Re: Get rid of WALBufMappingLock - Mailing list pgsql-hackers

From Yura Sokolov
Subject Re: Get rid of WALBufMappingLock
Date
Msg-id 72962bea-2c77-4153-a7d6-a36727437ea1@postgrespro.ru
Whole thread Raw
In response to Re: Get rid of WALBufMappingLock  (Alexander Korotkov <aekorotkov@gmail.com>)
List pgsql-hackers
26.02.2025 14:48, Alexander Korotkov пишет:
> Hi, Michael!
> 
> On Wed, Feb 26, 2025 at 3:04 AM Michael Paquier <michael@paquier.xyz> wrote:
>>
>> On Tue, Feb 25, 2025 at 05:19:29PM +0200, Alexander Korotkov wrote:
>>> It seems that I managed to reproduce the issue on my Raspberry PI 4.
>>> After running our test suite in a loop for 2 days I found one timeout.
>>
>> Hmm.  It's surprising to not see a higher occurence.  My buildfarm
>> host has caught that on its first run after the patch, for two
>> different animals which are both on the same machine.
>>
>>> One way or another, we need protection against this situation any way.
>>> The updated patch is attached.  Now, after acquiring ReservedPtr it
>>> waits till OldPageRqstPtr gets initialized.  Additionally I've to
>>> implement more accurate calculation of OldPageRqstPtr.  I run tests
>>> with new patch on my Raspberry in a loop.  Let's see how it goes.
>>
>> Perhaps you'd prefer that I do more tests with your patch?  This is
>> time-consuming for you.  This is not a review of the internals of the
>> patch, and I cannot give you access to the host, but if my stuff is
>> the only place where we have a good reproducibility of the issue, I'm
>> OK to grab some time and run a couple of checks to avoid again a
>> freeze of the buildfarm.
> 
> Thank you for offering the help.  Updated version of patch is attached
> (I've added one memory barrier there just in case).  I would
> appreciate if you could run it on batta, hachi or similar hardware.

Good day, Alexander.

Checked your additions to patch. They're clear and robust.

-------
regards
Yura Sokolov aka funny-falcon



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