Previous episodes:

• MySQL replication monitoring 101

MySQL replication in action - Part 1: GTID & CoMySQL replication in action - Part 2 - Fan-in topology


In the previous article, we saw the basics of establishing replication from multiple origins to the same destination. By extending that concept, we can deploy more complex topologies, such as the point-to-point (P2P) all-masters topology, a robust and …

Oracle recently published the MySQL 5.7.5 Development Milestone release, a pre-production release providing numerous improvements to the MySQL server. You can download the release here: http://dev.mysql.com/downloads/mysql/5.7.html

This release carries some incompatible changes, as explained in the release notes and in the blog post describing the release. During my work in the Server QA team I have experienced some of these changes first hand already, and we have had to modify some tests and tools to adapt to some of it.

One very big change (well, some may not notice at all, while others may need to adjust their tools and applications) is the new default value …

Today, I was reminded of a Jim Starkey quote on the Random Query Generator:

“The Colonoscopy of Database Software”
– Jim Starkey

If your project does not have something that you can adapt that quote to, odds are your testing is inadequate.

During a typical release cycle for TokuDB at Tokutek, we spend time qualifying and hardening the product using numerous tools.  For example, we run stress and unit tests directly on the Fractal Tree indexes, MySQL Test Runner (MTR) tests on the storage engine as well as numerous performance benchmarks to prevent regressions. In addition, we have recently been implementing the Random Query Generator (RQG) framework internally here at Tokutek to more exhaustively stress TokuDB.  My name is Joel Epstein and I am a Quality Assurance Engineer here at Tokutek who has been integrating RQG into the overall test plan strategy.

At a high level, RQG is a …

While user bug reports are the most important ones, there is a category of external reporters which I historically have a special interest in and great expectations for: entry-level testers. I was one, trained some, interviewed many, had a few hired, and have always wanted someone to wake them up and get going before it’s too late.

There is no secret that quality control is not as glamourous as other IT specialities, and there are no famous (or maybe any) student programs for testers. Usually people come into testing because it is deceptively open for newbies, planning to obtain a few points for a CV and switch either to development or to project management as soon as they can. Most do, a few stay.

It creates a vicious cycle. Since this is a well-known pattern, employers hire testers without experience not to teach …

During FOSDEM PGDay I watched the "Indexes: The neglected performance all-rounder" talk by Markus Winand. Both his talk and the "SQL Performance Explained" book (which is also available online) are great.

The conclusion of the talk is that we should put more effort in carefully designing indexes. But how can we make sure the indexes are really used now and in the future? We need to write some tests for it.

So I wrote a small Python script to test index usage per query. This uses the JSON explain format available in MySQL 5.6. It's just a proof-of-concept so don't expect too much of it yet (but please sent pull requests!).

A short example:

#!/usr/bin/python3
import indextest

 …

My fellow testers and others who run RQG tests on MySQL flavors might be interested in some additions that are being used for MariaDB testing. While none of them is a major breakthrough, maybe they will make somebody’s life a little easier.

RQG Introduction

A quick introduction for those who have never heard of RQG, but are still curious what this blog post is about.

RQG stands for Random Query Generator, also known as randgen — an open-source product, available under the GPL v2 license. Quoting its home page on Launchpad, it is a “pseudo-random data and query generator that can be used to test any Perl DBI, JDBC or ODBC-compatible SQL server, in particular MySQL, but also JavaDB and PostgreSQL”.

The framework was created by my former colleague Philip Stoev, who not only developed a great tool, …

MySQL Sandbox has been updated again. The latest version is 3.0.38, which was just released. There were four releases in the space of one week, and this last one is just a polished edition.

Cherry-picking from the Change log:

• Added option --bind_address to complement the effects of --remote_access;
• The script 'enable_gtid' (for MySQL 5.6 +) now is durable. Previously the changes did not survive a restart.
• Now you can install MariaDB with its bizarre version '10.0'
• It also works well with MySQL 5.7. A bug prevented the creation of 'enable_gtid', but it …

In the MySQL QA teams in Oracle we have been using a tool called the Random Query Generator (or "RQG" for short) for some time now. The main RQG testing effort has been on new server development, including regression testing. The recent MySQL 5.6 GA is a result of a couple of years of hard work, including a lot of RQG testing and bugfixing as a result of that.

I can easily say that the RQG has helped making MySQL 5.6 a better release than it would otherwise be. It is of course not our only testing tool, but there are plenty of bugs this tool has uncovered that would likely not have been seen in our other testing. Such issues include:

• crashes and asserts
• memory management bugs (valgrind errors)
• wrong results

The main clue to the power of the RQG is its …

yum

It’s often pain to guess package names when you need to install stuff on, lets say, CentOS. So there is a list, although maybe not full, of what I needed to get another VM build and run MariaDB server and to execute at least some tests on it (all done via yum install):

cmake
gcc
ncurses-devel
bison
g++
gcc-c++
aclocal
automake
libtool
perl-DBD-MySQL
gdb
libaio-devel
openssl-devel

Same in one line, for lazy me:
sudo yum install cmake gcc ncurses-devel bison g++ gcc-c++ perl-DBD-MySQL gdb libaio-devel openssl-devel

To install bzr (if it’s not in the official repo):

su -c ‘rpm -Uvh http://download.fedora.redhat.com/pub/epel/5/i386/epel-release-5-2.noarch.rpm’
(check the architecture)

and then can use yum install
bzr

Another story (taken …