On the weekend, I upgraded the database engine for GrabPERF to Mysql 5.1 and switched the main data table from MyISAM to InnoDB. The switch to InnoDB was done because of the locking issues that were occurring during long queries, especially when doing ad-hoc analysis. The row-level (versus table-lev...

We finally managed to get Intel X25-E SSD drive into our lab. I attached it to our Dell PowerEdge R900. The story making it running is worth separate mentioning - along with Intel X25-E I got HighPoint 2300 controller and CentOS 5.2 just could not start with two RAID controllers (Perc/6i and HighPoi...

Today we announce release 1.0.2-3 of our XtraDB storage engine. Here is a list of enhancements: Move to MySQL 5.1.31 Scalability fix — ability to use several rollback segments Increasing the number of rseg may be helpful for CPU scale of write-intentional workloads. See benchmark results. Scalabil...

If you are using InnoDB Hot Backup utility and the innobackup.pl wrapper script, be very careful if you are not running backups under the system mysql user. There is a bug which causes InnoDB Hot Backup to sometimes report a successful backup when it actually failed. (more…)...

If you are using InnoDB Hot Backup and a recent version of mysqld (at least 5.0.67 or higher, including 5.1.30, though it may be later versions), your backup will run fine and output OK! at the end, as it should. Except for one thing. The binary log file and position do not appear in their rightful ...

One of InnoDB’s features is that memory allocated for internal tables definitions is not limited and may grow indefinitely. You may not notice it if you have an usual application with say 100-1000 tables. But for hosting providers and for user oriented applications ( each user has dedicated da...

Are you running MySQL on Debian or Ubuntu with InnoDB? You might want to disable /etc/mysql/debian-start. When you run /etc/init.d/mysql start it runs this script, which runs mysqlcheck, which can destroy performance. It can happen on a server with MyISAM tables, if there are enough tables, but it i...

Had an interesting situation come up today with a client. We had a situation where a server crashed because it ran out of memory. The calculation we used to monitor memory usage did not take into account all factors. When looking at this, I noticed a couple of things: There are numerous calculations...

Recently I wrote about InnoDB scalability on 24-core box, and we made research of scalability problems in sysbench write workload (benchmark emulates intensive insert/delete queries). By our results the problem is in concurrency on rollback segment, which by default is single and all transactions ar...

Despite being standard Innodb feature forever Insert Buffers remains some kind of mysterious thing for a lot of people, so let me try to explain thing a little bit. Innodb uses insert buffer to “cheat” and not to update index leaf pages when at once but “buffer” such updates ...