Hi,
Read "5.4.3 How MySQL Uses Indexes" from documentation.
Regards,
Gelu
_____________________________________________________
G.NET SOFTWARE COMPANY
Permanent e-mail address : [EMAIL PROTECTED]
[EMAIL PROTECTED]
----- Original Message -----
From: "andy" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Monday, May 20, 2002 1:48 PM
Subject: Join takes way too long. How to optimize this smal query?
> Hi there,
>
> after reading a nice articel on normalisation, I did split my tables and
now
> I am suffering performance lost.
>
> this query (finding out the amount of user which have posted an article on
> germany) takes 4.5 s:
>
> SELECT count(DISTINCT user_recommending)
> FROM recommendations t
> INNER JOIN geo.cities AS c ON t.city_id = c.ID AND c.country_code = 'gm'
>
> Is there a way to optimize it? The recommendationstable has a city and
city
> table has the corresponding country_code.
> So the city table has 2.5 million entries and the recommendations table
> 32733..
>
> Explain results in:
>
> | table | type | possible_keys | key |
> key_len | ref | rows | Extra |
>
+-------+--------+--------------------------+--------------------------+----
> -----+-----------+-------+-------------+
> | t | index | idx_search_engine_cityid | idx_search_for_same_spot |
> 6 | NULL | 32733 | Using index |
> | c | eq_ref | PRIMARY,idx_cp | PRIMARY |
> 3 | t.city_id | 1 | where used |
>
> Has anybody a good trick to solve boost it to a 0. time?
>
> Thanx, Andy
>
>
> ---------------------------------------------------------------------
> Before posting, please check:
> http://www.mysql.com/manual.php (the manual)
> http://lists.mysql.com/ (the list archive)
>
> To request this thread, e-mail <[EMAIL PROTECTED]>
> To unsubscribe, e-mail <[EMAIL PROTECTED]>
> Trouble unsubscribing? Try: http://lists.mysql.com/php/unsubscribe.php
>
>
---------------------------------------------------------------------
Before posting, please check:
http://www.mysql.com/manual.php (the manual)
http://lists.mysql.com/ (the list archive)
To request this thread, e-mail <[EMAIL PROTECTED]>
To unsubscribe, e-mail <[EMAIL PROTECTED]>
Trouble unsubscribing? Try: http://lists.mysql.com/php/unsubscribe.php
