Horton

Re: upgrades in row-level locks can deadlock

Oleksii Kliukin <alexk@hintbits.com>

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From: Oleksii Kliukin <alexk@hintbits.com>
To: Álvaro Herrera <alvherre@2ndquadrant.com>
Cc: PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2019-06-14T07:52:18Z
Lists: pgsql-hackers 
Alvaro Herrera <alvherre@2ndquadrant.com> wrote:

> On 2019-Jun-13, Alvaro Herrera wrote:
> 
>> On 2019-Jun-13, Oleksii Kliukin wrote:
>> 
>>> Makes sense. For the symmetry I have included those that perform lock
>>> upgrades in one session and those that doesn’t, while the other sessions
>>> acquire locks, do updates or deletes. For those that don’t upgrade locks the
>>> test checks that the locks are acquired in the correct order.
>> 
>> Thanks for the updated patch!  I'm about to push to branches 9.6-master.
>> It applies semi-cleanly (only pgindent-maturity whitespace conflicts).
> 
> Done, thanks for the report and patch!
> 
> I tried hard to find a scenario that this patch breaks, but couldn't
> find anything.

Thank you very much for reviewing and committing it!

Cheers,
Oleksii

Commits

  1. Avoid spurious deadlocks when upgrading a tuple lock