From: Amit Kapila <akapila@postgresql.org>
To: pgsql-committers@lists.postgresql.org
Subject: pgsql: Don't retreat slot's confirmed_flush LSN.
Date: Mon, 19 May 2025 07:02:00 +0000
Message-ID: <E1uGuVb-002MCH-2d@gemulon.postgresql.org> (raw)
Don't retreat slot's confirmed_flush LSN.
Prevent moving the confirmed_flush backwards, as this could lead to data
duplication issues caused by replicating already replicated changes.
This can happen when a client acknowledges an LSN it doesn't have to do
anything for, and thus didn't store persistently. After a restart, the
client can send the prior LSN that it stored persistently as an
acknowledgement, but we need to ignore such an LSN to avoid retreating
confirm_flush LSN.
Diagnosed-by: Zhijie Hou <houzj.fnst@fujitsu.com>
Author: shveta malik <shveta.malik@gmail.com>
Reviewed-by: Amit Kapila <amit.kapila16@gmail.com>
Reviewed-by: Dilip Kumar <dilipbalaut@gmail.com>
Tested-by: Nisha Moond <nisha.moond412@gmail.com>
Backpatch-through: 13
Discussion: https://postgr.es/m/CAJpy0uDZ29P=BYB1JDWMCh-6wXaNqMwG1u1mB4=10Ly0x7HhwQ@mail.gmail.com
Discussion: https://postgr.es/m/OS0PR01MB57164AB5716AF2E477D53F6F9489A@OS0PR01MB5716.jpnprd01.prod.outlook.com
Branch
------
master
Details
-------
https://git.postgresql.org/pg/commitdiff/ad5eaf390c58294e2e4c1509aa87bf13261a5d15
Modified Files
--------------
src/backend/replication/logical/logical.c | 23 +++++++++++++++++++++--
1 file changed, 21 insertions(+), 2 deletions(-)
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To: pgsql-committers@postgresql.org
Cc: akapila@postgresql.org, pgsql-committers@lists.postgresql.org
Subject: Re: pgsql: Don't retreat slot's confirmed_flush LSN.
In-Reply-To: <E1uGuVb-002MCH-2d@gemulon.postgresql.org>
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