Munin graphing of MySQL

While there are many graphing tools out there and we’ve used Munin for a while now. The MySQL plugin for Munin had fallen out of date and the show engine innodb status output changed in 5.5 making some bits of the plugin simply not work any more. Also the show global status has some extra variables so […]

innodb_flush_logs_on_trx_commit and Galera Cluster

We deploy Galera Cluster (in MariaDB) for some clients, and innodb_flush_logs_on_trx_commit is one of the settings we’ve been playing with. The options according to the manual: =0 don’t write or flush at commit, write and flush once per second =1 write and flush at trx commit =2 write log, but only flush once per second The flush […]

Mixing databases usually not optimal

Dan McKinley (Etsy) wrote an [IMHO] insightful article Why MongoDB Never Worked at Etsy. First off, it’s important to realise that it’s not a snipe at MongoDB – it’s a fine tool. The lessons are related to mixing multiple databases in a deployment (administration and monitoring overhead) and the acknowledgement that issues of schema design, […]

Luxbet, MariaDB and Melbourne Cup

Yesterday was Melbourne Cup day in Australia – the biggest annual horse race event in the country, and in the state of Victoria it’s even a public holiday. Open Query does work for Luxbet (part of Tabcorp), and Melbourne Cup day is by far their biggest day of the year in terms of traffic. It’s […]

MySQL Connector/Arduino

Chuck Bell, one of my former colleague from MySQL AB, has created a connector for Arduino to MySQL. So this allows Arduino code to be a direct client of a MySQL or MariaDB server, with Ethernet and WiFi shields supported. With Arduino boards being used more and more, this can come in really handy – not […]

Hint of the day: noatime and relatime in fstab

It’s been written about everywhere, but since we keep spotting installations in the wild where people don’t know about it, it probably deserves another mention. By default, Linux uses the atime option on a disk mount, which means it writes a timestamp (e.g. a write to the drive) every time it reads anything. So in […]

LEVENSHTEIN MySQL stored function

At Open Query we steer clear of code development for clients. We sometimes advise on code, but as a company we don’t want to be in the programmer role. Naturally we do write scripts and other necessities to do our job. Assisting with an Open Source project, I encountered three old UDFs. User Defined Functions […]

Storage caching options in Linux 3.9 kernel

dm-cache is (albeit still classified “experimental”) is in the just released Linux 3.9 kernel. It deals with generic block devices and uses the device mapper framework. While there have been a few other similar tools flying around, since this one has been adopted into the kernel it looks like this will be the one that […]

MariaDB Foundation

You may have already seen the announcement MariaDB Foundation to Safeguard Leading Open Source Database. We at Open Query wholeheartedly support this (r)evolution of the MySQL ecosystem, which appears to be increasingly necessary as Oracle Corp is seriously dropping the ball with security updates and actually just general development and innovation. Oracle has actually done some […]

MariaDB security updates

Important Security Fix for a Buffer Overflow Bug: MariaDB 5.5.28a, 5.3.11, 5.2.13 and 5.1.66 include a fix for CVE-2012-5579, a vulnerability that allowed an authenticated user to crash MariaDB server or to execute arbitrary code with the privileges of the mysqld process. This is a serious security issue. We recommend upgrading from older versions as […]