Horton

Re: pg_waldump and PREPARE

Michael Paquier <michael@paquier.xyz>

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From: Michael Paquier <michael@paquier.xyz>
To: Julien Rouhaud <rjuju123@gmail.com>
Cc: Fujii Masao <masao.fujii@gmail.com>, Alvaro Herrera <alvherre@2ndquadrant.com>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2019-07-04T07:45:12Z
Lists: pgsql-hackers 
On Wed, Jul 03, 2019 at 08:23:44PM +0200, Julien Rouhaud wrote:
> So the patch compiles and works as intended. I don't have much to say
> about it, it all looks good to me, since the concerns about xactdesc.c
> aren't worth the trouble.
> 
> I'm not sure that I understand Michael's objection though, as
> xl_xact_prepare is not a new definition and AFAICS it couldn't contain
> the records anyway.  So I'll let him say if he has further objections
> or if it's ready for committer!

This patch provides parsing information only for the header of the 2PC
record.  Wouldn't it be interesting to get more information from the
various TwoPhaseRecordOnDisk's callbacks?  We could also print much
more information in xact_desc_prepare().  Like the subxacts, the XID,
the invalidation messages and the delete-on-abort/commit rels.
--
Michael

Commits

  1. Fix comment in xact.h

  2. Make pg_waldump report more detail information about PREPARE TRANSACTION record.

  3. Store 2PC GID in commit/abort WAL recs for logical decoding