April 19, 2014

Useful MySQL 5.6 features you get for free in PXC 5.6

I get a lot of questions about Percona XtraDB Cluster 5.6 (PXC 5.6), specifically about whether such and such MySQL 5.6 Community Edition feature is in PXC 5.6.  The short answer is: yes, all features in community MySQL 5.6 are in Percona Server 5.6 and, in turn, are in PXC 5.6.  Whether or not the new […]

QA: Advanced Option Combinatorics (Pairwise Testing): Combinatorial mysqld Option Test Case Generation

How do we ensure that, when we have 35+ testable option combinations for mysqld, we test each and every combination of them? For example: will a different innodb_log_file_size combined with more innodb_log_files_in_group and a modified innodb_fast_shutdown setting truly not affect Percona’s log archiving feature? Most option-related bugs are caused by the setting of 1 or […]

InnoDB adaptive flushing in MySQL 5.6: checkpoint age and io capacity

In MySQL 5.6 InnoDB has a dedicated thread (page_cleaner) that’s responsible for performing flushing operations. Page_cleaner performs flushing of the dirty pages from the buffer pool based on two factors: – access pattern  -  the least recently used pages will be flushed by LRU flusher from LRU_list when buffer pool has no free pages anymore; […]

MySQL 5.6 New Replication Features: Webinar followup Q&A

I want to thank all attendees of my webinar, “MySQL 5.6 New Replication Features: Benefits, Challenges and Limitations“. We had questions that I didn’t have the time to answer: Q: If I run on Amazon’s RDS, do I need to worry about enabling crash-safe slaves, or is that already in place? A: Crash-safe replication is […]

High-availability options for MySQL, October 2013 update

The technologies allowing to build highly-available (HA) MySQL solutions are in constant evolution and they cover very different needs and use cases. In order to help people choose the best HA solution for their needs, we decided, Jay Janssen and I, to publish, on a regular basis (hopefully, this is the first), an update on […]

Designing one to many relations – MongoDB vs MySQL

We already discussed one to one relations in MongoDB, and the main conclusion was that you should design your collections according to the most frequent access pattern. With one to many relations, this is still valid, but other factors may come into play. Let’s look at a simple problem: we are a shop and we […]

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 […]

Handling long-running queries in MySQL with Percona XtraBackup

I recently had a case where replication lag on a slave was caused by a backup script. First reaction was to incriminate the additional pressure on the disks, but it turned out to be more subtle: Percona XtraBackup was not able to execute FLUSH TABLES WITH READ LOCK due to a long-running query, and the […]

Tuning MySQL 5.6 configuration – Webinar followup

We had a wonderful time during the Sept. 25 webinar, “MySQL 5.6 Configuration Optimization,” and I got a lot more questions than I could answer during the hour. So here is a followup with answers to the most interesting questions you guys asked. (You can also watch a recording of entire webinar here.) Q: What […]

MySQL 5.7 multi-source replication

Recently Oracle announced several new features for the latest available development version of MySQL that is 5.7.2 at the time of writing this article. Most of them are performance and replication related that show us how incredible the new release will be. In this post I’m going to try to explain in some easy steps […]