MyISAM storage engine has key compression which makes its indexes much smaller, allowing better fit in caches and so improving performance dramatically. Actually packed indexes not a bit longer rows is frequent reason of MyISAM performing better than Innodb. In this article I’ll get in a bit more details about packed keys and performance […]Read more
In MySQL 5.0.19 the meaning of innodb_thread_concurrency variable was changed (yeah, again).
Now innodb_thread_concurrency=0 means unlimitied count of concurrent threads inside InnoDB. It’s logical, but there was long way. In MySQL versions below 5.0.8 for unlimited threads you had to set innodb_thread_concurrency over 500 (and default value for innodb_thread_concurrency was 8 ).
Starting with MySQL 5.0.8, […]
Thinking more about the problems I wrote about yesterday I had a question why so ugly workaround and guesses or manual configuration is needed ? The answer seems to be Operation Interfaces just do not provide IO interface which is good enough. The big missing piece is priority. There are process and threads priorities […]Read more
As you might know Innodb storage engines uses Fuzzy Checkpointing technique as part of it recovery strategy.Â It is very nice approach which means database never needs to “stall” to perform total modified pages flush but instead flushing of dirty pages happens gradually in small chunks so database load is very even.
This works great […]
During the recent months I’ve seen few cases of customers upgrading to MySQL 5.0 and having serious performance slow downs, up to 10 times in certain cases. What was the most surprising for them is the problem was hardware and even OS specific – it could show up with one OS version but not […]Read more