From b6d147bcbbf29b7f422f7185192eb57593f3cfc7 Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Fri, 5 Aug 2022 13:58:37 -0400 Subject: [PATCH] Fix non-bulletproof ScalarArrayOpExpr code for extended statistics. statext_is_compatible_clause_internal() checked that the arguments of a ScalarArrayOpExpr are one Var and one Const, but it would allow cases where the Const was on the left. Subsequent uses of the clause are not expecting that and would suffer assertion failures or core dumps. mcv.c also had not bothered to cope with the case of a NULL array constant, which seems really unacceptably sloppy of somebody. (Although our tools failed us there too, since AFAIK neither Coverity nor any compiler warned of the obvious use-of-uninitialized-variable condition.) It seems best to handle that by having statext_is_compatible_clause_internal() reject it. Noted while fixing bug #17570. Back-patch to v13 where the extended stats code grew some awareness of ScalarArrayOpExpr. --- src/backend/statistics/extended_stats.c | 12 +++++++++--- src/backend/statistics/mcv.c | 23 ++++++++++------------- src/test/regress/expected/stats_ext.out | 22 ++++++++++++++++++---- src/test/regress/sql/stats_ext.sql | 14 ++++++++++---- 4 files changed, 47 insertions(+), 24 deletions(-) diff --git a/src/backend/statistics/extended_stats.c b/src/backend/statistics/extended_stats.c index 348ade809f0..fcdb82e2c37 100644 --- a/src/backend/statistics/extended_stats.c +++ b/src/backend/statistics/extended_stats.c @@ -1331,8 +1331,8 @@ choose_best_statistics(List *stats, char requiredkind, bool inh, * * (c) combinations using AND/OR/NOT * - * (d) ScalarArrayOpExprs of the form (Var/Expr op ANY (array)) or (Var/Expr - * op ALL (array)) + * (d) ScalarArrayOpExprs of the form (Var/Expr op ANY (Const)) or + * (Var/Expr op ALL (Const)) * * In the future, the range of supported clauses may be expanded to more * complex cases, for example (Var op Var). @@ -1452,13 +1452,19 @@ 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. */ if (list_length(expr->args) != 2) return false; /* Check if the expression has the right shape (one Var, one Const) */ - if (!examine_opclause_args(expr->args, &clause_expr, NULL, NULL)) + if (!examine_opclause_args(expr->args, &clause_expr, &cst, &expronleft)) + return false; + + /* We only support Var on left and non-null array constants */ + if (!expronleft || cst->constisnull) return false; /* diff --git a/src/backend/statistics/mcv.c b/src/backend/statistics/mcv.c index f10642df4f7..35bb21c43ea 100644 --- a/src/backend/statistics/mcv.c +++ b/src/backend/statistics/mcv.c @@ -1746,20 +1746,17 @@ mcv_get_match_bitmap(PlannerInfo *root, List *clauses, if (!examine_opclause_args(expr->args, &clause_expr, &cst, &expronleft)) elog(ERROR, "incompatible clause"); - /* ScalarArrayOpExpr has the Var always on the left */ - Assert(expronleft); + /* We expect Var on left and non-null constant on right */ + if (!expronleft || cst->constisnull) + elog(ERROR, "incompatible clause"); - /* XXX what if (cst->constisnull == NULL)? */ - 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); - } + 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); diff --git a/src/test/regress/expected/stats_ext.out b/src/test/regress/expected/stats_ext.out index 4f27c78e33d..fbd872524a6 100644 --- a/src/test/regress/expected/stats_ext.out +++ b/src/test/regress/expected/stats_ext.out @@ -1837,7 +1837,8 @@ CREATE TABLE mcv_lists ( b VARCHAR, filler3 DATE, c INT, - d TEXT + d TEXT, + ia INT[] ) WITH (autovacuum_enabled = off); -- random data (no MCV list) @@ -1907,8 +1908,9 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,7) = 1 A -- 100 distinct combinations, all in the MCV list TRUNCATE mcv_lists; DROP STATISTICS mcv_lists_stats; -INSERT INTO mcv_lists (a, b, c, filler1) - SELECT mod(i,100), mod(i,50), mod(i,25), i FROM generate_series(1,5000) s(i); +INSERT INTO mcv_lists (a, b, c, ia, filler1) + SELECT mod(i,100), mod(i,50), mod(i,25), array[mod(i,25)], i + FROM generate_series(1,5000) s(i); ANALYZE mcv_lists; SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 AND b = ''1'''); estimated | actual @@ -2048,8 +2050,14 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a < ALL (ARRAY 1 | 100 (1 row) +SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = ANY (ARRAY[4,5]) AND 4 = ANY(ia)'); + estimated | actual +-----------+-------- + 4 | 50 +(1 row) + -- create statistics -CREATE STATISTICS mcv_lists_stats (mcv) ON a, b, c FROM mcv_lists; +CREATE STATISTICS mcv_lists_stats (mcv) ON a, b, c, ia FROM mcv_lists; ANALYZE mcv_lists; SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 AND b = ''1'''); estimated | actual @@ -2195,6 +2203,12 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a < ALL (ARRAY 100 | 100 (1 row) +SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = ANY (ARRAY[4,5]) AND 4 = ANY(ia)'); + estimated | actual +-----------+-------- + 4 | 50 +(1 row) + -- check change of unrelated column type does not reset the MCV statistics ALTER TABLE mcv_lists ALTER COLUMN d TYPE VARCHAR(64); SELECT d.stxdmcv IS NOT NULL diff --git a/src/test/regress/sql/stats_ext.sql b/src/test/regress/sql/stats_ext.sql index 2be4ca89dc9..4394ede8c8b 100644 --- a/src/test/regress/sql/stats_ext.sql +++ b/src/test/regress/sql/stats_ext.sql @@ -909,7 +909,8 @@ CREATE TABLE mcv_lists ( b VARCHAR, filler3 DATE, c INT, - d TEXT + d TEXT, + ia INT[] ) WITH (autovacuum_enabled = off); @@ -958,8 +959,9 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,7) = 1 A TRUNCATE mcv_lists; DROP STATISTICS mcv_lists_stats; -INSERT INTO mcv_lists (a, b, c, filler1) - SELECT mod(i,100), mod(i,50), mod(i,25), i FROM generate_series(1,5000) s(i); +INSERT INTO mcv_lists (a, b, c, ia, filler1) + SELECT mod(i,100), mod(i,50), mod(i,25), array[mod(i,25)], i + FROM generate_series(1,5000) s(i); ANALYZE mcv_lists; @@ -1009,8 +1011,10 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a < ALL (ARRAY SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a < ALL (ARRAY[4, 5]) AND b IN (''1'', ''2'', NULL, ''3'') AND c > ANY (ARRAY[1, 2, NULL, 3])'); +SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = ANY (ARRAY[4,5]) AND 4 = ANY(ia)'); + -- create statistics -CREATE STATISTICS mcv_lists_stats (mcv) ON a, b, c FROM mcv_lists; +CREATE STATISTICS mcv_lists_stats (mcv) ON a, b, c, ia FROM mcv_lists; ANALYZE mcv_lists; @@ -1062,6 +1066,8 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a < ALL (ARRAY SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a < ALL (ARRAY[4, 5]) AND b IN (''1'', ''2'', NULL, ''3'') AND c > ANY (ARRAY[1, 2, NULL, 3])'); +SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = ANY (ARRAY[4,5]) AND 4 = ANY(ia)'); + -- check change of unrelated column type does not reset the MCV statistics ALTER TABLE mcv_lists ALTER COLUMN d TYPE VARCHAR(64);