At end of recovery, reset all sinval-managed caches.

An inplace update's invalidation messages are part of its transaction's
commit record.  However, the update survives even if its transaction
aborts or we stop recovery before replaying its transaction commit.
After recovery, a backend that started in recovery could update the row
without incorporating the inplace update.  That could result in a table
with an index, yet relhasindex=f.  That is a source of index corruption.

This bulk invalidation avoids the functional consequences.  A future
change can fix the !RecoveryInProgress() scenario without changing the
WAL format.  Back-patch to v17 - v12 (all supported versions).  v18 will
instead add invalidations to WAL.

Discussion: https://postgr.es/m/20240618152349.7f.nmisch@google.com

src/backend/storage/ipc/sinvaladt.c

@@ -683,6 +683,48 @@ SICleanupQueue(bool callerHasWriteLock, int minFree)
 	}
 }
 
+/*
+ * SIResetAll
+ *		Mark all active backends as "reset"
+ *
+ * Use this when we don't know what needs to be invalidated.  It's a
+ * cluster-wide InvalidateSystemCaches().  This was a back-branch-only remedy
+ * to avoid a WAL format change.
+ *
+ * The implementation is like SICleanupQueue(false, MAXNUMMESSAGES + 1), with
+ * one addition.  SICleanupQueue() assumes minFree << MAXNUMMESSAGES, so it
+ * assumes hasMessages==true for any backend it resets.  We're resetting even
+ * fully-caught-up backends, so we set hasMessages.
+ */
+void
+SIResetAll(void)
+{
+	SISeg	   *segP = shmInvalBuffer;
+	int			i;
+
+	LWLockAcquire(SInvalWriteLock, LW_EXCLUSIVE);
+	LWLockAcquire(SInvalReadLock, LW_EXCLUSIVE);
+
+	for (i = 0; i < segP->numProcs; i++)
+	{
+		ProcState  *stateP = &segP->procState[segP->pgprocnos[i]];
+
+		Assert(stateP->procPid != 0);
+		if (stateP->sendOnly)
+			continue;
+
+		/* Consuming the reset will update "nextMsgNum" and "signaled". */
+		stateP->resetState = true;
+		stateP->hasMessages = true;
+	}
+
+	segP->minMsgNum = segP->maxMsgNum;
+	segP->nextThreshold = CLEANUP_MIN;
+
+	LWLockRelease(SInvalReadLock);
+	LWLockRelease(SInvalWriteLock);
+}
+
 
 /*
  * GetNextLocalTransactionId --- allocate a new LocalTransactionId