From 74fc54085d20955cef4d5b7ce4b49d10351b1fbd Mon Sep 17 00:00:00 2001 From: Kyotaro Horiguchi Date: Thu, 21 Jul 2016 15:45:04 +0900 Subject: [PATCH 1/2] Add the reason why we use replayEndRecPtr as recovery-end point. --- src/backend/access/transam/xlog.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c index aecede1..13ef75f 100644 --- a/src/backend/access/transam/xlog.c +++ b/src/backend/access/transam/xlog.c @@ -10409,10 +10409,14 @@ do_pg_stop_backup(char *labelfile, bool waitforarchive, TimeLineID *stoptli_p) * required files are available, a user should wait for them to be * archived, or include them into the backup. * - * We return the current minimum recovery point as the backup end - * location. Note that it can be greater than the exact backup end - * location if the minimum recovery point is updated after the backup of - * pg_control. This is harmless for current uses. + * minRecoveryPoint can go behind the last checkpoint's redo location when + * the checkpoint writes out no buffer. This does no harm to performing a + * recovery but such inversion seems inconsistent from the view of the + * callers and prevents them from knowing WAL segments needed by sane + * calcuation. For the reason we return the last replayed point as the + * backup end location. Note that it can be greater than the exact backup + * end location or even the minimum recovery point of pg_control at the + * time. This is harmless for current uses. * * XXX currently a backup history file is for informational and debug * purposes only. It's not essential for an online backup. Furthermore, -- 1.8.3.1