Last year i’ve gave one of my sites to people who really enjoys from opening undesirable sites on multi-user blogging sites. The site was a Wordpress MU site.

After that day they opened about 5K blogs on that site. 5K site means about 55K tables and 165K files on a single mySQL database. Till last month the site worked fine but after that some problems started to occur.

The main problem was sleeping zombie mysql threads created by wordpress mu. They could not be closed until they reach default wait_timeout (which is about 28800 secs.). So after about 20 process or according to server load mySQL starts to not respond requests and reaches maksimum connection limit.

I searched a lot but could not find out a solution. Here are some explanations to improve performance on high volume wordpress mu sites but those solutions won’t help me much. Was trying to decrease wait_timeout to 30 secs won’t help so much too cause whenever server load reaches high values according to high volume of created threads this timeout value could not help you.

So what i did? I simply closed that site. That’s why that site is not important for me, i’m just making a stress test on Wordpress and Wordpress Mu.

But if you’re planning to use Wordpress MU and you are considering that your site will reach thousands of blogs i will not suggest you to use Wordpress MU. This is experimental ofcourse but i’m sure that it’ll end soon with a failure.

mySQL is a performance devil if you’re using it on your localhost or LAN. But using it on internet as a remote storage server is not mean the performance you got will performance you got in your localhost or LAN.

If you want me to sample it with an absolute ratio i can clearly say that if you’re getting 100% performance in your localhost or LAN you’ll get 15% performance while you’re connecting remote mySQL server over tcp/ip.

There is a one configuration that you can increase performance about 5 to 15 percent. That’s to disable name resolving on mySQL. You can do this by adding a line in your mySQL config (my.cnf or my.ini) after [mysqld] line (if you’re using mysqld standart daemon) : skip-name-resolve

You can test it if you want. This will make move your remote connection performance from 15% to 20 to 30%.

But infact this performance increasement will not fit your needs. It’s still so slow for me to use it. Thus please think twice if you’re willing to use mySQL as a remote database server for your client applications. ( Yeah but still it rocks on localhost or LAN )

You can check how mySQL uses DNS resolve from this document. ( Document mirror on focus on code (16KB) )

net stop mysql
rar a -ag+YYYYMMDDHHMMSS- -rr -r -k -s -m0
      C:\\BACKUPS\\MYSQL-BACKUP.RAR C:\\MYSQL\\data
net start mysql

Save three lines as something.bat or autoexec.bat and then use it by Cron Jobs. Output file names like this :


20060808120000-MYSQL-BACKUP.RAR
20060808120001-MYSQL-BACKUP.RAR
20060808120002-MYSQL-BACKUP.RAR


( Before this you can update you path configuration. You can add a line at the end of PATH variable like this : C:\Program Files\WinRAR\ etc.)

I searched a lot for a good working ajax upload script with simultaneous progress bar. At last i found one. File Chucker is the best i think.

If you need to save binary files to a mySQL database you must see this article first : Binary Data + MySQL + PHP. Thanks to writer for good article.

You know that Wordpress has a very well menu on blog entry pages. In fact that is not only a menu, that is a couple of blocks than can include lots of menus. The blocks are not static, you can drag and drop them. Don’t worry, the script will remember where you move and drop them! I searched for the script if it’s a lib. And at last i found that this is a script created by Brothercake.com. The name of the script is Docking Boxes. It has a lot of features than we can’t mention in here. ( And of course you can view all of the pages at brothercake. Very very nice site with very nice code! )

When using Zeos Database Objects you can encounter some problems about charset. The main charset problem will be that you’re using a charset different than latin1. In this case you can get some errors while showing or fetching data from mySQL.

We have a simple solution :

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You’ve backuped your database using mysqldump utility. Want to transfer your old database schema to your new database on a new server. But when you try to insert your schema you got an error like this :

#1044 - Access denied for user: 'your_user_name@localhost' to database 'your_database'

Why this error occured?

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