From 88b3a6cd262344f5de64eab31804a0f39a7c6337 Mon Sep 17 00:00:00 2001 From: Noah Misch Date: Sat, 21 Mar 2020 09:38:26 -0700 Subject: [PATCH] During heap rebuild, lock any TOAST index until end of transaction. swap_relation_files() calls toast_get_valid_index() to find and lock this index, just before swapping with the rebuilt TOAST index. The latter function releases the lock before returning. Potential for mischief is low; a concurrent session can issue ALTER INDEX ... SET (fillfactor = ...), which is not alarming. Nonetheless, changing pg_class.relfilenode without a lock is unconventional. Back-patch to 9.5 (all supported versions), because another fix needs this. Discussion: https://postgr.es/m/20191226001521.GA1772687@rfd.leadboat.com --- src/backend/access/heap/tuptoaster.c | 4 ++-- src/backend/commands/cluster.c | 2 +- 2 files changed, 3 insertions(+), 3 deletions(-) diff --git a/src/backend/access/heap/tuptoaster.c b/src/backend/access/heap/tuptoaster.c index 55d6e91d1c..3a9d2ff38e 100644 --- a/src/backend/access/heap/tuptoaster.c +++ b/src/backend/access/heap/tuptoaster.c @@ -1436,8 +1436,8 @@ toast_get_valid_index(Oid toastoid, LOCKMODE lock) validIndexOid = RelationGetRelid(toastidxs[validIndex]); /* Close the toast relation and all its indexes */ - toast_close_indexes(toastidxs, num_indexes, lock); - table_close(toastrel, lock); + toast_close_indexes(toastidxs, num_indexes, NoLock); + table_close(toastrel, NoLock); return validIndexOid; } diff --git a/src/backend/commands/cluster.c b/src/backend/commands/cluster.c index ebaec4f8dd..c7fda21634 100644 --- a/src/backend/commands/cluster.c +++ b/src/backend/commands/cluster.c @@ -1490,7 +1490,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap, /* Get the associated valid index to be renamed */ toastidx = toast_get_valid_index(newrel->rd_rel->reltoastrelid, - AccessShareLock); + NoLock); /* rename the toast table ... */ snprintf(NewToastName, NAMEDATALEN, "pg_toast_%u",