From 7a50ea8527634a39ccb9abbf8f573883faccd353 Mon Sep 17 00:00:00 2001 From: Jim Jones Date: Wed, 25 Mar 2026 23:14:12 +0100 Subject: [PATCH v4 1/2] Skip other sessions' temp tables in REPACK, CLUSTER, and VACUUM FULL get_tables_to_repack() was including other sessions' temporary tables in the work list, causing REPACK and CLUSTER (without arguments) to attempt to acquire AccessExclusiveLock on them, potentially blocking for an extended time. Fix by skipping other-session temp tables early in get_tables_to_repack(), before they are added to the list. Because an AccessShareLock has already been acquired per relation at that point, release it before continuing. Similarly, get_all_vacuum_rels() suffered from the same problem for VACUUM FULL. Since no per-relation lock is held during list-building there, a plain skip suffices. Author: Jim Jones Reviewed-by: Chao Li Reviewed-by: Zsolt Parragi --- src/backend/commands/cluster.c | 25 ++++++++++++++++++++++++- src/backend/commands/vacuum.c | 5 +++++ 2 files changed, 29 insertions(+), 1 deletion(-) diff --git a/src/backend/commands/cluster.c b/src/backend/commands/cluster.c index f241e18b153..ffbc5ed6f85 100644 --- a/src/backend/commands/cluster.c +++ b/src/backend/commands/cluster.c @@ -1679,6 +1679,8 @@ get_tables_to_repack(RepackCommand cmd, bool usingindex, MemoryContext permcxt) { RelToCluster *rtc; Form_pg_index index; + HeapTuple classtup; + Form_pg_class classForm; MemoryContext oldcxt; index = (Form_pg_index) GETSTRUCT(tuple); @@ -1693,11 +1695,24 @@ get_tables_to_repack(RepackCommand cmd, bool usingindex, MemoryContext permcxt) continue; /* Verify that the table still exists; skip if not */ - if (!SearchSysCacheExists1(RELOID, ObjectIdGetDatum(index->indrelid))) + classtup = SearchSysCache1(RELOID, ObjectIdGetDatum(index->indrelid)); + if (!HeapTupleIsValid(classtup)) { UnlockRelationOid(index->indrelid, AccessShareLock); continue; } + classForm = (Form_pg_class) GETSTRUCT(classtup); + + /* Skip temp relations belonging to other sessions */ + if (classForm->relpersistence == RELPERSISTENCE_TEMP && + !isTempOrTempToastNamespace(classForm->relnamespace)) + { + ReleaseSysCache(classtup); + UnlockRelationOid(index->indrelid, AccessShareLock); + continue; + } + + ReleaseSysCache(classtup); /* noisily skip rels which the user can't process */ if (!repack_is_permitted_for_relation(cmd, index->indrelid, @@ -1753,6 +1768,14 @@ get_tables_to_repack(RepackCommand cmd, bool usingindex, MemoryContext permcxt) continue; } + /* Skip temp relations belonging to other sessions */ + if (class->relpersistence == RELPERSISTENCE_TEMP && + !isTempOrTempToastNamespace(class->relnamespace)) + { + UnlockRelationOid(class->oid, AccessShareLock); + continue; + } + /* noisily skip rels which the user can't process */ if (!repack_is_permitted_for_relation(cmd, class->oid, GetUserId())) diff --git a/src/backend/commands/vacuum.c b/src/backend/commands/vacuum.c index 0ed363d1c85..913dfb4ea8d 100644 --- a/src/backend/commands/vacuum.c +++ b/src/backend/commands/vacuum.c @@ -1062,6 +1062,11 @@ get_all_vacuum_rels(MemoryContext vac_context, int options) classForm->relkind != RELKIND_PARTITIONED_TABLE) continue; + /* Skip temp relations belonging to other sessions */ + if (classForm->relpersistence == RELPERSISTENCE_TEMP && + !isTempOrTempToastNamespace(classForm->relnamespace)) + continue; + /* check permissions of relation */ if (!vacuum_is_permitted_for_relation(relid, classForm, options)) continue; -- 2.43.0