Horton

Re: Speedup twophase transactions

Nikhil Sontakke <nikhils@2ndquadrant.com>

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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: 2017-03-17T08:00:01Z
Lists: pgsql-hackers 
>
> >
> > Ok, we can do that and then yes, RecoverPreparedTransaction() can just
> have
> > one loop going through the shmem entries. BUT, we cannot ignore
> > "inredo"+"ondisk" entries. For such entries, we will have to read and
> > recover from the corresponding 2PC files.
>
> Yes. About other things I found... In CheckPointTwoPhase(), I am
> actually surprised that prepare_start_lsn and prepare_end_lsn are not
> reset to InvalidXLogRecPtr when a shmem entry is flushed to disk after
> ondisk is set to true, there is no need for them as the data does not
> need to be fetched from WAL segments so we had better be consistent
> (regression tests fail if I do that). And the two extra arguments in
> MarkAsPreparing() are really unnecessary, they get set all the time to
> InvalidXLogRecPtr.
>

Micheal, it looks like you are working on a final version of this patch? I
will wait to review it from my end, then.

Regards,
Nikhils
-- 
 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