Movatterモバイル変換

[0]ホーム
URL:

Skip to content

Navigation Menu

Sign in
Appearance settings

Search code, repositories, users, issues, pull requests...

Provide feedback

We read every piece of feedback, and take your input very seriously.

Saved searches

Use saved searches to filter your results more quickly

 Sign up
Appearance settings

Commitad5eaf3

Browse files
author
Amit Kapila
committed
Don't retreat slot's confirmed_flush LSN.
Prevent moving the confirmed_flush backwards, as this could lead to dataduplication issues caused by replicating already replicated changes.This can happen when a client acknowledges an LSN it doesn't have to doanything for, and thus didn't store persistently. After a restart, theclient can send the prior LSN that it stored persistently as anacknowledgement, but we need to ignore such an LSN to avoid retreatingconfirm_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: 13Discussion:https://postgr.es/m/CAJpy0uDZ29P=BYB1JDWMCh-6wXaNqMwG1u1mB4=10Ly0x7HhwQ@mail.gmail.comDiscussion:https://postgr.es/m/OS0PR01MB57164AB5716AF2E477D53F6F9489A@OS0PR01MB5716.jpnprd01.prod.outlook.com
1 parentf8db5c7 commitad5eaf3

File tree

1 file changed

+21
-2
lines changed

1 file changed

+21
-2
lines changed

‎src/backend/replication/logical/logical.c

Lines changed: 21 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -1828,7 +1828,19 @@ LogicalConfirmReceivedLocation(XLogRecPtr lsn)
18281828

18291829
SpinLockAcquire(&MyReplicationSlot->mutex);
18301830

1831-
MyReplicationSlot->data.confirmed_flush=lsn;
1831+
/*
1832+
* Prevent moving the confirmed_flush backwards, as this could lead to
1833+
* data duplication issues caused by replicating already replicated
1834+
* changes.
1835+
*
1836+
* This can happen when a client acknowledges an LSN it doesn't have
1837+
* to do anything for, and thus didn't store persistently. After a
1838+
* restart, the client can send the prior LSN that it stored
1839+
* persistently as an acknowledgement, but we need to ignore such an
1840+
* LSN. See similar case handling in CreateDecodingContext.
1841+
*/
1842+
if (lsn>MyReplicationSlot->data.confirmed_flush)
1843+
MyReplicationSlot->data.confirmed_flush=lsn;
18321844

18331845
/* if we're past the location required for bumping xmin, do so */
18341846
if (MyReplicationSlot->candidate_xmin_lsn!=InvalidXLogRecPtr&&
@@ -1893,7 +1905,14 @@ LogicalConfirmReceivedLocation(XLogRecPtr lsn)
18931905
else
18941906
{
18951907
SpinLockAcquire(&MyReplicationSlot->mutex);
1896-
MyReplicationSlot->data.confirmed_flush=lsn;
1908+
1909+
/*
1910+
* Prevent moving the confirmed_flush backwards. See comments above
1911+
* for the details.
1912+
*/
1913+
if (lsn>MyReplicationSlot->data.confirmed_flush)
1914+
MyReplicationSlot->data.confirmed_flush=lsn;
1915+
18971916
SpinLockRelease(&MyReplicationSlot->mutex);
18981917
}
18991918
}

0 commit comments

Comments
 (0)
[8]ページ先頭
©2009-2025 Movatter.jp