Horton

Re: COUNT(*) again (was Re: [HACKERS] Index/Function organized table layout)

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

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Bruce Momjian <pgman@candle.pha.pa.us>
Cc: Hannu Krosing <hannu@tm.ee>, Christopher Browne <cbbrowne@libertyrms.info>, pgsql-performance@postgresql.org, "pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>
Date: 2003-10-05T06:08:31Z
Lists: pgsql-hackers, pgsql-performance 
Bruce Momjian <pgman@candle.pha.pa.us> writes:
> Tom Lane wrote:
>> I think that's not happening, conditionally or otherwise.  The atomicity
>> problems alone are sufficient reason why not, even before you look at
>> the performance issues.

> What are the atomicity problems of adding a create/expire xid to the
> index tuples?

You can't update a tuple's status in just one place ... you have to
update the copies in the indexes too.

			regards, tom lane