RE: slow query
| Newsgroups | gmane.comp.db.mysql.windows |
|---|---|
| Message-ID | <[email protected]> |
What client and client connection (ODBC, .NET Connector, C library etc.) are you using? Your hardware/network environment may also be a factor. With that number of records you should expect it to take a while, but 40 mins seems a bit much! John B. -----Original Message----- From: Ilavajuthy Palanisamy [mailto:[email protected]] Sent: Wednesday, 17 May 2006 9:04 AM To: [email protected] Subject: slow query 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. -- MySQL Windows Mailing List For list archives: http://lists.mysql.com/win32 To unsubscribe: http://lists.mysql.com/[email protected]