Horton

Re: Win2K Questions

Neil Conway <neilc@samurai.com>

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From: Neil Conway <neilc@samurai.com>
To: Jean-Luc Lachance <jllachan@nsd.ca>
Cc: "scott.marlowe" <scott.marlowe@ihs.com>, Bruce Momjian <pgman@candle.pha.pa.us>, "Charles H. Woloszynski" <chw@clearmetrix.com>, Richard Huxton <dev@archonet.com>, pgsql-general@postgresql.org
Date: 2002-11-08T23:26:01Z
Lists: pgsql-general 
Jean-Luc Lachance <jllachan@nsd.ca> writes:
> unless id is indexed there is nothing that can be done with 
> select count(*) from table where id >10000;
> Otherwise, the index should be scanned, not the table.

Indexes don't store heap tuple visibility information; you'd need to
scan the heap as well in order to determine which tuples your
transaction can see.

Cheers,

Neil

-- 
Neil Conway <neilc@samurai.com> || PGP Key ID: DB3C29FC