Fix ancient docs/comments thinko: XID comparison is mod 2^32, not 2^31.

Pointed out by Gianni Ciolli.

1 files changed, 1 insertions, 1 deletions

diff --git a/src/backend/access/transam/transam.c b/src/backend/access/transam/transam.c
index a7214cf34de..833f3cd1cc7 100644
--- a/src/backend/access/transam/transam.c
+++ b/src/backend/access/transam/transam.c
@@ -304,7 +304,7 @@ TransactionIdPrecedes(TransactionId id1, TransactionId id2)
 {
 	/*
 	 * If either ID is a permanent XID then we can just do unsigned
-	 * comparison.	If both are normal, do a modulo-2^31 comparison.
+	 * comparison.	If both are normal, do a modulo-2^32 comparison.
 	 */
 	int32		diff;