Yes.. There is an index on users.username :)
David
----- Original Message -----
From: "Tore Van Grembergen" <[EMAIL PROTECTED]>
To: "David Wolf" <[EMAIL PROTECTED]>; <[EMAIL PROTECTED]>
Sent: Sunday, October 28, 2001 8:46 AM
Subject: Re: Optimizing query (2nd attempt)
> do you have an index defined on users.username ?
>
>
> ----- Original Message -----
> From: "David Wolf" <[EMAIL PROTECTED]>
> To: <[EMAIL PROTECTED]>
> Sent: Sunday, October 28, 2001 4:26 PM
> Subject: Optimizing query (2nd attempt)
>
>
> > I have a query as follows:
> >
> > SELECT log.entity, log.action,
> > LEFT(users.username,10) AS username,
> > LEFT(boards.title,15) AS Board,
> > LEFT(topics.subject,22) as Subject,
> > log.postid, log.extraid,
> > LEFT(from_unixtime(log.logtime),19) AS time, log.ip
> > FROM log LEFT JOIN users ON log.userid = users.id
> > LEFT JOIN boards ON log.boardid=boards.id
> > LEFT JOIN topics ON log.topicid = topics.id
> > WHERE log.logTime > UNIX_TIMESTAMP("2000-10-26 23:00:00")
> > AND users.username="testuser";
> >
> > When I run an 'explain' on it, I get:
> >
> >
>
+--------+--------+---------------+---------+---------+-------------+-------
> > --+------------+
> > | table | type | possible_keys | key | key_len | ref |
rows
> > | Extra |
> >
>
+--------+--------+---------------+---------+---------+-------------+-------
> > --+------------+
> > | log | ALL | time | NULL | NULL | NULL |
> > 1192384 | where used |
> > | users | eq_ref | PRIMARY | PRIMARY | 4 | log.userId |
> > 1 | where used |
> > | boards | eq_ref | PRIMARY | PRIMARY | 4 | log.boardId |
> > 1 | |
> > | topics | eq_ref | PRIMARY | PRIMARY | 4 | log.topicId |
> > 1 | |
> >
>
+--------+--------+---------------+---------+---------+-------------+-------
> > --+------------+
> > 4 rows in set (0.01 sec)
> >
> > Now.. If I exclude the 'users.username="testuser"' and substitute it for
> the
> > userid that I got in a previous query (i.e. userid=2) so that the query
> > becomes:
> >
> > SELECT log.entity, log.action,
> > LEFT(users.username,10) AS username,
> > LEFT(boards.title,15) AS Board,
> > LEFT(topics.subject,22) as Subject,
> > log.postid, log.extraid,
> > LEFT(from_unixtime(log.logtime),19) AS time, log.ip
> > FROM log LEFT JOIN users ON log.userid = users.id
> > LEFT JOIN boards ON log.boardid=boards.id
> > LEFT JOIN topics ON log.topicid = topics.id
> > WHERE log.logTime > UNIX_TIMESTAMP("2000-10-26 23:00:00")
> > AND log.userid=2;
> >
> >
> > and run an explain, I get...
> >
> >
>
+--------+--------+---------------+---------+---------+-------------+-------
> > +------------+
> > | table | type | possible_keys | key | key_len | ref |
rows
> > | Extra |
> >
>
+--------+--------+---------------+---------+---------+-------------+-------
> > +------------+
> > | log | ref | time,userid | userid | 4 | const |
> 27198
> > | where used |
> > | users | eq_ref | PRIMARY | PRIMARY | 4 | log.userId |
> 1
> > | |
> > | boards | eq_ref | PRIMARY | PRIMARY | 4 | log.boardId |
> 1
> > | |
> > | topics | eq_ref | PRIMARY | PRIMARY | 4 | log.topicId |
> 1
> > | |
> >
>
+--------+--------+---------------+---------+---------+-------------+-------
> > +------------+
> > 4 rows in set (0.00 sec)
> >
> > Big difference from 1.19million rows to 27198 rows... My question is
this.
> > How can I optimize the query with the left joins so that the optimizer
> will
> > first grab the userid from the username and then use the userid index on
> log
> > to return the results fast?
> >
> > Thanks in advance,
> >
> > David
> >
> >
> >
> >
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> >
>
>
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