MySQL has a nice feature, slow query log, which allows you to log all queries that exceed a predefined about of time to execute. Peter Zaitsev first wrote about this back in 2006 – there have been a few other posts here on the MySQL Performance Blog since then (check this and this, too) but […]
MySQL and Scaling-up (using more powerful hardware) was always a hot topic. Originally MySQL did not scale well with multiple CPUs; there were times when InnoDB performed poorer with more CPU cores than with less CPU cores. MySQL 5.6 can scale significantly better; however there is still 1 big limitation: 1 SQL query will eventually use only […]
The latest Percona Server release has one new feature: now MEMORY tables can have BLOB and TEXT columns, and VARCHAR columns will not waste space due to implicit extension to CHAR.
Whilst working with a client recently I noticed a large number of temporary tables being created on disk.
show global status like 'Created_tmp%'
| Created_tmp_disk_tables | 91970 |
| Created_tmp_files | 19624 |
| Created_tmp_tables | 1617031 |
For a couple of months there have been no updates to our msl patch, however recently I managed some time to change this. The functionality was extended a little bit and whatâ€™s even more important the patch is available for all the recent MySQL releases. To remind anyone who has not yet come across this […]
Really often in customers’ application we can see a huge tables with varchar/char fields, with small sets of possible values. These are “state”, “gender”, “status”, “weapon_type”, etc, etc. Frequently we suggest to change such fields to use ENUM column type, but is it really necessary (from performance standpoint)? In this post I’d like to present […]
If you’ve been reading enough database related forums, mailing lists or blogs you probably heard complains about MySQL being unable to handle more than 1.000.000 (or select any other number) rows by some of the users. On other hand it is well known with customers like Google, Yahoo, LiveJournal,Technocarati MySQL has installations with many billions […]
Hosting a shared MySQL instance for your internal or external clients (“multi-tenant”) was always a challenge. Multi-tenants approach or a “schema-per-customer” approach is pretty common nowadays to host multiple clients on the same MySQL sever. One of issues of this approach, however, is the lack of visibility: it is hard to tell how many resources (queries, disk, […]
Notes from the Newb. I’m relatively new to MySQL having come from the world of embedded micro-databases, and though I’m pretty familiar with a number of database systems, I’ve discovered that I have a lot to learn about MySQL. As a new member to the Percona team, I thought I’d have an ongoing blog theme […]
This blog, MySQLPerformanceBlog.com, is powered by WordPress, but we never really looked into what kind of queries to MySQL are used by WordPress. So for couple months we ran a Query Analytics (part of Percona Cloud Tools) agent there, and now it is interesting to take a look on queries. Query Analytics uses reports produced […]