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pathkeys.c File Reference
#include "postgres.h"
#include "access/stratnum.h"
#include "nodes/makefuncs.h"
#include "nodes/nodeFuncs.h"
#include "nodes/plannodes.h"
#include "optimizer/clauses.h"
#include "optimizer/pathnode.h"
#include "optimizer/paths.h"
#include "optimizer/tlist.h"
#include "utils/lsyscache.h"
Include dependency graph for pathkeys.c:

Go to the source code of this file.

Functions

static bool pathkey_is_redundant (PathKey *new_pathkey, List *pathkeys)
 
static bool right_merge_direction (PlannerInfo *root, PathKey *pathkey)
 
PathKeymake_canonical_pathkey (PlannerInfo *root, EquivalenceClass *eclass, Oid opfamily, int strategy, bool nulls_first)
 
static PathKeymake_pathkey_from_sortinfo (PlannerInfo *root, Expr *expr, Relids nullable_relids, Oid opfamily, Oid opcintype, Oid collation, bool reverse_sort, bool nulls_first, Index sortref, Relids rel, bool create_it)
 
static PathKeymake_pathkey_from_sortop (PlannerInfo *root, Expr *expr, Relids nullable_relids, Oid ordering_op, bool nulls_first, Index sortref, bool create_it)
 
PathKeysComparison compare_pathkeys (List *keys1, List *keys2)
 
bool pathkeys_contained_in (List *keys1, List *keys2)
 
Pathget_cheapest_path_for_pathkeys (List *paths, List *pathkeys, Relids required_outer, CostSelector cost_criterion, bool require_parallel_safe)
 
Pathget_cheapest_fractional_path_for_pathkeys (List *paths, List *pathkeys, Relids required_outer, double fraction)
 
Pathget_cheapest_parallel_safe_total_inner (List *paths)
 
Listbuild_index_pathkeys (PlannerInfo *root, IndexOptInfo *index, ScanDirection scandir)
 
Listbuild_expression_pathkey (PlannerInfo *root, Expr *expr, Relids nullable_relids, Oid opno, Relids rel, bool create_it)
 
Listconvert_subquery_pathkeys (PlannerInfo *root, RelOptInfo *rel, List *subquery_pathkeys, List *subquery_tlist)
 
Listbuild_join_pathkeys (PlannerInfo *root, RelOptInfo *joinrel, JoinType jointype, List *outer_pathkeys)
 
Listmake_pathkeys_for_sortclauses (PlannerInfo *root, List *sortclauses, List *tlist)
 
void initialize_mergeclause_eclasses (PlannerInfo *root, RestrictInfo *restrictinfo)
 
void update_mergeclause_eclasses (PlannerInfo *root, RestrictInfo *restrictinfo)
 
Listfind_mergeclauses_for_pathkeys (PlannerInfo *root, List *pathkeys, bool outer_keys, List *restrictinfos)
 
Listselect_outer_pathkeys_for_merge (PlannerInfo *root, List *mergeclauses, RelOptInfo *joinrel)
 
Listmake_inner_pathkeys_for_merge (PlannerInfo *root, List *mergeclauses, List *outer_pathkeys)
 
static int pathkeys_useful_for_merging (PlannerInfo *root, RelOptInfo *rel, List *pathkeys)
 
static int pathkeys_useful_for_ordering (PlannerInfo *root, List *pathkeys)
 
Listtruncate_useless_pathkeys (PlannerInfo *root, RelOptInfo *rel, List *pathkeys)
 
bool has_useful_pathkeys (PlannerInfo *root, RelOptInfo *rel)
 

Function Documentation

List* build_expression_pathkey ( PlannerInfo root,
Expr expr,
Relids  nullable_relids,
Oid  opno,
Relids  rel,
bool  create_it 
)

Definition at line 553 of file pathkeys.c.

References BTGreaterStrategyNumber, elog, ERROR, exprCollation(), get_ordering_op_properties(), list_make1, make_pathkey_from_sortinfo(), and NIL.

Referenced by set_function_pathlist().

559 {
560  List *pathkeys;
561  Oid opfamily,
562  opcintype;
563  int16 strategy;
564  PathKey *cpathkey;
565 
566  /* Find the operator in pg_amop --- failure shouldn't happen */
567  if (!get_ordering_op_properties(opno,
568  &opfamily, &opcintype, &strategy))
569  elog(ERROR, "operator %u is not a valid ordering operator",
570  opno);
571 
572  cpathkey = make_pathkey_from_sortinfo(root,
573  expr,
574  nullable_relids,
575  opfamily,
576  opcintype,
577  exprCollation((Node *) expr),
578  (strategy == BTGreaterStrategyNumber),
579  (strategy == BTGreaterStrategyNumber),
580  0,
581  rel,
582  create_it);
583 
584  if (cpathkey)
585  pathkeys = list_make1(cpathkey);
586  else
587  pathkeys = NIL;
588 
589  return pathkeys;
590 }
signed short int16
Definition: c.h:255
#define NIL
Definition: pg_list.h:69
#define BTGreaterStrategyNumber
Definition: stratnum.h:33
Definition: nodes.h:509
unsigned int Oid
Definition: postgres_ext.h:31
#define list_make1(x1)
Definition: pg_list.h:139
#define ERROR
Definition: elog.h:43
bool get_ordering_op_properties(Oid opno, Oid *opfamily, Oid *opcintype, int16 *strategy)
Definition: lsyscache.c:204
Oid exprCollation(const Node *expr)
Definition: nodeFuncs.c:720
#define elog
Definition: elog.h:219
static PathKey * make_pathkey_from_sortinfo(PlannerInfo *root, Expr *expr, Relids nullable_relids, Oid opfamily, Oid opcintype, Oid collation, bool reverse_sort, bool nulls_first, Index sortref, Relids rel, bool create_it)
Definition: pathkeys.c:170
Definition: pg_list.h:45
List* build_index_pathkeys ( PlannerInfo root,
IndexOptInfo index,
ScanDirection  scandir 
)

Definition at line 460 of file pathkeys.c.

References TargetEntry::expr, i, indexcol_is_bool_constant_for_query(), IndexOptInfo::indexcollations, IndexOptInfo::indextlist, lappend(), lfirst, make_pathkey_from_sortinfo(), NIL, NULL, IndexOptInfo::nulls_first, IndexOptInfo::opcintype, pathkey_is_redundant(), IndexOptInfo::rel, RelOptInfo::relids, IndexOptInfo::reverse_sort, ScanDirectionIsBackward, and IndexOptInfo::sortopfamily.

Referenced by build_index_paths().

463 {
464  List *retval = NIL;
465  ListCell *lc;
466  int i;
467 
468  if (index->sortopfamily == NULL)
469  return NIL; /* non-orderable index */
470 
471  i = 0;
472  foreach(lc, index->indextlist)
473  {
474  TargetEntry *indextle = (TargetEntry *) lfirst(lc);
475  Expr *indexkey;
476  bool reverse_sort;
477  bool nulls_first;
478  PathKey *cpathkey;
479 
480  /* We assume we don't need to make a copy of the tlist item */
481  indexkey = indextle->expr;
482 
483  if (ScanDirectionIsBackward(scandir))
484  {
485  reverse_sort = !index->reverse_sort[i];
486  nulls_first = !index->nulls_first[i];
487  }
488  else
489  {
490  reverse_sort = index->reverse_sort[i];
491  nulls_first = index->nulls_first[i];
492  }
493 
494  /*
495  * OK, try to make a canonical pathkey for this sort key. Note we're
496  * underneath any outer joins, so nullable_relids should be NULL.
497  */
498  cpathkey = make_pathkey_from_sortinfo(root,
499  indexkey,
500  NULL,
501  index->sortopfamily[i],
502  index->opcintype[i],
503  index->indexcollations[i],
504  reverse_sort,
505  nulls_first,
506  0,
507  index->rel->relids,
508  false);
509 
510  if (cpathkey)
511  {
512  /*
513  * We found the sort key in an EquivalenceClass, so it's relevant
514  * for this query. Add it to list, unless it's redundant.
515  */
516  if (!pathkey_is_redundant(cpathkey, retval))
517  retval = lappend(retval, cpathkey);
518  }
519  else
520  {
521  /*
522  * Boolean index keys might be redundant even if they do not
523  * appear in an EquivalenceClass, because of our special treatment
524  * of boolean equality conditions --- see the comment for
525  * indexcol_is_bool_constant_for_query(). If that applies, we can
526  * continue to examine lower-order index columns. Otherwise, the
527  * sort key is not an interesting sort order for this query, so we
528  * should stop considering index columns; any lower-order sort
529  * keys won't be useful either.
530  */
532  break;
533  }
534 
535  i++;
536  }
537 
538  return retval;
539 }
#define NIL
Definition: pg_list.h:69
Oid * indexcollations
Definition: relation.h:643
List * indextlist
Definition: relation.h:656
Oid * sortopfamily
Definition: relation.h:646
#define ScanDirectionIsBackward(direction)
Definition: sdir.h:41
RelOptInfo * rel
Definition: relation.h:633
Relids relids
Definition: relation.h:525
static bool pathkey_is_redundant(PathKey *new_pathkey, List *pathkeys)
Definition: pathkeys.c:128
List * lappend(List *list, void *datum)
Definition: list.c:128
#define NULL
Definition: c.h:229
#define lfirst(lc)
Definition: pg_list.h:106
Expr * expr
Definition: primnodes.h:1368
Oid * opcintype
Definition: relation.h:645
bool indexcol_is_bool_constant_for_query(IndexOptInfo *index, int indexcol)
Definition: indxpath.c:3131
int i
static PathKey * make_pathkey_from_sortinfo(PlannerInfo *root, Expr *expr, Relids nullable_relids, Oid opfamily, Oid opcintype, Oid collation, bool reverse_sort, bool nulls_first, Index sortref, Relids rel, bool create_it)
Definition: pathkeys.c:170
bool * nulls_first
Definition: relation.h:648
bool * reverse_sort
Definition: relation.h:647
Definition: pg_list.h:45
List* build_join_pathkeys ( PlannerInfo root,
RelOptInfo joinrel,
JoinType  jointype,
List outer_pathkeys 
)

Definition at line 822 of file pathkeys.c.

References JOIN_FULL, JOIN_RIGHT, NIL, and truncate_useless_pathkeys().

Referenced by consider_parallel_mergejoin(), consider_parallel_nestloop(), match_unsorted_outer(), and sort_inner_and_outer().

826 {
827  if (jointype == JOIN_FULL || jointype == JOIN_RIGHT)
828  return NIL;
829 
830  /*
831  * This used to be quite a complex bit of code, but now that all pathkey
832  * sublists start out life canonicalized, we don't have to do a darn thing
833  * here!
834  *
835  * We do, however, need to truncate the pathkeys list, since it may
836  * contain pathkeys that were useful for forming this joinrel but are
837  * uninteresting to higher levels.
838  */
839  return truncate_useless_pathkeys(root, joinrel, outer_pathkeys);
840 }
#define NIL
Definition: pg_list.h:69
List * truncate_useless_pathkeys(PlannerInfo *root, RelOptInfo *rel, List *pathkeys)
Definition: pathkeys.c:1518
PathKeysComparison compare_pathkeys ( List keys1,
List keys2 
)

Definition at line 278 of file pathkeys.c.

References forboth, lfirst, NULL, PATHKEYS_BETTER1, PATHKEYS_BETTER2, PATHKEYS_DIFFERENT, and PATHKEYS_EQUAL.

Referenced by add_partial_path(), add_partial_path_precheck(), add_path(), add_path_precheck(), add_paths_to_append_rel(), pathkeys_contained_in(), and set_cheapest().

279 {
280  ListCell *key1,
281  *key2;
282 
283  /*
284  * Fall out quickly if we are passed two identical lists. This mostly
285  * catches the case where both are NIL, but that's common enough to
286  * warrant the test.
287  */
288  if (keys1 == keys2)
289  return PATHKEYS_EQUAL;
290 
291  forboth(key1, keys1, key2, keys2)
292  {
293  PathKey *pathkey1 = (PathKey *) lfirst(key1);
294  PathKey *pathkey2 = (PathKey *) lfirst(key2);
295 
296  if (pathkey1 != pathkey2)
297  return PATHKEYS_DIFFERENT; /* no need to keep looking */
298  }
299 
300  /*
301  * If we reached the end of only one list, the other is longer and
302  * therefore not a subset.
303  */
304  if (key1 != NULL)
305  return PATHKEYS_BETTER1; /* key1 is longer */
306  if (key2 != NULL)
307  return PATHKEYS_BETTER2; /* key2 is longer */
308  return PATHKEYS_EQUAL;
309 }
#define forboth(cell1, list1, cell2, list2)
Definition: pg_list.h:180
#define NULL
Definition: c.h:229
#define lfirst(lc)
Definition: pg_list.h:106
List* convert_subquery_pathkeys ( PlannerInfo root,
RelOptInfo rel,
List subquery_pathkeys,
List subquery_tlist 
)

Definition at line 607 of file pathkeys.c.

References Assert, canonicalize_ec_expression(), EquivalenceClass::ec_collation, EquivalenceClass::ec_has_volatile, EquivalenceClass::ec_members, EquivalenceClass::ec_opfamilies, EquivalenceClass::ec_sortref, elog, EquivalenceMember::em_datatype, EquivalenceMember::em_expr, EquivalenceMember::em_is_child, equal(), ERROR, TargetEntry::expr, get_eclass_for_sort_expr(), get_sortgroupref_tle(), i, lappend(), lfirst, linitial, list_length(), list_nth(), make_canonical_pathkey(), makeVarFromTargetEntry(), NIL, NULL, pathkey_is_redundant(), PathKey::pk_eclass, PathKey::pk_nulls_first, PathKey::pk_opfamily, PathKey::pk_strategy, PlannerInfo::query_pathkeys, RelOptInfo::relid, RelOptInfo::relids, and TargetEntry::resjunk.

Referenced by set_subquery_pathlist().

610 {
611  List *retval = NIL;
612  int retvallen = 0;
613  int outer_query_keys = list_length(root->query_pathkeys);
614  ListCell *i;
615 
616  foreach(i, subquery_pathkeys)
617  {
618  PathKey *sub_pathkey = (PathKey *) lfirst(i);
619  EquivalenceClass *sub_eclass = sub_pathkey->pk_eclass;
620  PathKey *best_pathkey = NULL;
621 
622  if (sub_eclass->ec_has_volatile)
623  {
624  /*
625  * If the sub_pathkey's EquivalenceClass is volatile, then it must
626  * have come from an ORDER BY clause, and we have to match it to
627  * that same targetlist entry.
628  */
629  TargetEntry *tle;
630 
631  if (sub_eclass->ec_sortref == 0) /* can't happen */
632  elog(ERROR, "volatile EquivalenceClass has no sortref");
633  tle = get_sortgroupref_tle(sub_eclass->ec_sortref, subquery_tlist);
634  Assert(tle);
635  /* resjunk items aren't visible to outer query */
636  if (!tle->resjunk)
637  {
638  /* We can represent this sub_pathkey */
639  EquivalenceMember *sub_member;
640  Expr *outer_expr;
641  EquivalenceClass *outer_ec;
642 
643  Assert(list_length(sub_eclass->ec_members) == 1);
644  sub_member = (EquivalenceMember *) linitial(sub_eclass->ec_members);
645  outer_expr = (Expr *) makeVarFromTargetEntry(rel->relid, tle);
646 
647  /*
648  * Note: it might look funny to be setting sortref = 0 for a
649  * reference to a volatile sub_eclass. However, the
650  * expression is *not* volatile in the outer query: it's just
651  * a Var referencing whatever the subquery emitted. (IOW, the
652  * outer query isn't going to re-execute the volatile
653  * expression itself.) So this is okay. Likewise, it's
654  * correct to pass nullable_relids = NULL, because we're
655  * underneath any outer joins appearing in the outer query.
656  */
657  outer_ec =
659  outer_expr,
660  NULL,
661  sub_eclass->ec_opfamilies,
662  sub_member->em_datatype,
663  sub_eclass->ec_collation,
664  0,
665  rel->relids,
666  false);
667 
668  /*
669  * If we don't find a matching EC, sub-pathkey isn't
670  * interesting to the outer query
671  */
672  if (outer_ec)
673  best_pathkey =
675  outer_ec,
676  sub_pathkey->pk_opfamily,
677  sub_pathkey->pk_strategy,
678  sub_pathkey->pk_nulls_first);
679  }
680  }
681  else
682  {
683  /*
684  * Otherwise, the sub_pathkey's EquivalenceClass could contain
685  * multiple elements (representing knowledge that multiple items
686  * are effectively equal). Each element might match none, one, or
687  * more of the output columns that are visible to the outer query.
688  * This means we may have multiple possible representations of the
689  * sub_pathkey in the context of the outer query. Ideally we
690  * would generate them all and put them all into an EC of the
691  * outer query, thereby propagating equality knowledge up to the
692  * outer query. Right now we cannot do so, because the outer
693  * query's EquivalenceClasses are already frozen when this is
694  * called. Instead we prefer the one that has the highest "score"
695  * (number of EC peers, plus one if it matches the outer
696  * query_pathkeys). This is the most likely to be useful in the
697  * outer query.
698  */
699  int best_score = -1;
700  ListCell *j;
701 
702  foreach(j, sub_eclass->ec_members)
703  {
704  EquivalenceMember *sub_member = (EquivalenceMember *) lfirst(j);
705  Expr *sub_expr = sub_member->em_expr;
706  Oid sub_expr_type = sub_member->em_datatype;
707  Oid sub_expr_coll = sub_eclass->ec_collation;
708  ListCell *k;
709 
710  if (sub_member->em_is_child)
711  continue; /* ignore children here */
712 
713  foreach(k, subquery_tlist)
714  {
715  TargetEntry *tle = (TargetEntry *) lfirst(k);
716  Expr *tle_expr;
717  Expr *outer_expr;
718  EquivalenceClass *outer_ec;
719  PathKey *outer_pk;
720  int score;
721 
722  /* resjunk items aren't visible to outer query */
723  if (tle->resjunk)
724  continue;
725 
726  /*
727  * The targetlist entry is considered to match if it
728  * matches after sort-key canonicalization. That is
729  * needed since the sub_expr has been through the same
730  * process.
731  */
732  tle_expr = canonicalize_ec_expression(tle->expr,
733  sub_expr_type,
734  sub_expr_coll);
735  if (!equal(tle_expr, sub_expr))
736  continue;
737 
738  /*
739  * Build a representation of this targetlist entry as an
740  * outer Var.
741  */
742  outer_expr = (Expr *) makeVarFromTargetEntry(rel->relid,
743  tle);
744 
745  /* See if we have a matching EC for that */
746  outer_ec = get_eclass_for_sort_expr(root,
747  outer_expr,
748  NULL,
749  sub_eclass->ec_opfamilies,
750  sub_expr_type,
751  sub_expr_coll,
752  0,
753  rel->relids,
754  false);
755 
756  /*
757  * If we don't find a matching EC, this sub-pathkey isn't
758  * interesting to the outer query
759  */
760  if (!outer_ec)
761  continue;
762 
763  outer_pk = make_canonical_pathkey(root,
764  outer_ec,
765  sub_pathkey->pk_opfamily,
766  sub_pathkey->pk_strategy,
767  sub_pathkey->pk_nulls_first);
768  /* score = # of equivalence peers */
769  score = list_length(outer_ec->ec_members) - 1;
770  /* +1 if it matches the proper query_pathkeys item */
771  if (retvallen < outer_query_keys &&
772  list_nth(root->query_pathkeys, retvallen) == outer_pk)
773  score++;
774  if (score > best_score)
775  {
776  best_pathkey = outer_pk;
777  best_score = score;
778  }
779  }
780  }
781  }
782 
783  /*
784  * If we couldn't find a representation of this sub_pathkey, we're
785  * done (we can't use the ones to its right, either).
786  */
787  if (!best_pathkey)
788  break;
789 
790  /*
791  * Eliminate redundant ordering info; could happen if outer query
792  * equivalences subquery keys...
793  */
794  if (!pathkey_is_redundant(best_pathkey, retval))
795  {
796  retval = lappend(retval, best_pathkey);
797  retvallen++;
798  }
799  }
800 
801  return retval;
802 }
#define NIL
Definition: pg_list.h:69
List * query_pathkeys
Definition: relation.h:262
bool equal(const void *a, const void *b)
Definition: equalfuncs.c:2962
EquivalenceClass * get_eclass_for_sort_expr(PlannerInfo *root, Expr *expr, Relids nullable_relids, List *opfamilies, Oid opcintype, Oid collation, Index sortref, Relids rel, bool create_it)
Definition: equivclass.c:581
Var * makeVarFromTargetEntry(Index varno, TargetEntry *tle)
Definition: makefuncs.c:104
Index ec_sortref
Definition: relation.h:783
PathKey * make_canonical_pathkey(PlannerInfo *root, EquivalenceClass *eclass, Oid opfamily, int strategy, bool nulls_first)
Definition: pathkeys.c:51
unsigned int Oid
Definition: postgres_ext.h:31
int pk_strategy
Definition: relation.h:853
bool resjunk
Definition: primnodes.h:1375
#define linitial(l)
Definition: pg_list.h:111
bool pk_nulls_first
Definition: relation.h:854
#define ERROR
Definition: elog.h:43
Expr * canonicalize_ec_expression(Expr *expr, Oid req_type, Oid req_collation)
Definition: equivclass.c:456
void * list_nth(const List *list, int n)
Definition: list.c:410
Relids relids
Definition: relation.h:525
static bool pathkey_is_redundant(PathKey *new_pathkey, List *pathkeys)
Definition: pathkeys.c:128
TargetEntry * get_sortgroupref_tle(Index sortref, List *targetList)
Definition: tlist.c:348
Index relid
Definition: relation.h:553
List * lappend(List *list, void *datum)
Definition: list.c:128
List * ec_opfamilies
Definition: relation.h:772
#define NULL
Definition: c.h:229
#define Assert(condition)
Definition: c.h:676
#define lfirst(lc)
Definition: pg_list.h:106
Expr * expr
Definition: primnodes.h:1368
EquivalenceClass * pk_eclass
Definition: relation.h:851
static int list_length(const List *l)
Definition: pg_list.h:89
bool ec_has_volatile
Definition: relation.h:780
Oid pk_opfamily
Definition: relation.h:852
int i
#define elog
Definition: elog.h:219
Definition: pg_list.h:45
List * ec_members
Definition: relation.h:774
List* find_mergeclauses_for_pathkeys ( PlannerInfo root,
List pathkeys,
bool  outer_keys,
List restrictinfos 
)

Definition at line 1003 of file pathkeys.c.

References i, lappend(), RestrictInfo::left_ec, lfirst, list_concat(), NIL, RestrictInfo::outer_is_left, PathKey::pk_eclass, RestrictInfo::right_ec, and update_mergeclause_eclasses().

Referenced by generate_mergejoin_paths(), and sort_inner_and_outer().

1007 {
1008  List *mergeclauses = NIL;
1009  ListCell *i;
1010 
1011  /* make sure we have eclasses cached in the clauses */
1012  foreach(i, restrictinfos)
1013  {
1014  RestrictInfo *rinfo = (RestrictInfo *) lfirst(i);
1015 
1016  update_mergeclause_eclasses(root, rinfo);
1017  }
1018 
1019  foreach(i, pathkeys)
1020  {
1021  PathKey *pathkey = (PathKey *) lfirst(i);
1022  EquivalenceClass *pathkey_ec = pathkey->pk_eclass;
1023  List *matched_restrictinfos = NIL;
1024  ListCell *j;
1025 
1026  /*----------
1027  * A mergejoin clause matches a pathkey if it has the same EC.
1028  * If there are multiple matching clauses, take them all. In plain
1029  * inner-join scenarios we expect only one match, because
1030  * equivalence-class processing will have removed any redundant
1031  * mergeclauses. However, in outer-join scenarios there might be
1032  * multiple matches. An example is
1033  *
1034  * select * from a full join b
1035  * on a.v1 = b.v1 and a.v2 = b.v2 and a.v1 = b.v2;
1036  *
1037  * Given the pathkeys ({a.v1}, {a.v2}) it is okay to return all three
1038  * clauses (in the order a.v1=b.v1, a.v1=b.v2, a.v2=b.v2) and indeed
1039  * we *must* do so or we will be unable to form a valid plan.
1040  *
1041  * We expect that the given pathkeys list is canonical, which means
1042  * no two members have the same EC, so it's not possible for this
1043  * code to enter the same mergeclause into the result list twice.
1044  *
1045  * It's possible that multiple matching clauses might have different
1046  * ECs on the other side, in which case the order we put them into our
1047  * result makes a difference in the pathkeys required for the other
1048  * input path. However this routine hasn't got any info about which
1049  * order would be best, so we don't worry about that.
1050  *
1051  * It's also possible that the selected mergejoin clauses produce
1052  * a noncanonical ordering of pathkeys for the other side, ie, we
1053  * might select clauses that reference b.v1, b.v2, b.v1 in that
1054  * order. This is not harmful in itself, though it suggests that
1055  * the clauses are partially redundant. Since it happens only with
1056  * redundant query conditions, we don't bother to eliminate it.
1057  * make_inner_pathkeys_for_merge() has to delete duplicates when
1058  * it constructs the canonical pathkeys list, and we also have to
1059  * deal with the case in create_mergejoin_plan().
1060  *----------
1061  */
1062  foreach(j, restrictinfos)
1063  {
1064  RestrictInfo *rinfo = (RestrictInfo *) lfirst(j);
1065  EquivalenceClass *clause_ec;
1066 
1067  if (outer_keys)
1068  clause_ec = rinfo->outer_is_left ?
1069  rinfo->left_ec : rinfo->right_ec;
1070  else
1071  clause_ec = rinfo->outer_is_left ?
1072  rinfo->right_ec : rinfo->left_ec;
1073  if (clause_ec == pathkey_ec)
1074  matched_restrictinfos = lappend(matched_restrictinfos, rinfo);
1075  }
1076 
1077  /*
1078  * If we didn't find a mergeclause, we're done --- any additional
1079  * sort-key positions in the pathkeys are useless. (But we can still
1080  * mergejoin if we found at least one mergeclause.)
1081  */
1082  if (matched_restrictinfos == NIL)
1083  break;
1084 
1085  /*
1086  * If we did find usable mergeclause(s) for this sort-key position,
1087  * add them to result list.
1088  */
1089  mergeclauses = list_concat(mergeclauses, matched_restrictinfos);
1090  }
1091 
1092  return mergeclauses;
1093 }
#define NIL
Definition: pg_list.h:69
List * list_concat(List *list1, List *list2)
Definition: list.c:321
EquivalenceClass * right_ec
Definition: relation.h:1796
bool outer_is_left
Definition: relation.h:1802
List * lappend(List *list, void *datum)
Definition: list.c:128
#define lfirst(lc)
Definition: pg_list.h:106
EquivalenceClass * pk_eclass
Definition: relation.h:851
EquivalenceClass * left_ec
Definition: relation.h:1795
int i
Definition: pg_list.h:45
void update_mergeclause_eclasses(PlannerInfo *root, RestrictInfo *restrictinfo)
Definition: pathkeys.c:968
Path* get_cheapest_fractional_path_for_pathkeys ( List paths,
List pathkeys,
Relids  required_outer,
double  fraction 
)

Definition at line 388 of file pathkeys.c.

References bms_is_subset(), compare_fractional_path_costs(), lfirst, NULL, PATH_REQ_OUTER, Path::pathkeys, and pathkeys_contained_in().

Referenced by build_minmax_path().

392 {
393  Path *matched_path = NULL;
394  ListCell *l;
395 
396  foreach(l, paths)
397  {
398  Path *path = (Path *) lfirst(l);
399 
400  /*
401  * Since cost comparison is a lot cheaper than pathkey comparison, do
402  * that first. (XXX is that still true?)
403  */
404  if (matched_path != NULL &&
405  compare_fractional_path_costs(matched_path, path, fraction) <= 0)
406  continue;
407 
408  if (pathkeys_contained_in(pathkeys, path->pathkeys) &&
409  bms_is_subset(PATH_REQ_OUTER(path), required_outer))
410  matched_path = path;
411  }
412  return matched_path;
413 }
bool bms_is_subset(const Bitmapset *a, const Bitmapset *b)
Definition: bitmapset.c:308
bool pathkeys_contained_in(List *keys1, List *keys2)
Definition: pathkeys.c:317
List * pathkeys
Definition: relation.h:968
#define NULL
Definition: c.h:229
#define lfirst(lc)
Definition: pg_list.h:106
int compare_fractional_path_costs(Path *path1, Path *path2, double fraction)
Definition: pathnode.c:107
#define PATH_REQ_OUTER(path)
Definition: relation.h:973
Definition: relation.h:948
Path* get_cheapest_parallel_safe_total_inner ( List paths)

Definition at line 421 of file pathkeys.c.

References bms_is_empty(), lfirst, NULL, Path::parallel_safe, and PATH_REQ_OUTER.

Referenced by hash_inner_and_outer(), match_unsorted_outer(), and sort_inner_and_outer().

422 {
423  ListCell *l;
424 
425  foreach(l, paths)
426  {
427  Path *innerpath = (Path *) lfirst(l);
428 
429  if (innerpath->parallel_safe &&
430  bms_is_empty(PATH_REQ_OUTER(innerpath)))
431  return innerpath;
432  }
433 
434  return NULL;
435 }
bool bms_is_empty(const Bitmapset *a)
Definition: bitmapset.c:663
#define NULL
Definition: c.h:229
#define lfirst(lc)
Definition: pg_list.h:106
bool parallel_safe
Definition: relation.h:960
#define PATH_REQ_OUTER(path)
Definition: relation.h:973
Definition: relation.h:948
Path* get_cheapest_path_for_pathkeys ( List paths,
List pathkeys,
Relids  required_outer,
CostSelector  cost_criterion,
bool  require_parallel_safe 
)

Definition at line 343 of file pathkeys.c.

References bms_is_subset(), compare_path_costs(), lfirst, NULL, Path::parallel_safe, PATH_REQ_OUTER, Path::pathkeys, and pathkeys_contained_in().

Referenced by generate_mergeappend_paths(), generate_mergejoin_paths(), and get_cheapest_parameterized_child_path().

347 {
348  Path *matched_path = NULL;
349  ListCell *l;
350 
351  foreach(l, paths)
352  {
353  Path *path = (Path *) lfirst(l);
354 
355  /*
356  * Since cost comparison is a lot cheaper than pathkey comparison, do
357  * that first. (XXX is that still true?)
358  */
359  if (matched_path != NULL &&
360  compare_path_costs(matched_path, path, cost_criterion) <= 0)
361  continue;
362 
363  if (require_parallel_safe && !path->parallel_safe)
364  continue;
365 
366  if (pathkeys_contained_in(pathkeys, path->pathkeys) &&
367  bms_is_subset(PATH_REQ_OUTER(path), required_outer))
368  matched_path = path;
369  }
370  return matched_path;
371 }
bool bms_is_subset(const Bitmapset *a, const Bitmapset *b)
Definition: bitmapset.c:308
int compare_path_costs(Path *path1, Path *path2, CostSelector criterion)
Definition: pathnode.c:61
bool pathkeys_contained_in(List *keys1, List *keys2)
Definition: pathkeys.c:317
List * pathkeys
Definition: relation.h:968
#define NULL
Definition: c.h:229
#define lfirst(lc)
Definition: pg_list.h:106
bool parallel_safe
Definition: relation.h:960
#define PATH_REQ_OUTER(path)
Definition: relation.h:973
Definition: relation.h:948
bool has_useful_pathkeys ( PlannerInfo root,
RelOptInfo rel 
)

Definition at line 1558 of file pathkeys.c.

References RelOptInfo::has_eclass_joins, RelOptInfo::joininfo, NIL, and PlannerInfo::query_pathkeys.

Referenced by build_index_paths(), and set_append_rel_size().

1559 {
1560  if (rel->joininfo != NIL || rel->has_eclass_joins)
1561  return true; /* might be able to use pathkeys for merging */
1562  if (root->query_pathkeys != NIL)
1563  return true; /* might be able to use them for ordering */
1564  return false; /* definitely useless */
1565 }
bool has_eclass_joins
Definition: relation.h:591
#define NIL
Definition: pg_list.h:69
List * query_pathkeys
Definition: relation.h:262
List * joininfo
Definition: relation.h:589
void initialize_mergeclause_eclasses ( PlannerInfo root,
RestrictInfo restrictinfo 
)

Definition at line 919 of file pathkeys.c.

References Assert, RestrictInfo::clause, get_eclass_for_sort_expr(), get_leftop(), get_rightop(), RestrictInfo::left_ec, RestrictInfo::mergeopfamilies, NIL, NULL, RestrictInfo::nullable_relids, op_input_types(), and RestrictInfo::right_ec.

Referenced by distribute_qual_to_rels().

920 {
921  Expr *clause = restrictinfo->clause;
922  Oid lefttype,
923  righttype;
924 
925  /* Should be a mergeclause ... */
926  Assert(restrictinfo->mergeopfamilies != NIL);
927  /* ... with links not yet set */
928  Assert(restrictinfo->left_ec == NULL);
929  Assert(restrictinfo->right_ec == NULL);
930 
931  /* Need the declared input types of the operator */
932  op_input_types(((OpExpr *) clause)->opno, &lefttype, &righttype);
933 
934  /* Find or create a matching EquivalenceClass for each side */
935  restrictinfo->left_ec =
937  (Expr *) get_leftop(clause),
938  restrictinfo->nullable_relids,
939  restrictinfo->mergeopfamilies,
940  lefttype,
941  ((OpExpr *) clause)->inputcollid,
942  0,
943  NULL,
944  true);
945  restrictinfo->right_ec =
947  (Expr *) get_rightop(clause),
948  restrictinfo->nullable_relids,
949  restrictinfo->mergeopfamilies,
950  righttype,
951  ((OpExpr *) clause)->inputcollid,
952  0,
953  NULL,
954  true);
955 }
#define NIL
Definition: pg_list.h:69
EquivalenceClass * get_eclass_for_sort_expr(PlannerInfo *root, Expr *expr, Relids nullable_relids, List *opfamilies, Oid opcintype, Oid collation, Index sortref, Relids rel, bool create_it)
Definition: equivclass.c:581
EquivalenceClass * right_ec
Definition: relation.h:1796
unsigned int Oid
Definition: postgres_ext.h:31
List * mergeopfamilies
Definition: relation.h:1792
Node * get_leftop(const Expr *clause)
Definition: clauses.c:199
void op_input_types(Oid opno, Oid *lefttype, Oid *righttype)
Definition: lsyscache.c:1167
Expr * clause
Definition: relation.h:1747
Relids nullable_relids
Definition: relation.h:1771
#define NULL
Definition: c.h:229
#define Assert(condition)
Definition: c.h:676
Node * get_rightop(const Expr *clause)
Definition: clauses.c:216
EquivalenceClass * left_ec
Definition: relation.h:1795
PathKey* make_canonical_pathkey ( PlannerInfo root,
EquivalenceClass eclass,
Oid  opfamily,
int  strategy,
bool  nulls_first 
)

Definition at line 51 of file pathkeys.c.

References PlannerInfo::canon_pathkeys, EquivalenceClass::ec_merged, eclass(), lappend(), lfirst, makeNode, MemoryContextSwitchTo(), PathKey::pk_eclass, PathKey::pk_nulls_first, PathKey::pk_opfamily, PathKey::pk_strategy, and PlannerInfo::planner_cxt.

Referenced by convert_subquery_pathkeys(), get_useful_pathkeys_for_relation(), make_inner_pathkeys_for_merge(), make_pathkey_from_sortinfo(), and select_outer_pathkeys_for_merge().

54 {
55  PathKey *pk;
56  ListCell *lc;
57  MemoryContext oldcontext;
58 
59  /* The passed eclass might be non-canonical, so chase up to the top */
60  while (eclass->ec_merged)
61  eclass = eclass->ec_merged;
62 
63  foreach(lc, root->canon_pathkeys)
64  {
65  pk = (PathKey *) lfirst(lc);
66  if (eclass == pk->pk_eclass &&
67  opfamily == pk->pk_opfamily &&
68  strategy == pk->pk_strategy &&
69  nulls_first == pk->pk_nulls_first)
70  return pk;
71  }
72 
73  /*
74  * Be sure canonical pathkeys are allocated in the main planning context.
75  * Not an issue in normal planning, but it is for GEQO.
76  */
77  oldcontext = MemoryContextSwitchTo(root->planner_cxt);
78 
79  pk = makeNode(PathKey);
80  pk->pk_eclass = eclass;
81  pk->pk_opfamily = opfamily;
82  pk->pk_strategy = strategy;
83  pk->pk_nulls_first = nulls_first;
84 
85  root->canon_pathkeys = lappend(root->canon_pathkeys, pk);
86 
87  MemoryContextSwitchTo(oldcontext);
88 
89  return pk;
90 }
static MemoryContext MemoryContextSwitchTo(MemoryContext context)
Definition: palloc.h:109
int pk_strategy
Definition: relation.h:853
static struct cvec * eclass(struct vars *v, chr c, int cases)
Definition: regc_locale.c:508
bool pk_nulls_first
Definition: relation.h:854
List * canon_pathkeys
Definition: relation.h:237
List * lappend(List *list, void *datum)
Definition: list.c:128
#define makeNode(_type_)
Definition: nodes.h:557
#define lfirst(lc)
Definition: pg_list.h:106
EquivalenceClass * pk_eclass
Definition: relation.h:851
Oid pk_opfamily
Definition: relation.h:852
MemoryContext planner_cxt
Definition: relation.h:287
struct EquivalenceClass * ec_merged
Definition: relation.h:786
List* make_inner_pathkeys_for_merge ( PlannerInfo root,
List mergeclauses,
List outer_pathkeys 
)

Definition at line 1292 of file pathkeys.c.

References elog, ERROR, lappend(), RestrictInfo::left_ec, lfirst, list_head(), lnext, make_canonical_pathkey(), NIL, NULL, RestrictInfo::outer_is_left, pathkey_is_redundant(), PathKey::pk_eclass, PathKey::pk_nulls_first, PathKey::pk_opfamily, PathKey::pk_strategy, RestrictInfo::right_ec, and update_mergeclause_eclasses().

Referenced by generate_mergejoin_paths(), and sort_inner_and_outer().

1295 {
1296  List *pathkeys = NIL;
1297  EquivalenceClass *lastoeclass;
1298  PathKey *opathkey;
1299  ListCell *lc;
1300  ListCell *lop;
1301 
1302  lastoeclass = NULL;
1303  opathkey = NULL;
1304  lop = list_head(outer_pathkeys);
1305 
1306  foreach(lc, mergeclauses)
1307  {
1308  RestrictInfo *rinfo = (RestrictInfo *) lfirst(lc);
1309  EquivalenceClass *oeclass;
1310  EquivalenceClass *ieclass;
1311  PathKey *pathkey;
1312 
1313  update_mergeclause_eclasses(root, rinfo);
1314 
1315  if (rinfo->outer_is_left)
1316  {
1317  oeclass = rinfo->left_ec;
1318  ieclass = rinfo->right_ec;
1319  }
1320  else
1321  {
1322  oeclass = rinfo->right_ec;
1323  ieclass = rinfo->left_ec;
1324  }
1325 
1326  /* outer eclass should match current or next pathkeys */
1327  /* we check this carefully for debugging reasons */
1328  if (oeclass != lastoeclass)
1329  {
1330  if (!lop)
1331  elog(ERROR, "too few pathkeys for mergeclauses");
1332  opathkey = (PathKey *) lfirst(lop);
1333  lop = lnext(lop);
1334  lastoeclass = opathkey->pk_eclass;
1335  if (oeclass != lastoeclass)
1336  elog(ERROR, "outer pathkeys do not match mergeclause");
1337  }
1338 
1339  /*
1340  * Often, we'll have same EC on both sides, in which case the outer
1341  * pathkey is also canonical for the inner side, and we can skip a
1342  * useless search.
1343  */
1344  if (ieclass == oeclass)
1345  pathkey = opathkey;
1346  else
1347  pathkey = make_canonical_pathkey(root,
1348  ieclass,
1349  opathkey->pk_opfamily,
1350  opathkey->pk_strategy,
1351  opathkey->pk_nulls_first);
1352 
1353  /*
1354  * Don't generate redundant pathkeys (can happen if multiple
1355  * mergeclauses refer to same EC).
1356  */
1357  if (!pathkey_is_redundant(pathkey, pathkeys))
1358  pathkeys = lappend(pathkeys, pathkey);
1359  }
1360 
1361  return pathkeys;
1362 }
#define NIL
Definition: pg_list.h:69
PathKey * make_canonical_pathkey(PlannerInfo *root, EquivalenceClass *eclass, Oid opfamily, int strategy, bool nulls_first)
Definition: pathkeys.c:51
EquivalenceClass * right_ec
Definition: relation.h:1796
int pk_strategy
Definition: relation.h:853
bool pk_nulls_first
Definition: relation.h:854
#define ERROR
Definition: elog.h:43
bool outer_is_left
Definition: relation.h:1802
static ListCell * list_head(const List *l)
Definition: pg_list.h:77
static bool pathkey_is_redundant(PathKey *new_pathkey, List *pathkeys)
Definition: pathkeys.c:128
#define lnext(lc)
Definition: pg_list.h:105
List * lappend(List *list, void *datum)
Definition: list.c:128
#define NULL
Definition: c.h:229
#define lfirst(lc)
Definition: pg_list.h:106
EquivalenceClass * pk_eclass
Definition: relation.h:851
Oid pk_opfamily
Definition: relation.h:852
EquivalenceClass * left_ec
Definition: relation.h:1795
#define elog
Definition: elog.h:219
Definition: pg_list.h:45
void update_mergeclause_eclasses(PlannerInfo *root, RestrictInfo *restrictinfo)
Definition: pathkeys.c:968
static PathKey* make_pathkey_from_sortinfo ( PlannerInfo root,
Expr expr,
Relids  nullable_relids,
Oid  opfamily,
Oid  opcintype,
Oid  collation,
bool  reverse_sort,
bool  nulls_first,
Index  sortref,
Relids  rel,
bool  create_it 
)
static

Definition at line 170 of file pathkeys.c.

References BTEqualStrategyNumber, BTGreaterStrategyNumber, BTLessStrategyNumber, eclass(), elog, ERROR, get_eclass_for_sort_expr(), get_mergejoin_opfamilies(), get_opfamily_member(), make_canonical_pathkey(), NULL, and OidIsValid.

Referenced by build_expression_pathkey(), build_index_pathkeys(), and make_pathkey_from_sortop().

181 {
182  int16 strategy;
183  Oid equality_op;
184  List *opfamilies;
186 
187  strategy = reverse_sort ? BTGreaterStrategyNumber : BTLessStrategyNumber;
188 
189  /*
190  * EquivalenceClasses need to contain opfamily lists based on the family
191  * membership of mergejoinable equality operators, which could belong to
192  * more than one opfamily. So we have to look up the opfamily's equality
193  * operator and get its membership.
194  */
195  equality_op = get_opfamily_member(opfamily,
196  opcintype,
197  opcintype,
199  if (!OidIsValid(equality_op)) /* shouldn't happen */
200  elog(ERROR, "missing operator %d(%u,%u) in opfamily %u",
201  BTEqualStrategyNumber, opcintype, opcintype, opfamily);
202  opfamilies = get_mergejoin_opfamilies(equality_op);
203  if (!opfamilies) /* certainly should find some */
204  elog(ERROR, "could not find opfamilies for equality operator %u",
205  equality_op);
206 
207  /* Now find or (optionally) create a matching EquivalenceClass */
208  eclass = get_eclass_for_sort_expr(root, expr, nullable_relids,
209  opfamilies, opcintype, collation,
210  sortref, rel, create_it);
211 
212  /* Fail if no EC and !create_it */
213  if (!eclass)
214  return NULL;
215 
216  /* And finally we can find or create a PathKey node */
217  return make_canonical_pathkey(root, eclass, opfamily,
218  strategy, nulls_first);
219 }
signed short int16
Definition: c.h:255
#define BTGreaterStrategyNumber
Definition: stratnum.h:33
List * get_mergejoin_opfamilies(Oid opno)
Definition: lsyscache.c:363
EquivalenceClass * get_eclass_for_sort_expr(PlannerInfo *root, Expr *expr, Relids nullable_relids, List *opfamilies, Oid opcintype, Oid collation, Index sortref, Relids rel, bool create_it)
Definition: equivclass.c:581
PathKey * make_canonical_pathkey(PlannerInfo *root, EquivalenceClass *eclass, Oid opfamily, int strategy, bool nulls_first)
Definition: pathkeys.c:51
unsigned int Oid
Definition: postgres_ext.h:31
#define OidIsValid(objectId)
Definition: c.h:538
static struct cvec * eclass(struct vars *v, chr c, int cases)
Definition: regc_locale.c:508
#define ERROR
Definition: elog.h:43
Oid get_opfamily_member(Oid opfamily, Oid lefttype, Oid righttype, int16 strategy)
Definition: lsyscache.c:163
#define NULL
Definition: c.h:229
#define elog
Definition: elog.h:219
#define BTLessStrategyNumber
Definition: stratnum.h:29
Definition: pg_list.h:45
#define BTEqualStrategyNumber
Definition: stratnum.h:31
static PathKey* make_pathkey_from_sortop ( PlannerInfo root,
Expr expr,
Relids  nullable_relids,
Oid  ordering_op,
bool  nulls_first,
Index  sortref,
bool  create_it 
)
static

Definition at line 229 of file pathkeys.c.

References BTGreaterStrategyNumber, elog, ERROR, exprCollation(), get_ordering_op_properties(), make_pathkey_from_sortinfo(), and NULL.

Referenced by make_pathkeys_for_sortclauses().

236 {
237  Oid opfamily,
238  opcintype,
239  collation;
240  int16 strategy;
241 
242  /* Find the operator in pg_amop --- failure shouldn't happen */
243  if (!get_ordering_op_properties(ordering_op,
244  &opfamily, &opcintype, &strategy))
245  elog(ERROR, "operator %u is not a valid ordering operator",
246  ordering_op);
247 
248  /* Because SortGroupClause doesn't carry collation, consult the expr */
249  collation = exprCollation((Node *) expr);
250 
251  return make_pathkey_from_sortinfo(root,
252  expr,
253  nullable_relids,
254  opfamily,
255  opcintype,
256  collation,
257  (strategy == BTGreaterStrategyNumber),
258  nulls_first,
259  sortref,
260  NULL,
261  create_it);
262 }
signed short int16
Definition: c.h:255
#define BTGreaterStrategyNumber
Definition: stratnum.h:33
Definition: nodes.h:509
unsigned int Oid
Definition: postgres_ext.h:31
#define ERROR
Definition: elog.h:43
#define NULL
Definition: c.h:229
bool get_ordering_op_properties(Oid opno, Oid *opfamily, Oid *opcintype, int16 *strategy)
Definition: lsyscache.c:204
Oid exprCollation(const Node *expr)
Definition: nodeFuncs.c:720
#define elog
Definition: elog.h:219
static PathKey * make_pathkey_from_sortinfo(PlannerInfo *root, Expr *expr, Relids nullable_relids, Oid opfamily, Oid opcintype, Oid collation, bool reverse_sort, bool nulls_first, Index sortref, Relids rel, bool create_it)
Definition: pathkeys.c:170
List* make_pathkeys_for_sortclauses ( PlannerInfo root,
List sortclauses,
List tlist 
)

Definition at line 865 of file pathkeys.c.

References Assert, get_sortgroupclause_expr(), lappend(), lfirst, make_pathkey_from_sortop(), NIL, PlannerInfo::nullable_baserels, SortGroupClause::nulls_first, OidIsValid, pathkey_is_redundant(), SortGroupClause::sortop, and SortGroupClause::tleSortGroupRef.

Referenced by generate_nonunion_path(), get_column_info_for_window(), grouping_planner(), make_pathkeys_for_window(), make_union_unique(), minmax_qp_callback(), and standard_qp_callback().

868 {
869  List *pathkeys = NIL;
870  ListCell *l;
871 
872  foreach(l, sortclauses)
873  {
874  SortGroupClause *sortcl = (SortGroupClause *) lfirst(l);
875  Expr *sortkey;
876  PathKey *pathkey;
877 
878  sortkey = (Expr *) get_sortgroupclause_expr(sortcl, tlist);
879  Assert(OidIsValid(sortcl->sortop));
880  pathkey = make_pathkey_from_sortop(root,
881  sortkey,
882  root->nullable_baserels,
883  sortcl->sortop,
884  sortcl->nulls_first,
885  sortcl->tleSortGroupRef,
886  true);
887 
888  /* Canonical form eliminates redundant ordering keys */
889  if (!pathkey_is_redundant(pathkey, pathkeys))
890  pathkeys = lappend(pathkeys, pathkey);
891  }
892  return pathkeys;
893 }
#define NIL
Definition: pg_list.h:69
static PathKey * make_pathkey_from_sortop(PlannerInfo *root, Expr *expr, Relids nullable_relids, Oid ordering_op, bool nulls_first, Index sortref, bool create_it)
Definition: pathkeys.c:229
Index tleSortGroupRef
Definition: parsenodes.h:1184
Node * get_sortgroupclause_expr(SortGroupClause *sgClause, List *targetList)
Definition: tlist.c:382
#define OidIsValid(objectId)
Definition: c.h:538
static bool pathkey_is_redundant(PathKey *new_pathkey, List *pathkeys)
Definition: pathkeys.c:128
List * lappend(List *list, void *datum)
Definition: list.c:128
#define Assert(condition)
Definition: c.h:676
#define lfirst(lc)
Definition: pg_list.h:106
Relids nullable_baserels
Definition: relation.h:204
Definition: pg_list.h:45
static bool pathkey_is_redundant ( PathKey new_pathkey,
List pathkeys 
)
static

Definition at line 128 of file pathkeys.c.

References EC_MUST_BE_REDUNDANT, lfirst, and PathKey::pk_eclass.

Referenced by build_index_pathkeys(), convert_subquery_pathkeys(), make_inner_pathkeys_for_merge(), make_pathkeys_for_sortclauses(), and select_outer_pathkeys_for_merge().

129 {
130  EquivalenceClass *new_ec = new_pathkey->pk_eclass;
131  ListCell *lc;
132 
133  /* Check for EC containing a constant --- unconditionally redundant */
134  if (EC_MUST_BE_REDUNDANT(new_ec))
135  return true;
136 
137  /* If same EC already used in list, then redundant */
138  foreach(lc, pathkeys)
139  {
140  PathKey *old_pathkey = (PathKey *) lfirst(lc);
141 
142  if (new_ec == old_pathkey->pk_eclass)
143  return true;
144  }
145 
146  return false;
147 }
#define EC_MUST_BE_REDUNDANT(eclass)
Definition: relation.h:793
#define lfirst(lc)
Definition: pg_list.h:106
EquivalenceClass * pk_eclass
Definition: relation.h:851
static int pathkeys_useful_for_merging ( PlannerInfo root,
RelOptInfo rel,
List pathkeys 
)
static

Definition at line 1393 of file pathkeys.c.

References eclass_useful_for_merging(), RelOptInfo::has_eclass_joins, i, RelOptInfo::joininfo, RestrictInfo::left_ec, lfirst, RestrictInfo::mergeopfamilies, NIL, PathKey::pk_eclass, RestrictInfo::right_ec, right_merge_direction(), and update_mergeclause_eclasses().

Referenced by truncate_useless_pathkeys().

1394 {
1395  int useful = 0;
1396  ListCell *i;
1397 
1398  foreach(i, pathkeys)
1399  {
1400  PathKey *pathkey = (PathKey *) lfirst(i);
1401  bool matched = false;
1402  ListCell *j;
1403 
1404  /* If "wrong" direction, not useful for merging */
1405  if (!right_merge_direction(root, pathkey))
1406  break;
1407 
1408  /*
1409  * First look into the EquivalenceClass of the pathkey, to see if
1410  * there are any members not yet joined to the rel. If so, it's
1411  * surely possible to generate a mergejoin clause using them.
1412  */
1413  if (rel->has_eclass_joins &&
1414  eclass_useful_for_merging(root, pathkey->pk_eclass, rel))
1415  matched = true;
1416  else
1417  {
1418  /*
1419  * Otherwise search the rel's joininfo list, which contains
1420  * non-EquivalenceClass-derivable join clauses that might
1421  * nonetheless be mergejoinable.
1422  */
1423  foreach(j, rel->joininfo)
1424  {
1425  RestrictInfo *restrictinfo = (RestrictInfo *) lfirst(j);
1426 
1427  if (restrictinfo->mergeopfamilies == NIL)
1428  continue;
1429  update_mergeclause_eclasses(root, restrictinfo);
1430 
1431  if (pathkey->pk_eclass == restrictinfo->left_ec ||
1432  pathkey->pk_eclass == restrictinfo->right_ec)
1433  {
1434  matched = true;
1435  break;
1436  }
1437  }
1438  }
1439 
1440  /*
1441  * If we didn't find a mergeclause, we're done --- any additional
1442  * sort-key positions in the pathkeys are useless. (But we can still
1443  * mergejoin if we found at least one mergeclause.)
1444  */
1445  if (matched)
1446  useful++;
1447  else
1448  break;
1449  }
1450 
1451  return useful;
1452 }
bool has_eclass_joins
Definition: relation.h:591
#define NIL
Definition: pg_list.h:69
bool eclass_useful_for_merging(PlannerInfo *root, EquivalenceClass *eclass, RelOptInfo *rel)
Definition: equivclass.c:2398
EquivalenceClass * right_ec
Definition: relation.h:1796
List * mergeopfamilies
Definition: relation.h:1792
List * joininfo
Definition: relation.h:589
#define lfirst(lc)
Definition: pg_list.h:106
EquivalenceClass * pk_eclass
Definition: relation.h:851
EquivalenceClass * left_ec
Definition: relation.h:1795
int i
void update_mergeclause_eclasses(PlannerInfo *root, RestrictInfo *restrictinfo)
Definition: pathkeys.c:968
static bool right_merge_direction(PlannerInfo *root, PathKey *pathkey)
Definition: pathkeys.c:1460
static int pathkeys_useful_for_ordering ( PlannerInfo root,
List pathkeys 
)
static

Definition at line 1496 of file pathkeys.c.

References list_length(), NIL, pathkeys_contained_in(), and PlannerInfo::query_pathkeys.

Referenced by truncate_useless_pathkeys().

1497 {
1498  if (root->query_pathkeys == NIL)
1499  return 0; /* no special ordering requested */
1500 
1501  if (pathkeys == NIL)
1502  return 0; /* unordered path */
1503 
1504  if (pathkeys_contained_in(root->query_pathkeys, pathkeys))
1505  {
1506  /* It's useful ... or at least the first N keys are */
1507  return list_length(root->query_pathkeys);
1508  }
1509 
1510  return 0; /* path ordering not useful */
1511 }
#define NIL
Definition: pg_list.h:69
List * query_pathkeys
Definition: relation.h:262
bool pathkeys_contained_in(List *keys1, List *keys2)
Definition: pathkeys.c:317
static int list_length(const List *l)
Definition: pg_list.h:89
static bool right_merge_direction ( PlannerInfo root,
PathKey pathkey 
)
static

Definition at line 1460 of file pathkeys.c.

References BTLessStrategyNumber, lfirst, PathKey::pk_eclass, PathKey::pk_opfamily, PathKey::pk_strategy, and PlannerInfo::query_pathkeys.

Referenced by pathkeys_useful_for_merging().

1461 {
1462  ListCell *l;
1463 
1464  foreach(l, root->query_pathkeys)
1465  {
1466  PathKey *query_pathkey = (PathKey *) lfirst(l);
1467 
1468  if (pathkey->pk_eclass == query_pathkey->pk_eclass &&
1469  pathkey->pk_opfamily == query_pathkey->pk_opfamily)
1470  {
1471  /*
1472  * Found a matching query sort column. Prefer this pathkey's
1473  * direction iff it matches. Note that we ignore pk_nulls_first,
1474  * which means that a sort might be needed anyway ... but we still
1475  * want to prefer only one of the two possible directions, and we
1476  * might as well use this one.
1477  */
1478  return (pathkey->pk_strategy == query_pathkey->pk_strategy);
1479  }
1480  }
1481 
1482  /* If no matching ORDER BY request, prefer the ASC direction */
1483  return (pathkey->pk_strategy == BTLessStrategyNumber);
1484 }
List * query_pathkeys
Definition: relation.h:262
int pk_strategy
Definition: relation.h:853
#define lfirst(lc)
Definition: pg_list.h:106
EquivalenceClass * pk_eclass
Definition: relation.h:851
Oid pk_opfamily
Definition: relation.h:852
#define BTLessStrategyNumber
Definition: stratnum.h:29
List* select_outer_pathkeys_for_merge ( PlannerInfo root,
List mergeclauses,
RelOptInfo joinrel 
)

Definition at line 1120 of file pathkeys.c.

References Assert, bms_overlap(), BTLessStrategyNumber, EquivalenceClass::ec_members, EquivalenceClass::ec_opfamilies, EquivalenceMember::em_is_child, EquivalenceMember::em_is_const, EquivalenceMember::em_relids, lappend(), RestrictInfo::left_ec, lfirst, linitial_oid, list_copy(), list_length(), make_canonical_pathkey(), NIL, NULL, RestrictInfo::outer_is_left, palloc(), pathkey_is_redundant(), pfree(), PathKey::pk_eclass, PlannerInfo::query_pathkeys, RelOptInfo::relids, RestrictInfo::right_ec, and update_mergeclause_eclasses().

Referenced by sort_inner_and_outer().

1123 {
1124  List *pathkeys = NIL;
1125  int nClauses = list_length(mergeclauses);
1126  EquivalenceClass **ecs;
1127  int *scores;
1128  int necs;
1129  ListCell *lc;
1130  int j;
1131 
1132  /* Might have no mergeclauses */
1133  if (nClauses == 0)
1134  return NIL;
1135 
1136  /*
1137  * Make arrays of the ECs used by the mergeclauses (dropping any
1138  * duplicates) and their "popularity" scores.
1139  */
1140  ecs = (EquivalenceClass **) palloc(nClauses * sizeof(EquivalenceClass *));
1141  scores = (int *) palloc(nClauses * sizeof(int));
1142  necs = 0;
1143 
1144  foreach(lc, mergeclauses)
1145  {
1146  RestrictInfo *rinfo = (RestrictInfo *) lfirst(lc);
1147  EquivalenceClass *oeclass;
1148  int score;
1149  ListCell *lc2;
1150 
1151  /* get the outer eclass */
1152  update_mergeclause_eclasses(root, rinfo);
1153 
1154  if (rinfo->outer_is_left)
1155  oeclass = rinfo->left_ec;
1156  else
1157  oeclass = rinfo->right_ec;
1158 
1159  /* reject duplicates */
1160  for (j = 0; j < necs; j++)
1161  {
1162  if (ecs[j] == oeclass)
1163  break;
1164  }
1165  if (j < necs)
1166  continue;
1167 
1168  /* compute score */
1169  score = 0;
1170  foreach(lc2, oeclass->ec_members)
1171  {
1173 
1174  /* Potential future join partner? */
1175  if (!em->em_is_const && !em->em_is_child &&
1176  !bms_overlap(em->em_relids, joinrel->relids))
1177  score++;
1178  }
1179 
1180  ecs[necs] = oeclass;
1181  scores[necs] = score;
1182  necs++;
1183  }
1184 
1185  /*
1186  * Find out if we have all the ECs mentioned in query_pathkeys; if so we
1187  * can generate a sort order that's also useful for final output. There is
1188  * no percentage in a partial match, though, so we have to have 'em all.
1189  */
1190  if (root->query_pathkeys)
1191  {
1192  foreach(lc, root->query_pathkeys)
1193  {
1194  PathKey *query_pathkey = (PathKey *) lfirst(lc);
1195  EquivalenceClass *query_ec = query_pathkey->pk_eclass;
1196 
1197  for (j = 0; j < necs; j++)
1198  {
1199  if (ecs[j] == query_ec)
1200  break; /* found match */
1201  }
1202  if (j >= necs)
1203  break; /* didn't find match */
1204  }
1205  /* if we got to the end of the list, we have them all */
1206  if (lc == NULL)
1207  {
1208  /* copy query_pathkeys as starting point for our output */
1209  pathkeys = list_copy(root->query_pathkeys);
1210  /* mark their ECs as already-emitted */
1211  foreach(lc, root->query_pathkeys)
1212  {
1213  PathKey *query_pathkey = (PathKey *) lfirst(lc);
1214  EquivalenceClass *query_ec = query_pathkey->pk_eclass;
1215 
1216  for (j = 0; j < necs; j++)
1217  {
1218  if (ecs[j] == query_ec)
1219  {
1220  scores[j] = -1;
1221  break;
1222  }
1223  }
1224  }
1225  }
1226  }
1227 
1228  /*
1229  * Add remaining ECs to the list in popularity order, using a default sort
1230  * ordering. (We could use qsort() here, but the list length is usually
1231  * so small it's not worth it.)
1232  */
1233  for (;;)
1234  {
1235  int best_j;
1236  int best_score;
1237  EquivalenceClass *ec;
1238  PathKey *pathkey;
1239 
1240  best_j = 0;
1241  best_score = scores[0];
1242  for (j = 1; j < necs; j++)
1243  {
1244  if (scores[j] > best_score)
1245  {
1246  best_j = j;
1247  best_score = scores[j];
1248  }
1249  }
1250  if (best_score < 0)
1251  break; /* all done */
1252  ec = ecs[best_j];
1253  scores[best_j] = -1;
1254  pathkey = make_canonical_pathkey(root,
1255  ec,
1258  false);
1259  /* can't be redundant because no duplicate ECs */
1260  Assert(!pathkey_is_redundant(pathkey, pathkeys));
1261  pathkeys = lappend(pathkeys, pathkey);
1262  }
1263 
1264  pfree(ecs);
1265  pfree(scores);
1266 
1267  return pathkeys;
1268 }
#define NIL
Definition: pg_list.h:69
List * query_pathkeys
Definition: relation.h:262
List * list_copy(const List *oldlist)
Definition: list.c:1160
PathKey * make_canonical_pathkey(PlannerInfo *root, EquivalenceClass *eclass, Oid opfamily, int strategy, bool nulls_first)
Definition: pathkeys.c:51
EquivalenceClass * right_ec
Definition: relation.h:1796
void pfree(void *pointer)
Definition: mcxt.c:950
bool outer_is_left
Definition: relation.h:1802
Relids relids
Definition: relation.h:525
static bool pathkey_is_redundant(PathKey *new_pathkey, List *pathkeys)
Definition: pathkeys.c:128
List * lappend(List *list, void *datum)
Definition: list.c:128
List * ec_opfamilies
Definition: relation.h:772
Relids em_relids
Definition: relation.h:823
#define NULL
Definition: c.h:229
#define Assert(condition)
Definition: c.h:676
#define lfirst(lc)
Definition: pg_list.h:106
EquivalenceClass * pk_eclass
Definition: relation.h:851
#define linitial_oid(l)
Definition: pg_list.h:113
static int list_length(const List *l)
Definition: pg_list.h:89
bool bms_overlap(const Bitmapset *a, const Bitmapset *b)
Definition: bitmapset.c:443
void * palloc(Size size)
Definition: mcxt.c:849
EquivalenceClass * left_ec
Definition: relation.h:1795
#define BTLessStrategyNumber
Definition: stratnum.h:29
Definition: pg_list.h:45
void update_mergeclause_eclasses(PlannerInfo *root, RestrictInfo *restrictinfo)
Definition: pathkeys.c:968
List * ec_members
Definition: relation.h:774
List* truncate_useless_pathkeys ( PlannerInfo root,
RelOptInfo rel,
List pathkeys 
)

Definition at line 1518 of file pathkeys.c.

References list_copy(), list_length(), list_truncate(), NIL, pathkeys_useful_for_merging(), and pathkeys_useful_for_ordering().

Referenced by build_index_paths(), and build_join_pathkeys().

1521 {
1522  int nuseful;
1523  int nuseful2;
1524 
1525  nuseful = pathkeys_useful_for_merging(root, rel, pathkeys);
1526  nuseful2 = pathkeys_useful_for_ordering(root, pathkeys);
1527  if (nuseful2 > nuseful)
1528  nuseful = nuseful2;
1529 
1530  /*
1531  * Note: not safe to modify input list destructively, but we can avoid
1532  * copying the list if we're not actually going to change it
1533  */
1534  if (nuseful == 0)
1535  return NIL;
1536  else if (nuseful == list_length(pathkeys))
1537  return pathkeys;
1538  else
1539  return list_truncate(list_copy(pathkeys), nuseful);
1540 }
#define NIL
Definition: pg_list.h:69
List * list_truncate(List *list, int new_size)
Definition: list.c:350
List * list_copy(const List *oldlist)
Definition: list.c:1160
static int pathkeys_useful_for_ordering(PlannerInfo *root, List *pathkeys)
Definition: pathkeys.c:1496
static int list_length(const List *l)
Definition: pg_list.h:89
static int pathkeys_useful_for_merging(PlannerInfo *root, RelOptInfo *rel, List *pathkeys)
Definition: pathkeys.c:1393
void update_mergeclause_eclasses ( PlannerInfo root,
RestrictInfo restrictinfo 
)

Definition at line 968 of file pathkeys.c.

References Assert, EquivalenceClass::ec_merged, RestrictInfo::left_ec, RestrictInfo::mergeopfamilies, NIL, NULL, and RestrictInfo::right_ec.

Referenced by find_mergeclauses_for_pathkeys(), get_useful_ecs_for_relation(), make_inner_pathkeys_for_merge(), pathkeys_useful_for_merging(), select_mergejoin_clauses(), and select_outer_pathkeys_for_merge().

969 {
970  /* Should be a merge clause ... */
971  Assert(restrictinfo->mergeopfamilies != NIL);
972  /* ... with pointers already set */
973  Assert(restrictinfo->left_ec != NULL);
974  Assert(restrictinfo->right_ec != NULL);
975 
976  /* Chase up to the top as needed */
977  while (restrictinfo->left_ec->ec_merged)
978  restrictinfo->left_ec = restrictinfo->left_ec->ec_merged;
979  while (restrictinfo->right_ec->ec_merged)
980  restrictinfo->right_ec = restrictinfo->right_ec->ec_merged;
981 }
#define NIL
Definition: pg_list.h:69
EquivalenceClass * right_ec
Definition: relation.h:1796
List * mergeopfamilies
Definition: relation.h:1792
#define NULL
Definition: c.h:229
#define Assert(condition)
Definition: c.h:676
EquivalenceClass * left_ec
Definition: relation.h:1795
struct EquivalenceClass * ec_merged
Definition: relation.h:786