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authorNoah Misch <noah@leadboat.com>2024-09-24 15:25:18 -0700
committerNoah Misch <noah@leadboat.com>2024-09-24 15:25:18 -0700
commitaac2c9b4fde889d13f859c233c2523345e72d32b (patch)
tree65d5e1b73059d4c423dee459bcf58bc0c47b8a9a /src/include/nodes/execnodes.h
parenta07e03fd8fa7daf4d1356f7cb501ffe784ea6257 (diff)
downloadpostgresql-aac2c9b4fde889d13f859c233c2523345e72d32b.tar.gz
postgresql-aac2c9b4fde889d13f859c233c2523345e72d32b.zip
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/nodes/execnodes.h')
-rw-r--r--src/include/nodes/execnodes.h3
1 files changed, 3 insertions, 0 deletions
diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
index 88467977f89..aab59d681cf 100644
--- a/src/include/nodes/execnodes.h
+++ b/src/include/nodes/execnodes.h
@@ -485,6 +485,9 @@ typedef struct ResultRelInfo
/* Have the projection and the slots above been initialized? */
bool ri_projectNewInfoValid;
+ /* updates do LockTuple() before oldtup read; see README.tuplock */
+ bool ri_needLockTagTuple;
+
/* triggers to be fired, if any */
TriggerDesc *ri_TrigDesc;