Re: [HACKERS] Speedup twophase transactions - Mailing list pgsql-hackers

From Nikhil Sontakke
Subject Re: [HACKERS] Speedup twophase transactions
Date
Msg-id CAMGcDxfb2fhXvxnhzbvOeFemyh4f4qgj89CUra2SRbSaHJrs0A@mail.gmail.com
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In response to Re: [HACKERS] Speedup twophase transactions  (Michael Paquier <michael.paquier@gmail.com>)
Responses Re: [HACKERS] Speedup twophase transactions  (Michael Paquier <michael.paquier@gmail.com>)
List 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

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