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

Commite684594

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 parenta1e0e70 commite684594

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
@@ -1718,7 +1718,19 @@ LogicalConfirmReceivedLocation(XLogRecPtr lsn)
17181718

17191719
SpinLockAcquire(&MyReplicationSlot->mutex);
17201720

1721-
MyReplicationSlot->data.confirmed_flush=lsn;
1721+
/*
1722+
* Prevent moving the confirmed_flush backwards, as this could lead to
1723+
* data duplication issues caused by replicating already replicated
1724+
* changes.
1725+
*
1726+
* This can happen when a client acknowledges an LSN it doesn't have
1727+
* to do anything for, and thus didn't store persistently. After a
1728+
* restart, the client can send the prior LSN that it stored
1729+
* persistently as an acknowledgement, but we need to ignore such an
1730+
* LSN. See similar case handling in CreateDecodingContext.
1731+
*/
1732+
if (lsn>MyReplicationSlot->data.confirmed_flush)
1733+
MyReplicationSlot->data.confirmed_flush=lsn;
17221734

17231735
/* if we're past the location required for bumping xmin, do so */
17241736
if (MyReplicationSlot->candidate_xmin_lsn!=InvalidXLogRecPtr&&
@@ -1783,7 +1795,14 @@ LogicalConfirmReceivedLocation(XLogRecPtr lsn)
17831795
else
17841796
{
17851797
SpinLockAcquire(&MyReplicationSlot->mutex);
1786-
MyReplicationSlot->data.confirmed_flush=lsn;
1798+
1799+
/*
1800+
* Prevent moving the confirmed_flush backwards. See comments above
1801+
* for the details.
1802+
*/
1803+
if (lsn>MyReplicationSlot->data.confirmed_flush)
1804+
MyReplicationSlot->data.confirmed_flush=lsn;
1805+
17871806
SpinLockRelease(&MyReplicationSlot->mutex);
17881807
}
17891808
}

0 commit comments

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