From: | Simon Riggs <simon(at)2ndQuadrant(dot)com> |
---|---|
To: | pgsql-committers(at)postgresql(dot)org |
Subject: | pgsql: Dirty replication slots when using sql interface |
Date: | 2016-09-05 08:46:00 |
Message-ID: | E1bgpXV-0005pR-04@gemulon.postgresql.org |
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Thread: | |
Lists: | pgsql-committers |
Dirty replication slots when using sql interface
When pg_logical_slot_get_changes(...) sets confirmed_flush_lsn to the point at
which replay stopped, it doesn't dirty the replication slot. So if the replay
didn't cause restart_lsn or catalog_xmin to change as well, this change will
not get written out to disk. Even on a clean shutdown.
If Pg crashes or restarts, a subsequent pg_logical_slot_get_changes(...) call
will see the same changes already replayed since it uses the slot's
confirmed_flush_lsn as the start point for fetching changes. The caller can't
specify a start LSN when using the SQL interface.
Mark the slot as dirty after reading changes using the SQL interface so that
users won't see repeated changes after a clean shutdown. Repeated changes still
occur when using the walsender interface or after an unclean shutdown.
Craig Ringer
Branch
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master
Details
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http://git.postgresql.org/pg/commitdiff/d851bef2d60ff9345249ff67c053e37fe4b364cc
Modified Files
--------------
src/backend/replication/logical/logicalfuncs.c | 15 ++++++++++
src/test/recovery/Makefile | 2 ++
src/test/recovery/t/006_logical_decoding.pl | 40 ++++++++++++++++++++++++++
3 files changed, 57 insertions(+)
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