Re: tracking commit timestamps - Mailing list pgsql-hackers

From Michael Paquier
Subject Re: tracking commit timestamps
Date
Msg-id CAB7nPqR-AZgFUn4yEnyHGh+q0dJY3QomrL-eUuyPEg_EJRyi3A@mail.gmail.com
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In response to Re: tracking commit timestamps  (Andres Freund <andres@2ndquadrant.com>)
Responses Re: tracking commit timestamps  (Andres Freund <andres@2ndquadrant.com>)
List pgsql-hackers


On Tue, Nov 4, 2014 at 5:23 PM, Andres Freund <andres@2ndquadrant.com> wrote:
On 2014-11-04 17:19:18 +0900, Michael Paquier wrote:
> 5) Reading the code, TransactionTreeSetCommitTimestamp is always called
> with do_xlog = false, making that actually no timestamps are WAL'd... Hence
> WriteSetTimestampXlogRec is just dead code with the latest version of the
> patch. IMO, this should be always WAL-logged when track_commit_timestamp is
> on.

It's callable via a 'extern' function. So, I'd not consider it dead. And
the WAL logging is provided by xact.c's own WAL logging - it always does
the corresponding committs calls.
The code path is unused. We'd better make the XLOG record mandatory if tracking is enabled, as this information is useful on standbys as well.
 
> 7) pg_xlogdump has no support for RM_COMMITTS_ID, something that would be
> useful for developers.

What do you mean by that? There's the corresponding rmgrdesc.c support I
think?
Oops sorry. I thought there was some big switch in pg_xlogdump when writing this comment. Yeah that's fine.
--
Michael

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