One of the most painful troubleshooting tasks with MySQL is troubleshooting memory usage. The problem usually starts like this – you have configured MySQL to use reasonable global buffers, such as innodb_buffer_size, key_buffer_size etc, you have reasonable amount of connections but yet MySQL takes much more memory than you would expect, causing swapping or other […]
I have been working with Peter in preparation for the talk comparing the optimizer enhancements in MySQL 5.6 and MariaDB 5.5. We are taking a look at and benchmarking optimizer enhancements one by one. So in the same way this blog post is aimed at a new optimizer enhancement Index Condition Pushdown (ICP). Its available […]
In this post, I’ll cover the new MySQL monitoring plugins we created for Nagios, and explain their features and intended purpose. I want to add a little context. What problem were we trying to solve with these plugins? Why yet another set of MySQL monitoring plugins? The typical problem with Nagios monitoring (and indeed with […]
This is a time-honored topic, and there’s no shortage of articles on the topic on this blog. I wanted to write a post trying to condense and clarify those posts, as it has taken me a while to really understand this relationship. Some basic facts Most of us know that writing into Innodb updates buffer […]
It is no secret that bugs related to multithreading–deadlocks, data races, starvations etc–have a big impact on application’s stability and are at the same time hard to find due to their nondeterministic nature. Any tool that makes finding such bugs easier, preferably before anybody is aware of their existence, is very welcome.
or… “the case of Stewart recognizing parameters to the read() system call in strace output”. Last week, a colleague asked a question: I have an instance of MySQL with 100 tables and the table_definition_cache set to 1000. My understanding of this is that MySQL won’t revert to opening the FRM files to read the table […]
It is known that MySQL due internal limitations is not able to utilize all CPU and IO resources available on modern hardware. Idea is to run multiple instances of MySQL to gain better performance on Fusion-io ioDrive card. Full report is available in PDF
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.
MySQL 5.5 and Percona Server 5.5 do not solve all scalability problems even for read only workloads. Workloads which got a lot of attention such as Sysbench and DBT2/TPC-C scale pretty well a they got a lot of attention, there can be other quite typical workloads however which do not scale that well. This is […]
Over last few years I’ve been suggesting more people to disable Query Cache than to enable it. It can cause contention problems as well as stalls and due to coarse invalidation is not as efficient as it could be. These are however mostly due to neglect Query Cache received over almost 10 years, with very […]