Hi,
----- Original Message -----
From: "Fournier Jocelyn [Presence-PC]" <joc@stripped>
To: "Paul Cadach" <paul@stripped>
Cc: <internals@stripped>
Sent: Thursday, September 06, 2001 1:26 PM
Subject: Re: ORDER BY ... DESC LIMIT 1 optimization ?
> It doesn't change anything, the query is still slow.
Can you show results of:
select count(*) from threadhardwarefr7
and
select count(*) from threadhardwarefr7 where numeropost=5347
May be better to do some optimizations or additional fast queries to
minimize selection count? One solution is to have additional table, say
threadhardwarefr7_stats, with fields numeropost and max_numresponse, which
updates when new post is done with next query:
update threadhardwarefr7_stats set max_numresponse=<current_reponse_id>
where numeropost=<value for this post>
then you do next selects:
select max_numresponse from threadhardwarefr7_stats where
numeropost=<value of numeropost>
and
SELECT contenu,pseudo,signature FROM threadhardwarefr7 WHERE
numeropost=<value of numeropost> and num_response=<value of previous select>
At least this will be fastest as possible (unique index on
(numeropost,num_response) must be exists to fetch single row with previous
query fast).
WBR,
Paul.
