MySQL Performance: MySQL => From time to time very slow UPDATE

Members

Help

Home

Home » Performance » MySQL » From time to time very slow UPDATE

Show: Today's Messages :: Show Polls :: Message Navigator

From time to time very slow UPDATE [message #978]

Fri, 23 March 2007 13:23

4matic
Messages: 2
Registered: March 2007

Junior Member

I have a system:
Windows XP SP2
MySQL 5.0.27
PHP 5.2.0 (mysqli ext)

CREATE TABLE `parts` (                                
          `partid` int(10) unsigned NOT NULL auto_increment,  
          `oenumsearch` char(30) NOT NULL,                    
          `tmid` smallint(5) unsigned NOT NULL default '0',   
          `oenum` char(35) NOT NULL,                          
          `isset` smallint(5) unsigned default '0',           
          `numtypeid` smallint(5) unsigned default '0',       
          `textid` int(10) unsigned default NULL,             
          `texts` char(255) default NULL,                     
          `isttx` tinyint(1) unsigned NOT NULL default '0',   
          `isimg` tinyint(1) unsigned NOT NULL default '0',   
          `isauto` tinyint(1) unsigned NOT NULL default '0',  
          `remarks` char(255) default NULL,                   
          PRIMARY KEY  (`partid`),                            
          KEY `tmid` (`tmid`),                                
          KEY `oenums` (`oenumsearch`,`tmid`),                
          KEY `oenumsearch` (`oenumsearch`),                  
          KEY `isset` (`isset`),                              
          KEY `numtypeid` (`numtypeid`),                      
          KEY `textid` (`textid`)                             
        ) ENGINE=InnoDB

I start transaction and update some tables. One of the updated tables is `parts`. When start query:

UPDATE `parts` SET `textid`=1471, `texts`="Some text" WHERE `partid`=47437

Database is stuck, and query executed about 300-400 seconds. In this time I cant start another query. Another query is wait while ends query for update.
This stuks is happend form time to time. Only one client sends query, thats means database is not busy.

Where looking for problem? I dont uderstand what to do. Help me, please.

P.S. Sorry for my dreadful English, my native language is PHP Smile

[Updated on: Fri, 23 March 2007 13:31]

Report message to a moderator

Re: From time to time very slow UPDATE [message #982 is a reply to message #978 ]

Sun, 25 March 2007 11:01

Speeple
Messages: 91
Registered: August 2006

Member

How many rows does this table have?

You have a quite a few indexes which will slow down updates.

Also note that KEY `oenumsearch` (`oenumsearch`) is a redundent index. Key lookups on the column oenumsearch can happily be performed on the KEY `oenums` (`oenumsearch`,`tmid`) index.

Martin Gallagher | Speeple: The latest news

Report message to a moderator

Re: From time to time very slow UPDATE [message #985 is a reply to message #982 ]

Mon, 26 March 2007 03:20

4matic
Messages: 2
Registered: March 2007

Junior Member

Quote:

Also note that KEY `oenumsearch` (`oenumsearch`) is a redundent index. Key lookups on the column oenumsearch can happily be performed on the KEY `oenums` (`oenumsearch`,`tmid`) index.

Thanks. I will drop this index. I knew this, but I did this for sure.

Quote:

How many rows does this table have?

About 7 000 000 and still growing. It will stop about 20 000 000 rows.

Quote:

You have a quite a few indexes which will slow down updates

I understand, that indexes is slow down updates. I dont understand, why one update fast, another update - slow?

Report message to a moderator

Previous Topic:	Is This ODBC connectivity error or VB application error
Next Topic:	Slow query

Goto Forum:

-=] Back to Top [=-

[ Generate printable PDF ] [ Syndicate this forum (XML) ] [

]

Current Time: Thu Jan 8 23:10:56 EST 2009

Total time taken to generate the page: 0.06754 seconds

.:: Contact :: Home :: MySQL Support by Percona.com ::.