diff options
| author | Noah Misch | 2024-09-24 22:25:18 +0000 |
|---|---|---|
| committer | Noah Misch | 2024-09-24 22:25:22 +0000 |
| commit | 3b7a689e1a805c4dac2f35ff14fd5c9fdbddf150 (patch) | |
| tree | bd10c0861a06a7fd4109ef1fa1e27aab2704be54 /src/include | |
| 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/include')
| -rw-r--r-- | src/include/nodes/execnodes.h | 3 | ||||
| -rw-r--r-- | src/include/storage/lockdefs.h | 2 | ||||
| -rw-r--r-- | src/include/utils/syscache.h | 5 |
3 files changed, 10 insertions, 0 deletions
diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h index cd1b16296b5..418c81f4be2 100644 --- a/src/include/nodes/execnodes.h +++ b/src/include/nodes/execnodes.h @@ -592,6 +592,9 @@ typedef struct ResultRelInfo * one of its ancestors; see ExecCrossPartitionUpdateForeignKey(). */ List *ri_ancestorResultRels; + + /* updates do LockTuple() before oldtup read; see README.tuplock */ + bool ri_needLockTagTuple; } ResultRelInfo; /* ---------------- diff --git a/src/include/storage/lockdefs.h b/src/include/storage/lockdefs.h index 934ba84f6a2..810b297edf9 100644 --- a/src/include/storage/lockdefs.h +++ b/src/include/storage/lockdefs.h @@ -47,6 +47,8 @@ typedef int LOCKMODE; #define MaxLockMode 8 /* highest standard lock mode */ +/* See README.tuplock section "Locking to write inplace-updated tables" */ +#define InplaceUpdateTupleLock ExclusiveLock /* WAL representation of an AccessExclusiveLock on a table */ typedef struct xl_standby_lock diff --git a/src/include/utils/syscache.h b/src/include/utils/syscache.h index 03a27dd0a83..b541911c8fc 100644 --- a/src/include/utils/syscache.h +++ b/src/include/utils/syscache.h @@ -43,9 +43,14 @@ extern HeapTuple SearchSysCache4(int cacheId, extern void ReleaseSysCache(HeapTuple tuple); +extern HeapTuple SearchSysCacheLocked1(int cacheId, + Datum key1); + /* convenience routines */ extern HeapTuple SearchSysCacheCopy(int cacheId, Datum key1, Datum key2, Datum key3, Datum key4); +extern HeapTuple SearchSysCacheLockedCopy1(int cacheId, + Datum key1); extern bool SearchSysCacheExists(int cacheId, Datum key1, Datum key2, Datum key3, Datum key4); extern Oid GetSysCacheOid(int cacheId, AttrNumber oidcol, |