July 23, 2014

How to debug long-running transactions in MySQL

Among the many things that can cause a “server stall” is a long-running transaction. If a transaction remains open for a very long time without committing, and has modified data, then other transactions could block and fail with a lock wait timeout. The problem is, it can be very difficult to find the offending code […]

High availability for MySQL on Amazon EC2 – Part 5 – The instance monitoring script

This post is the fifth of a series that started here. From the previous posts of this series, we now have nearly everything setup, only a few pieces are missing. One of the missing pieces is the Pacemaker script that run on the MySQL instance.

Impact of the number of idle connections in MySQL

Be careful with my findings, I appear to have compile in debug mode, I am redoing the benchmarks. Updated version here. I recently had to work with many customers having large number of connections opened in MySQL and although I told them this was not optimal, I had no solid arguments to present. More than […]

Impact of the sort buffer size in MySQL

The parameter sort_buffer_size is one the MySQL parameters that is far from obvious to adjust. It is a per session buffer that is allocated every time it is needed. The problem with the sort buffer comes from the way Linux allocates memory. Monty Taylor (here) have described the underlying issue in detail, but basically above […]

High availability for MySQL on Amazon EC2 – Part 5 – The instance monitoring script

This post is the fifth of a series that started here. From the previous posts of this series, we now have an instance restart script that can restart the database node in case of failure and automatically reconfigure Pacemaker and the other servers that needs to access the MySQL server. What we will cover in […]

High availability for MySQL on Amazon EC2 – Part 4 – The instance restart script

This post is the fourth of a series that started here. From the previous of this series, we now have resources configured but instead of starting MySQL, Pacemaker invokes a script to start (or restart) the EC2 instance running MySQL. This blog post describes the instance restart script. Remember, I am more a DBA than […]

Optimizing repeated subexpressions in MySQL

How smart is the MySQL optimizer? If it sees an expression repeated many times, does it realize they’re all the same and not calculate the result for each of them? I had a specific case where I needed to find out for sure, so I made a little benchmark. The query looks something like this:

MySQL Performance Engineer opening

As you know we love to analyze performance of various MySQL features, benchmark, compare, analyze things and post our findings on MySQL Performance Blog. However recently we got too busy with serving out customers and the backlog of things to take a look and write about is just growing larger and larger. So we decided […]

How to setup Docker for Percona ClusterControl and add existing Percona XtraDB Cluster

In my previous post I showed you how to setup Percona XtraDB Cluster 5.6 on Docker. This time I will show you how to setup Percona ClusterControl and add the existing Percona XtraDB Cluster 5.6 that we’ve managed to setup from the previous post. Let us note the following details about our existing containers: 172.17.0.2 […]

Installing Percona XtraDB Cluster 5.6 with the Docker open-source engine

In my previous post, I blogged about using Percona Server with Docker and have shown you how fast and easy it was to create a virtual environment with just a few commands. This time I will be showing you how to setup a three-node Percona XtraDB Cluster (PXC) 5.6 on the Docker open-source engine. Just […]