diff options
Diffstat (limited to 'src/backend/optimizer/path')
| -rw-r--r-- | src/backend/optimizer/path/equivclass.c | 19 | ||||
| -rw-r--r-- | src/backend/optimizer/path/pathkeys.c | 32 |
2 files changed, 45 insertions, 6 deletions
diff --git a/src/backend/optimizer/path/equivclass.c b/src/backend/optimizer/path/equivclass.c index 711b161c0d1..baddd34a741 100644 --- a/src/backend/optimizer/path/equivclass.c +++ b/src/backend/optimizer/path/equivclass.c @@ -510,6 +510,13 @@ add_eq_member(EquivalenceClass *ec, Expr *expr, Relids relids, * equivalence class it is a member of; if none, optionally build a new * single-member EquivalenceClass for it. * + * expr is the expression, and nullable_relids is the set of base relids + * that are potentially nullable below it. We actually only care about + * the set of such relids that are used in the expression; but for caller + * convenience, we perform that intersection step here. The caller need + * only be sure that nullable_relids doesn't omit any nullable rels that + * might appear in the expr. + * * sortref is the SortGroupRef of the originating SortGroupClause, if any, * or zero if not. (It should never be zero if the expression is volatile!) * @@ -538,6 +545,7 @@ add_eq_member(EquivalenceClass *ec, Expr *expr, Relids relids, EquivalenceClass * get_eclass_for_sort_expr(PlannerInfo *root, Expr *expr, + Relids nullable_relids, List *opfamilies, Oid opcintype, Oid collation, @@ -545,6 +553,7 @@ get_eclass_for_sort_expr(PlannerInfo *root, Relids rel, bool create_it) { + Relids expr_relids; EquivalenceClass *newec; EquivalenceMember *newem; ListCell *lc1; @@ -556,6 +565,12 @@ get_eclass_for_sort_expr(PlannerInfo *root, expr = canonicalize_ec_expression(expr, opcintype, collation); /* + * Get the precise set of nullable relids appearing in the expression. + */ + expr_relids = pull_varnos((Node *) expr); + nullable_relids = bms_intersect(nullable_relids, expr_relids); + + /* * Scan through the existing EquivalenceClasses for a match */ foreach(lc1, root->eq_classes) @@ -629,8 +644,8 @@ get_eclass_for_sort_expr(PlannerInfo *root, if (newec->ec_has_volatile && sortref == 0) /* should not happen */ elog(ERROR, "volatile EquivalenceClass has no sortref"); - newem = add_eq_member(newec, copyObject(expr), pull_varnos((Node *) expr), - NULL, false, opcintype); + newem = add_eq_member(newec, copyObject(expr), expr_relids, + nullable_relids, false, opcintype); /* * add_eq_member doesn't check for volatile functions, set-returning diff --git a/src/backend/optimizer/path/pathkeys.c b/src/backend/optimizer/path/pathkeys.c index 67249969195..032b2cdc133 100644 --- a/src/backend/optimizer/path/pathkeys.c +++ b/src/backend/optimizer/path/pathkeys.c @@ -154,6 +154,9 @@ pathkey_is_redundant(PathKey *new_pathkey, List *pathkeys) * Given an expression and sort-order information, create a PathKey. * The result is always a "canonical" PathKey, but it might be redundant. * + * expr is the expression, and nullable_relids is the set of base relids + * that are potentially nullable below it. + * * If the PathKey is being generated from a SortGroupClause, sortref should be * the SortGroupClause's SortGroupRef; otherwise zero. * @@ -169,6 +172,7 @@ pathkey_is_redundant(PathKey *new_pathkey, List *pathkeys) static PathKey * make_pathkey_from_sortinfo(PlannerInfo *root, Expr *expr, + Relids nullable_relids, Oid opfamily, Oid opcintype, Oid collation, @@ -204,8 +208,8 @@ make_pathkey_from_sortinfo(PlannerInfo *root, equality_op); /* Now find or (optionally) create a matching EquivalenceClass */ - eclass = get_eclass_for_sort_expr(root, expr, opfamilies, - opcintype, collation, + eclass = get_eclass_for_sort_expr(root, expr, nullable_relids, + opfamilies, opcintype, collation, sortref, rel, create_it); /* Fail if no EC and !create_it */ @@ -227,6 +231,7 @@ make_pathkey_from_sortinfo(PlannerInfo *root, static PathKey * make_pathkey_from_sortop(PlannerInfo *root, Expr *expr, + Relids nullable_relids, Oid ordering_op, bool nulls_first, Index sortref, @@ -248,6 +253,7 @@ make_pathkey_from_sortop(PlannerInfo *root, return make_pathkey_from_sortinfo(root, expr, + nullable_relids, opfamily, opcintype, collation, @@ -461,9 +467,13 @@ build_index_pathkeys(PlannerInfo *root, nulls_first = index->nulls_first[i]; } - /* OK, try to make a canonical pathkey for this sort key */ + /* + * OK, try to make a canonical pathkey for this sort key. Note we're + * underneath any outer joins, so nullable_relids should be NULL. + */ cpathkey = make_pathkey_from_sortinfo(root, indexkey, + NULL, index->sortopfamily[i], index->opcintype[i], index->indexcollations[i], @@ -551,11 +561,14 @@ convert_subquery_pathkeys(PlannerInfo *root, RelOptInfo *rel, * expression is *not* volatile in the outer query: it's just * a Var referencing whatever the subquery emitted. (IOW, the * outer query isn't going to re-execute the volatile - * expression itself.) So this is okay. + * expression itself.) So this is okay. Likewise, it's + * correct to pass nullable_relids = NULL, because we're + * underneath any outer joins appearing in the outer query. */ outer_ec = get_eclass_for_sort_expr(root, outer_expr, + NULL, sub_eclass->ec_opfamilies, sub_member->em_datatype, sub_eclass->ec_collation, @@ -643,6 +656,7 @@ convert_subquery_pathkeys(PlannerInfo *root, RelOptInfo *rel, /* See if we have a matching EC for that */ outer_ec = get_eclass_for_sort_expr(root, outer_expr, + NULL, sub_eclass->ec_opfamilies, sub_expr_type, sub_expr_coll, @@ -748,6 +762,13 @@ build_join_pathkeys(PlannerInfo *root, * The resulting PathKeys are always in canonical form. (Actually, there * is no longer any code anywhere that creates non-canonical PathKeys.) * + * We assume that root->nullable_baserels is the set of base relids that could + * have gone to NULL below the SortGroupClause expressions. This is okay if + * the expressions came from the query's top level (ORDER BY, DISTINCT, etc) + * and if this function is only invoked after deconstruct_jointree. In the + * future we might have to make callers pass in the appropriate + * nullable-relids set, but for now it seems unnecessary. + * * 'sortclauses' is a list of SortGroupClause nodes * 'tlist' is the targetlist to find the referenced tlist entries in */ @@ -769,6 +790,7 @@ make_pathkeys_for_sortclauses(PlannerInfo *root, Assert(OidIsValid(sortcl->sortop)); pathkey = make_pathkey_from_sortop(root, sortkey, + root->nullable_baserels, sortcl->sortop, sortcl->nulls_first, sortcl->tleSortGroupRef, @@ -824,6 +846,7 @@ initialize_mergeclause_eclasses(PlannerInfo *root, RestrictInfo *restrictinfo) restrictinfo->left_ec = get_eclass_for_sort_expr(root, (Expr *) get_leftop(clause), + restrictinfo->nullable_relids, restrictinfo->mergeopfamilies, lefttype, ((OpExpr *) clause)->inputcollid, @@ -833,6 +856,7 @@ initialize_mergeclause_eclasses(PlannerInfo *root, RestrictInfo *restrictinfo) restrictinfo->right_ec = get_eclass_for_sort_expr(root, (Expr *) get_rightop(clause), + restrictinfo->nullable_relids, restrictinfo->mergeopfamilies, righttype, ((OpExpr *) clause)->inputcollid, |