From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Wed, 5 Apr 2023 19:56:07 +0000 (-0400)
Subject: Acquire locks on views in AcquirePlannerLocks, too.
X-Git-Tag: REL_16_BETA1~310
X-Git-Url: http://git.postgresql.org/gitweb/?a=commitdiff_plain;h=65eb2d00c6c1bab29db9fa6575185a40d823fe9d;p=postgresql.git

Acquire locks on views in AcquirePlannerLocks, too.

Commit 47bb9db75 taught AcquireExecutorLocks to re-acquire locks
on views using data from their RTE_SUBQUERY replacements, but
it now seems like we should make AcquirePlannerLocks do the same.
In this way, if a view has been redefined, we will notice that
a bit earlier while checking validity of a cached plan and thereby
avoid some wasted work.

Report and patch by Amit Langote.

Discussion: https://postgr.es/m/CA+HiwqH0xZOQ+GQAdKeckY1R4NOeHdzhtfxkAMJLSchpapNk5w@mail.gmail.com
---

diff --git a/src/backend/utils/cache/plancache.c b/src/backend/utils/cache/plancache.c
index 77c2ba3f8f4..87210fcf627 100644
--- a/src/backend/utils/cache/plancache.c
+++ b/src/backend/utils/cache/plancache.c
@@ -1846,6 +1846,14 @@ ScanQueryForLocks(Query *parsetree, bool acquire)
 				break;
 
 			case RTE_SUBQUERY:
+				/* If this was a view, must lock/unlock the view */
+				if (OidIsValid(rte->relid))
+				{
+					if (acquire)
+						LockRelationOid(rte->relid, rte->rellockmode);
+					else
+						UnlockRelationOid(rte->relid, rte->rellockmode);
+				}
 				/* Recurse into subquery-in-FROM */
 				ScanQueryForLocks(rte->subquery, acquire);
 				break;