| From: | Michael Paquier <michael(dot)paquier(at)gmail(dot)com> |
|---|---|
| To: | Nikhil Sontakke <nikhils(at)2ndquadrant(dot)com> |
| Cc: | David Steele <david(at)pgmasters(dot)net>, Stas Kelvich <s(dot)kelvich(at)postgrespro(dot)ru>, Simon Riggs <simon(at)2ndquadrant(dot)com>, PostgreSQL mailing lists <pgsql-hackers(at)postgresql(dot)org>, Jesper Pedersen <jesper(dot)pedersen(at)redhat(dot)com>, Robert Haas <robertmhaas(at)gmail(dot)com> |
| Subject: | Re: Speedup twophase transactions |
| Date: | 2017-03-17 08:15:19 |
| Message-ID: | CAB7nPqQ45Hy_RZKV7cSJCacrCuqwjU83jtT0adRrhJKsvYzBOA@mail.gmail.com |
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On Fri, Mar 17, 2017 at 5:00 PM, Nikhil Sontakke
<nikhils(at)2ndquadrant(dot)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
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