Horton

Re: [PATCH] Transaction traceability - txid_status(bigint)

Craig Ringer <craig@2ndquadrant.com>

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From: Craig Ringer <craig@2ndquadrant.com>
To: Petr Jelinek <petr@2ndquadrant.com>
Cc: Simon Riggs <simon@2ndquadrant.com>, PostgreSQL Hackers <pgsql-hackers@postgresql.org>, Andres Freund <andres@anarazel.de>, Jim Nasby <Jim.Nasby@bluetreble.com>, Robert Haas <robertmhaas@gmail.com>
Date: 2016-09-16T00:52:17Z
Lists: pgsql-hackers

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On 2 September 2016 at 23:29, Petr Jelinek <petr@2ndquadrant.com> wrote:

> You could put it to txid.c where all the other txid stuff is in?

Yeah, even though it's in adt/ I think it'll do.

I thought I'd need get_xid_in_recent_past() for catalog_xmin hot
standby feedback, but upon closer examination the needed logic isn't
the same anymore. txid_status() wants to ensure clog lookups are safe
and limit by oldest xid, wheras the walsender doesn't actually care
about that and is just avoiding wrapped xids.

I'm just going back to how it was, all in adt/txid.c, and making it
static again. We can move it and make it non-static if a need to do so
comes up.

Attached rebased patch updated and vs master.

-- 
 Craig Ringer                   http://www.2ndQuadrant.com/
 PostgreSQL Development, 24x7 Support, Training & Services

Commits

  1. Add a txid_status function.

  2. Track the oldest XID that can be safely looked up in CLOG.