Sometimes due to programming error or due to very complex query you can get your PHP script running too long, well after user stopped waiting for the page to render and went browsing other sites. Looking at Server-Status I’ve seen scripts executing for hours sometimes which is obviously the problem – they take Apache Slot, [...]
Using LoadAvg for Performance Optimization
December 4, 2006 By 5 Comments
Linux and Unixes have excellent metric of system load called “loadavg”. In fact load average is is 3 numbers which correspond to “load average” calculated for one five and 15 minutes. It is computed as exponential moving average so most recent load have more weight in the value than old one. What does Load Average [...]
Slow Query Log analyzes tools
September 6, 2006 By 84 Comments
MySQL has simple but quite handy feature – slow query log, which allows you to log all queries which took over define number of seconds to execute. There is also an option to enable logging queries which do not use indexes even if they take less time (–log-queries-not-using-indexes) Slow query log is great to spot [...]
MySQL Server Variables – SQL layer or Storage Engine specific.
June 8, 2006 By 14 Comments
MySQL Server has tons of variables which may be adjusted to change behavior or for performance purposes. They are documented in the manual as well as on new page Jay has created. Still I see constant confusion out where which of variables apply to storage engines only and which are used on SQL layer and [...]
MySQL Server Memory Usage
May 17, 2006 By 21 Comments
Every so often people ask me the question how should they estimate memory consumption by MySQL Server in given configuration. What is the formula they could use. The reasons to worry about memory usage are quite understandable. If you configure MySQL Server so it uses too small amount of memory it will likey perform suboptimally. [...]
