From 91280a30af4f4b8fe98d21c669306176048c8cd0 Mon Sep 17 00:00:00 2001 From: Yuya Watari Date: Fri, 25 Aug 2023 10:43:36 +0900 Subject: [PATCH v36 2/2] Speed up searches for child EquivalenceMembers Traditionally, child EquivalenceMembers were in the EquivalenceClass->ec_members. When we wanted to find some child members matching a request, we had to perform a linear search. This search became heavy when tables had many partitions, leading to much planning time. After this commit, child EquivalenceMembers no longer exist in ec_members. Instead, RelOptInfos have them. This change demonstrates a significant performance improvement in planning time. --- contrib/postgres_fdw/postgres_fdw.c | 15 +- src/backend/nodes/outfuncs.c | 1 + src/backend/optimizer/path/equivclass.c | 353 +++++++++++++++++------- src/backend/optimizer/path/indxpath.c | 15 +- src/backend/optimizer/path/pathkeys.c | 9 +- src/include/nodes/pathnodes.h | 51 ++++ src/include/optimizer/paths.h | 6 + src/tools/pgindent/typedefs.list | 1 + 8 files changed, 340 insertions(+), 111 deletions(-) diff --git a/contrib/postgres_fdw/postgres_fdw.c b/contrib/postgres_fdw/postgres_fdw.c index ac14c06c715..90c7a212379 100644 --- a/contrib/postgres_fdw/postgres_fdw.c +++ b/contrib/postgres_fdw/postgres_fdw.c @@ -7847,14 +7847,13 @@ conversion_error_callback(void *arg) EquivalenceMember * find_em_for_rel(PlannerInfo *root, EquivalenceClass *ec, RelOptInfo *rel) { - ListCell *lc; - PgFdwRelationInfo *fpinfo = (PgFdwRelationInfo *) rel->fdw_private; + EquivalenceMemberIterator it; + EquivalenceMember *em; - foreach(lc, ec->ec_members) + setup_eclass_member_iterator(root, &it, ec, rel->relids); + while ((em = eclass_member_iterator_next(&it)) != NULL) { - EquivalenceMember *em = (EquivalenceMember *) lfirst(lc); - /* * Note we require !bms_is_empty, else we'd accept constant * expressions which are not suitable for the purpose. @@ -7865,6 +7864,7 @@ find_em_for_rel(PlannerInfo *root, EquivalenceClass *ec, RelOptInfo *rel) is_foreign_expr(root, rel, em->em_expr)) return em; } + dispose_eclass_member_iterator(&it); return NULL; } @@ -7918,9 +7918,8 @@ find_em_for_rel_target(PlannerInfo *root, EquivalenceClass *ec, if (em->em_is_const) continue; - /* Ignore child members */ - if (em->em_is_child) - continue; + /* Child members should not exist in ec_members */ + Assert(!em->em_is_child); /* Match if same expression (after stripping relabel) */ em_expr = em->em_expr; diff --git a/src/backend/nodes/outfuncs.c b/src/backend/nodes/outfuncs.c index bb9bdd67192..306df44f293 100644 --- a/src/backend/nodes/outfuncs.c +++ b/src/backend/nodes/outfuncs.c @@ -466,6 +466,7 @@ _outEquivalenceClass(StringInfo str, const EquivalenceClass *node) WRITE_NODE_FIELD(ec_opfamilies); WRITE_OID_FIELD(ec_collation); WRITE_NODE_FIELD(ec_members); + /* XXX ec_childmembers? */ WRITE_NODE_FIELD(ec_sources); WRITE_NODE_FIELD(ec_derives); WRITE_BITMAPSET_FIELD(ec_relids); diff --git a/src/backend/optimizer/path/equivclass.c b/src/backend/optimizer/path/equivclass.c index 7fe7cdff468..9d36194fccf 100644 --- a/src/backend/optimizer/path/equivclass.c +++ b/src/backend/optimizer/path/equivclass.c @@ -33,11 +33,23 @@ #include "utils/lsyscache.h" +static EquivalenceMember *make_eq_member(EquivalenceClass *ec, + Expr *expr, Relids relids, + JoinDomain *jdomain, + EquivalenceMember *parent, + Oid datatype); static EquivalenceMember *add_eq_member(EquivalenceClass *ec, Expr *expr, Relids relids, JoinDomain *jdomain, - EquivalenceMember *parent, Oid datatype); +static EquivalenceMember *add_child_eq_member(PlannerInfo *root, + EquivalenceClass *ec, + int ec_index, Expr *expr, + Relids relids, + JoinDomain *jdomain, + EquivalenceMember *parent_em, + Oid datatype, + Relids child_relids); static void generate_base_implied_equalities_const(PlannerInfo *root, EquivalenceClass *ec); static void generate_base_implied_equalities_no_const(PlannerInfo *root, @@ -268,7 +280,8 @@ process_equivalence(PlannerInfo *root, { EquivalenceMember *cur_em = (EquivalenceMember *) lfirst(lc2); - Assert(!cur_em->em_is_child); /* no children yet */ + /* Child members should not exist in ec_members */ + Assert(!cur_em->em_is_child); /* * Match constants only within the same JoinDomain (see @@ -373,7 +386,7 @@ process_equivalence(PlannerInfo *root, { /* Case 3: add item2 to ec1 */ em2 = add_eq_member(ec1, item2, item2_relids, - jdomain, NULL, item2_type); + jdomain, item2_type); ec1->ec_sources = lappend(ec1->ec_sources, restrictinfo); ec1->ec_min_security = Min(ec1->ec_min_security, restrictinfo->security_level); @@ -390,7 +403,7 @@ process_equivalence(PlannerInfo *root, { /* Case 3: add item1 to ec2 */ em1 = add_eq_member(ec2, item1, item1_relids, - jdomain, NULL, item1_type); + jdomain, item1_type); ec2->ec_sources = lappend(ec2->ec_sources, restrictinfo); ec2->ec_min_security = Min(ec2->ec_min_security, restrictinfo->security_level); @@ -422,9 +435,9 @@ process_equivalence(PlannerInfo *root, ec->ec_max_security = restrictinfo->security_level; ec->ec_merged = NULL; em1 = add_eq_member(ec, item1, item1_relids, - jdomain, NULL, item1_type); + jdomain, item1_type); em2 = add_eq_member(ec, item2, item2_relids, - jdomain, NULL, item2_type); + jdomain, item2_type); root->eq_classes = lappend(root->eq_classes, ec); @@ -510,11 +523,16 @@ canonicalize_ec_expression(Expr *expr, Oid req_type, Oid req_collation) } /* - * add_eq_member - build a new EquivalenceMember and add it to an EC + * make_eq_member + * + * Build a new EquivalenceMember without adding it to an EC. If 'parent' + * parameter is NULL, the result will be a parent member, otherwise a child + * member. Note that child EquivalenceMembers should not be added to its + * parent EquivalenceClass. */ static EquivalenceMember * -add_eq_member(EquivalenceClass *ec, Expr *expr, Relids relids, - JoinDomain *jdomain, EquivalenceMember *parent, Oid datatype) +make_eq_member(EquivalenceClass *ec, Expr *expr, Relids relids, + JoinDomain *jdomain, EquivalenceMember *parent, Oid datatype) { EquivalenceMember *em = makeNode(EquivalenceMember); @@ -541,11 +559,60 @@ add_eq_member(EquivalenceClass *ec, Expr *expr, Relids relids, ec->ec_has_const = true; /* it can't affect ec_relids */ } - else if (!parent) /* child members don't add to ec_relids */ + + return em; +} + +/* + * add_eq_member - build a new non-child EquivalenceMember and add it to 'ec'. + */ +static EquivalenceMember * +add_eq_member(EquivalenceClass *ec, Expr *expr, Relids relids, + JoinDomain *jdomain, Oid datatype) +{ + EquivalenceMember *em = make_eq_member(ec, expr, relids, jdomain, + NULL, datatype); + + ec->ec_members = lappend(ec->ec_members, em); + ec->ec_relids = bms_add_members(ec->ec_relids, relids); + return em; +} + +/* + * add_child_eq_member + * Create an em_is_child=true EquivalenceMember and add it to 'ec'. + */ +static EquivalenceMember * +add_child_eq_member(PlannerInfo *root, EquivalenceClass *ec, int ec_index, + Expr *expr, Relids relids, JoinDomain *jdomain, + EquivalenceMember *parent_em, Oid datatype, + Relids child_relids) +{ + EquivalenceMember *em; + int relid; + + Assert(parent_em != NULL); + + if (ec->ec_childmembers == NULL) + ec->ec_childmembers = (List **) palloc0(root->simple_rel_array_size * sizeof(List *)); + + em = make_eq_member(ec, expr, relids, jdomain, parent_em, datatype); + + relid = -1; + while ((relid = bms_next_member(child_relids, relid)) >= 0) { - ec->ec_relids = bms_add_members(ec->ec_relids, relids); + + ec->ec_childmembers[relid] = lappend(ec->ec_childmembers[relid], em); + + /* Record this EC index for the child rel */ + if (ec_index >= 0) + { + RelOptInfo *child_rel = root->simple_rel_array[relid]; + + child_rel->eclass_indexes = + bms_add_member(child_rel->eclass_indexes, ec_index); + } } - ec->ec_members = lappend(ec->ec_members, em); return em; } @@ -616,7 +683,8 @@ get_eclass_for_sort_expr(PlannerInfo *root, foreach(lc1, root->eq_classes) { EquivalenceClass *cur_ec = (EquivalenceClass *) lfirst(lc1); - ListCell *lc2; + EquivalenceMemberIterator it; + EquivalenceMember *cur_em; /* * Never match to a volatile EC, except when we are looking at another @@ -631,10 +699,9 @@ get_eclass_for_sort_expr(PlannerInfo *root, if (!equal(opfamilies, cur_ec->ec_opfamilies)) continue; - foreach(lc2, cur_ec->ec_members) + setup_eclass_member_iterator(root, &it, cur_ec, rel); + while ((cur_em = eclass_member_iterator_next(&it)) != NULL) { - EquivalenceMember *cur_em = (EquivalenceMember *) lfirst(lc2); - /* * Ignore child members unless they match the request. */ @@ -653,6 +720,7 @@ get_eclass_for_sort_expr(PlannerInfo *root, equal(expr, cur_em->em_expr)) return cur_ec; /* Match! */ } + dispose_eclass_member_iterator(&it); } /* No match; does caller want a NULL result? */ @@ -690,7 +758,7 @@ get_eclass_for_sort_expr(PlannerInfo *root, expr_relids = pull_varnos(root, (Node *) expr); newem = add_eq_member(newec, copyObject(expr), expr_relids, - jdomain, NULL, opcintype); + jdomain, opcintype); /* * add_eq_member doesn't check for volatile functions, set-returning @@ -764,15 +832,16 @@ find_ec_member_matching_expr(PlannerInfo *root, EquivalenceClass *ec, Expr *expr, Relids relids) { - ListCell *lc; + EquivalenceMemberIterator it; + EquivalenceMember *em; /* We ignore binary-compatible relabeling on both ends */ while (expr && IsA(expr, RelabelType)) expr = ((RelabelType *) expr)->arg; - foreach(lc, ec->ec_members) + setup_eclass_member_iterator(root, &it, ec, relids); + while ((em = eclass_member_iterator_next(&it)) != NULL) { - EquivalenceMember *em = (EquivalenceMember *) lfirst(lc); Expr *emexpr; /* @@ -799,6 +868,7 @@ find_ec_member_matching_expr(PlannerInfo *root, EquivalenceClass *ec, if (equal(emexpr, expr)) return em; } + dispose_eclass_member_iterator(&it); return NULL; } @@ -841,7 +911,8 @@ find_computable_ec_member(PlannerInfo *root, bool require_parallel_safe) { List *exprvars; - ListCell *lc; + EquivalenceMemberIterator it; + EquivalenceMember *em; /* * Pull out the Vars and quasi-Vars present in "exprs". In the typical @@ -855,9 +926,9 @@ find_computable_ec_member(PlannerInfo *root, PVC_INCLUDE_PLACEHOLDERS | PVC_INCLUDE_CONVERTROWTYPES); - foreach(lc, ec->ec_members) + setup_eclass_member_iterator(root, &it, ec, relids); + while ((em = eclass_member_iterator_next(&it)) != NULL) { - EquivalenceMember *em = (EquivalenceMember *) lfirst(lc); List *emvars; ListCell *lc2; @@ -901,6 +972,7 @@ find_computable_ec_member(PlannerInfo *root, return em; /* found usable expression */ } + dispose_eclass_member_iterator(&it); return NULL; } @@ -1162,7 +1234,8 @@ generate_base_implied_equalities_const(PlannerInfo *root, Oid eq_op; RestrictInfo *rinfo; - Assert(!cur_em->em_is_child); /* no children yet */ + Assert(!cur_em->em_is_child); /* Child members should not exist in + * ec_members */ if (cur_em == const_em) continue; eq_op = select_equality_operator(ec, @@ -1231,7 +1304,8 @@ generate_base_implied_equalities_no_const(PlannerInfo *root, EquivalenceMember *cur_em = (EquivalenceMember *) lfirst(lc); int relid; - Assert(!cur_em->em_is_child); /* no children yet */ + Assert(!cur_em->em_is_child); /* Child members should not exist in + * ec_members */ if (!bms_get_singleton_member(cur_em->em_relids, &relid)) continue; Assert(relid < root->simple_rel_array_size); @@ -1564,7 +1638,8 @@ generate_join_implied_equalities_normal(PlannerInfo *root, List *new_members = NIL; List *outer_members = NIL; List *inner_members = NIL; - ListCell *lc1; + EquivalenceMemberIterator it; + EquivalenceMember *cur_em; /* * First, scan the EC to identify member values that are computable at the @@ -1575,10 +1650,9 @@ generate_join_implied_equalities_normal(PlannerInfo *root, * as well as to at least one input member, plus enforce at least one * outer-rel member equal to at least one inner-rel member. */ - foreach(lc1, ec->ec_members) + setup_eclass_member_iterator(root, &it, ec, join_relids); + while ((cur_em = eclass_member_iterator_next(&it)) != NULL) { - EquivalenceMember *cur_em = (EquivalenceMember *) lfirst(lc1); - /* * We don't need to check explicitly for child EC members. This test * against join_relids will cause them to be ignored except when @@ -1594,6 +1668,7 @@ generate_join_implied_equalities_normal(PlannerInfo *root, else new_members = lappend(new_members, cur_em); } + dispose_eclass_member_iterator(&it); /* * First, select the joinclause if needed. We can equate any one outer @@ -1611,6 +1686,7 @@ generate_join_implied_equalities_normal(PlannerInfo *root, Oid best_eq_op = InvalidOid; int best_score = -1; RestrictInfo *rinfo; + ListCell *lc1; foreach(lc1, outer_members) { @@ -1685,6 +1761,7 @@ generate_join_implied_equalities_normal(PlannerInfo *root, List *old_members = list_concat(outer_members, inner_members); EquivalenceMember *prev_em = NULL; RestrictInfo *rinfo; + ListCell *lc1; /* For now, arbitrarily take the first old_member as the one to use */ if (old_members) @@ -1692,7 +1769,7 @@ generate_join_implied_equalities_normal(PlannerInfo *root, foreach(lc1, new_members) { - EquivalenceMember *cur_em = (EquivalenceMember *) lfirst(lc1); + cur_em = (EquivalenceMember *) lfirst(lc1); if (prev_em != NULL) { @@ -2181,7 +2258,8 @@ reconsider_outer_join_clause(PlannerInfo *root, OuterJoinClauseInfo *ojcinfo, { EquivalenceMember *cur_em = (EquivalenceMember *) lfirst(lc2); - Assert(!cur_em->em_is_child); /* no children yet */ + Assert(!cur_em->em_is_child); /* Child members should not exist + * in ec_members */ if (equal(outervar, cur_em->em_expr)) { match = true; @@ -2308,7 +2386,8 @@ reconsider_full_join_clause(PlannerInfo *root, OuterJoinClauseInfo *ojcinfo) foreach(lc2, cur_ec->ec_members) { coal_em = (EquivalenceMember *) lfirst(lc2); - Assert(!coal_em->em_is_child); /* no children yet */ + Assert(!coal_em->em_is_child); /* Child members should not exist + * in ec_members */ if (IsA(coal_em->em_expr, CoalesceExpr)) { CoalesceExpr *cexpr = (CoalesceExpr *) coal_em->em_expr; @@ -2526,8 +2605,8 @@ exprs_known_equal(PlannerInfo *root, Node *item1, Node *item2, Oid opfamily) { EquivalenceMember *em = (EquivalenceMember *) lfirst(lc2); - if (em->em_is_child) - continue; /* ignore children here */ + Assert(!em->em_is_child); /* Child members should not exist in + * ec_members */ if (equal(item1, em->em_expr)) item1member = true; else if (equal(item2, em->em_expr)) @@ -2598,8 +2677,8 @@ match_eclasses_to_foreign_key_col(PlannerInfo *root, EquivalenceMember *em = (EquivalenceMember *) lfirst(lc2); Var *var; - if (em->em_is_child) - continue; /* ignore children here */ + /* Child members should not exist in ec_members */ + Assert(!em->em_is_child); /* EM must be a Var, possibly with RelabelType */ var = (Var *) em->em_expr; @@ -2696,6 +2775,7 @@ add_child_rel_equivalences(PlannerInfo *root, Relids top_parent_relids = child_rel->top_parent_relids; Relids child_relids = child_rel->relids; int i; + ListCell *lc; /* * EC merging should be complete already, so we can use the parent rel's @@ -2708,7 +2788,6 @@ add_child_rel_equivalences(PlannerInfo *root, while ((i = bms_next_member(parent_rel->eclass_indexes, i)) >= 0) { EquivalenceClass *cur_ec = (EquivalenceClass *) list_nth(root->eq_classes, i); - int num_members; /* * If this EC contains a volatile expression, then generating child @@ -2721,29 +2800,15 @@ add_child_rel_equivalences(PlannerInfo *root, /* Sanity check eclass_indexes only contain ECs for parent_rel */ Assert(bms_is_subset(top_parent_relids, cur_ec->ec_relids)); - /* - * We don't use foreach() here because there's no point in scanning - * newly-added child members, so we can stop after the last - * pre-existing EC member. - */ - num_members = list_length(cur_ec->ec_members); - for (int pos = 0; pos < num_members; pos++) + foreach(lc, cur_ec->ec_members) { - EquivalenceMember *cur_em = (EquivalenceMember *) list_nth(cur_ec->ec_members, pos); + EquivalenceMember *cur_em = lfirst_node(EquivalenceMember, lc); if (cur_em->em_is_const) continue; /* ignore consts here */ - /* - * We consider only original EC members here, not - * already-transformed child members. Otherwise, if some original - * member expression references more than one appendrel, we'd get - * an O(N^2) explosion of useless derived expressions for - * combinations of children. (But add_child_join_rel_equivalences - * may add targeted combinations for partitionwise-join purposes.) - */ - if (cur_em->em_is_child) - continue; /* ignore children here */ + /* Child members should not exist in ec_members */ + Assert(!cur_em->em_is_child); /* * Consider only members that reference and can be computed at @@ -2788,12 +2853,15 @@ add_child_rel_equivalences(PlannerInfo *root, top_parent_relids); new_relids = bms_add_members(new_relids, child_relids); - (void) add_eq_member(cur_ec, child_expr, new_relids, - cur_em->em_jdomain, - cur_em, cur_em->em_datatype); - - /* Record this EC index for the child rel */ - child_rel->eclass_indexes = bms_add_member(child_rel->eclass_indexes, i); + add_child_eq_member(root, + cur_ec, + i, + child_expr, + new_relids, + cur_em->em_jdomain, + cur_em, + cur_em->em_datatype, + child_rel->relids); } } } @@ -2840,7 +2908,7 @@ add_child_join_rel_equivalences(PlannerInfo *root, while ((i = bms_next_member(matching_ecs, i)) >= 0) { EquivalenceClass *cur_ec = (EquivalenceClass *) list_nth(root->eq_classes, i); - int num_members; + ListCell *lc; /* * If this EC contains a volatile expression, then generating child @@ -2853,25 +2921,15 @@ add_child_join_rel_equivalences(PlannerInfo *root, /* Sanity check on get_eclass_indexes_for_relids result */ Assert(bms_overlap(top_parent_relids, cur_ec->ec_relids)); - /* - * We don't use foreach() here because there's no point in scanning - * newly-added child members, so we can stop after the last - * pre-existing EC member. - */ - num_members = list_length(cur_ec->ec_members); - for (int pos = 0; pos < num_members; pos++) + foreach(lc, cur_ec->ec_members) { - EquivalenceMember *cur_em = (EquivalenceMember *) list_nth(cur_ec->ec_members, pos); + EquivalenceMember *cur_em = lfirst_node(EquivalenceMember, lc); if (cur_em->em_is_const) continue; /* ignore consts here */ - /* - * We consider only original EC members here, not - * already-transformed child members. - */ - if (cur_em->em_is_child) - continue; /* ignore children here */ + /* Child members should not exist in ec_members */ + Assert(!cur_em->em_is_child); /* * We may ignore expressions that reference a single baserel, @@ -2916,9 +2974,15 @@ add_child_join_rel_equivalences(PlannerInfo *root, top_parent_relids); new_relids = bms_add_members(new_relids, child_relids); - (void) add_eq_member(cur_ec, child_expr, new_relids, - cur_em->em_jdomain, - cur_em, cur_em->em_datatype); + add_child_eq_member(root, + cur_ec, + -1, + child_expr, + new_relids, + cur_em->em_jdomain, + cur_em, + cur_em->em_datatype, + child_joinrel->relids); } } } @@ -2965,14 +3029,18 @@ add_setop_child_rel_equivalences(PlannerInfo *root, RelOptInfo *child_rel, * We can safely pass the parent member as the first member in the * ec_members list as this is added first in generate_union_paths, * likewise, the JoinDomain can be that of the initial member of the - * Pathkey's EquivalenceClass. + * Pathkey's EquivalenceClass. We pass -1 for ec_index since we + * maintain the eclass_indexes for the child_rel after the loop. */ - add_eq_member(pk->pk_eclass, - tle->expr, - child_rel->relids, - parent_em->em_jdomain, - parent_em, - exprType((Node *) tle->expr)); + add_child_eq_member(root, + pk->pk_eclass, + -1, + tle->expr, + child_rel->relids, + parent_em->em_jdomain, + parent_em, + exprType((Node *) tle->expr), + child_rel->relids); lc2 = lnext(setop_pathkeys, lc2); } @@ -2987,6 +3055,103 @@ add_setop_child_rel_equivalences(PlannerInfo *root, RelOptInfo *child_rel, list_length(root->eq_classes) - 1); } +/* + * setup_eclass_member_iterator + * Setup an EquivalenceMemberIterator 'it' to iterate over all parent + * EquivalenceMembers and child members associated with the given 'ec' that + * are relevant to the specified 'relids'. + * + * This iterator returns: + * - All parent members stored directly in ec->ec_members. + * - The child members whose em_relids is a subset of the given 'relids'. + * + * Note: + * - The iterator may return false positives, i.e., child members whose + * em_relids is not a subset. So the caller must check that they satisfy + * the desired condition. + * - Once used, the caller should dispose of the iterator by calling + * dispose_eclass_member_iterator(). + * - The given 'relids' must remain allocated and not be changed for the + * lifetime of the iterator. + * + * Parameters: + * root - The PlannerInfo context. + * it - A pointer to the iterator to set up. + * ec - The EquivalenceClass from which to iterate members. + * relids - The Relids used to filter for relevant child members. + */ +void +setup_eclass_member_iterator(PlannerInfo *root, EquivalenceMemberIterator *it, + EquivalenceClass *ec, Relids relids) +{ + it->root = root; + it->ec = ec; + it->relids = ec->ec_childmembers ? relids : NULL; + it->current_relid = -1; + it->current_list = ec->ec_members; + it->current_cell = list_head(it->current_list); +} + +/* + * eclass_member_iterator_next + * Get a next EquivalenceMember from an EquivalenceMemberIterator 'it' + * that was setup by setup_eclass_member_iterator(). NULL is + * returned if there are no members left, in which case callers must not + * call eclass_member_iterator_next() again for the given iterator. + */ +EquivalenceMember * +eclass_member_iterator_next(EquivalenceMemberIterator *it) +{ + EquivalenceMember *em = NULL; + + while (it->current_list != NULL) + { +nextcell: + while (it->current_cell != NULL) + { + em = lfirst_node(EquivalenceMember, it->current_cell); + it->current_cell = lnext(it->current_list, it->current_cell); + goto end; + } + + /* Search for the next list to return members from */ + while ((it->current_relid = bms_next_member(it->relids, it->current_relid)) > 0) + { + it->current_list = it->ec->ec_childmembers[it->current_relid]; + + /* + * If there are members in this list, use it, this will exclude + * RELOPT_BASERELs as ec_childmembers[] are not populated for + * those. + */ + if (it->current_list != NIL) + { + /* point current_cell to the head of this list */ + it->current_cell = list_head(it->current_list); + goto nextcell; + } + } + + /* + * XXX because we don't NULLify current_list here, the iterator is not + * safe to call again after it returns NULL. Is that worth doing? + */ + goto end; + } + +end: + return em; +} + +/* + * dispose_eclass_member_iterator + * Free any memory allocated by the iterator. + */ +void +dispose_eclass_member_iterator(EquivalenceMemberIterator *it) +{ +} + /* * generate_implied_equalities_for_column @@ -3041,6 +3206,7 @@ generate_implied_equalities_for_column(PlannerInfo *root, EquivalenceClass *cur_ec = (EquivalenceClass *) list_nth(root->eq_classes, i); EquivalenceMember *cur_em; ListCell *lc2; + EquivalenceMemberIterator it; /* Sanity check eclass_indexes only contain ECs for rel */ Assert(is_child_rel || bms_is_subset(rel->relids, cur_ec->ec_relids)); @@ -3062,15 +3228,14 @@ generate_implied_equalities_for_column(PlannerInfo *root, * corner cases, so for now we live with just reporting the first * match. See also get_eclass_for_sort_expr.) */ - cur_em = NULL; - foreach(lc2, cur_ec->ec_members) + setup_eclass_member_iterator(root, &it, cur_ec, rel->relids); + while ((cur_em = eclass_member_iterator_next(&it)) != NULL) { - cur_em = (EquivalenceMember *) lfirst(lc2); if (bms_equal(cur_em->em_relids, rel->relids) && callback(root, rel, cur_ec, cur_em, callback_arg)) break; - cur_em = NULL; } + dispose_eclass_member_iterator(&it); if (!cur_em) continue; @@ -3085,8 +3250,8 @@ generate_implied_equalities_for_column(PlannerInfo *root, Oid eq_op; RestrictInfo *rinfo; - if (other_em->em_is_child) - continue; /* ignore children here */ + /* Child members should not exist in ec_members */ + Assert(!other_em->em_is_child); /* Make sure it'll be a join to a different rel */ if (other_em == cur_em || @@ -3304,8 +3469,8 @@ eclass_useful_for_merging(PlannerInfo *root, { EquivalenceMember *cur_em = (EquivalenceMember *) lfirst(lc); - if (cur_em->em_is_child) - continue; /* ignore children here */ + /* Child members should not exist in ec_members */ + Assert(!cur_em->em_is_child); if (!bms_overlap(cur_em->em_relids, relids)) return true; diff --git a/src/backend/optimizer/path/indxpath.c b/src/backend/optimizer/path/indxpath.c index 6386ce82253..275695b07c0 100644 --- a/src/backend/optimizer/path/indxpath.c +++ b/src/backend/optimizer/path/indxpath.c @@ -190,7 +190,7 @@ static IndexClause *expand_indexqual_rowcompare(PlannerInfo *root, IndexOptInfo *index, Oid expr_op, bool var_on_left); -static void match_pathkeys_to_index(IndexOptInfo *index, List *pathkeys, +static void match_pathkeys_to_index(PlannerInfo *root, IndexOptInfo *index, List *pathkeys, List **orderby_clauses_p, List **clause_columns_p); static Expr *match_clause_to_ordering_op(IndexOptInfo *index, @@ -934,7 +934,7 @@ build_index_paths(PlannerInfo *root, RelOptInfo *rel, * query_pathkeys will allow an incremental sort to be considered on * the index's partially sorted results. */ - match_pathkeys_to_index(index, root->query_pathkeys, + match_pathkeys_to_index(root, index, root->query_pathkeys, &orderbyclauses, &orderbyclausecols); if (list_length(root->query_pathkeys) == list_length(orderbyclauses)) @@ -3796,7 +3796,7 @@ expand_indexqual_rowcompare(PlannerInfo *root, * item in the given 'pathkeys' list. */ static void -match_pathkeys_to_index(IndexOptInfo *index, List *pathkeys, +match_pathkeys_to_index(PlannerInfo *root, IndexOptInfo *index, List *pathkeys, List **orderby_clauses_p, List **clause_columns_p) { @@ -3813,7 +3813,8 @@ match_pathkeys_to_index(IndexOptInfo *index, List *pathkeys, { PathKey *pathkey = (PathKey *) lfirst(lc1); bool found = false; - ListCell *lc2; + EquivalenceMemberIterator it; + EquivalenceMember *member; /* Pathkey must request default sort order for the target opfamily */ @@ -3833,9 +3834,10 @@ match_pathkeys_to_index(IndexOptInfo *index, List *pathkeys, * be considered to match more than one pathkey list, which is OK * here. See also get_eclass_for_sort_expr.) */ - foreach(lc2, pathkey->pk_eclass->ec_members) + setup_eclass_member_iterator(root, &it, pathkey->pk_eclass, + index->rel->relids); + while ((member = eclass_member_iterator_next(&it)) != NULL) { - EquivalenceMember *member = (EquivalenceMember *) lfirst(lc2); int indexcol; /* No possibility of match if it references other relations */ @@ -3870,6 +3872,7 @@ match_pathkeys_to_index(IndexOptInfo *index, List *pathkeys, if (found) /* don't want to look at remaining members */ break; } + dispose_eclass_member_iterator(&it); /* * Return the matches found so far when this pathkey couldn't be diff --git a/src/backend/optimizer/path/pathkeys.c b/src/backend/optimizer/path/pathkeys.c index 154eb505d75..a9419d37e2f 100644 --- a/src/backend/optimizer/path/pathkeys.c +++ b/src/backend/optimizer/path/pathkeys.c @@ -1151,8 +1151,8 @@ convert_subquery_pathkeys(PlannerInfo *root, RelOptInfo *rel, Oid sub_expr_coll = sub_eclass->ec_collation; ListCell *k; - if (sub_member->em_is_child) - continue; /* ignore children here */ + /* Child members should not exist in ec_members */ + Assert(!sub_member->em_is_child); foreach(k, subquery_tlist) { @@ -1709,8 +1709,11 @@ select_outer_pathkeys_for_merge(PlannerInfo *root, { EquivalenceMember *em = (EquivalenceMember *) lfirst(lc2); + /* Child members should not exist in ec_members */ + Assert(!em->em_is_child); + /* Potential future join partner? */ - if (!em->em_is_const && !em->em_is_child && + if (!em->em_is_const && !bms_overlap(em->em_relids, joinrel->relids)) score++; } diff --git a/src/include/nodes/pathnodes.h b/src/include/nodes/pathnodes.h index ac3af528bc6..34b2510741b 100644 --- a/src/include/nodes/pathnodes.h +++ b/src/include/nodes/pathnodes.h @@ -1402,6 +1402,12 @@ typedef struct JoinDomain * entry: consider SELECT random() AS a, random() AS b ... ORDER BY b,a. * So we record the SortGroupRef of the originating sort clause. * + * 'ec_members' is a List of all EquivalenceMembers belonging to + * RELOPT_BASERELs. EquivalenceMembers for any RELOPT_OTHER_MEMBER_REL and + * RELOPT_OTHER_JOINREL relations are stored in the 'ec_childmembers' array in + * the index corresponding to the relid. 'ec_childmembers' may be NULL if the + * class has no child EquivalenceMembers. + * * NB: if ec_merged isn't NULL, this class has been merged into another, and * should be ignored in favor of using the pointed-to class. * @@ -1420,6 +1426,8 @@ typedef struct EquivalenceClass List *ec_opfamilies; /* btree operator family OIDs */ Oid ec_collation; /* collation, if datatypes are collatable */ List *ec_members; /* list of EquivalenceMembers */ + List **ec_childmembers; /* array of Lists of child + * EquivalenceMembers */ List *ec_sources; /* list of generating RestrictInfos */ List *ec_derives; /* list of derived RestrictInfos */ Relids ec_relids; /* all relids appearing in ec_members, except @@ -1478,6 +1486,49 @@ typedef struct EquivalenceMember struct EquivalenceMember *em_parent pg_node_attr(read_write_ignore); } EquivalenceMember; +/* + * EquivalenceMemberIterator + * + * EquivalenceMemberIterator is designed to iterate over all parent + * EquivalenceMembers and child members associated with the given 'ec' that + * are relevant to the specified 'relids'. In particular, it iterates over: + * - All parent members stored directly in ec->ec_members. + * - The child members whose em_relids is a subset of the given 'relids'. + * + * Note: + * - The iterator may return false positives, i.e., child members whose + * em_relids is not a subset. So the caller must check that they satisfy + * the desired condition. + * + * The most common way to use this iterator is as follows: + * ----- + * PlannerInfo *root = given; + * EquivalenceMemberIterator it; + * EquivalenceClass *ec = given; + * Relids relids = given; + * EquivalenceMember *em; + * + * setup_eclass_member_iterator(root, &it, ec, relids); + * while ((em = eclass_member_iterator_next(&it)) != NULL) + * { + * use em ...; + * } + * dispose_eclass_member_iterator(&it); + * ----- + */ +typedef struct +{ + PlannerInfo *root; /* The PlannerInfo where 'ec' belongs */ + EquivalenceClass *ec; /* The EquivalenceClass to iterate over */ + int current_relid; /* Current relid position within 'relids'. -1 + * when still looping over ec_members and -2 + * at the end of iteration */ + Relids relids; /* Relids of child relations of interest. + * Non-child rels are ignored */ + ListCell *current_cell; /* Next cell to return within current_list */ + List *current_list; /* Current list of members being returned */ +} EquivalenceMemberIterator; + /* * PathKeys * diff --git a/src/include/optimizer/paths.h b/src/include/optimizer/paths.h index 84a000a3ef1..82e51fef742 100644 --- a/src/include/optimizer/paths.h +++ b/src/include/optimizer/paths.h @@ -183,6 +183,12 @@ extern void add_setop_child_rel_equivalences(PlannerInfo *root, RelOptInfo *child_rel, List *child_tlist, List *setop_pathkeys); +extern void setup_eclass_member_iterator(PlannerInfo *root, + EquivalenceMemberIterator *it, + EquivalenceClass *ec, + Relids relids); +extern EquivalenceMember *eclass_member_iterator_next(EquivalenceMemberIterator *it); +extern void dispose_eclass_member_iterator(EquivalenceMemberIterator *it); extern List *generate_implied_equalities_for_column(PlannerInfo *root, RelOptInfo *rel, ec_matches_callback_type callback, diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 8f28d8ff28e..ba964a0d17d 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -709,6 +709,7 @@ EphemeralNamedRelationMetadata EphemeralNamedRelationMetadataData EquivalenceClass EquivalenceMember +EquivalenceMemberIterator ErrorContextCallback ErrorData ErrorSaveContext -- 2.43.0