Hi,
> ----- Original Message -----
> From: Fournier Jocelyn [Presence-PC]
> To: Timothy Smith
> Cc: internals@stripped
> Sent: Thursday, September 06, 2001 6:31 AM
> Subject: Re: ORDER BY ... DESC LIMIT 1 optimization ?
>
>
> BTW, here is the EXPLAIN + INDEX structure :
>
> mysql> EXPLAIN SELECT contenu,pseudo,signature FROM threadhardwarefr7
WHERE
> numeropost=5347
> -> ORDER BY numreponse DESC LIMIT 1;
>
+-------------------+------+---------------+---------+---------+-------+----
> --+----------------------------+
> | table | type | possible_keys | key | key_len | ref |
> rows | Extra |
>
+-------------------+------+---------------+---------+---------+-------+----
> --+----------------------------+
> | threadhardwarefr7 | ref | PRIMARY | PRIMARY | 3 | const |
> 6475 | where used; Using filesort |
>
+-------------------+------+---------------+---------+---------+-------+----
> --+----------------------------+
> 1 row in set (0.00 sec)
As I see your problem is that you don't have any indices at numeropost
column. Just add unique (preferred) or non-unique index to this column and
compare select speed...
[skip]
WBR,
Paul.
