;
    2299         738 :     pathnode->path.total_cost = total_cost;
    2300         738 :     pathnode->path.pathkeys = pathkeys;
    2301             : 
    2302         738 :     pathnode->fdw_outerpath = fdw_outerpath;
    2303         738 :     pathnode->fdw_private = fdw_private;
    2304             : 
    2305         738 :     return pathnode;
    2306             : }
    2307             : 
    2308             : /*
    2309             :  * create_foreign_upper_path
    2310             :  *    Creates a path corresponding to an upper relation that's computed
    2311             :  *    directly by an FDW, returning the pathnode.
    2312             :  *
    2313             :  * This function is never called from core Postgres; rather, it's expected to
    2314             :  * be called by the GetForeignUpperPaths function of a foreign data wrapper.
    2315             :  * We make the FDW supply all fields of the path, since we do not have any way
    2316             :  * to calculate them in core.  However, there is a usually-sane default for
    2317             :  * the pathtarget (rel->reltarget), so we let a NULL for "target" select that.
    2318             :  */
    2319             : ForeignPath *
    2320         546 : create_foreign_upper_path(PlannerInfo *root, RelOptInfo *rel,
    2321             :                           PathTarget *target,
    2322             :                           double rows, Cost startup_cost, Cost total_cost,
    2323             :                           List *pathkeys,
    2324             :                           Path *fdw_outerpath,
    2325             :                           List *fdw_private)
    2326             : {
    2327         546 :     ForeignPath *pathnode = makeNode(ForeignPath);
    2328             : 
    2329             :     /*
    2330             :      * Upper relations should never have any lateral references, since joining
    2331             :      * is complete.
    2332             :      */
    2333             :     Assert(bms_is_empty(rel->lateral_relids));
    2334             : 
    2335         546 :     pathnode->path.pathtype = T_ForeignScan;
    2336         546 :     pathnode->path.parent = rel;
    2337         546 :     pathnode->path.pathtarget = target ? target : rel->reltarget;
    2338         546 :     pathnode->path.param_info = NULL;
    2339         546 :     pathnode->path.parallel_aware = false;
    2340         546 :     pathnode->path.parallel_safe = rel->consider_parallel;
    2341         546 :     pathnode->path.parallel_workers = 0;
    2342         546 :     pathnode->path.rows = rows;
    2343         546 :     pathnode->path.startup_cost = startup_cost;
    2344         546 :     pathnode->path.total_cost = total_cost;
    2345         546 :     pathnode->path.pathkeys = pathkeys;
    2346             : 
    2347         546 :     pathnode->fdw_outerpath = fdw_outerpath;
    2348         546 :     pathnode->fdw_private = fdw_private;
    2349             : 
    2350         546 :     return pathnode;
    2351             : }
    2352             : 
    2353             : /*
    2354             :  * calc_nestloop_required_outer
    2355             :  *    Compute the required_outer set for a nestloop join path
    2356             :  *
    2357             :  * Note: result must not share storage with either input
    2358             :  */
    2359             : Relids
    2360     1919240 : calc_nestloop_required_outer(Relids outerrelids,
    2361             :                              Relids outer_paramrels,
    2362             :                              Relids innerrelids,
    2363             :                              Relids inner_paramrels)
    2364             : {
    2365             :     Relids      required_outer;
    2366             : 
    2367             :     /* inner_path can require rels from outer path, but not vice versa */
    2368             :     Assert(!bms_overlap(outer_paramrels, innerrelids));
    2369             :     /* easy case if inner path is not parameterized */
    2370     1919240 :     if (!inner_paramrels)
    2371     1301992 :         return bms_copy(outer_paramrels);
    2372             :     /* else, form the union ... */
    2373      617248 :     required_outer = bms_union(outer_paramrels, inner_paramrels);
    2374             :     /* ... and remove any mention of now-satisfied outer rels */
    2375      617248 :     required_outer = bms_del_members(required_outer,
    2376             :                                      outerrelids);
    2377      617248 :     return required_outer;
    2378             : }
    2379             : 
    2380             : /*
    2381             :  * calc_non_nestloop_required_outer
    2382             :  *    Compute the required_outer set for a merge or hash join path
    2383             :  *
    2384             :  * Note: result must not share storage with either input
    2385             :  */
    2386             : Relids
    2387     1313604 : calc_non_nestloop_required_outer(Path *outer_path, Path *inner_path)
    2388             : {
    2389     1313604 :     Relids      outer_paramrels = PATH_REQ_OUTER(outer_path);
    2390     1313604 :     Relids      inner_paramrels = PATH_REQ_OUTER(inner_path);
    2391             :     Relids      required_outer;
    2392             : 
    2393             :     /* neither path can require rels from the other */
    2394             :     Assert(!bms_overlap(outer_paramrels, inner_path->parent->relids));
    2395             :     Assert(!bms_overlap(inner_paramrels, outer_path->parent->relids));
    2396             :     /* form the union ... */
    2397     1313604 :     required_outer = bms_union(outer_paramrels, inner_paramrels);
    2398             :     /* we do not need an explicit test for empty; bms_union gets it right */
    2399     1313604 :     return required_outer;
    2400             : }
    2401             : 
    2402             : /*
    2403             :  * create_nestloop_path
    2404             :  *    Creates a pathnode corresponding to a nestloop join between two
    2405             :  *    relations.
    2406             :  *
    2407             :  * 'joinrel' is the join relation.
    2408             :  * 'jointype' is the type of join required
    2409             :  * 'workspace' is the result from initial_cost_nestloop
    2410             :  * 'extra' contains various information about the join
    2411             :  * 'outer_path' is the outer path
    2412             :  * 'inner_path' is the inner path
    2413             :  * 'restrict_clauses' are the RestrictInfo nodes to apply at the join
    2414             :  * 'pathkeys' are the path keys of the new join path
    2415             :  * 'required_outer' is the set of required outer rels
    2416             :  *
    2417             :  * Returns the resulting path node.
    2418             :  */
    2419             : NestPath *
    2420      852102 : create_nestloop_path(PlannerInfo *root,
    2421             :                      RelOptInfo *joinrel,
    2422             :                      JoinType jointype,
    2423             :                      JoinCostWorkspace *workspace,
    2424             :                      JoinPathExtraData *extra,
    2425             :                      Path *outer_path,
    2426             :                      Path *inner_path,
    2427             :                      List *restrict_clauses,
    2428             :                      List *pathkeys,
    2429             :                      Relids required_outer)
    2430             : {
    2431      852102 :     NestPath   *pathnode = makeNode(NestPath);
    2432      852102 :     Relids      inner_req_outer = PATH_REQ_OUTER(inner_path);
    2433             : 
    2434             :     /*
    2435             :      * If the inner path is parameterized by the outer, we must drop any
    2436             :      * restrict_clauses that are due to be moved into the inner path.  We have
    2437             :      * to do this now, rather than postpone the work till createplan time,
    2438             :      * because the restrict_clauses list can affect the size and cost
    2439             :      * estimates for this path.  We detect such clauses by checking for serial
    2440             :      * number match to clauses already enforced in the inner path.
    2441             :      */
    2442      852102 :     if (bms_overlap(inner_req_outer, outer_path->parent->relids))
    2443             :     {
    2444      235408 :         Bitmapset  *enforced_serials = get_param_path_clause_serials(inner_path);
    2445      235408 :         List       *jclauses = NIL;
    2446             :         ListCell   *lc;
    2447             : 
    2448      503070 :         foreach(lc, restrict_clauses)
    2449             :         {
    2450      267662 :             RestrictInfo *rinfo = (RestrictInfo *) lfirst(lc);
    2451             : 
    2452      267662 :             if (!bms_is_member(rinfo->rinfo_serial, enforced_serials))
    2453       29512 :                 jclauses = lappend(jclauses, rinfo);
    2454             :         }
    2455      235408 :         restrict_clauses = jclauses;
    2456             :     }
    2457             : 
    2458      852102 :     pathnode->jpath.path.pathtype = T_NestLoop;
    2459      852102 :     pathnode->jpath.path.parent = joinrel;
    2460      852102 :     pathnode->jpath.path.pathtarget = joinrel->reltarget;
    2461      852102 :     pathnode->jpath.path.param_info =
    2462      852102 :         get_joinrel_parampathinfo(root,
    2463             :                                   joinrel,
    2464             :                                   outer_path,
    2465             :                                   inner_path,
    2466             :                                   extra->sjinfo,
    2467             :                                   required_outer,
    2468             :                                   &restrict_clauses);
    2469      852102 :     pathnode->jpath.path.parallel_aware = false;
    2470     2455772 :     pathnode->jpath.path.parallel_safe = joinrel->consider_parallel &&
    2471      852102 :         outer_path->parallel_safe && inner_path->parallel_safe;
    2472             :     /* This is a foolish way to estimate parallel_workers, but for now... */
    2473      852102 :     pathnode->jpath.path.parallel_workers = outer_path->parallel_workers;
    2474      852102 :     pathnode->jpath.path.pathkeys = pathkeys;
    2475      852102 :     pathnode->jpath.jointype = jointype;
    2476      852102 :     pathnode->jpath.inner_unique = extra->inner_unique;
    2477      852102 :     pathnode->jpath.outerjoinpath = outer_path;
    2478      852102 :     pathnode->jpath.innerjoinpath = inner_path;
    2479      852102 :     pathnode->jpath.joinrestrictinfo = restrict_clauses;
    2480             : 
    2481      852102 :     final_cost_nestloop(root, pathnode, workspace, extra);
    2482             : 
    2483      852102 :     return pathnode;
    2484             : }
    2485             : 
    2486             : /*
    2487             :  * create_mergejoin_path
    2488             :  *    Creates a pathnode corresponding to a mergejoin join between
    2489             :  *    two relations
    2490             :  *
    2491             :  * 'joinrel' is the join relation
    2492             :  * 'jointype' is the type of join required
    2493             :  * 'workspace' is the result from initial_cost_mergejoin
    2494             :  * 'extra' contains various information about the join
    2495             :  * 'outer_path' is the outer path
    2496             :  * 'inner_path' is the inner path
    2497             :  * 'restrict_clauses' are the RestrictInfo nodes to apply at the join
    2498             :  * 'pathkeys' are the path keys of the new join path
    2499             :  * 'required_outer' is the set of required outer rels
    2500             :  * 'mergeclauses' are the RestrictInfo nodes to use as merge clauses
    2501             :  *      (this should be a subset of the restrict_clauses list)
    2502             :  * 'outersortkeys' are the sort varkeys for the outer relation
    2503             :  * 'innersortkeys' are the sort varkeys for the inner relation
    2504             :  */
    2505             : MergePath *
    2506      203002 : create_mergejoin_path(PlannerInfo *root,
    2507             :                       RelOptInfo *joinrel,
    2508             :                       JoinType jointype,
    2509             :                       JoinCostWorkspace *workspace,
    2510             :                       JoinPathExtraData *extra,
    2511             :                       Path *outer_path,
    2512             :                       Path *inner_path,
    2513             :                       List *restrict_clauses,
    2514             :                       List *pathkeys,
    2515             :                       Relids required_outer,
    2516             :                       List *mergeclauses,
    2517             :                       List *outersortkeys,
    2518             :                       List *innersortkeys)
    2519             : {
    2520      203002 :     MergePath  *pathnode = makeNode(MergePath);
    2521             : 
    2522      203002 :     pathnode->jpath.path.pathtype = T_MergeJoin;
    2523      203002 :     pathnode->jpath.path.parent = joinrel;
    2524      203002 :     pathnode->jpath.path.pathtarget = joinrel->reltarget;
    2525      203002 :     pathnode->jpath.path.param_info =
    2526      203002 :         get_joinrel_parampathinfo(root,
    2527             :                                   joinrel,
    2528             :                                   outer_path,
    2529             :                                   inner_path,
    2530             :                                   extra->sjinfo,
    2531             :                                   required_outer,
    2532             :                                   &restrict_clauses);
    2533      203002 :     pathnode->jpath.path.parallel_aware = false;
    2534      576590 :     pathnode->jpath.path.parallel_safe = joinrel->consider_parallel &&
    2535      203002 :         outer_path->parallel_safe && inner_path->parallel_safe;
    2536             :     /* This is a foolish way to estimate parallel_workers, but for now... */
    2537      203002 :     pathnode->jpath.path.parallel_workers = outer_path->parallel_workers;
    2538      203002 :     pathnode->jpath.path.pathkeys = pathkeys;
    2539      203002 :     pathnode->jpath.jointype = jointype;
    2540      203002 :     pathnode->jpath.inner_unique = extra->inner_unique;
    2541      203002 :     pathnode->jpath.outerjoinpath = outer_path;
    2542      203002 :     pathnode->jpath.innerjoinpath = inner_path;
    2543      203002 :     pathnode->jpath.joinrestrictinfo = restrict_clauses;
    2544      203002 :     pathnode->path_mergeclauses = mergeclauses;
    2545      203002 :     pathnode->outersortkeys = outersortkeys;
    2546      203002 :     pathnode->innersortkeys = innersortkeys;
    2547             :     /* pathnode->skip_mark_restore will be set by final_cost_mergejoin */
    2548             :     /* pathnode->materialize_inner will be set by final_cost_mergejoin */
    2549             : 
    2550      203002 :     final_cost_mergejoin(root, pathnode, workspace, extra);
    2551             : 
    2552      203002 :     return pathnode;
    2553             : }
    2554             : 
    2555             : /*
    2556             :  * create_hashjoin_path
    2557             :  *    Creates a pathnode corresponding to a hash join between two relations.
    2558             :  *
    2559             :  * 'joinrel' is the join relation
    2560             :  * 'jointype' is the type of join required
    2561             :  * 'workspace' is the result from initial_cost_hashjoin
    2562             :  * 'extra' contains various information about the join
    2563             :  * 'outer_path' is the cheapest outer path
    2564             :  * 'inner_path' is the cheapest inner path
    2565             :  * 'parallel_hash' to select Parallel Hash of inner path (shared hash table)
    2566             :  * 'restrict_clauses' are the RestrictInfo nodes to apply at the join
    2567             :  * 'required_outer' is the set of required outer rels
    2568             :  * 'hashclauses' are the RestrictInfo nodes to use as hash clauses
    2569             :  *      (this should be a subset of the restrict_clauses list)
    2570             :  */
    2571             : HashPath *
    2572      189866 : create_hashjoin_path(PlannerInfo *root,
    2573             :                      RelOptInfo *joinrel,
    2574             :                      JoinType jointype,
    2575             :                      JoinCostWorkspace *workspace,
    2576             :                      JoinPathExtraData *extra,
    2577             :                      Path *outer_path,
    2578             :                      Path *inner_path,
    2579             :                      bool parallel_hash,
    2580             :                      List *restrict_clauses,
    2581             :                      Relids required_outer,
    2582             :                      List *hashclauses)
    2583             : {
    2584      189866 :     HashPath   *pathnode = makeNode(HashPath);
    2585             : 
    2586      189866 :     pathnode->jpath.path.pathtype = T_HashJoin;
    2587      189866 :     pathnode->jpath.path.parent = joinrel;
    2588      189866 :     pathnode->jpath.path.pathtarget = joinrel->reltarget;
    2589      189866 :     pathnode->jpath.path.param_info =
    2590      189866 :         get_joinrel_parampathinfo(root,
    2591             :                                   joinrel,
    2592             :                                   outer_path,
    2593             :                                   inner_path,
    2594             :                                   extra->sjinfo,
    2595             :                                   required_outer,
    2596             :                                   &restrict_clauses);
    2597      189866 :     pathnode->jpath.path.parallel_aware =
    2598      189866 :         joinrel->consider_parallel && parallel_hash;
    2599      534714 :     pathnode->jpath.path.parallel_safe = joinrel->consider_parallel &&
    2600      189866 :         outer_path->parallel_safe && inner_path->parallel_safe;
    2601             :     /* This is a foolish way to estimate parallel_workers, but for now... */
    2602      189866 :     pathnode->jpath.path.parallel_workers = outer_path->parallel_workers;
    2603             : 
    2604             :     /*
    2605             :      * A hashjoin never has pathkeys, since its output ordering is
    2606             :      * unpredictable due to possible batching.  XXX If the inner relation is
    2607             :      * small enough, we could instruct the executor that it must not batch,
    2608             :      * and then we could assume that the output inherits the outer relation's
    2609             :      * ordering, which might save a sort step.  However there is considerable
    2610             :      * downside if our estimate of the inner relation size is badly off. For
    2611             :      * the moment we don't risk it.  (Note also that if we wanted to take this
    2612             :      * seriously, joinpath.c would have to consider many more paths for the
    2613             :      * outer rel than it does now.)
    2614             :      */
    2615      189866 :     pathnode->jpath.path.pathkeys = NIL;
    2616      189866 :     pathnode->jpath.jointype = jointype;
    2617      189866 :     pathnode->jpath.inner_unique = extra->inner_unique;
    2618      189866 :     pathnode->jpath.outerjoinpath = outer_path;
    2619      189866 :     pathnode->jpath.innerjoinpath = inner_path;
    2620      189866 :     pathnode->jpath.joinrestrictinfo = restrict_clauses;
    2621      189866 :     pathnode->path_hashclauses = hashclauses;
    2622             :     /* final_cost_hashjoin will fill in pathnode->num_batches */
    2623             : 
    2624      189866 :     final_cost_hashjoin(root, pathnode, workspace, extra);
    2625             : 
    2626      189866 :     return pathnode;
    2627             : }
    2628             : 
    2629             : /*
    2630             :  * create_projection_path
    2631             :  *    Creates a pathnode that represents performing a projection.
    2632             :  *
    2633             :  * 'rel' is the parent relation associated with the result
    2634             :  * 'subpath' is the path representing the source of data
    2635             :  * 'target' is the PathTarget to be computed
    2636             :  */
    2637             : ProjectionPath *
    2638      340714 : create_projection_path(PlannerInfo *root,
    2639             :                        RelOptInfo *rel,
    2640             :                        Path *subpath,
    2641             :                        PathTarget *target)
    2642             : {
    2643      340714 :     ProjectionPath *pathnode = makeNode(ProjectionPath);
    2644             :     PathTarget *oldtarget;
    2645             : 
    2646             :     /*
    2647             :      * We mustn't put a ProjectionPath directly above another; it's useless
    2648             :      * and will confuse create_projection_plan.  Rather than making sure all
    2649             :      * callers handle that, let's implement it here, by stripping off any
    2650             :      * ProjectionPath in what we're given.  Given this rule, there won't be
    2651             :      * more than one.
    2652             :      */
    2653      340714 :     if (IsA(subpath, ProjectionPath))
    2654             :     {
    2655          12 :         ProjectionPath *subpp = (ProjectionPath *) subpath;
    2656             : 
    2657             :         Assert(subpp->path.parent == rel);
    2658          12 :         subpath = subpp->subpath;
    2659             :         Assert(!IsA(subpath, ProjectionPath));
    2660             :     }
    2661             : 
    2662      340714 :     pathnode->path.pathtype = T_Result;
    2663      340714 :     pathnode->path.parent = rel;
    2664      340714 :     pathnode->path.pathtarget = target;
    2665             :     /* For now, assume we are above any joins, so no parameterization */
    2666      340714 :     pathnode->path.param_info = NULL;
    2667      340714 :     pathnode->path.parallel_aware = false;
    2668      748462 :     pathnode->path.parallel_safe = rel->consider_parallel &&
    2669      406292 :         subpath->parallel_safe &&
    2670       65578 :         is_parallel_safe(root, (Node *) target->exprs);
    2671      340714 :     pathnode->path.parallel_workers = subpath->parallel_workers;
    2672             :     /* Projection does not change the sort order */
    2673      340714 :     pathnode->path.pathkeys = subpath->pathkeys;
    2674             : 
    2675      340714 :     pathnode->subpath = subpath;
    2676             : 
    2677             :     /*
    2678             :      * We might not need a separate Result node.  If the input plan node type
    2679             :      * can project, we can just tell it to project something else.  Or, if it
    2680             :      * can't project but the desired target has the same expression list as
    2681             :      * what the input will produce anyway, we can still give it the desired
    2682             :      * tlist (possibly changing its ressortgroupref labels, but nothing else).
    2683             :      * Note: in the latter case, create_projection_plan has to recheck our
    2684             :      * conclusion; see comments therein.
    2685             :      */
    2686      340714 :     oldtarget = subpath->pathtarget;
    2687      352656 :     if (is_projection_capable_path(subpath) ||
    2688       11942 :         equal(oldtarget->exprs, target->exprs))
    2689             :     {
    2690             :         /* No separate Result node needed */
    2691      338712 :         pathnode->dummypp = true;
    2692             : 
    2693             :         /*
    2694             :          * Set cost of plan as subpath's cost, adjusted for tlist replacement.
    2695             :          */
    2696      338712 :         pathnode->path.rows = subpath->rows;
    2697      338712 :         pathnode->path.startup_cost = subpath->startup_cost +
    2698      338712 :             (target->cost.startup - oldtarget->cost.startup);
    2699      338712 :         pathnode->path.total_cost = subpath->total_cost +
    2700      338712 :             (target->cost.startup - oldtarget->cost.startup) +
    2701      338712 :             (target->cost.per_tuple - oldtarget->cost.per_tuple) * subpath->rows;
    2702             :     }
    2703             :     else
    2704             :     {
    2705             :         /* We really do need the Result node */
    2706        2002 :         pathnode->dummypp = false;
    2707             : 
    2708             :         /*
    2709             :          * The Result node's cost is cpu_tuple_cost per row, plus the cost of
    2710             :          * evaluating the tlist.  There is no qual to worry about.
    2711             :          */
    2712        2002 :         pathnode->path.rows = subpath->rows;
    2713        2002 :         pathnode->path.startup_cost = subpath->startup_cost +
    2714        2002 :             target->cost.startup;
    2715        2002 :         pathnode->path.total_cost = subpath->total_cost +
    2716        2002 :             target->cost.startup +
    2717        2002 :             (cpu_tuple_cost + target->cost.per_tuple) * subpath->rows;
    2718             :     }
    2719             : 
    2720      340714 :     return pathnode;
    2721             : }
    2722             : 
    2723             : /*
    2724             :  * apply_projection_to_path
    2725             :  *    Add a projection step, or just apply the target directly to given path.
    2726             :  *
    2727             :  * This has the same net effect as create_projection_path(), except that if
    2728             :  * a separate Result plan node isn't needed, we just replace the given path's
    2729             :  * pathtarget with the desired one.  This must be used only when the caller
    2730             :  * knows that the given path isn't referenced elsewhere and so can be modified
    2731             :  * in-place.
    2732             :  *
    2733             :  * If the input path is a GatherPath or GatherMergePath, we try to push the
    2734             :  * new target down to its input as well; this is a yet more invasive
    2735             :  * modification of the input path, which create_projection_path() can't do.
    2736             :  *
    2737             :  * Note that we mustn't change the source path's parent link; so when it is
    2738             :  * add_path'd to "rel" things will be a bit inconsistent.  So far that has
    2739             :  * not caused any trouble.
    2740             :  *
    2741             :  * 'rel' is the parent relation associated with the result
    2742             :  * 'path' is the path representing the source of data
    2743             :  * 'target' is the PathTarget to be computed
    2744             :  */
    2745             : Path *
    2746       22512 : apply_projection_to_path(PlannerInfo *root,
    2747             :                          RelOptInfo *rel,
    2748             :                          Path *path,
    2749             :                          PathTarget *target)
    2750             : {
    2751             :     QualCost    oldcost;
    2752             : 
    2753             :     /*
    2754             :      * If given path can't project, we might need a Result node, so make a
    2755             :      * separate ProjectionPath.
    2756             :      */
    2757       22512 :     if (!is_projection_capable_path(path))
    2758       10868 :         return (Path *) create_projection_path(root, rel, path, target);
    2759             : 
    2760             :     /*
    2761             :      * We can just jam the desired tlist into the existing path, being sure to
    2762             :      * update its cost estimates appropriately.
    2763             :      */
    2764       11644 :     oldcost = path->pathtarget->cost;
    2765       11644 :     path->pathtarget = target;
    2766             : 
    2767       11644 :     path->startup_cost += target->cost.startup - oldcost.startup;
    2768       11644 :     path->total_cost += target->cost.startup - oldcost.startup +
    2769       11644 :         (target->cost.per_tuple - oldcost.per_tuple) * path->rows;
    2770             : 
    2771             :     /*
    2772             :      * If the path happens to be a Gather or GatherMerge path, we'd like to
    2773             :      * arrange for the subpath to return the required target list so that
    2774             :      * workers can help project.  But if there is something that is not
    2775             :      * parallel-safe in the target expressions, then we can't.
    2776             :      */
    2777       12082 :     if ((IsA(path, GatherPath) || IsA(path, GatherMergePath)) &&
    2778         438 :         is_parallel_safe(root, (Node *) target->exprs))
    2779             :     {
    2780             :         /*
    2781             :          * We always use create_projection_path here, even if the subpath is
    2782             :          * projection-capable, so as to avoid modifying the subpath in place.
    2783             :          * It seems unlikely at present that there could be any other
    2784             :          * references to the subpath, but better safe than sorry.
    2785             :          *
    2786             :          * Note that we don't change the parallel path's cost estimates; it
    2787             :          * might be appropriate to do so, to reflect the fact that the bulk of
    2788             :          * the target evaluation will happen in workers.
    2789             :          */
    2790         438 :         if (IsA(path, GatherPath))
    2791             :         {
    2792           0 :             GatherPath *gpath = (GatherPath *) path;
    2793             : 
    2794           0 :             gpath->subpath = (Path *)
    2795           0 :                 create_projection_path(root,
    2796           0 :                                        gpath->subpath->parent,
    2797             :                                        gpath->subpath,
    2798             :                                        target);
    2799             :         }
    2800             :         else
    2801             :         {
    2802         438 :             GatherMergePath *gmpath = (GatherMergePath *) path;
    2803             : 
    2804         438 :             gmpath->subpath = (Path *)
    2805         438 :                 create_projection_path(root,
    2806         438 :                                        gmpath->subpath->parent,
    2807             :                                        gmpath->subpath,
    2808             :                                        target);
    2809             :         }
    2810             :     }
    2811       11206 :     else if (path->parallel_safe &&
    2812        4616 :              !is_parallel_safe(root, (Node *) target->exprs))
    2813             :     {
    2814             :         /*
    2815             :          * We're inserting a parallel-restricted target list into a path
    2816             :          * currently marked parallel-safe, so we have to mark it as no longer
    2817             :          * safe.
    2818             :          */
    2819          12 :         path->parallel_safe = false;
    2820             :     }
    2821             : 
    2822       11644 :     return path;
    2823             : }
    2824             : 
    2825             : /*
    2826             :  * create_set_projection_path
    2827             :  *    Creates a pathnode that represents performing a projection that
    2828             :  *    includes set-returning functions.
    2829             :  *
    2830             :  * 'rel' is the parent relation associated with the result
    2831             :  * 'subpath' is the path representing the source of data
    2832             :  * 'target' is the PathTarget to be computed
    2833             :  */
    2834             : ProjectSetPath *
    2835        6578 : create_set_projection_path(PlannerInfo *root,
    2836             :                            RelOptInfo *rel,
    2837             :                            Path *subpath,
    2838             :                            PathTarget *target)
    2839             : {
    2840        6578 :     ProjectSetPath *pathnode = makeNode(ProjectSetPath);
    2841             :     double      tlist_rows;
    2842             :     ListCell   *lc;
    2843             : 
    2844        6578 :     pathnode->path.pathtype = T_ProjectSet;
    2845        6578 :     pathnode->path.parent = rel;
    2846        6578 :     pathnode->path.pathtarget = target;
    2847             :     /* For now, assume we are above any joins, so no parameterization */
    2848        6578 :     pathnode->path.param_info = NULL;
    2849        6578 :     pathnode->path.parallel_aware = false;
    2850       14224 :     pathnode->path.parallel_safe = rel->consider_parallel &&
    2851        7598 :         subpath->parallel_safe &&
    2852        1020 :         is_parallel_safe(root, (Node *) target->exprs);
    2853        6578 :     pathnode->path.parallel_workers = subpath->parallel_workers;
    2854             :     /* Projection does not change the sort order XXX? */
    2855        6578 :     pathnode->path.pathkeys = subpath->pathkeys;
    2856             : 
    2857        6578 :     pathnode->subpath = subpath;
    2858             : 
    2859             :     /*
    2860             :      * Estimate number of rows produced by SRFs for each row of input; if
    2861             :      * there's more than one in this node, use the maximum.
    2862             :      */
    2863        6578 :     tlist_rows = 1;
    2864       14992 :     foreach(lc, target->exprs)
    2865             :     {
    2866        8414 :         Node       *node = (Node *) lfirst(lc);
    2867             :         double      itemrows;
    2868             : 
    2869        8414 :         itemrows = expression_returns_set_rows(root, node);
    2870        8414 :         if (tlist_rows < itemrows)
    2871        6378 :             tlist_rows = itemrows;
    2872             :     }
    2873             : 
    2874             :     /*
    2875             :      * In addition to the cost of evaluating the tlist, charge cpu_tuple_cost
    2876             :      * per input row, and half of cpu_tuple_cost for each added output row.
    2877             :      * This is slightly bizarre maybe, but it's what 9.6 did; we may revisit
    2878             :      * this estimate later.
    2879             :      */
    2880        6578 :     pathnode->path.rows = subpath->rows * tlist_rows;
    2881        6578 :     pathnode->path.startup_cost = subpath->startup_cost +
    2882        6578 :         target->cost.startup;
    2883        6578 :     pathnode->path.total_cost = subpath->total_cost +
    2884        6578 :         target->cost.startup +
    2885        6578 :         (cpu_tuple_cost + target->cost.per_tuple) * subpath->rows +
    2886        6578 :         (pathnode->path.rows - subpath->rows) * cpu_tuple_cost / 2;
    2887             : 
    2888        6578 :     return pathnode;
    2889             : }
    2890             : 
    2891             : /*
    2892             :  * create_incremental_sort_path
    2893             :  *    Creates a pathnode that represents performing an incremental sort.
    2894             :  *
    2895             :  * 'rel' is the parent relation associated with the result
    2896             :  * 'subpath' is the path representing the source of data
    2897             :  * 'pathkeys' represents the desired sort order
    2898             :  * 'presorted_keys' is the number of keys by which the input path is
    2899             :  *      already sorted
    2900             :  * 'limit_tuples' is the estimated bound on the number of output tuples,
    2901             :  *      or -1 if no LIMIT or couldn't estimate
    2902             :  */
    2903             : IncrementalSortPath *
    2904        4058 : create_incremental_sort_path(PlannerInfo *root,
    2905             :                              RelOptInfo *rel,
    2906             :                              Path *subpath,
    2907             :                              List *pathkeys,
    2908             :                              int presorted_keys,
    2909             :                              double limit_tuples)
    2910             : {
    2911        4058 :     IncrementalSortPath *sort = makeNode(IncrementalSortPath);
    2912        4058 :     SortPath   *pathnode = &sort->spath;
    2913             : 
    2914        4058 :     pathnode->path.pathtype = T_IncrementalSort;
    2915        4058 :     pathnode->path.parent = rel;
    2916             :     /* Sort doesn't project, so use source path's pathtarget */
    2917        4058 :     pathnode->path.pathtarget = subpath->pathtarget;
    2918             :     /* For now, assume we are above any joins, so no parameterization */
    2919        4058 :     pathnode->path.param_info = NULL;
    2920        4058 :     pathnode->path.parallel_aware = false;
    2921        7126 :     pathnode->path.parallel_safe = rel->consider_parallel &&
    2922        3068 :         subpath->parallel_safe;
    2923        4058 :     pathnode->path.parallel_workers = subpath->parallel_workers;
    2924        4058 :     pathnode->path.pathkeys = pathkeys;
    2925             : 
    2926        4058 :     pathnode->subpath = subpath;
    2927             : 
    2928        4058 :     cost_incremental_sort(&pathnode->path,
    2929             :                           root, pathkeys, presorted_keys,
    2930             :                           subpath->startup_cost,
    2931             :                           subpath->total_cost,
    2932             :                           subpath->rows,
    2933        4058 :                           subpath->pathtarget->width,
    2934             :                           0.0,  /* XXX comparison_cost shouldn't be 0? */
    2935             :                           work_mem, limit_tuples);
    2936             : 
    2937        4058 :     sort->nPresortedCols = presorted_keys;
    2938             : 
    2939        4058 :     return sort;
    2940             : }
    2941             : 
    2942             : /*
    2943             :  * create_sort_path
    2944             :  *    Creates a pathnode that represents performing an explicit sort.
    2945             :  *
    2946             :  * 'rel' is the parent relation associated with the result
    2947             :  * 'subpath' is the path representing the source of data
    2948             :  * 'pathkeys' represents the desired sort order
    2949             :  * 'limit_tuples' is the estimated bound on the number of output tuples,
    2950             :  *      or -1 if no LIMIT or couldn't estimate
    2951             :  */
    2952             : SortPath *
    2953       59706 : create_sort_path(PlannerInfo *root,
    2954             :                  RelOptInfo *rel,
    2955             :                  Path *subpath,
    2956             :                  List *pathkeys,
    2957             :                  double limit_tuples)
    2958             : {
    2959       59706 :     SortPath   *pathnode = makeNode(SortPath);
    2960             : 
    2961       59706 :     pathnode->path.pathtype = T_Sort;
    2962       59706 :     pathnode->path.parent = rel;
    2963             :     /* Sort doesn't project, so use source path's pathtarget */
    2964       59706 :     pathnode->path.pathtarget = subpath->pathtarget;
    2965             :     /* For now, assume we are above any joins, so no parameterization */
    2966       59706 :     pathnode->path.param_info = NULL;
    2967       59706 :     pathnode->path.parallel_aware = false;
    2968      101310 :     pathnode->path.parallel_safe = rel->consider_parallel &&
    2969       41604 :         subpath->parallel_safe;
    2970       59706 :     pathnode->path.parallel_workers = subpath->parallel_workers;
    2971       59706 :     pathnode->path.pathkeys = pathkeys;
    2972             : 
    2973       59706 :     pathnode->subpath = subpath;
    2974             : 
    2975       59706 :     cost_sort(&pathnode->path, root, pathkeys,
    2976             :               subpath->total_cost,
    2977             :               subpath->rows,
    2978       59706 :               subpath->pathtarget->width,
    2979             :               0.0,              /* XXX comparison_cost shouldn't be 0? */
    2980             :               work_mem, limit_tuples);
    2981             : 
    2982       59706 :     return pathnode;
    2983             : }
    2984             : 
    2985             : /*
    2986             :  * create_group_path
    2987             :  *    Creates a pathnode that represents performing grouping of presorted input
    2988             :  *
    2989             :  * 'rel' is the parent relation associated with the result
    2990             :  * 'subpath' is the path representing the source of data
    2991             :  * 'target' is the PathTarget to be computed
    2992             :  * 'groupClause' is a list of SortGroupClause's representing the grouping
    2993             :  * 'qual' is the HAVING quals if any
    2994             :  * 'numGroups' is the estimated number of groups
    2995             :  */
    2996             : GroupPath *
    2997        1070 : create_group_path(PlannerInfo *root,
    2998             :                   RelOptInfo *rel,
    2999             :                   Path *subpath,
    3000             :                   List *groupClause,
    3001             :                   List *qual,
    3002             :                   double numGroups)
    3003             : {
    3004        1070 :     GroupPath  *pathnode = makeNode(GroupPath);
    3005        1070 :     PathTarget *target = rel->reltarget;
    3006             : 
    3007        1070 :     pathnode->path.pathtype = T_Group;
    3008        1070 :     pathnode->path.parent = rel;
    3009        1070 :     pathnode->path.pathtarget = target;
    3010             :     /* For now, assume we are above any joins, so no parameterization */
    3011        1070 :     pathnode->path.param_info = NULL;
    3012        1070 :     pathnode->path.parallel_aware = false;
    3013        1758 :     pathnode->path.parallel_safe = rel->consider_parallel &&
    3014         688 :         subpath->parallel_safe;
    3015        1070 :     pathnode->path.parallel_workers = subpath->parallel_workers;
    3016             :     /* Group doesn't change sort ordering */
    3017        1070 :     pathnode->path.pathkeys = subpath->pathkeys;
    3018             : 
    3019        1070 :     pathnode->subpath = subpath;
    3020             : 
    3021        1070 :     pathnode->groupClause = groupClause;
    3022        1070 :     pathnode->qual = qual;
    3023             : 
    3024        1070 :     cost_group(&pathnode->path, root,
    3025             :                list_length(groupClause),
    3026             :                numGroups,
    3027             :                qual,
    3028             :                subpath->startup_cost, subpath->total_cost,
    3029             :                subpath->rows);
    3030             : 
    3031             :     /* add tlist eval cost for each output row */
    3032        1070 :     pathnode->path.startup_cost += target->cost.startup;
    3033        1070 :     pathnode->path.total_cost += target->cost.startup +
    3034        1070 :         target->cost.per_tuple * pathnode->path.rows;
    3035             : 
    3036        1070 :     return pathnode;
    3037             : }
    3038             : 
    3039             : /*
    3040             :  * create_upper_unique_path
    3041             :  *    Creates a pathnode that represents performing an explicit Unique step
    3042             :  *    on presorted input.
    3043             :  *
    3044             :  * This produces a Unique plan node, but the use-case is so different from
    3045             :  * create_unique_path that it doesn't seem worth trying to merge the two.
    3046             :  *
    3047             :  * 'rel' is the parent relation associated with the result
    3048             :  * 'subpath' is the path representing the source of data
    3049             :  * 'numCols' is the number of grouping columns
    3050             :  * 'numGroups' is the estimated number of groups
    3051             :  *
    3052             :  * The input path must be sorted on the grouping columns, plus possibly
    3053             :  * additional columns; so the first numCols pathkeys are the grouping columns
    3054             :  */
    3055             : UpperUniquePath *
    3056        3028 : create_upper_unique_path(PlannerInfo *root,
    3057             :                          RelOptInfo *rel,
    3058             :                          Path *subpath,
    3059             :                          int numCols,
    3060             :                          double numGroups)
    3061             : {
    3062        3028 :     UpperUniquePath *pathnode = makeNode(UpperUniquePath);
    3063             : 
    3064        3028 :     pathnode->path.pathtype = T_Unique;
    3065        3028 :     pathnode->path.parent = rel;
    3066             :     /* Unique doesn't project, so use source path's pathtarget */
    3067        3028 :     pathnode->path.pathtarget = subpath->pathtarget;
    3068             :     /* For now, assume we are above any joins, so no parameterization */
    3069        3028 :     pathnode->path.param_info = NULL;
    3070        3028 :     pathnode->path.parallel_aware = false;
    3071        5578 :     pathnode->path.parallel_safe = rel->consider_parallel &&
    3072        2550 :         subpath->parallel_safe;
    3073        3028 :     pathnode->path.parallel_workers = subpath->parallel_workers;
    3074             :     /* Unique doesn't change the input ordering */
    3075        3028 :     pathnode->path.pathkeys = subpath->pathkeys;
    3076             : 
    3077        3028 :     pathnode->subpath = subpath;
    3078        3028 :     pathnode->numkeys = numCols;
    3079             : 
    3080             :     /*
    3081             :      * Charge one cpu_operator_cost per comparison per input tuple. We assume
    3082             :      * all columns get compared at most of the tuples.  (XXX probably this is
    3083             :      * an overestimate.)
    3084             :      */
    3085        3028 :     pathnode->path.startup_cost = subpath->startup_cost;
    3086        3028 :     pathnode->path.total_cost = subpath->total_cost +
    3087        3028 :         cpu_operator_cost * subpath->rows * numCols;
    3088        3028 :     pathnode->path.rows = numGroups;
    3089             : 
    3090        3028 :     return pathnode;
    3091             : }
    3092             : 
    3093             : /*
    3094             :  * create_agg_path
    3095             :  *    Creates a pathnode that represents performing aggregation/grouping
    3096             :  *
    3097             :  * 'rel' is the parent relation associated with the result
    3098             :  * 'subpath' is the path representing the source of data
    3099             :  * 'target' is the PathTarget to be computed
    3100             :  * 'aggstrategy' is the Agg node's basic implementation strategy
    3101             :  * 'aggsplit' is the Agg node's aggregate-splitting mode
    3102             :  * 'groupClause' is a list of SortGroupClause's representing the grouping
    3103             :  * 'qual' is the HAVING quals if any
    3104             :  * 'aggcosts' contains cost info about the aggregate functions to be computed
    3105             :  * 'numGroups' is the estimated number of groups (1 if not grouping)
    3106             :  */
    3107             : AggPath *
    3108       48674 : create_agg_path(PlannerInfo *root,
    3109             :                 RelOptInfo *rel,
    3110             :                 Path *subpath,
    3111             :                 PathTarget *target,
    3112             :                 AggStrategy aggstrategy,
    3113             :                 AggSplit aggsplit,
    3114             :                 List *groupClause,
    3115             :                 List *qual,
    3116             :                 const AggClauseCosts *aggcosts,
    3117             :                 double numGroups)
    3118             : {
    3119       48674 :     AggPath    *pathnode = makeNode(AggPath);
    3120             : 
    3121       48674 :     pathnode->path.pathtype = T_Agg;
    3122       48674 :     pathnode->path.parent = rel;
    3123       48674 :     pathnode->path.pathtarget = target;
    3124             :     /* For now, assume we are above any joins, so no parameterization */
    3125       48674 :     pathnode->path.param_info = NULL;
    3126       48674 :     pathnode->path.parallel_aware = false;
    3127       82480 :     pathnode->path.parallel_safe = rel->consider_parallel &&
    3128       33806 :         subpath->parallel_safe;
    3129       48674 :     pathnode->path.parallel_workers = subpath->parallel_workers;
    3130       48674 :     if (aggstrategy == AGG_SORTED)
    3131        7026 :         pathnode->path.pathkeys = subpath->pathkeys;  /* preserves order */
    3132             :     else
    3133       41648 :         pathnode->path.pathkeys = NIL;   /* output is unordered */
    3134       48674 :     pathnode->subpath = subpath;
    3135             : 
    3136       48674 :     pathnode->aggstrategy = aggstrategy;
    3137       48674 :     pathnode->aggsplit = aggsplit;
    3138       48674 :     pathnode->numGroups = numGroups;
    3139       48674 :     pathnode->transitionSpace = aggcosts ? aggcosts->transitionSpace : 0;
    3140       48674 :     pathnode->groupClause = groupClause;
    3141       48674 :     pathnode->qual = qual;
    3142             : 
    3143       48674 :     cost_agg(&pathnode->path, root,
    3144             :              aggstrategy, aggcosts,
    3145             :              list_length(groupClause), numGroups,
    3146             :              qual,
    3147             :              subpath->startup_cost, subpath->total_cost,
    3148       48674 :              subpath->rows, subpath->pathtarget->width);
    3149             : 
    3150             :     /* add tlist eval cost for each output row */
    3151       48674 :     pathnode->path.startup_cost += target->cost.startup;
    3152       48674 :     pathnode->path.total_cost += target->cost.startup +
    3153       48674 :         target->cost.per_tuple * pathnode->path.rows;
    3154             : 
    3155       48674 :     return pathnode;
    3156             : }
    3157             : 
    3158             : /*
    3159             :  * create_groupingsets_path
    3160             :  *    Creates a pathnode that represents performing GROUPING SETS aggregation
    3161             :  *
    3162             :  * GroupingSetsPath represents sorted grouping with one or more grouping sets.
    3163             :  * The input path's result must be sorted to match the last entry in
    3164             :  * rollup_groupclauses.
    3165             :  *
    3166             :  * 'rel' is the parent relation associated with the result
    3167             :  * 'subpath' is the path representing the source of data
    3168             :  * 'target' is the PathTarget to be computed
    3169             :  * 'having_qual' is the HAVING quals if any
    3170             :  * 'rollups' is a list of RollupData nodes
    3171             :  * 'agg_costs' contains cost info about the aggregate functions to be computed
    3172             :  */
    3173             : GroupingSetsPath *
    3174        1792 : create_groupingsets_path(PlannerInfo *root,
    3175             :                          RelOptInfo *rel,
    3176             :                          Path *subpath,
    3177             :                          List *having_qual,
    3178             :                          AggStrategy aggstrategy,
    3179             :                          List *rollups,
    3180             :                          const AggClauseCosts *agg_costs)
    3181             : {
    3182        1792 :     GroupingSetsPath *pathnode = makeNode(GroupingSetsPath);
    3183        1792 :     PathTarget *target = rel->reltarget;
    3184             :     ListCell   *lc;
    3185        1792 :     bool        is_first = true;
    3186        1792 :     bool        is_first_sort = true;
    3187             : 
    3188             :     /* The topmost generated Plan node will be an Agg */
    3189        1792 :     pathnode->path.pathtype = T_Agg;
    3190        1792 :     pathnode->path.parent = rel;
    3191        1792 :     pathnode->path.pathtarget = target;
    3192        1792 :     pathnode->path.param_info = subpath->param_info;
    3193        1792 :     pathnode->path.parallel_aware = false;
    3194        2614 :     pathnode->path.parallel_safe = rel->consider_parallel &&
    3195         822 :         subpath->parallel_safe;
    3196        1792 :     pathnode->path.parallel_workers = subpath->parallel_workers;
    3197        1792 :     pathnode->subpath = subpath;
    3198             : 
    3199             :     /*
    3200             :      * Simplify callers by downgrading AGG_SORTED to AGG_PLAIN, and AGG_MIXED
    3201             :      * to AGG_HASHED, here if possible.
    3202             :      */
    3203        2556 :     if (aggstrategy == AGG_SORTED &&
    3204         764 :         list_length(rollups) == 1 &&
    3205         362 :         ((RollupData *) linitial(rollups))->groupClause == NIL)
    3206          42 :         aggstrategy = AGG_PLAIN;
    3207             : 
    3208        2636 :     if (aggstrategy == AGG_MIXED &&
    3209         844 :         list_length(rollups) == 1)
    3210           0 :         aggstrategy = AGG_HASHED;
    3211             : 
    3212             :     /*
    3213             :      * Output will be in sorted order by group_pathkeys if, and only if, there
    3214             :      * is a single rollup operation on a non-empty list of grouping
    3215             :      * expressions.
    3216             :      */
    3217        1792 :     if (aggstrategy == AGG_SORTED && list_length(rollups) == 1)
    3218         320 :         pathnode->path.pathkeys = root->group_pathkeys;
    3219             :     else
    3220        1472 :         pathnode->path.pathkeys = NIL;
    3221             : 
    3222        1792 :     pathnode->aggstrategy = aggstrategy;
    3223        1792 :     pathnode->rollups = rollups;
    3224        1792 :     pathnode->qual = having_qual;
    3225        1792 :     pathnode->transitionSpace = agg_costs ? agg_costs->transitionSpace : 0;
    3226             : 
    3227             :     Assert(rollups != NIL);
    3228             :     Assert(aggstrategy != AGG_PLAIN || list_length(rollups) == 1);
    3229             :     Assert(aggstrategy != AGG_MIXED || list_length(rollups) > 1);
    3230             : 
    3231        6396 :     foreach(lc, rollups)
    3232             :     {
    3233        4604 :         RollupData *rollup = lfirst(lc);
    3234        4604 :         List       *gsets = rollup->gsets;
    3235        4604 :         int         numGroupCols = list_length(linitial(gsets));
    3236             : 
    3237             :         /*
    3238             :          * In AGG_SORTED or AGG_PLAIN mode, the first rollup takes the
    3239             :          * (already-sorted) input, and following ones do their own sort.
    3240             :          *
    3241             :          * In AGG_HASHED mode, there is one rollup for each grouping set.
    3242             :          *
    3243             :          * In AGG_MIXED mode, the first rollups are hashed, the first
    3244             :          * non-hashed one takes the (already-sorted) input, and following ones
    3245             :          * do their own sort.
    3246             :          */
    3247        4604 :         if (is_first)
    3248             :         {
    3249        1792 :             cost_agg(&pathnode->path, root,
    3250             :                      aggstrategy,
    3251             :                      agg_costs,
    3252             :                      numGroupCols,
    3253             :                      rollup->numGroups,
    3254             :                      having_qual,
    3255             :                      subpath->startup_cost,
    3256             :                      subpath->total_cost,
    3257             :                      subpath->rows,
    3258        1792 :                      subpath->pathtarget->width);
    3259        1792 :             is_first = false;
    3260        1792 :             if (!rollup->is_hashed)
    3261         764 :                 is_first_sort = false;
    3262             :         }
    3263             :         else
    3264             :         {
    3265             :             Path        sort_path;  /* dummy for result of cost_sort */
    3266             :             Path        agg_path;   /* dummy for result of cost_agg */
    3267             : 
    3268        2812 :             if (rollup->is_hashed || is_first_sort)
    3269             :             {
    3270             :                 /*
    3271             :                  * Account for cost of aggregation, but don't charge input
    3272             :                  * cost again
    3273             :                  */
    3274        2158 :                 cost_agg(&agg_path, root,
    3275        2158 :                          rollup->is_hashed ? AGG_HASHED : AGG_SORTED,
    3276             :                          agg_costs,
    3277             :                          numGroupCols,
    3278             :                          rollup->numGroups,
    3279             :                          having_qual,
    3280             :                          0.0, 0.0,
    3281             :                          subpath->rows,
    3282        2158 :                          subpath->pathtarget->width);
    3283        2158 :                 if (!rollup->is_hashed)
    3284         844 :                     is_first_sort = false;
    3285             :             }
    3286             :             else
    3287             :             {
    3288             :                 /* Account for cost of sort, but don't charge input cost again */
    3289         654 :                 cost_sort(&sort_path, root, NIL,
    3290             :                           0.0,
    3291             :                           subpath->rows,
    3292         654 :                           subpath->pathtarget->width,
    3293             :                           0.0,
    3294             :                           work_mem,
    3295             :                           -1.0);
    3296             : 
    3297             :                 /* Account for cost of aggregation */
    3298             : 
    3299         654 :                 cost_agg(&agg_path, root,
    3300             :                          AGG_SORTED,
    3301             :                          agg_costs,
    3302             :                          numGroupCols,
    3303             :                          rollup->numGroups,
    3304             :                          having_qual,
    3305             :                          sort_path.startup_cost,
    3306             :                          sort_path.total_cost,
    3307             :                          sort_path.rows,
    3308         654 :                          subpath->pathtarget->width);
    3309             :             }
    3310             : 
    3311        2812 :             pathnode->path.total_cost += agg_path.total_cost;
    3312        2812 :             pathnode->path.rows += agg_path.rows;
    3313             :         }
    3314             :     }
    3315             : 
    3316             :     /* add tlist eval cost for each output row */
    3317        1792 :     pathnode->path.startup_cost += target->cost.startup;
    3318        1792 :     pathnode->path.total_cost += target->cost.startup +
    3319        1792 :         target->cost.per_tuple * pathnode->path.rows;
    3320             : 
    3321        1792 :     return pathnode;
    3322             : }
    3323             : 
    3324             : /*
    3325             :  * create_minmaxagg_path
    3326             :  *    Creates a pathnode that represents computation of MIN/MAX aggregates
    3327             :  *
    3328             :  * 'rel' is the parent relation associated with the result
    3329             :  * 'target' is the PathTarget to be computed
    3330             :  * 'mmaggregates' is a list of MinMaxAggInfo structs
    3331             :  * 'quals' is the HAVING quals if any
    3332             :  */
    3333             : MinMaxAggPath *
    3334         380 : create_minmaxagg_path(PlannerInfo *root,
    3335             :                       RelOptInfo *rel,
    3336             :                       PathTarget *target,
    3337             :                       List *mmaggregates,
    3338             :                       List *quals)
    3339             : {
    3340         380 :     MinMaxAggPath *pathnode = makeNode(MinMaxAggPath);
    3341             :     Cost        initplan_cost;
    3342             :     ListCell   *lc;
    3343             : 
    3344             :     /* The topmost generated Plan node will be a Result */
    3345         380 :     pathnode->path.pathtype = T_Result;
    3346         380 :     pathnode->path.parent = rel;
    3347         380 :     pathnode->path.pathtarget = target;
    3348             :     /* For now, assume we are above any joins, so no parameterization */
    3349         380 :     pathnode->path.param_info = NULL;
    3350         380 :     pathnode->path.parallel_aware = false;
    3351             :     /* A MinMaxAggPath implies use of initplans, so cannot be parallel-safe */
    3352         380 :     pathnode->path.parallel_safe = false;
    3353         380 :     pathnode->path.parallel_workers = 0;
    3354             :     /* Result is one unordered row */
    3355         380 :     pathnode->path.rows = 1;
    3356         380 :     pathnode->path.pathkeys = NIL;
    3357             : 
    3358         380 :     pathnode->mmaggregates = mmaggregates;
    3359         380 :     pathnode->quals = quals;
    3360             : 
    3361             :     /* Calculate cost of all the initplans ... */
    3362         380 :     initplan_cost = 0;
    3363         796 :     foreach(lc, mmaggregates)
    3364             :     {
    3365         416 :         MinMaxAggInfo *mminfo = (MinMaxAggInfo *) lfirst(lc);
    3366             : 
    3367         416 :         initplan_cost += mminfo->pathcost;
    3368             :     }
    3369             : 
    3370             :     /* add tlist eval cost for each output row, plus cpu_tuple_cost */
    3371         380 :     pathnode->path.startup_cost = initplan_cost + target->cost.startup;
    3372         380 :     pathnode->path.total_cost = initplan_cost + target->cost.startup +
    3373         380 :         target->cost.per_tuple + cpu_tuple_cost;
    3374             : 
    3375             :     /*
    3376             :      * Add cost of qual, if any --- but we ignore its selectivity, since our
    3377             :      * rowcount estimate should be 1 no matter what the qual is.
    3378             :      */
    3379         380 :     if (quals)
    3380             :     {
    3381             :         QualCost    qual_cost;
    3382             : 
    3383           0 :         cost_qual_eval(&qual_cost, quals, root);
    3384           0 :         pathnode->path.startup_cost += qual_cost.startup;
    3385           0 :         pathnode->path.total_cost += qual_cost.startup + qual_cost.per_tuple;
    3386             :     }
    3387             : 
    3388         380 :     return pathnode;
    3389             : }
    3390             : 
    3391             : /*
    3392             :  * create_windowagg_path
    3393             :  *    Creates a pathnode that represents computation of window functions
    3394             :  *
    3395             :  * 'rel' is the parent relation associated with the result
    3396             :  * 'subpath' is the path representing the source of data
    3397             :  * 'target' is the PathTarget to be computed
    3398             :  * 'windowFuncs' is a list of WindowFunc structs
    3399             :  * 'winclause' is a WindowClause that is common to all the WindowFuncs
    3400             :  * 'qual' WindowClause.runconditions from lower-level WindowAggPaths.
    3401             :  *      Must always be NIL when topwindow == false
    3402             :  * 'topwindow' pass as true only for the top-level WindowAgg. False for all
    3403             :  *      intermediate WindowAggs.
    3404             :  *
    3405             :  * The input must be sorted according to the WindowClause's PARTITION keys
    3406             :  * plus ORDER BY keys.
    3407             :  */
    3408             : WindowAggPath *
    3409        2310 : create_windowagg_path(PlannerInfo *root,
    3410             :                       RelOptInfo *rel,
    3411             :                       Path *subpath,
    3412             :                       PathTarget *target,
    3413             :                       List *windowFuncs,
    3414             :                       WindowClause *winclause,
    3415             :                       List *qual,
    3416             :                       bool topwindow)
    3417             : {
    3418        2310 :     WindowAggPath *pathnode = makeNode(WindowAggPath);
    3419             : 
    3420             :     /* qual can only be set for the topwindow */
    3421             :     Assert(qual == NIL || topwindow);
    3422             : 
    3423        2310 :     pathnode->path.pathtype = T_WindowAgg;
    3424        2310 :     pathnode->path.parent = rel;
    3425        2310 :     pathnode->path.pathtarget = target;
    3426             :     /* For now, assume we are above any joins, so no parameterization */
    3427        2310 :     pathnode->path.param_info = NULL;
    3428        2310 :     pathnode->path.parallel_aware = false;
    3429        2310 :     pathnode->path.parallel_safe = rel->consider_parallel &&
    3430           0 :         subpath->parallel_safe;
    3431        2310 :     pathnode->path.parallel_workers = subpath->parallel_workers;
    3432             :     /* WindowAgg preserves the input sort order */
    3433        2310 :     pathnode->path.pathkeys = subpath->pathkeys;
    3434             : 
    3435        2310 :     pathnode->subpath = subpath;
    3436        2310 :     pathnode->winclause = winclause;
    3437        2310 :     pathnode->qual = qual;
    3438        2310 :     pathnode->topwindow = topwindow;
    3439             : 
    3440             :     /*
    3441             :      * For costing purposes, assume that there are no redundant partitioning
    3442             :      * or ordering columns; it's not worth the trouble to deal with that
    3443             :      * corner case here.  So we just pass the unmodified list lengths to
    3444             :      * cost_windowagg.
    3445             :      */
    3446        2310 :     cost_windowagg(&pathnode->path, root,
    3447             :                    windowFuncs,
    3448        2310 :                    list_length(winclause->partitionClause),
    3449        2310 :                    list_length(winclause->orderClause),
    3450             :                    subpath->startup_cost,
    3451             :                    subpath->total_cost,
    3452             :                    subpath->rows);
    3453             : 
    3454             :     /* add tlist eval cost for each output row */
    3455        2310 :     pathnode->path.startup_cost += target->cost.startup;
    3456        2310 :     pathnode->path.total_cost += target->cost.startup +
    3457        2310 :         target->cost.per_tuple * pathnode->path.rows;
    3458             : 
    3459        2310 :     return pathnode;
    3460             : }
    3461             : 
    3462             : /*
    3463             :  * create_setop_path
    3464             :  *    Creates a pathnode that represents computation of INTERSECT or EXCEPT
    3465             :  *
    3466             :  * 'rel' is the parent relation associated with the result
    3467             :  * 'subpath' is the path representing the source of data
    3468             :  * 'cmd' is the specific semantics (INTERSECT or EXCEPT, with/without ALL)
    3469             :  * 'strategy' is the implementation strategy (sorted or hashed)
    3470             :  * 'distinctList' is a list of SortGroupClause's representing the grouping
    3471             :  * 'flagColIdx' is the column number where the flag column will be, if any
    3472             :  * 'firstFlag' is the flag value for the first input relation when hashing;
    3473             :  *      or -1 when sorting
    3474             :  * 'numGroups' is the estimated number of distinct groups
    3475             :  * 'outputRows' is the estimated number of output rows
    3476             :  */
    3477             : SetOpPath *
    3478         594 : create_setop_path(PlannerInfo *root,
    3479             :                   RelOptInfo *rel,
    3480             :                   Path *subpath,
    3481             :                   SetOpCmd cmd,
    3482             :                   SetOpStrategy strategy,
    3483             :                   List *distinctList,
    3484             :                   AttrNumber flagColIdx,
    3485             :                   int firstFlag,
    3486             :                   double numGroups,
    3487             :                   double outputRows)
    3488             : {
    3489         594 :     SetOpPath  *pathnode = makeNode(SetOpPath);
    3490             : 
    3491         594 :     pathnode->path.pathtype = T_SetOp;
    3492         594 :     pathnode->path.parent = rel;
    3493             :     /* SetOp doesn't project, so use source path's pathtarget */
    3494         594 :     pathnode->path.pathtarget = subpath->pathtarget;
    3495             :     /* For now, assume we are above any joins, so no parameterization */
    3496         594 :     pathnode->path.param_info = NULL;
    3497         594 :     pathnode->path.parallel_aware = false;
    3498         594 :     pathnode->path.parallel_safe = rel->consider_parallel &&
    3499           0 :         subpath->parallel_safe;
    3500         594 :     pathnode->path.parallel_workers = subpath->parallel_workers;
    3501             :     /* SetOp preserves the input sort order if in sort mode */
    3502         594 :     pathnode->path.pathkeys =
    3503         594 :         (strategy == SETOP_SORTED) ? subpath->pathkeys : NIL;
    3504             : 
    3505         594 :     pathnode->subpath = subpath;
    3506         594 :     pathnode->cmd = cmd;
    3507         594 :     pathnode->strategy = strategy;
    3508         594 :     pathnode->distinctList = distinctList;
    3509         594 :     pathnode->flagColIdx = flagColIdx;
    3510         594 :     pathnode->firstFlag = firstFlag;
    3511         594 :     pathnode->numGroups = numGroups;
    3512             : 
    3513             :     /*
    3514             :      * Charge one cpu_operator_cost per comparison per input tuple. We assume
    3515             :      * all columns get compared at most of the tuples.
    3516             :      */
    3517         594 :     pathnode->path.startup_cost = subpath->startup_cost;
    3518        1188 :     pathnode->path.total_cost = subpath->total_cost +
    3519         594 :         cpu_operator_cost * subpath->rows * list_length(distinctList);
    3520         594 :     pathnode->path.rows = outputRows;
    3521             : 
    3522         594 :     return pathnode;
    3523             : }
    3524             : 
    3525             : /*
    3526             :  * create_recursiveunion_path
    3527             :  *    Creates a pathnode that represents a recursive UNION node
    3528             :  *
    3529             :  * 'rel' is the parent relation associated with the result
    3530             :  * 'leftpath' is the source of data for the non-recursive term
    3531             :  * 'rightpath' is the source of data for the recursive term
    3532             :  * 'target' is the PathTarget to be computed
    3533             :  * 'distinctList' is a list of SortGroupClause's representing the grouping
    3534             :  * 'wtParam' is the ID of Param representing work table
    3535             :  * 'numGroups' is the estimated number of groups
    3536             :  *
    3537             :  * For recursive UNION ALL, distinctList is empty and numGroups is zero
    3538             :  */
    3539             : RecursiveUnionPath *
    3540         702 : create_recursiveunion_path(PlannerInfo *root,
    3541             :                            RelOptInfo *rel,
    3542             :                            Path *leftpath,
    3543             :                            Path *rightpath,
    3544             :                            PathTarget *target,
    3545             :                            List *distinctList,
    3546             :                            int wtParam,
    3547             :                            double numGroups)
    3548             : {
    3549         702 :     RecursiveUnionPath *pathnode = makeNode(RecursiveUnionPath);
    3550             : 
    3551         702 :     pathnode->path.pathtype = T_RecursiveUnion;
    3552         702 :     pathnode->path.parent = rel;
    3553         702 :     pathnode->path.pathtarget = target;
    3554             :     /* For now, assume we are above any joins, so no parameterization */
    3555         702 :     pathnode->path.param_info = NULL;
    3556         702 :     pathnode->path.parallel_aware = false;
    3557        1404 :     pathnode->path.parallel_safe = rel->consider_parallel &&
    3558         702 :         leftpath->parallel_safe && rightpath->parallel_safe;
    3559             :     /* Foolish, but we'll do it like joins for now: */
    3560         702 :     pathnode->path.parallel_workers = leftpath->parallel_workers;
    3561             :     /* RecursiveUnion result is always unsorted */
    3562         702 :     pathnode->path.pathkeys = NIL;
    3563             : 
    3564         702 :     pathnode->leftpath = leftpath;
    3565         702 :     pathnode->rightpath = rightpath;
    3566         702 :     pathnode->distinctList = distinctList;
    3567         702 :     pathnode->wtParam = wtParam;
    3568         702 :     pathnode->numGroups = numGroups;
    3569             : 
    3570         702 :     cost_recursive_union(&pathnode->path, leftpath, rightpath);
    3571             : 
    3572         702 :     return pathnode;
    3573             : }
    3574             : 
    3575             : /*
    3576             :  * create_lockrows_path
    3577             :  *    Creates a pathnode that represents acquiring row locks
    3578             :  *
    3579             :  * 'rel' is the parent relation associated with the result
    3580             :  * 'subpath' is the path representing the source of data
    3581             :  * 'rowMarks' is a list of PlanRowMark's
    3582             :  * 'epqParam' is the ID of Param for EvalPlanQual re-eval
    3583             :  */
    3584             : LockRowsPath *
    3585        7178 : create_lockrows_path(PlannerInfo *root, RelOptInfo *rel,
    3586             :                      Path *subpath, List *rowMarks, int epqParam)
    3587             : {
    3588        7178 :     LockRowsPath *pathnode = makeNode(LockRowsPath);
    3589             : 
    3590        7178 :     pathnode->path.pathtype = T_LockRows;
    3591        7178 :     pathnode->path.parent = rel;
    3592             :     /* LockRows doesn't project, so use source path's pathtarget */
    3593        7178 :     pathnode->path.pathtarget = subpath->pathtarget;
    3594             :     /* For now, assume we are above any joins, so no parameterization */
    3595        7178 :     pathnode->path.param_info = NULL;
    3596        7178 :     pathnode->path.parallel_aware = false;
    3597        7178 :     pathnode->path.parallel_safe = false;
    3598        7178 :     pathnode->path.parallel_workers = 0;
    3599        7178 :     pathnode->path.rows = subpath->rows;
    3600             : 
    3601             :     /*
    3602             :      * The result cannot be assumed sorted, since locking might cause the sort
    3603             :      * key columns to be replaced with new values.
    3604             :      */
    3605        7178 :     pathnode->path.pathkeys = NIL;
    3606             : 
    3607        7178 :     pathnode->subpath = subpath;
    3608        7178 :     pathnode->rowMarks = rowMarks;
    3609        7178 :     pathnode->epqParam = epqParam;
    3610             : 
    3611             :     /*
    3612             :      * We should charge something extra for the costs of row locking and
    3613             :      * possible refetches, but it's hard to say how much.  For now, use
    3614             :      * cpu_tuple_cost per row.
    3615             :      */
    3616        7178 :     pathnode->path.startup_cost = subpath->startup_cost;
    3617        7178 :     pathnode->path.total_cost = subpath->total_cost +
    3618        7178 :         cpu_tuple_cost * subpath->rows;
    3619             : 
    3620        7178 :     return pathnode;
    3621             : }
    3622             : 
    3623             : /*
    3624             :  * create_modifytable_path
    3625             :  *    Creates a pathnode that represents performing INSERT/UPDATE/DELETE/MERGE
    3626             :  *    mods
    3627             :  *
    3628             :  * 'rel' is the parent relation associated with the result
    3629             :  * 'subpath' is a Path producing source data
    3630             :  * 'operation' is the operation type
    3631             :  * 'canSetTag' is true if we set the command tag/es_processed
    3632             :  * 'nominalRelation' is the parent RT index for use of EXPLAIN
    3633             :  * 'rootRelation' is the partitioned table root RT index, or 0 if none
    3634             :  * 'partColsUpdated' is true if any partitioning columns are being updated,
    3635             :  *      either from the target relation or a descendent partitioned table.
    3636             :  * 'resultRelations' is an integer list of actual RT indexes of target rel(s)
    3637             :  * 'updateColnosLists' is a list of UPDATE target column number lists
    3638             :  *      (one sublist per rel); or NIL if not an UPDATE
    3639             :  * 'withCheckOptionLists' is a list of WCO lists (one per rel)
    3640             :  * 'returningLists' is a list of RETURNING tlists (one per rel)
    3641             :  * 'rowMarks' is a list of PlanRowMarks (non-locking only)
    3642             :  * 'onconflict' is the ON CONFLICT clause, or NULL
    3643             :  * 'epqParam' is the ID of Param for EvalPlanQual re-eval
    3644             :  * 'mergeActionLists' is a list of lists of MERGE actions (one per rel)
    3645             :  */
    3646             : ModifyTablePath *
    3647      107736 : create_modifytable_path(PlannerInfo *root, RelOptInfo *rel,
    3648             :                         Path *subpath,
    3649             :                         CmdType operation, bool canSetTag,
    3650             :                         Index nominalRelation, Index rootRelation,
    3651             :                         bool partColsUpdated,
    3652             :                         List *resultRelations,
    3653             :                         List *updateColnosLists,
    3654             :                         List *withCheckOptionLists, List *returningLists,
    3655             :                         List *rowMarks, OnConflictExpr *onconflict,
    3656             :                         List *mergeActionLists, int epqParam)
    3657             : {
    3658      107736 :     ModifyTablePath *pathnode = makeNode(ModifyTablePath);
    3659             : 
    3660             :     Assert(operation == CMD_MERGE ||
    3661             :            (operation == CMD_UPDATE ?
    3662             :             list_length(resultRelations) == list_length(updateColnosLists) :
    3663             :             updateColnosLists == NIL));
    3664             :     Assert(withCheckOptionLists == NIL ||
    3665             :            list_length(resultRelations) == list_length(withCheckOptionLists));
    3666             :     Assert(returningLists == NIL ||
    3667             :            list_length(resultRelations) == list_length(returningLists));
    3668             : 
    3669      107736 :     pathnode->path.pathtype = T_ModifyTable;
    3670      107736 :     pathnode->path.parent = rel;
    3671             :     /* pathtarget is not interesting, just make it minimally valid */
    3672      107736 :     pathnode->path.pathtarget = rel->reltarget;
    3673             :     /* For now, assume we are above any joins, so no parameterization */
    3674      107736 :     pathnode->path.param_info = NULL;
    3675      107736 :     pathnode->path.parallel_aware = false;
    3676      107736 :     pathnode->path.parallel_safe = false;
    3677      107736 :     pathnode->path.parallel_workers = 0;
    3678      107736 :     pathnode->path.pathkeys = NIL;
    3679             : 
    3680             :     /*
    3681             :      * Compute cost & rowcount as subpath cost & rowcount (if RETURNING)
    3682             :      *
    3683             :      * Currently, we don't charge anything extra for the actual table
    3684             :      * modification work, nor for the WITH CHECK OPTIONS or RETURNING
    3685             :      * expressions if any.  It would only be window dressing, since
    3686             :      * ModifyTable is always a top-level node and there is no way for the
    3687             :      * costs to change any higher-level planning choices.  But we might want
    3688             :      * to make it look better sometime.
    3689             :      */
    3690      107736 :     pathnode->path.startup_cost = subpath->startup_cost;
    3691      107736 :     pathnode->path.total_cost = subpath->total_cost;
    3692      107736 :     if (returningLists != NIL)
    3693             :     {
    3694        2256 :         pathnode->path.rows = subpath->rows;
    3695             : 
    3696             :         /*
    3697             :          * Set width to match the subpath output.  XXX this is totally wrong:
    3698             :          * we should return an average of the RETURNING tlist widths.  But
    3699             :          * it's what happened historically, and improving it is a task for
    3700             :          * another day.  (Again, it's mostly window dressing.)
    3701             :          */
    3702        2256 :         pathnode->path.pathtarget->width = subpath->pathtarget->width;
    3703             :     }
    3704             :     else
    3705             :     {
    3706      105480 :         pathnode->path.rows = 0;
    3707      105480 :         pathnode->path.pathtarget->width = 0;
    3708             :     }
    3709             : 
    3710      107736 :     pathnode->subpath = subpath;
    3711      107736 :     pathnode->operation = operation;
    3712      107736 :     pathnode->canSetTag = canSetTag;
    3713      107736 :     pathnode->nominalRelation = nominalRelation;
    3714      107736 :     pathnode->rootRelation = rootRelation;
    3715      107736 :     pathnode->partColsUpdated = partColsUpdated;
    3716      107736 :     pathnode->resultRelations = resultRelations;
    3717      107736 :     pathnode->updateColnosLists = updateColnosLists;
    3718      107736 :     pathnode->withCheckOptionLists = withCheckOptionLists;
    3719      107736 :     pathnode->returningLists = returningLists;
    3720      107736 :     pathnode->rowMarks = rowMarks;
    3721      107736 :     pathnode->onconflict = onconflict;
    3722      107736 :     pathnode->epqParam = epqParam;
    3723      107736 :     pathnode->mergeActionLists = mergeActionLists;
    3724             : 
    3725      107736 :     return pathnode;
    3726             : }
    3727             : 
    3728             : /*
    3729             :  * create_limit_path
    3730             :  *    Creates a pathnode that represents performing LIMIT/OFFSET
    3731             :  *
    3732             :  * In addition to providing the actual OFFSET and LIMIT expressions,
    3733             :  * the caller must provide estimates of their values for costing purposes.
    3734             :  * The estimates are as computed by preprocess_limit(), ie, 0 represents
    3735             :  * the clause not being present, and -1 means it's present but we could
    3736             :  * not estimate its value.
    3737             :  *
    3738             :  * 'rel' is the parent relation associated with the result
    3739             :  * 'subpath' is the path representing the source of data
    3740             :  * 'limitOffset' is the actual OFFSET expression, or NULL
    3741             :  * 'limitCount' is the actual LIMIT expression, or NULL
    3742             :  * 'offset_est' is the estimated value of the OFFSET expression
    3743             :  * 'count_est' is the estimated value of the LIMIT expression
    3744             :  */
    3745             : LimitPath *
    3746        5712 : create_limit_path(PlannerInfo *root, RelOptInfo *rel,
    3747             :                   Path *subpath,
    3748             :                   Node *limitOffset, Node *limitCount,
    3749             :                   LimitOption limitOption,
    3750             :                   int64 offset_est, int64 count_est)
    3751             : {
    3752        5712 :     LimitPath  *pathnode = makeNode(LimitPath);
    3753             : 
    3754        5712 :     pathnode->path.pathtype = T_Limit;
    3755        5712 :     pathnode->path.parent = rel;
    3756             :     /* Limit doesn't project, so use source path's pathtarget */
    3757        5712 :     pathnode->path.pathtarget = subpath->pathtarget;
    3758             :     /* For now, assume we are above any joins, so no parameterization */
    3759        5712 :     pathnode->path.param_info = NULL;
    3760        5712 :     pathnode->path.parallel_aware = false;
    3761        7722 :     pathnode->path.parallel_safe = rel->consider_parallel &&
    3762        2010 :         subpath->parallel_safe;
    3763        5712 :     pathnode->path.parallel_workers = subpath->parallel_workers;
    3764        5712 :     pathnode->path.rows = subpath->rows;
    3765        5712 :     pathnode->path.startup_cost = subpath->startup_cost;
    3766        5712 :     pathnode->path.total_cost = subpath->total_cost;
    3767        5712 :     pathnode->path.pathkeys = subpath->pathkeys;
    3768        5712 :     pathnode->subpath = subpath;
    3769        5712 :     pathnode->limitOffset = limitOffset;
    3770        5712 :     pathnode->limitCount = limitCount;
    3771        5712 :     pathnode->limitOption = limitOption;
    3772             : 
    3773             :     /*
    3774             :      * Adjust the output rows count and costs according to the offset/limit.
    3775             :      */
    3776        5712 :     adjust_limit_rows_costs(&pathnode->path.rows,
    3777             :                             &pathnode->path.startup_cost,
    3778             :                             &pathnode->path.total_cost,
    3779             :                             offset_est, count_est);
    3780             : 
    3781        5712 :     return pathnode;
    3782             : }
    3783             : 
    3784             : /*
    3785             :  * adjust_limit_rows_costs
    3786             :  *    Adjust the size and cost estimates for a LimitPath node according to the
    3787             :  *    offset/limit.
    3788             :  *
    3789             :  * This is only a cosmetic issue if we are at top level, but if we are
    3790             :  * building a subquery then it's important to report correct info to the outer
    3791             :  * planner.
    3792             :  *
    3793             :  * When the offset or count couldn't be estimated, use 10% of the estimated
    3794             :  * number of rows emitted from the subpath.
    3795             :  *
    3796             :  * XXX we don't bother to add eval costs of the offset/limit expressions
    3797             :  * themselves to the path costs.  In theory we should, but in most cases those
    3798             :  * expressions are trivial and it's just not worth the trouble.
    3799             :  */
    3800             : void
    3801        5894 : adjust_limit_rows_costs(double *rows,   /* in/out parameter */
    3802             :                         Cost *startup_cost, /* in/out parameter */
    3803             :                         Cost *total_cost,   /* in/out parameter */
    3804             :                         int64 offset_est,
    3805             :                         int64 count_est)
    3806             : {
    3807        5894 :     double      input_rows = *rows;
    3808        5894 :     Cost        input_startup_cost = *startup_cost;
    3809        5894 :     Cost        input_total_cost = *total_cost;
    3810             : 
    3811        5894 :     if (offset_est != 0)
    3812             :     {
    3813             :         double      offset_rows;
    3814             : 
    3815         670 :         if (offset_est > 0)
    3816         646 :             offset_rows = (double) offset_est;
    3817             :         else
    3818          24 :             offset_rows = clamp_row_est(input_rows * 0.10);
    3819         670 :         if (offset_rows > *rows)
    3820          26 :             offset_rows = *rows;
    3821         670 :         if (input_rows > 0)
    3822         670 :             *startup_cost +=
    3823         670 :                 (input_total_cost - input_startup_cost)
    3824         670 :                 * offset_rows / input_rows;
    3825         670 :         *rows -= offset_rows;
    3826         670 :         if (*rows < 1)
    3827          26 :             *rows = 1;
    3828             :     }
    3829             : 
    3830        5894 :     if (count_est != 0)
    3831             :     {
    3832             :         double      count_rows;
    3833             : 
    3834        5846 :         if (count_est > 0)
    3835        5840 :             count_rows = (double) count_est;
    3836             :         else
    3837           6 :             count_rows = clamp_row_est(input_rows * 0.10);
    3838        5846 :         if (count_rows > *rows)
    3839         240 :             count_rows = *rows;
    3840        5846 :         if (input_rows > 0)
    3841        5846 :             *total_cost = *startup_cost +
    3842        5846 :                 (input_total_cost - input_startup_cost)
    3843        5846 :                 * count_rows / input_rows;
    3844        5846 :         *rows = count_rows;
    3845        5846 :         if (*rows < 1)
    3846           0 :             *rows = 1;
    3847             :     }
    3848        5894 : }
    3849             : 
    3850             : 
    3851             : /*
    3852             :  * reparameterize_path
    3853             :  *      Attempt to modify a Path to have greater parameterization
    3854             :  *
    3855             :  * We use this to attempt to bring all child paths of an appendrel to the
    3856             :  * same parameterization level, ensuring that they all enforce the same set
    3857             :  * of join quals (and thus that that parameterization can be attributed to
    3858             :  * an append path built from such paths).  Currently, only a few path types
    3859             :  * are supported here, though more could be added at need.  We return NULL
    3860             :  * if we can't reparameterize the given path.
    3861             :  *
    3862             :  * Note: we intentionally do not pass created paths to add_path(); it would
    3863             :  * possibly try to delete them on the grounds of being cost-inferior to the
    3864             :  * paths they were made from, and we don't want that.  Paths made here are
    3865             :  * not necessarily of general-purpose usefulness, but they can be useful
    3866             :  * as members of an append path.
    3867             :  */
    3868             : Path *
    3869         308 : reparameterize_path(PlannerInfo *root, Path *path,
    3870             :                     Relids required_outer,
    3871             :                     double loop_count)
    3872             : {
    3873         308 :     RelOptInfo *rel = path->parent;
    3874             : 
    3875             :     /* Can only increase, not decrease, path's parameterization */
    3876         308 :     if (!bms_is_subset(PATH_REQ_OUTER(path), required_outer))
    3877           0 :         return NULL;
    3878         308 :     switch (path->pathtype)
    3879             :     {
    3880         228 :         case T_SeqScan:
    3881         228 :             return create_seqscan_path(root, rel, required_outer, 0);
    3882           0 :         case T_SampleScan:
    3883           0 :             return (Path *) create_samplescan_path(root, rel, required_outer);
    3884           0 :         case T_IndexScan:
    3885             :         case T_IndexOnlyScan:
    3886             :             {
    3887           0 :                 IndexPath  *ipath = (IndexPath *) path;
    3888           0 :                 IndexPath  *newpath = makeNode(IndexPath);
    3889             : 
    3890             :                 /*
    3891             :                  * We can't use create_index_path directly, and would not want
    3892             :                  * to because it would re-compute the indexqual conditions
    3893             :                  * which is wasted effort.  Instead we hack things a bit:
    3894             :                  * flat-copy the path node, revise its param_info, and redo
    3895             :                  * the cost estimate.
    3896             :                  */
    3897           0 :                 memcpy(newpath, ipath, sizeof(IndexPath));
    3898           0 :                 newpath->path.param_info =
    3899           0 :                     get_baserel_parampathinfo(root, rel, required_outer);
    3900           0 :                 cost_index(newpath, root, loop_count, false);
    3901           0 :                 return (Path *) newpath;
    3902             :             }
    3903           0 :         case T_BitmapHeapScan:
    3904             :             {
    3905           0 :                 BitmapHeapPath *bpath = (BitmapHeapPath *) path;
    3906             : 
    3907           0 :                 return (Path *) create_bitmap_heap_path(root,
    3908             :                                                         rel,
    3909             :                                                         bpath->bitmapqual,
    3910             :                                                         required_outer,
    3911             :                                                         loop_count, 0);
    3912             :             }
    3913           0 :         case T_SubqueryScan:
    3914             :             {
    3915           0 :                 SubqueryScanPath *spath = (SubqueryScanPath *) path;
    3916           0 :                 Path       *subpath = spath->subpath;
    3917             :                 bool        trivial_pathtarget;
    3918             : 
    3919             :                 /*
    3920             :                  * If existing node has zero extra cost, we must have decided
    3921             :                  * its target is trivial.  (The converse is not true, because
    3922             :                  * it might have a trivial target but quals to enforce; but in
    3923             :                  * that case the new node will too, so it doesn't matter
    3924             :                  * whether we get the right answer here.)
    3925             :                  */
    3926           0 :                 trivial_pathtarget =
    3927           0 :                     (subpath->total_cost == spath->path.total_cost);
    3928             : 
    3929           0 :                 return (Path *) create_subqueryscan_path(root,
    3930             :                                                          rel,
    3931             :                                                          subpath,
    3932             :                                                          trivial_pathtarget,
    3933             :                                                          spath->path.pathkeys,
    3934             :                                                          required_outer);
    3935             :             }
    3936          48 :         case T_Result:
    3937             :             /* Supported only for RTE_RESULT scan paths */
    3938          48 :             if (IsA(path, Path))
    3939          48 :                 return create_resultscan_path(root, rel, required_outer);
    3940           0 :             break;
    3941           0 :         case T_Append:
    3942             :             {
    3943           0 :                 AppendPath *apath = (AppendPath *) path;
    3944           0 :                 List       *childpaths = NIL;
    3945           0 :                 List       *partialpaths = NIL;
    3946             :                 int         i;
    3947             :                 ListCell   *lc;
    3948             : 
    3949             :                 /* Reparameterize the children */
    3950           0 :                 i = 0;
    3951           0 :                 foreach(lc, apath->subpaths)
    3952             :                 {
    3953           0 :                     Path       *spath = (Path *) lfirst(lc);
    3954             : 
    3955           0 :                     spath = reparameterize_path(root, spath,
    3956             :                                                 required_outer,
    3957             :                                                 loop_count);
    3958           0 :                     if (spath == NULL)
    3959           0 :                         return NULL;
    3960             :                     /* We have to re-split the regular and partial paths */
    3961           0 :                     if (i < apath->first_partial_path)
    3962           0 :                         childpaths = lappend(childpaths, spath);
    3963             :                     else
    3964           0 :                         partialpaths = lappend(partialpaths, spath);
    3965           0 :                     i++;
    3966             :                 }
    3967           0 :                 return (Path *)
    3968           0 :                     create_append_path(root, rel, childpaths, partialpaths,
    3969             :                                        apath->path.pathkeys, required_outer,
    3970             :                                        apath->path.parallel_workers,
    3971           0 :                                        apath->path.parallel_aware,
    3972             :                                        -1);
    3973             :             }
    3974           0 :         case T_Material:
    3975             :             {
    3976           0 :                 MaterialPath *mpath = (MaterialPath *) path;
    3977           0 :                 Path       *spath = mpath->subpath;
    3978             : 
    3979           0 :                 spath = reparameterize_path(root, spath,
    3980             :                                             required_outer,
    3981             :                                             loop_count);
    3982           0 :                 if (spath == NULL)
    3983           0 :                     return NULL;
    3984           0 :                 return (Path *) create_material_path(rel, spath);
    3985             :             }
    3986           0 :         case T_Memoize:
    3987             :             {
    3988           0 :                 MemoizePath *mpath = (MemoizePath *) path;
    3989           0 :                 Path       *spath = mpath->subpath;
    3990             : 
    3991           0 :                 spath = reparameterize_path(root, spath,
    3992             :                                             required_outer,
    3993             :                                             loop_count);
    3994           0 :                 if (spath == NULL)
    3995           0 :                     return NULL;
    3996           0 :                 return (Path *) create_memoize_path(root, rel,
    3997             :                                                     spath,
    3998             :                                                     mpath->param_exprs,
    3999             :                                                     mpath->hash_operators,
    4000           0 :                                                     mpath->singlerow,
    4001           0 :                                                     mpath->binary_mode,
    4002             :                                                     mpath->calls);
    4003             :             }
    4004          32 :         default:
    4005          32 :             break;
    4006             :     }
    4007          32 :     return NULL;
    4008             : }
    4009             : 
    4010             : /*
    4011             :  * reparameterize_path_by_child
    4012             :  *      Given a path parameterized by the parent of the given child relation,
    4013             :  *      translate the path to be parameterized by the given child relation.
    4014             :  *
    4015             :  * The function creates a new path of the same type as the given path, but
    4016             :  * parameterized by the given child relation.  Most fields from the original
    4017             :  * path can simply be flat-copied, but any expressions must be adjusted to
    4018             :  * refer to the correct varnos, and any paths must be recursively
    4019             :  * reparameterized.  Other fields that refer to specific relids also need
    4020             :  * adjustment.
    4021             :  *
    4022             :  * The cost, number of rows, width and parallel path properties depend upon
    4023             :  * path->parent, which does not change during the translation. Hence those
    4024             :  * members are copied as they are.
    4025             :  *
    4026             :  * Currently, only a few path types are supported here, though more could be
    4027             :  * added at need.  We return NULL if we can't reparameterize the given path.
    4028             :  */
    4029             : Path *
    4030        8404 : reparameterize_path_by_child(PlannerInfo *root, Path *path,
    4031             :                              RelOptInfo *child_rel)
    4032             : {
    4033             : 
    4034             : #define FLAT_COPY_PATH(newnode, node, nodetype)  \
    4035             :     ( (newnode) = makeNode(nodetype), \
    4036             :       memcpy((newnode), (node), sizeof(nodetype)) )
    4037             : 
    4038             : #define ADJUST_CHILD_ATTRS(node) \
    4039             :     ((node) = \
    4040             :      (List *) adjust_appendrel_attrs_multilevel(root, (Node *) (node), \
    4041             :                                                 child_rel, \
    4042             :                                                 child_rel->top_parent))
    4043             : 
    4044             : #define REPARAMETERIZE_CHILD_PATH(path) \
    4045             : do { \
    4046             :     (path) = reparameterize_path_by_child(root, (path), child_rel); \
    4047             :     if ((path) == NULL) \
    4048             :         return NULL; \
    4049             : } while(0)
    4050             : 
    4051             : #define REPARAMETERIZE_CHILD_PATH_LIST(pathlist) \
    4052             : do { \
    4053             :     if ((pathlist) != NIL) \
    4054             :     { \
    4055             :         (pathlist) = reparameterize_pathlist_by_child(root, (pathlist), \
    4056             :                                                       child_rel); \
    4057             :         if ((pathlist) == NIL) \
    4058             :             return NULL; \
    4059             :     } \
    4060             : } while(0)
    4061             : 
    4062             :     Path       *new_path;
    4063             :     ParamPathInfo *new_ppi;
    4064             :     ParamPathInfo *old_ppi;
    4065             :     Relids      required_outer;
    4066             : 
    4067             :     /*
    4068             :      * If the path is not parameterized by parent of the given relation, it
    4069             :      * doesn't need reparameterization.
    4070             :      */
    4071        8404 :     if (!path->param_info ||
    4072        8320 :         !bms_overlap(PATH_REQ_OUTER(path), child_rel->top_parent_relids))
    4073         240 :         return path;
    4074             : 
    4075             :     /*
    4076             :      * If possible, reparameterize the given path, making a copy.
    4077             :      *
    4078             :      * This function is currently only applied to the inner side of a nestloop
    4079             :      * join that is being partitioned by the partitionwise-join code.  Hence,
    4080             :      * we need only support path types that plausibly arise in that context.
    4081             :      * (In particular, supporting sorted path types would be a waste of code
    4082             :      * and cycles: even if we translated them here, they'd just lose in
    4083             :      * subsequent cost comparisons.)  If we do see an unsupported path type,
    4084             :      * that just means we won't be able to generate a partitionwise-join plan
    4085             :      * using that path type.
    4086             :      */
    4087        8164 :     switch (nodeTag(path))
    4088             :     {
    4089         432 :         case T_Path:
    4090         432 :             FLAT_COPY_PATH(new_path, path, Path);
    4091         432 :             break;
    4092             : 
    4093        5040 :         case T_IndexPath:
    4094             :             {
    4095             :                 IndexPath  *ipath;
    4096             : 
    4097        5040 :                 FLAT_COPY_PATH(ipath, path, IndexPath);
    4098        5040 :                 ADJUST_CHILD_ATTRS(ipath->indexclauses);
    4099        5040 :                 new_path = (Path *) ipath;
    4100             :             }
    4101        5040 :             break;
    4102             : 
    4103          48 :         case T_BitmapHeapPath:
    4104             :             {
    4105             :                 BitmapHeapPath *bhpath;
    4106             : 
    4107          48 :                 FLAT_COPY_PATH(bhpath, path, BitmapHeapPath);
    4108          48 :                 REPARAMETERIZE_CHILD_PATH(bhpath->bitmapqual);
    4109          48 :                 new_path = (Path *) bhpath;
    4110             :             }
    4111          48 :             break;
    4112             : 
    4113          24 :         case T_BitmapAndPath:
    4114             :             {
    4115             :                 BitmapAndPath *bapath;
    4116             : 
    4117          24 :                 FLAT_COPY_PATH(bapath, path, BitmapAndPath);
    4118          24 :                 REPARAMETERIZE_CHILD_PATH_LIST(bapath->bitmapquals);
    4119          24 :                 new_path = (Path *) bapath;
    4120             :             }
    4121          24 :             break;
    4122             : 
    4123          24 :         case T_BitmapOrPath:
    4124             :             {
    4125             :                 BitmapOrPath *bopath;
    4126             : 
    4127          24 :                 FLAT_COPY_PATH(bopath, path, BitmapOrPath);
    4128          24 :                 REPARAMETERIZE_CHILD_PATH_LIST(bopath->bitmapquals);
    4129          24 :                 new_path = (Path *) bopath;
    4130             :             }
    4131          24 :             break;
    4132             : 
    4133          52 :         case T_ForeignPath:
    4134             :             {
    4135             :                 ForeignPath *fpath;
    4136             :                 ReparameterizeForeignPathByChild_function rfpc_func;
    4137             : 
    4138          52 :                 FLAT_COPY_PATH(fpath, path, ForeignPath);
    4139          52 :                 if (fpath->fdw_outerpath)
    4140           0 :                     REPARAMETERIZE_CHILD_PATH(fpath->fdw_outerpath);
    4141             : 
    4142             :                 /* Hand over to FDW if needed. */
    4143          52 :                 rfpc_func =
    4144          52 :                     path->parent->fdwroutine->ReparameterizeForeignPathByChild;
    4145          52 :                 if (rfpc_func)
    4146           0 :                     fpath->fdw_private = rfpc_func(root, fpath->fdw_private,
    4147             :                                                    child_rel);
    4148          52 :                 new_path = (Path *) fpath;
    4149             :             }
    4150          52 :             break;
    4151             : 
    4152           0 :         case T_CustomPath:
    4153             :             {
    4154             :                 CustomPath *cpath;
    4155             : 
    4156           0 :                 FLAT_COPY_PATH(cpath, path, CustomPath);
    4157           0 :                 REPARAMETERIZE_CHILD_PATH_LIST(cpath->custom_paths);
    4158           0 :                 if (cpath->methods &&
    4159           0 :                     cpath->methods->ReparameterizeCustomPathByChild)
    4160           0 :                     cpath->custom_private =
    4161           0 :                         cpath->methods->ReparameterizeCustomPathByChild(root,
    4162             :                                                                         cpath->custom_private,
    4163             :                                                                         child_rel);
    4164           0 :                 new_path = (Path *) cpath;
    4165             :             }
    4166           0 :             break;
    4167             : 
    4168         300 :         case T_NestPath:
    4169             :             {
    4170             :                 JoinPath   *jpath;
    4171             :                 NestPath   *npath;
    4172             : 
    4173         300 :                 FLAT_COPY_PATH(npath, path, NestPath);
    4174             : 
    4175         300 :                 jpath = (JoinPath *) npath;
    4176         300 :                 REPARAMETERIZE_CHILD_PATH(jpath->outerjoinpath);
    4177         300 :                 REPARAMETERIZE_CHILD_PATH(jpath->innerjoinpath);
    4178         300 :                 ADJUST_CHILD_ATTRS(jpath->joinrestrictinfo);
    4179         300 :                 new_path = (Path *) npath;
    4180             :             }
    4181         300 :             break;
    4182             : 
    4183          36 :         case T_MergePath:
    4184             :             {
    4185             :                 JoinPath   *jpath;
    4186             :                 MergePath  *mpath;
    4187             : 
    4188          36 :                 FLAT_COPY_PATH(mpath, path, MergePath);
    4189             : 
    4190          36 :                 jpath = (JoinPath *) mpath;
    4191          36 :                 REPARAMETERIZE_CHILD_PATH(jpath->outerjoinpath);
    4192          36 :                 REPARAMETERIZE_CHILD_PATH(jpath->innerjoinpath);
    4193          36 :                 ADJUST_CHILD_ATTRS(jpath->joinrestrictinfo);
    4194          36 :                 ADJUST_CHILD_ATTRS(mpath->path_mergeclauses);
    4195          36 :                 new_path = (Path *) mpath;
    4196             :             }
    4197          36 :             break;
    4198             : 
    4199         168 :         case T_HashPath:
    4200             :             {
    4201             :                 JoinPath   *jpath;
    4202             :                 HashPath   *hpath;
    4203             : 
    4204         168 :                 FLAT_COPY_PATH(hpath, path, HashPath);
    4205             : 
    4206         168 :                 jpath = (JoinPath *) hpath;
    4207         168 :                 REPARAMETERIZE_CHILD_PATH(jpath->outerjoinpath);
    4208         168 :                 REPARAMETERIZE_CHILD_PATH(jpath->innerjoinpath);
    4209         168 :                 ADJUST_CHILD_ATTRS(jpath->joinrestrictinfo);
    4210         168 :                 ADJUST_CHILD_ATTRS(hpath->path_hashclauses);
    4211         168 :                 new_path = (Path *) hpath;
    4212             :             }
    4213         168 :             break;
    4214             : 
    4215         120 :         case T_AppendPath:
    4216             :             {
    4217             :                 AppendPath *apath;
    4218             : 
    4219         120 :                 FLAT_COPY_PATH(apath, path, AppendPath);
    4220         120 :                 REPARAMETERIZE_CHILD_PATH_LIST(apath->subpaths);
    4221         120 :                 new_path = (Path *) apath;
    4222             :             }
    4223         120 :             break;
    4224             : 
    4225           0 :         case T_MaterialPath:
    4226             :             {
    4227             :                 MaterialPath *mpath;
    4228             : 
    4229           0 :                 FLAT_COPY_PATH(mpath, path, MaterialPath);
    4230           0 :                 REPARAMETERIZE_CHILD_PATH(mpath->subpath);
    4231           0 :                 new_path = (Path *) mpath;
    4232             :             }
    4233           0 :             break;
    4234             : 
    4235        1920 :         case T_MemoizePath:
    4236             :             {
    4237             :                 MemoizePath *mpath;
    4238             : 
    4239        1920 :                 FLAT_COPY_PATH(mpath, path, MemoizePath);
    4240        1920 :                 REPARAMETERIZE_CHILD_PATH(mpath->subpath);
    4241        1920 :                 ADJUST_CHILD_ATTRS(mpath->param_exprs);
    4242        1920 :                 new_path = (Path *) mpath;
    4243             :             }
    4244        1920 :             break;
    4245             : 
    4246           0 :         case T_GatherPath:
    4247             :             {
    4248             :                 GatherPath *gpath;
    4249             : 
    4250           0 :                 FLAT_COPY_PATH(gpath, path, GatherPath);
    4251           0 :                 REPARAMETERIZE_CHILD_PATH(gpath->subpath);
    4252           0 :                 new_path = (Path *) gpath;
    4253             :             }
    4254           0 :             break;
    4255             : 
    4256           0 :         default:
    4257             : 
    4258             :             /* We don't know how to reparameterize this path. */
    4259           0 :             return NULL;
    4260             :     }
    4261             : 
    4262             :     /*
    4263             :      * Adjust the parameterization information, which refers to the topmost
    4264             :      * parent. The topmost parent can be multiple levels away from the given
    4265             :      * child, hence use multi-level expression adjustment routines.
    4266             :      */
    4267        8164 :     old_ppi = new_path->param_info;
    4268             :     required_outer =
    4269        8164 :         adjust_child_relids_multilevel(root, old_ppi->ppi_req_outer,
    4270             :                                        child_rel,
    4271        8164 :                                        child_rel->top_parent);
    4272             : 
    4273             :     /* If we already have a PPI for this parameterization, just return it */
    4274        8164 :     new_ppi = find_param_path_info(new_path->parent, required_outer);
    4275             : 
    4276             :     /*
    4277             :      * If not, build a new one and link it to the list of PPIs. For the same
    4278             :      * reason as explained in mark_dummy_rel(), allocate new PPI in the same
    4279             :      * context the given RelOptInfo is in.
    4280             :      */
    4281        8164 :     if (new_ppi == NULL)
    4282             :     {
    4283             :         MemoryContext oldcontext;
    4284        2010 :         RelOptInfo *rel = path->parent;
    4285             : 
    4286        2010 :         oldcontext = MemoryContextSwitchTo(GetMemoryChunkContext(rel));
    4287             : 
    4288        2010 :         new_ppi = makeNode(ParamPathInfo);
    4289        2010 :         new_ppi->ppi_req_outer = bms_copy(required_outer);
    4290        2010 :         new_ppi->ppi_rows = old_ppi->ppi_rows;
    4291        2010 :         new_ppi->ppi_clauses = old_ppi->ppi_clauses;
    4292        2010 :         ADJUST_CHILD_ATTRS(new_ppi->ppi_clauses);
    4293        2010 :         new_ppi->ppi_serials = bms_copy(old_ppi->ppi_serials);
    4294        2010 :         rel->ppilist = lappend(rel->ppilist, new_ppi);
    4295             : 
    4296        2010 :         MemoryContextSwitchTo(oldcontext);
    4297             :     }
    4298        8164 :     bms_free(required_outer);
    4299             : 
    4300        8164 :     new_path->param_info = new_ppi;
    4301             : 
    4302             :     /*
    4303             :      * Adjust the path target if the parent of the outer relation is
    4304             :      * referenced in the targetlist. This can happen when only the parent of
    4305             :      * outer relation is laterally referenced in this relation.
    4306             :      */
    4307        8164 :     if (bms_overlap(path->parent->lateral_relids,
    4308        8164 :                     child_rel->top_parent_relids))
    4309             :     {
    4310        1152 :         new_path->pathtarget = copy_pathtarget(new_path->pathtarget);
    4311        1152 :         ADJUST_CHILD_ATTRS(new_path->pathtarget->exprs);
    4312             :     }
    4313             : 
    4314        8164 :     return new_path;
    4315             : }
    4316             : 
    4317             : /*
    4318             :  * reparameterize_pathlist_by_child
    4319             :  *      Helper function to reparameterize a list of paths by given child rel.
    4320             :  */
    4321             : static List *
    4322         168 : reparameterize_pathlist_by_child(PlannerInfo *root,
    4323             :                                  List *pathlist,
    4324             :                                  RelOptInfo *child_rel)
    4325             : {
    4326             :     ListCell   *lc;
    4327         168 :     List       *result = NIL;
    4328             : 
    4329         504 :     foreach(lc, pathlist)
    4330             :     {
    4331         336 :         Path       *path = reparameterize_path_by_child(root, lfirst(lc),
    4332             :                                                         child_rel);
    4333             : 
    4334         336 :         if (path == NULL)
    4335             :         {
    4336           0 :             list_free(result);
    4337           0 :             return NIL;
    4338             :         }
    4339             : 
    4340         336 :         result = lappend(result, path);
    4341             :     }
    4342             : 
    4343         168 :     return result;
    4344             : }

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