HandlerSocket has really generated a lot of interest because of the dual promises of ease-of-use and blazing-fast performance. The performance comes from eliminating CPU consumption. Akira Higuchi’s HandlerSocket presentation from a couple of months back had some really good profile results for libmysql versus libhsclient (starting at slide 15). Somebody in the audience at Percona […]
Understanding how well your tables and indexes fit to buffer pool are often very helpful to understand why some queries are IO bound and others not – it may be because the tables and indexes they are accessing are not in cache, for example being washed away by other queries. MySQL Server does not provide […]
Innodb/XtraDB tables do benefit from being reorganized often. You can get data physically laid out in primary key order as well as get better feel for primary key and index pages and so using less space, it is just OPTIMIZE TABLE might not be best way to do it. If you’re running Innodb Plugin on […]
I’ve been talking and writing a bit lately about the scaling problems I’m seeing on fast servers running lots of queries. As a rough guide, I’m seeing this in servers running 20k queries per second and higher, lots of memory, lots of CPU cores, and most queries are running faster than one millisecond; some in […]
When replication runs out of sync first question you often ask is if someone could be writing to the slave. Of course there is read_only setting which is good to set in the slave but it is not set always and also users with SUPER privilege bypass it. Looking into binary log is obvious choice […]
So you’re running the benchmark/stress test – how do you tell if MySQL server is really loaded ? This looks like the trivial question but in fact, especially when workload consists of simple queries I see the load generation and network really putting a lot less load on MySQL than expected. For example you may […]
A while back Friendfeed posted a blog post explaining how they changed from storing data in MySQL columns to serializing data and just storing it inside TEXT/BLOB columns. It seems that since then, the technique has gotten more popular with Ruby gems now around to do this for you automatically.
I had an interesting case recently. The customer dealing with large MySQL data warehouse had the table which was had data merged into it with INSERT ON DUPLICATE KEY UPDATE statements. The performance was extremely slow. I turned out it is caused by hundreds of daily partitions created for this table. What is the most […]
In the next week, I’ll be interviewing Paul McCullagh, the architect behind the PBXT storage engine. If you have any questions for Paul, please post them here by Monday 16th November. Note: The idea for this interview was inspired by a previous interview with Heikki Tuuri – creator of InnoDB. You can see the answers […]
One question which comes up very often is when one should use SAN with MySQL, which is especially popular among people got used to Oracle or other Enterprise database systems which are quite commonly deployed on SAN. My question in such case is always what exactly are you trying to get by using SAN ?