Comments on: MySQL Slow? Check for Fragmentation. http://blog.softlayer.com/2011/mysql-slow-check-for-fragmentation/ A Behind the Scenes Look at the Best Hosting Provider in the World Wed, 22 May 2013 17:40:38 +0000 hourly 1 http://wordpress.org/?v=3.4.1 By: MySQL Check For Fragmentation http://blog.softlayer.com/2011/mysql-slow-check-for-fragmentation/comment-page-1/#comment-47545 MySQL Check For Fragmentation Mon, 22 Apr 2013 17:53:20 +0000 http://blog.softlayer.com/2011/#comment-47545 [...] I was working with a mail archive MySQL database today and was twiddling my thumbs waiting for simple queries to complete.  The database has about 12 million rows and is on a 2x2GHz 2GB Linux Server x64.  I wanted to try to optimize the database and found this little gem from Lee at SoftLayer blog post. [...] [...] I was working with a mail archive MySQL database today and was twiddling my thumbs waiting for simple queries to complete.  The database has about 12 million rows and is on a 2x2GHz 2GB Linux Server x64.  I wanted to try to optimize the database and found this little gem from Lee at SoftLayer blog post. [...]

]]> By: PC http://blog.softlayer.com/2011/mysql-slow-check-for-fragmentation/comment-page-1/#comment-47460 PC Wed, 17 Apr 2013 12:51:17 +0000 http://blog.softlayer.com/2011/#comment-47460 Thanks Lee.. Thanks Lee..

]]> By: Steve http://blog.softlayer.com/2011/mysql-slow-check-for-fragmentation/comment-page-1/#comment-44136 Steve Sun, 28 Oct 2012 23:45:56 +0000 http://blog.softlayer.com/2011/#comment-44136 in your SQL statement, I reckon the data free should be greater than zero, not less than... otherwise, good article :) in your SQL statement, I reckon the data free should be greater than zero, not less than…
otherwise, good article :)

]]> By: Jordan http://blog.softlayer.com/2011/mysql-slow-check-for-fragmentation/comment-page-1/#comment-43541 Jordan Sun, 14 Oct 2012 23:36:30 +0000 http://blog.softlayer.com/2011/#comment-43541 If your site is that important that it needs a defrag, a planned maintenance isn't the end of the world. If your site is that important that it needs a defrag, a planned maintenance isn’t the end of the world.

]]> By: PJ Brunet http://blog.softlayer.com/2011/mysql-slow-check-for-fragmentation/comment-page-1/#comment-40356 PJ Brunet Wed, 20 Jun 2012 19:22:03 +0000 http://blog.softlayer.com/2011/#comment-40356 So what's the trick to defragment automatically without taking the site offline? If anyone knows how do to this I might be willing to pay for a solution because it seems like this is really important to keep things running fast. I just had an issue today where I think fragmented tables took my sites offline. After running mysqlcheck everything was fine but I had to restart mysql and nginx and this took the site offline for a few minutes--not good! Also, is there some way to track down which queries are fragmenting the tables in the first place? Maybe if I can find the root of the problem here... I don't want to deal with this on a regular basis. So what’s the trick to defragment automatically without taking the site offline? If anyone knows how do to this I might be willing to pay for a solution because it seems like this is really important to keep things running fast. I just had an issue today where I think fragmented tables took my sites offline. After running mysqlcheck everything was fine but I had to restart mysql and nginx and this took the site offline for a few minutes–not good! Also, is there some way to track down which queries are fragmenting the tables in the first place? Maybe if I can find the root of the problem here… I don’t want to deal with this on a regular basis.

]]> By: James http://blog.softlayer.com/2011/mysql-slow-check-for-fragmentation/comment-page-1/#comment-40172 James Wed, 13 Jun 2012 18:32:33 +0000 http://blog.softlayer.com/2011/#comment-40172 I believe the query you're using is incorrect. Running this: SELECT TABLE_SCHEMA, TABLE_NAME, CONCAT(ROUND(data_length / ( 1024 * 1024 ), 2), 'MB') DATA, CONCAT(ROUND(data_free / ( 1024 * 1024 ), 2), 'MB') FREE from information_schema.TABLES where TABLE_SCHEMA NOT IN ('information_schema','mysql') and Data_free 0 is I believe what you're looking for. I believe the query you’re using is incorrect. Running this:

SELECT TABLE_SCHEMA, TABLE_NAME, CONCAT(ROUND(data_length / ( 1024 * 1024 ), 2), ‘MB’) DATA, CONCAT(ROUND(data_free / ( 1024 * 1024 ), 2), ‘MB’) FREE from information_schema.TABLES where TABLE_SCHEMA NOT IN (‘information_schema’,'mysql’) and Data_free 0 is I believe what you’re looking for.

]]> By: Lee http://blog.softlayer.com/2011/mysql-slow-check-for-fragmentation/comment-page-1/#comment-28470 Lee Wed, 28 Sep 2011 17:53:21 +0000 http://blog.softlayer.com/2011/#comment-28470 Ricardo, Perfect example of using the tools of MySQL. You are correct it will do the optimize and repair. There are some bugs with mysqlcheck , for example mysqlcheck is 0, althought the corruption is detected. I do believe this was fixed for and I noticed this on a recent upgrade of MySQL using mysql_upgrade. There is no reason not to trust MySQL tools. Thank you. Ricardo,
Perfect example of using the tools of MySQL. You are correct it will do the optimize and repair.

There are some bugs with mysqlcheck , for example mysqlcheck is 0, althought the corruption is detected. I do believe this was fixed for and I noticed this on a recent upgrade of MySQL using mysql_upgrade. There is no reason not to trust MySQL tools.

Thank you.

]]> By: Ricardo Klein http://blog.softlayer.com/2011/mysql-slow-check-for-fragmentation/comment-page-1/#comment-28283 Ricardo Klein Wed, 21 Sep 2011 12:02:11 +0000 http://blog.softlayer.com/2011/#comment-28283 Lee, why not use only: mysqlcheck -Aao -auto-repair -u root -p"$MYSQLPWD" I mean, this will rebuild and optimize all tables in the MySQL instance... like your script, right? Lee,

why not use only:
mysqlcheck -Aao -auto-repair -u root -p”$MYSQLPWD”

I mean, this will rebuild and optimize all tables in the MySQL instance… like your script, right?

]]> By: Lee http://blog.softlayer.com/2011/mysql-slow-check-for-fragmentation/comment-page-1/#comment-27402 Lee Fri, 19 Aug 2011 15:07:12 +0000 http://blog.softlayer.com/2011/#comment-27402 Rob, You are correct, for a site that relies on the the database, you will need to discover other ways. One way I use this is to run the script on the slave and then change my config script to use the slave and rebuild the master. This usually takes less than 1 sec. So there should be no impact to SEO. Rob,
You are correct, for a site that relies on the the database, you will need to discover other ways. One way I use this is to run the script on the slave and then change my config script to use the slave and rebuild the master. This usually takes less than 1 sec. So there should be no impact to SEO.

]]> By: Rob http://blog.softlayer.com/2011/mysql-slow-check-for-fragmentation/comment-page-1/#comment-27373 Rob Tue, 16 Aug 2011 14:38:59 +0000 http://blog.softlayer.com/2011/#comment-27373 My entire web site is 100% data-driven. If I lock the tables, it will bring the entire web site down for a while. The Googlebots are hitting my web site every 30 to 90 seconds. If the site is down when the Googlebot comes and the bot sees that the site is down, it can hurt me in the rankings. How fast the site responds is part of Google's algorithm. It would be nice to copy the entire file some place else, defrag it and then move it back. My entire web site is 100% data-driven. If I lock the tables, it will bring the entire web site down for a while. The Googlebots are hitting my web site every 30 to 90 seconds. If the site is down when the Googlebot comes and the bot sees that the site is down, it can hurt me in the rankings. How fast the site responds is part of Google’s algorithm. It would be nice to copy the entire file some place else, defrag it and then move it back.

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