diff --git a/src/backend/storage/ipc/procarray.c b/src/backend/storage/ipc/procarray.c
index 5bc9fd6595e..193035ec262 100644
--- a/src/backend/storage/ipc/procarray.c
+++ b/src/backend/storage/ipc/procarray.c
@@ -1759,14 +1759,26 @@ GetSnapshotData(Snapshot snapshot)
 	snapshot->regd_count = 0;
 	snapshot->copied = false;
 
-	/*
-	 * Capture the current time and WAL stream location in case this snapshot
-	 * becomes old enough to need to fall back on the special "old snapshot"
-	 * logic.
-	 */
-	snapshot->lsn = GetXLogInsertRecPtr();
-	snapshot->whenTaken = GetSnapshotCurrentTimestamp();
-	MaintainOldSnapshotTimeMapping(snapshot->whenTaken, xmin);
+	if (old_snapshot_threshold < 0)
+	{
+		/*
+		 * If not using "snapshot too old" feature, fill related fields with
+		 * dummy values that don't require any locking.
+		 */
+		snapshot->lsn = InvalidXLogRecPtr;
+		snapshot->whenTaken = 0;
+	}
+	else
+	{
+		/*
+		 * Capture the current time and WAL stream location in case this
+		 * snapshot becomes old enough to need to fall back on the special
+		 * "old snapshot" logic.
+		 */
+		snapshot->lsn = GetXLogInsertRecPtr();
+		snapshot->whenTaken = GetSnapshotCurrentTimestamp();
+		MaintainOldSnapshotTimeMapping(snapshot->whenTaken, xmin);
+	}
 
 	return snapshot;
 }