November 23, 2014

OOM relation to vm.swappiness=0 in new kernel

I have recently been involved in diagnosing the reasons behind OOM invocation that would kill the MySQL server process. Of course these servers were primarily running MySQL. As such the MySQL server process was the one with the largest amount of memory allocated. But the strange thing was that in all the cases, there was […]

kernel_mutex problem cont. Or triple your throughput

This is to follow up my previous post with kernel_mutex problem. First, I may have an explanation why the performance degrades to significantly and why innodb_sync_spin_loops may fix it. Second, if that is correct ( or not, but we can try anyway), than playing with innodb_thread_concurrency also may help. So I ran some benchmarks with […]

kernel_mutex problem. Or double throughput with single variable

Problem with kernel_mutex in MySQL 5.1 and MySQL 5.5 is known: Bug report. In fact in MySQL 5.6 there are some fixes that suppose to provide a solution, but MySQL 5.6 yet has long way ahead before production, and it is also not clear if the problem is really fixed. Meantime the problem with kernel_mutex […]

Optimizing MySQL for Zabbix

This blog post was inspired by my visit at the annual Zabbix Conference in Riga, Latvia this year, where I gave a couple of talks on MySQL and beyond. It was a two day single-track event with some 200 participants, a number of interesting talks on Zabbix (and related technologies) and really well-organized evening activities. […]

Facebook MySQL database engineers ready for Percona Live London 2014

With 1.28 billion active users, Facebook MySQL database engineers are active and extremely valuable contributors to the global MySQL community. So naturally they are also active participants of Percona Live MySQL conferences! And next week’s Percona Live London 2014 (Nov. 3-4) is no exception. (Register now and use the promotional code “Facebook” to save £30!) […]

Percona XtraBackup 2.2.5 now available (free MySQL hot backup software)

Percona is glad to announce the release of Percona XtraBackup 2.2.5 on October 2, 2014. Downloads are available from our download site here and Percona Software Repositories. Percona XtraBackup enables MySQL backups without blocking user queries, making it ideal for companies with large data sets and mission-critical applications that cannot tolerate long periods of downtime. […]

Galera replication – how to recover a PXC cluster

Galera replication for MySQL brings not only the new, great features to our ecosystem, but also introduces completely new maintenance techniques. Are you concerned about adding such new complexity to your MySQL environment? Perhaps that concern is unnecessarily. I am going to present here some simple tips that hopefully will let fresh Galera users prevent […]

Benchmarking IBM eXFlash™ DIMM with sysbench fileio

Diablo Technologies engaged Percona to benchmark IBM eXFlash™ DIMMs in various aspects. An eXFlash™ DIMM itself is quite an interesting piece of technology. In a nutshell, it’s flash storage, which you can put in the memory DIMM slots. Enabled by Diablo’s Memory Channel Storage™ technology, this practically means low latency and some unique performance characteristics. These […]

Why TokuDB hates Transparent HugePages

If you try to install the TokuDB storage engine on a modern Linux distribution it might fail with following error message: 2014-07-17 19:02:55 13865 [ERROR] TokuDB will not run with transparent huge pages enabled. 2014-07-17 19:02:55 13865 [ERROR] Please disable them to continue. 2014-07-17 19:02:55 13865 [ERROR] (echo never > /sys/kernel/mm/transparent_hugepage/enabled) You might be curious […]

Systemtap solves phantom MySQLd SIGTERM / SIGKILL issue

The Percona Managed Services team recently faced a somewhat peculiar client issue. We’d receive pages about their MySQL service being unreachable. However, studying the logs showed nothing out of the ordinary…. for the most part it appeared to be a normal shutdown and there was nothing in anyone’s command history nor a cron task to speak […]