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

From Tom Lane
Subject Re: Re: [COMMITTERS] pgsql: Augment WAL records for btree delete with GetOldestXmin() to
Date
Msg-id 17024.1264974812@sss.pgh.pa.us
Whole thread Raw
In response to Re: Re: [COMMITTERS] pgsql: Augment WAL records for btree delete with GetOldestXmin() to  (Heikki Linnakangas <heikki.linnakangas@enterprisedb.com>)
Responses Re: Re: [COMMITTERS] pgsql: Augment WAL records for btree delete with GetOldestXmin() to  (Simon Riggs <simon@2ndQuadrant.com>)
List 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


pgsql-hackers by date:

Previous
From: Heikki Linnakangas
Date:
Subject: Re: Re: [COMMITTERS] pgsql: Augment WAL records for btree delete with GetOldestXmin() to
Next
From: Simon Riggs
Date:
Subject: Hot Standby and deadlock detection