Re: Speedup twophase transactions - Mailing list pgsql-hackers

From Michael Paquier
Subject Re: Speedup twophase transactions
Date
Msg-id CAB7nPqTAK=NA4HURt7GXxGeUOOhWq6OgY8rGEWkgp=mqL5Lo7A@mail.gmail.com
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In response to Re: Speedup twophase transactions  (Stas Kelvich <s.kelvich@postgrespro.ru>)
Responses Re: Speedup twophase transactions
List pgsql-hackers
On Wed, Apr 13, 2016 at 1:53 AM, Stas Kelvich <s.kelvich@postgrespro.ru> wrote:
>> On 12 Apr 2016, at 15:47, Michael Paquier <michael.paquier@gmail.com> wrote:
>>
>> It looks to be the case... The PREPARE phase replayed after the
>> standby is restarted in recovery creates a series of exclusive locks
>> on the table created and those are not taken on HEAD. Once those are
>> replayed the LOCK_STANDBY record is conflicting with it. In the case
>> of the failure, the COMMIT PREPARED record cannot be fetched from
>> master via the WAL stream so the relation never becomes visible.
>
> Yep, it is. It is okay for prepared xact hold a locks for created/changed tables,
> but code in standby_redo() was written in assumption that there are no prepared
> xacts at the time of recovery. I’ll look closer at checkpointer code and will send
> updated patch.
>
> And thanks again.

That's too late for 9.6 unfortunately, don't forget to add that in the next CF!
--
Michael



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