Horton

Re: Speedup twophase transactions

Stas Kelvich <s.kelvich@postgrespro.ru>

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From: Stas Kelvich <s.kelvich@postgrespro.ru>
To: Robert Haas <robertmhaas@gmail.com>
Cc: Simon Riggs <simon@2ndquadrant.com>, Andres Freund <andres@anarazel.de>, Alvaro Herrera <alvherre@2ndquadrant.com>, Jesper Pedersen <jesper.pedersen@redhat.com>, pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2016-04-08T18:57:59Z
Lists: pgsql-hackers 
> On 08 Apr 2016, at 21:42, Robert Haas <robertmhaas@gmail.com> wrote:
> 
> On Tue, Jan 26, 2016 at 7:43 AM, Stas Kelvich <s.kelvich@postgrespro.ru> wrote:
>> Hi,
>> 
>> Thanks for reviews and commit!
> 
> I apologize for being clueless here, but was this patch committed?
> It's still marked as "Needs Review" in the CommitFest application.

There was a patch to skip two phase file creation when there were no checkpoint
between PREPARE and COMMIT, and that patch was commited.
But that patch didn’t touch anything in replay, so replay speed of 2pc is significantly slower
than 2pc in normal mode. And that can cause constantly increasing replication lag for async
replication.
After that i’ve wrote new patch introducing same behaviour in replay and used the same
mail thread. Now Michael found a (heisen)bug in second patch, that i can’t reproduce.

Stas Kelvich
Postgres Professional: http://www.postgrespro.com
The Russian Postgres Company

Commits

  1. Speedup 2PC recovery by skipping two phase state files in normal path

  2. Add tests for two-phase commit

  3. Improve grammar of message about two-phase state files.

  4. Speedup 2PC by skipping two phase state files in normal path