From b9243cadad55e296e83839fb96457f64dcaaeb25 Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Fri, 5 Aug 2022 15:57:46 -0400 Subject: [PATCH] Partially undo commit 94da73281. On closer inspection, mcv.c isn't as broken for ScalarArrayOpExpr as I thought. The Var-on-right issue is real enough, but actually it does cope fine with a NULL array constant --- I was misled by an XXX comment suggesting it didn't. Undo that part of the code change, and replace the XXX comment with something less misleading. --- src/backend/statistics/extended_stats.c | 7 +++---- src/backend/statistics/mcv.c | 25 ++++++++++++++++--------- 2 files changed, 19 insertions(+), 13 deletions(-) diff --git a/src/backend/statistics/extended_stats.c b/src/backend/statistics/extended_stats.c index 21604f9e9c..d28c9d9b81 100644 --- a/src/backend/statistics/extended_stats.c +++ b/src/backend/statistics/extended_stats.c @@ -1452,7 +1452,6 @@ statext_is_compatible_clause_internal(PlannerInfo *root, Node *clause, RangeTblEntry *rte = root->simple_rte_array[relid]; ScalarArrayOpExpr *expr = (ScalarArrayOpExpr *) clause; Node *clause_expr; - Const *cst; bool expronleft; /* Only expressions with two arguments are considered compatible. */ @@ -1460,11 +1459,11 @@ statext_is_compatible_clause_internal(PlannerInfo *root, Node *clause, return false; /* Check if the expression has the right shape (one Var, one Const) */ - if (!examine_opclause_args(expr->args, &clause_expr, &cst, &expronleft)) + if (!examine_opclause_args(expr->args, &clause_expr, NULL, &expronleft)) return false; - /* We only support Var on left and non-null array constants */ - if (!expronleft || cst->constisnull) + /* We only support Var on left, Const on right */ + if (!expronleft) return false; /* diff --git a/src/backend/statistics/mcv.c b/src/backend/statistics/mcv.c index 50c65c3fde..0183775853 100644 --- a/src/backend/statistics/mcv.c +++ b/src/backend/statistics/mcv.c @@ -1740,17 +1740,24 @@ mcv_get_match_bitmap(PlannerInfo *root, List *clauses, if (!examine_opclause_args(expr->args, &clause_expr, &cst, &expronleft)) elog(ERROR, "incompatible clause"); - /* We expect Var on left and non-null constant on right */ - if (!expronleft || cst->constisnull) + /* We expect Var on left */ + if (!expronleft) elog(ERROR, "incompatible clause"); - arrayval = DatumGetArrayTypeP(cst->constvalue); - get_typlenbyvalalign(ARR_ELEMTYPE(arrayval), - &elmlen, &elmbyval, &elmalign); - deconstruct_array(arrayval, - ARR_ELEMTYPE(arrayval), - elmlen, elmbyval, elmalign, - &elem_values, &elem_nulls, &num_elems); + /* + * Deconstruct the array constant, unless it's NULL (we'll cover + * that case below) + */ + if (!cst->constisnull) + { + arrayval = DatumGetArrayTypeP(cst->constvalue); + get_typlenbyvalalign(ARR_ELEMTYPE(arrayval), + &elmlen, &elmbyval, &elmalign); + deconstruct_array(arrayval, + ARR_ELEMTYPE(arrayval), + elmlen, elmbyval, elmalign, + &elem_values, &elem_nulls, &num_elems); + } /* match the attribute/expression to a dimension of the statistic */ idx = mcv_match_expression(clause_expr, keys, exprs, &collid);