diff options
Diffstat (limited to 'src/backend/optimizer/path/equivclass.c')
| -rw-r--r-- | src/backend/optimizer/path/equivclass.c | 19 |
1 files changed, 17 insertions, 2 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 |