diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 351887b133..d294a5a47f 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -4033,9 +4033,9 @@ BackendRun(Port *port)
 	 */
 	random_seed = 0;
 	random_start_time.tv_usec = 0;
-	/* slightly hacky way to get integer microseconds part of timestamptz */
+	/* slightly hacky way to convert timestamptz into integers */
 	TimestampDifference(0, port->SessionStartTime, &secs, &usecs);
-	srandom((unsigned int) (MyProcPid ^ usecs));
+	srandom((unsigned int) (MyProcPid ^ (usecs << 12) ^ secs));
 
 	/*
 	 * Now, build the argv vector that will be given to PostgresMain.