Thread: pgsql: Don't retreat slot's confirmed_flush LSN.
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 ------ REL_17_STABLE Details ------- https://git.postgresql.org/pg/commitdiff/7318f241d29c0b90e0b8b7e39ebd1914f68fd37a Modified Files -------------- src/backend/replication/logical/logical.c | 23 +++++++++++++++++++++-- 1 file changed, 21 insertions(+), 2 deletions(-)