Since my first post on MySQL transaction descriptors optimization introduced in Percona Server 5.5.30-30.2 and a followup by Dimitri Kravchuk, we have received a large number of questions on why the benchmark results in both posts look rather different. We were curious as well, so we tried to answer that question by retrying benchmarks on [...]
Testing MySQL column stores
August 16, 2010 By 15 Comments
Recently I had the opportunity to do some testing on a large data set against two MySQL column-store storage engines. I’d like to note that this effort was sponsored by Infobright, but this analysis reflects my independent testing from an objective viewpoint. I performed two different types of testing. The first focused on core functionality [...]
Goal driven performance optimization
December 22, 2008 By Leave a Comment
When your goal is to optimize application performance it is very important to understand what goal do you really have. If you do not have a good understanding of the goal your performance optimization effort may well still bring its results but you may waste a lot of time before you reach same results as [...]
Speeding up GROUP BY if you want aproximate results
March 7, 2008 By 24 Comments
Doing performance analyzes today I wanted to count how many hits come to the pages which get more than couple of visits per day. We had SQL logs in the database so It was pretty simple query:
1 | select sum(cnt) from (select count(*) cnt from performance_log_080306 group by page having cnt>2) pv; |
Unfortunately this query ran for over half an hour badly overloaded server and I had to kill [...]
