Re: Re: [COMMITTERS] pgsql: Augment WAL records for btree delete with GetOldestXmin() to

Tom Lane <tgl@sss.pgh.pa.us>

From: Tom Lane <tgl@sss.pgh.pa.us>
To: Heikki Linnakangas <heikki.linnakangas@enterprisedb.com>
Cc: Simon Riggs <simon@2ndQuadrant.com>, Stefan Kaltenbrunner <stefan@kaltenbrunner.cc>, pgsql-hackers@postgresql.org
Date: 2010-01-31T21:53:32Z
Lists: pgsql-hackers
Heikki Linnakangas <heikki.linnakangas@enterprisedb.com> writes:
> IIRC it was Greg Stark who suggested last time this was discussed that
> we could calculate the exact value for latestRemovedXid in the standby.
> When replaying the deletion record, the standby could look at all the
> heap tuples whose index pointers are being removed, to see which one was
> newest.

This assumes that the standby can tell which heap tuples are being
removed, which I'm not sure is true --- consider the case where the
deletion record is carrying a page image instead of a list of deleted
tuples.  But maybe we could rejigger the representation to make sure
that the info is always available.  In general it sounds like a much
nicer answer.

			regards, tom lane