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| author | Noah Misch <noah@leadboat.com> | 2024-09-24 15:25:18 -0700 |
|---|---|---|
| committer | Noah Misch <noah@leadboat.com> | 2024-09-24 15:25:22 -0700 |
| commit | 3b7a689e1a805c4dac2f35ff14fd5c9fdbddf150 (patch) | |
| tree | bd10c0861a06a7fd4109ef1fa1e27aab2704be54 /src/backend/executor/execMain.c | |
| parent | fd27b878c2ea54b6132758084270cb13e5e66f2e (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/execMain.c')
| -rw-r--r-- | src/backend/executor/execMain.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/src/backend/executor/execMain.c b/src/backend/executor/execMain.c index 2365c6861be..f8113d116d0 100644 --- a/src/backend/executor/execMain.c +++ b/src/backend/executor/execMain.c @@ -1031,6 +1031,10 @@ CheckValidResultRel(ResultRelInfo *resultRelInfo, CmdType operation, Relation resultRel = resultRelInfo->ri_RelationDesc; FdwRoutine *fdwroutine; + /* Expect a fully-formed ResultRelInfo from InitResultRelInfo(). */ + Assert(resultRelInfo->ri_needLockTagTuple == + IsInplaceUpdateRelation(resultRel)); + switch (resultRel->rd_rel->relkind) { case RELKIND_RELATION: @@ -1211,6 +1215,8 @@ InitResultRelInfo(ResultRelInfo *resultRelInfo, resultRelInfo->ri_NumIndices = 0; resultRelInfo->ri_IndexRelationDescs = NULL; resultRelInfo->ri_IndexRelationInfo = NULL; + resultRelInfo->ri_needLockTagTuple = + IsInplaceUpdateRelation(resultRelationDesc); /* make a copy so as not to depend on relcache info not changing... */ resultRelInfo->ri_TrigDesc = CopyTriggerDesc(resultRelationDesc->trigdesc); if (resultRelInfo->ri_TrigDesc) |