Re: slow query

IMO, Ila, y'all need more structure in your data design and storage,
anticipating these questions that need fast answers.  Can't just lob
data into a haystack and expect to be able to find it without
computational work.

 - jtg

On Tue, 16 May 2006 16:33:30 -0700, "Ilavajuthy Palanisamy"
<[email protected]> said:
> Hi,
>
>
>
> I have a merged table with 35 million records, the below query takes
> around 40 mins to return.
>
>
>
> mysql> explain select distinct userid from mfs ;
>
> +----+-------------+-------+-------+---------------+------------------
> +- --------+------+----------+-------------+
>
> | id | select_type | table | type  | possible_keys | key
> | |
> key_len | ref  | rows     | Extra       |
>
> +----+-------------+-------+-------+---------------+------------------
> +- --------+------+----------+-------------+
>
> |  1 | SIMPLE      | mfs   | index | NULL          |
> |  mfs_userId_Index |
> 8 | NULL | 35539364 | Using index |
>
> +----+-------------+-------+-------+---------------+------------------
> +- --------+------+----------+-------------+
>
>
>
> There are approx 20K distinct userid are available.
>
>
>
> The show processlist stays in 'Sending Data' state for the complete
> query period (i.e. 40 mins).
>
>
>
> 502 | root | localhost:4166 | webnmsdb | Query   |  361 | Sending data
> | select distinct userid from mfs
>
>
>
> If I add a limit say limit 100 then it returns in 8 secs.
>
>
>
> I'm using MYSQL 4.1 on Windows.
>
>
>
> Is there any way to make this query faster?
>
>
>
> Ila.
>
>
>
-- 
Jan Theodore Galkowski   (o°)                    
 [email protected]
 http://tinyurl.com/qty7d



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