Fix pg_recvlogical avoidance of superfluous Standby Status Update.

nmisch · nmisch · commit cee9cadb592f · 2020-05-13T20:42:09.000-07:00
The defect suppressed a Standby Status Update message when bytes flushed to disk had changed but bytes received had not changed. If pg_recvlogical then exited with no intervening Standby Status Update, the next pg_recvlogical repeated already-flushed records. The defect could also cause superfluous messages, which are functionally harmless. Back-patch to 9.5 (all supported versions). Discussion: https://postgr.es/m/20200502221647.GA3941274@rfd.leadboat.com
diff --git a/src/bin/pg_basebackup/pg_recvlogical.c b/src/bin/pg_basebackup/pg_recvlogical.c
@@ -126,7 +126,7 @@ sendFeedback(PGconn *conn, TimestampTz now, bool force, bool replyRequested)
 	 */
 	if (!force &&
 		last_written_lsn == output_written_lsn &&
-		last_fsync_lsn != output_fsync_lsn)
+		last_fsync_lsn == output_fsync_lsn)
 		return true;
 
 	if (verbose)
