Horton

Re: [BUG] FailedAssertion in SnapBuildPurgeOlderTxn

Andres Freund <andres@anarazel.de>

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From: Andres Freund <andres@anarazel.de>
To: Maxim Orlov <orlovmg@gmail.com>, Amit Kapila <amit.kapila16@gmail.com>
Cc: Postgres hackers <pgsql-hackers@lists.postgresql.org>
Date: 2022-11-21T20:52:02Z
Lists: pgsql-hackers 
Hi,

On 2022-11-21 15:47:12 +0300, Maxim Orlov wrote:
> After some investigation, I think, the problem is in the snapbuild.c
> (commit 272248a0c1b1, see [0]). We do allocate InitialRunningXacts
> array in the context of builder->context, but for the time when we call
> SnapBuildPurgeOlderTxn this context may be already free'd. Thus,
> InitialRunningXacts array become array of 2139062143 (i.e. 0x7F7F7F7F)
> values. This is not caused buildfarm to fail due to that code:

Amit, that does indeed seem to be a problem...

Greetings,

Andres Freund

Commits

  1. Fix uninitialized access to InitialRunningXacts during decoding.

  2. Fix catalog lookup with the wrong snapshot during logical decoding.