Re: Speedup twophase transactions

From: Nikhil Sontakke <nikhils(at)2ndquadrant(dot)com>
To: Michael Paquier <michael(dot)paquier(at)gmail(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 08:00:01
Message-ID: CAMGcDxfb2fhXvxnhzbvOeFemyh4f4qgj89CUra2SRbSaHJrs0A@mail.gmail.com
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
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

In response to

Responses

Browse pgsql-hackers by date

  From Date Subject
Next Message Tsunakawa, Takayuki 2017-03-17 08:11:25 Re: Potential data loss of 2PC files
Previous Message Kyotaro HORIGUCHI 2017-03-17 07:58:07 Re: IF (NOT) EXISTS in psql-completion