April 25, 2014

Read Buffers, mmap, malloc and MySQL Performance

Monty Taylor posted interesting investigation of the fact read_buffer_size variable affects connection speed. This is not something you would expect right ? me too. Not only global user data is expected to be cached on startup but even if it is not why would you do full table scan to fetch single user information ? […]

What exactly is read_rnd_buffer_size

Looking for documentation for read_rnd_buffer_size you would find descriptions such as “The read_rnd_buffer_size is used after a sort, when reading rows in sorted order. If you use many queries with ORDER BY, upping this can improve performance” which is cool but it does not really tell you how exactly read_rnd_buffer_size works as well as which […]

Are larger buffers always better ?

Sometimes I see people thinking about buffers as “larger is always better” so if “large” MySQL sample configuration is designed for 2GB and they happen to have 16, they would simply multiply all/most values by 10 and hope it will work well. Obviously it does not. The least problem would be wasting memory, allocating a […]

Innodb redo log archiving

Percona Server 5.6.11-60.3 introduces a new “log archiving” feature. Percona XtraBackup 2.1.5 supports “apply archived logs.” What does it mean and how it can be used? Percona products propose three kinds of incremental backups. The first is full scan of data files and comparison the data with backup data to find some delta. This approach […]

Notes from the Newb

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 […]

Q&A: Common (but deadly) MySQL Development Mistakes

On Wednesday I gave a presentation on “How to Avoid Common (but Deadly) MySQL Development Mistakes” for Percona MySQL Webinars. If you missed it, you can still register to view the recording and my slides. Thanks to everyone who attended, and especially to folks who asked the great questions. I answered as many as we had time […]

Percona Server: Thread Pool Improvements for Transactional Workloads

In a previous thread pool post, I mentioned that in Percona Server we used an open source implementation of MariaDB’s thread pool, and enhanced/improved it further. Below I would like to describe some of these improvements for transactional workloads. When we were evaluating MariaDB’s thread pool implementation, we observed that it improves scalability for AUTOCOMMIT […]

MySQL server memory usage troubleshooting tips

There are many blog posts already written on topics related to “MySQL server memory usage,” but nevertheless there are some who still get confused when troubleshooting issues associated with memory usage for MySQL. As a Percona support engineer, I’m seeing many issues regularly related to heavy server loads – OR OOM killer got invoked and […]

The power of MySQL’s GROUP_CONCAT

In the very early days of Percona Vadim wrote very nice post about GROUP_CONCAT. But I want to show you a bit more about it. When is GROUP_CONCAT useful? Usually while working with Support customers I recommend it when you have aggregation of many-to-many info. It makes the view simpler and more beautiful and it […]

Innotop: A real-time, advanced investigation tool for MySQL

GUI monitoring tools for MySQL are not always suitable for all our needs or situations. Most of them are designed to provide historical views into what happens to our database over time rather then real-time insight into current MySQL server status. Excellent free tools for this include Cacti, Zabbix, Ganglia, Nagios, etc. But each of […]