Horton

Re: Speedup twophase transactions

Michael Paquier <michael.paquier@gmail.com>

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From: Michael Paquier <michael.paquier@gmail.com>
To: Nikhil Sontakke <nikhils@2ndquadrant.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: 2017-03-17T08:15:19Z
Lists: pgsql-hackers 
On Fri, Mar 17, 2017 at 5:00 PM, Nikhil Sontakke
<nikhils@2ndquadrant.com> wrote:
>> >
>> > 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.

I have to admit that I am beginning to get drawn into it...
-- 
Michael

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