Re: pg_waldump and PREPARE

From: Fujii Masao <masao(dot)fujii(at)gmail(dot)com>
To: Julien Rouhaud <rjuju123(at)gmail(dot)com>
Cc: Michael Paquier <michael(at)paquier(dot)xyz>, Alvaro Herrera <alvherre(at)2ndquadrant(dot)com>, PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: pg_waldump and PREPARE
Date: 2019-07-03 15:20:51
Message-ID: CAHGQGwFQgRWMOoRfbOOHXy1VdGM-YkwdwvWr_bD0TQXFTjD9Tw@mail.gmail.com
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On Tue, Jul 2, 2019 at 7:16 PM Julien Rouhaud <rjuju123(at)gmail(dot)com> wrote:
>
> On Fri, Apr 26, 2019 at 5:38 AM Michael Paquier <michael(at)paquier(dot)xyz> wrote:
> >
> > On Thu, Apr 25, 2019 at 03:08:36PM -0400, Alvaro Herrera wrote:
> > > On 2019-Apr-26, Fujii Masao wrote:
> > >> I did that arrangement because the format of PREPARE TRANSACTION record,
> > >> i.e., that struct, also needs to be accessed in backend and frontend.
> > >> But, of course, if there is smarter way, I'm happy to adopt that!
> > >
> > > I don't know. I spent some time staring at the code involved, and it
> > > seems it'd be possible to improve just a little bit on cleanliness
> > > grounds, with a lot of effort, but not enough practical value.
> >
> > Describing those records is something we should do. There are other
> > parsing routines in xactdesc.c for commit and abort records, so having
> > that extra routine for prepare at the same place does not sound
> > strange to me.
> >
> > +typedef xl_xact_prepare TwoPhaseFileHeader;
> > I find this mapping implementation a bit lazy, and your
> > newly-introduced xl_xact_prepare does not count for all the contents
> > of the actual WAL record for PREPARE TRANSACTION. Wouldn't it be
> > better to put all the contents of the record in the same structure,
> > and not only the 2PC header information?
>
> This patch doesn't apply anymore, could you send a rebase?

Yes, attached is the updated version of the patch.

Regards,

--
Fujii Masao

Attachment Content-Type Size
prepare-xact-desc_v2.patch application/octet-stream 7.4 KB

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