From 8463880872cf8a6fc6bb9a4ad34b84aded7a33e2 Mon Sep 17 00:00:00 2001 From: Simon Riggs Date: Sun, 23 Apr 2017 21:35:41 +0100 Subject: [PATCH] Fix LagTrackerRead() for timeline increments Bug was masked by error in running 004_timeline_switch.pl that was fixed recently in 7d68f2281a. Detective work by Alvaro Herrera and Tom Lane Author: Thomas Munro --- src/backend/replication/walsender.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 26090738fc..064cf5ee28 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -3328,7 +3328,16 @@ LagTrackerRead(int head, XLogRecPtr lsn, TimestampTz now) WalTimeSample prev = LagTracker.last_read[head]; WalTimeSample next = LagTracker.buffer[LagTracker.read_heads[head]]; - Assert(lsn >= prev.lsn); + if (lsn < prev.lsn) + { + /* + * Reported LSNs shouldn't normally go backwards, but it's + * possible when there is a timeline change. Treat as not + * found. + */ + return -1; + } + Assert(prev.lsn < next.lsn); if (prev.time > next.time) -- 2.40.0