From 6d554e3fcd6fb8be2dbcbd3521e2947ed7a552cb Mon Sep 17 00:00:00 2001 From: Tomas Vondra Date: Sun, 23 Jan 2022 02:49:41 +0100 Subject: [PATCH] Check syscache result in AlterStatistics The syscache lookup may return NULL even for valid OID, for example due to a concurrent DROP STATISTICS, so a HeapTupleIsValid is necessary. Without it, it may fail with a segfault. Reported by Alexander Lakhin, patch by me. Backpatch to 13, where ALTER STATISTICS ... SET STATISTICS was introduced. Backpatch-through: 13 Discussion: https://postgr.es/m/17372-bf3b6e947e35ae77%40postgresql.org --- src/backend/commands/statscmds.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/src/backend/commands/statscmds.c b/src/backend/commands/statscmds.c index f7419b8f562..54a190722df 100644 --- a/src/backend/commands/statscmds.c +++ b/src/backend/commands/statscmds.c @@ -657,6 +657,8 @@ AlterStatistics(AlterStatsStmt *stmt) rel = table_open(StatisticExtRelationId, RowExclusiveLock); oldtup = SearchSysCache1(STATEXTOID, ObjectIdGetDatum(stxoid)); + if (!HeapTupleIsValid(oldtup)) + elog(ERROR, "cache lookup failed for extended statistics object %u", stxoid); /* Must be owner of the existing statistics object */ if (!pg_statistics_object_ownercheck(stxoid, GetUserId()))