Horton

Re: [BUG] Panic due to incorrect missingContrecPtr after promotion

Kyotaro Horiguchi <horikyota.ntt@gmail.com>

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From: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
To: simseih@amazon.com
Cc: alvherre@alvh.no-ip.org, pgsql-hackers@postgresql.org
Date: 2022-05-27T01:59:24Z
Lists: pgsql-hackers 
At Thu, 26 May 2022 19:57:41 +0000, "Imseih (AWS), Sami" <simseih@amazon.com> wrote in 
> We see another occurrence of this bug with the last patch applied in 13.7.
> 
> After a promotion we observe the following in the logs:
...
> We think it's because VerifyOverwriteContrecord was not 
> called which is why we see this behavior. 
> 
> Are there are  other places where missingContrecPtr 
> should be invalidated, such as after a successful promotion?

The only cause known to me for EndOfLog being moved to such location
is missingContrecPtr. But if the next record is not
XLOG_OVERWRITE_CONTRECORD recovery should have stopped there. And if
XLOG_OVERWRITE_CONTRECORD is there, VerifyOverwriteContrecord should
have been called..

Could you inspect WAL files of the environment and see if the first
record of the '7/A8'th segment OVERWRITE_CONTRECORD?  I don't say that
makes some progress on this, but could be the first step.

regards.

-- 
Kyotaro Horiguchi
NTT Open Source Software Center

Commits

  1. Prevent WAL corruption after a standby promotion.

  2. Fix "missing continuation record" after standby promotion