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authorNoah Misch <noah@leadboat.com>2024-09-24 15:25:18 -0700
committerNoah Misch <noah@leadboat.com>2024-09-24 15:25:22 -0700
commit3b7a689e1a805c4dac2f35ff14fd5c9fdbddf150 (patch)
treebd10c0861a06a7fd4109ef1fa1e27aab2704be54 /src/backend/executor/execReplication.c
parentfd27b878c2ea54b6132758084270cb13e5e66f2e (diff)
For inplace update durability, make heap_update() callers wait.
The previous commit fixed some ways of losing an inplace update. It remained possible to lose one when a backend working toward a heap_update() copied a tuple into memory just before inplace update of that tuple. In catalogs eligible for inplace update, use LOCKTAG_TUPLE to govern admission to the steps of copying an old tuple, modifying it, and issuing heap_update(). This includes MERGE commands. To avoid changing most of the pg_class DDL, don't require LOCKTAG_TUPLE when holding a relation lock sufficient to exclude inplace updaters. Back-patch to v12 (all supported versions). In v13 and v12, "UPDATE pg_class" or "UPDATE pg_database" can still lose an inplace update. The v14+ UPDATE fix needs commit 86dc90056dfdbd9d1b891718d2e5614e3e432f35, and it wasn't worth reimplementing that fix without such infrastructure. Reviewed by Nitin Motiani and (in earlier versions) Heikki Linnakangas. Discussion: https://postgr.es/m/20231027214946.79.nmisch@google.com
Diffstat (limited to 'src/backend/executor/execReplication.c')
-rw-r--r--src/backend/executor/execReplication.c6
1 files changed, 5 insertions, 1 deletions
diff --git a/src/backend/executor/execReplication.c b/src/backend/executor/execReplication.c
index d0a89cd5778..f18efdb6f26 100644
--- a/src/backend/executor/execReplication.c
+++ b/src/backend/executor/execReplication.c
@@ -559,8 +559,12 @@ ExecSimpleRelationUpdate(ResultRelInfo *resultRelInfo,
Relation rel = resultRelInfo->ri_RelationDesc;
ItemPointer tid = &(searchslot->tts_tid);
- /* For now we support only tables. */
+ /*
+ * We support only non-system tables, with
+ * check_publication_add_relation() accountable.
+ */
Assert(rel->rd_rel->relkind == RELKIND_RELATION);
+ Assert(!IsCatalogRelation(rel));
CheckCmdReplicaIdentity(rel, CMD_UPDATE);