Re:Possible corruption by CreateRestartPoint at promotion

[Rui Zhao]

Kyotaro's patch seems good to me and fixes the test case in my patch.
Do you have interest in adding a test like one in my patch?


> +  LWLockAcquire(ControlFileLock, LW_EXCLUSIVE); > + >       /* > 
         * Remember the prior checkpoint's redo ptr for >     * 
UpdateCheckPointDistanceEstimate() >       */ >        PriorRedoPtr = 
ControlFile-&gt;checkPointCopy.redo; &gt;  &gt; +        Assert (PriorRedoPtr < 
RedoRecPtr);Maybe PriorRedoPtr does not need to be under LWLockAcquire?
regards. --  Zhao Rui Alibaba Cloud: https://www.aliyun.com/
------------------&nbsp;Original&nbsp;------------------
From:                                                                           
                                             "Kyotaro Horiguchi"                
                                                                    
<horikyota....@gmail.com&gt;;
Date:&nbsp;Wed, Mar 16, 2022 09:24 AM
To:&nbsp;"pgsql-hackers"<pgsql-hackers@lists.postgresql.org&gt;;
Cc:&nbsp;"masao.fujii"<masao.fu...@oss.nttdata.com&gt;;
Subject:&nbsp;Possible corruption by CreateRestartPoint at promotion



Hello,&nbsp; (Cc:ed Fujii-san)

This is a diverged topic from [1], which is summarized as $SUBJECT.

To recap:

While discussing on additional LSNs in checkpoint log message,
Fujii-san pointed out [2] that there is a case where
CreateRestartPoint leaves unrecoverable database when concurrent
promotion happens. That corruption is "fixed" by the next checkpoint
so it is not a severe corruption.

AFAICS since 9.5, no check(/restart)pionts won't run concurrently with
restartpoint [3].&nbsp; So I propose to remove the code path as attached.

regards.


[1] 
https://www.postgresql.org/message-id/20220316.091913.806120467943749797.horikyota.ntt%40gmail.com

[2] 
https://www.postgresql.org/message-id/7bfad665-db9c-0c2a-2604-9f54763c5f9e%40oss.nttdata.com

[3] 
https://www.postgresql.org/message-id/20220222.174401.765586897814316743.horikyota.ntt%40gmail.com

-- 
Kyotaro Horiguchi
NTT Open Source Software Center

0001-Test-of-this-problem-v14.patch
Description: Binary data