Message-ID: <571f7387-edfa-4733-a335-ccce7ce01574@enterprisedb.com>
Date: Mon, 24 Jun 2024 16:36:04 +0200
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Subject: Re: long-standing data loss bug in initial sync of logical
 replication
To: Amit Kapila <amit.kapila16@gmail.com>, Andres Freund <andres@anarazel.de>
Cc: PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
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From: Tomas Vondra <tomas.vondra@enterprisedb.com>
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On 6/24/24 12:54, Amit Kapila wrote:
> ...
>>
>>>> I'm not sure there are any cases where using SRE instead of AE would cause
>>>> problems for logical decoding, but it seems very hard to prove. I'd be very
>>>> surprised if just using SRE would not lead to corrupted cache contents in some
>>>> situations. The cases where a lower lock level is ok are ones where we just
>>>> don't care that the cache is coherent in that moment.
>>
>>> Are you saying it might break cases that are not corrupted now? How
>>> could obtaining a stronger lock have such effect?
>>
>> No, I mean that I don't know if using SRE instead of AE would have negative
>> consequences for logical decoding. I.e. whether, from a logical decoding POV,
>> it'd suffice to increase the lock level to just SRE instead of AE.
>>
>> Since I don't see how it'd be correct otherwise, it's kind of a moot question.
>>
> 
> We lost track of this thread and the bug is still open. IIUC, the
> conclusion is to use SRE in OpenTableList() to fix the reported issue.
> Andres, Tomas, please let me know if my understanding is wrong,
> otherwise, let's proceed and fix this issue.
> 

It's in the commitfest [https://commitfest.postgresql.org/48/4766/] so I
don't think we 'lost track' of it, but it's true we haven't done much
progress recently.

regards

-- 
Tomas Vondra
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