Re: Speedup twophase transactions

Nikhil Sontakke <nikhils@2ndquadrant.com>

From: Nikhil Sontakke <nikhils@2ndquadrant.com>
To: Michael Paquier <michael.paquier@gmail.com>
Cc: David Steele <david@pgmasters.net>, Stas Kelvich <s.kelvich@postgrespro.ru>, Simon Riggs <simon@2ndquadrant.com>, PostgreSQL mailing lists <pgsql-hackers@postgresql.org>, Jesper Pedersen <jesper.pedersen@redhat.com>, Robert Haas <robertmhaas@gmail.com>
Date: 2017-03-26T07:50:47Z
Lists: pgsql-hackers
Thanks Michael,

I was away for a bit. I will take a look at this patch and get back to you
soon.

Regards,
Nikhils

On 22 March 2017 at 07:40, Michael Paquier <michael.paquier@gmail.com>
wrote:

> On Fri, Mar 17, 2017 at 5:15 PM, Michael Paquier
> <michael.paquier@gmail.com> wrote:
> > On Fri, Mar 17, 2017 at 5:00 PM, Nikhil Sontakke
> > <nikhils@2ndquadrant.com> wrote:
> >> Micheal, it looks like you are working on a final version of this
> patch? I
> >> will wait to review it from my end, then.
> >
> > I have to admit that I am beginning to get drawn into it...
>
> And here is what I got. I have found a couple of inconsistencies in
> the patch, roughly:
> - During recovery entries marked with ondisk = true should have their
> start and end LSN reset to InvalidXLogRecPtr. This was actually
> leading to some inconsistencies in MarkAsPreparing() for 2PC
> transactions staying around for more than 2 checkpoints.
> - RecoverPreparedTransactions(), StandbyRecoverPreparedTransactions()
> and PrescanPreparedTransactions() doing both a scan of pg_twophase and
> the shared memory entries was way too complicated. I have changed
> things so as only memory entries are scanned by those routines, but an
> initial scan of pg_twophase is done before recovery.
> - Some inconsistencies in the comments and some typos found on the way.
> - Simplification of some routines used in redo, as well as simplified
> the set of routines made available to users.
>
> Tests are passing for me, an extra lookup would be nice.
> --
> Michael
>



-- 
 Nikhil Sontakke                   http://www.2ndQuadrant.com/
 PostgreSQL/Postgres-XL Development, 24x7 Support, Training & Services

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