Re: tracking commit timestamps

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.

> 6) Shouldn't any value update of track_commit_timestamp be tracked in
> XLogReportParameters? That's thinking about making the commit timestamp
> available on standbys as well..

Yes, it should.

> 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?

> 8) The redo and xlog routines of committs should be out in a dedicated
> file, like committsxlog.c or similar. The other rmgr do so, so let's be
> consistent.

Seems pointless to me. The file isn't that big and the other SLRUs don't
do it.

Greetings,

Andres Freund

--
Andres Freund http://www.2ndQuadrant.com/
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