4 files changed, 9 insertions, 7 deletions
diff --git a/src/backend/access/heap/heapam.c b/src/backend/access/heap/heapam.c
index 59d43e2ba92..4e6aeba3154 100644
--- a/src/backend/access/heap/heapam.c
+++ b/src/backend/access/heap/heapam.c
@@ -328,7 +328,7 @@ initscan(HeapScanDesc scan, ScanKey key, bool keep_startblock)
 	/*
 	 * copy the scan key, if appropriate
 	 */
-	if (key != NULL)
+	if (key != NULL && scan->rs_base.rs_nkeys > 0)
 		memcpy(scan->rs_base.rs_key, key, scan->rs_base.rs_nkeys * sizeof(ScanKeyData));
 
 	/*
diff --git a/src/backend/access/heap/heapam_visibility.c b/src/backend/access/heap/heapam_visibility.c
index ceadac70d57..ff0b8a688de 100644
--- a/src/backend/access/heap/heapam_visibility.c
+++ b/src/backend/access/heap/heapam_visibility.c
@@ -1564,8 +1564,8 @@ HeapTupleHeaderIsOnlyLocked(HeapTupleHeader tuple)
 static bool
 TransactionIdInArray(TransactionId xid, TransactionId *xip, Size num)
 {
-	return bsearch(&xid, xip, num,
-				   sizeof(TransactionId), xidComparator) != NULL;
+	return num > 0 &&
+		bsearch(&xid, xip, num, sizeof(TransactionId), xidComparator) != NULL;
 }
 
 /*
diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c
index de787c3d375..3d9088a7048 100644
--- a/src/backend/access/transam/clog.c
+++ b/src/backend/access/transam/clog.c
@@ -297,8 +297,9 @@ TransactionIdSetPageStatus(TransactionId xid, int nsubxids,
 	if (all_xact_same_page && xid == MyProc->xid &&
 		nsubxids <= THRESHOLD_SUBTRANS_CLOG_OPT &&
 		nsubxids == MyProc->subxidStatus.count &&
-		memcmp(subxids, MyProc->subxids.xids,
-			   nsubxids * sizeof(TransactionId)) == 0)
+		(nsubxids == 0 ||
+		 memcmp(subxids, MyProc->subxids.xids,
+				nsubxids * sizeof(TransactionId)) == 0))
 	{
 		/*
 		 * If we can immediately acquire XactSLRULock, we update the status of
diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c
index adf763a8ea4..8964ddf3ebf 100644
--- a/src/backend/access/transam/xact.c
+++ b/src/backend/access/transam/xact.c
@@ -5353,8 +5353,9 @@ SerializeTransactionState(Size maxsize, char *start_address)
 	{
 		if (FullTransactionIdIsValid(s->fullTransactionId))
 			workspace[i++] = XidFromFullTransactionId(s->fullTransactionId);
-		memcpy(&workspace[i], s->childXids,
-			   s->nChildXids * sizeof(TransactionId));
+		if (s->nChildXids > 0)
+			memcpy(&workspace[i], s->childXids,
+				   s->nChildXids * sizeof(TransactionId));
 		i += s->nChildXids;
 	}
 	Assert(i == nxids);