October 21, 2014

A schema change inconsistency with Galera Cluster for MySQL

I recently worked on a case where one node of a Galera cluster had its schema desynchronized with the other nodes. And that was although Total Order Isolation method was in effect to perform the schema changes. Let’s see what happened. Background For those of you who are not familiar with how Galera can perform […]

Using InfiniDB MySQL server with Hadoop cluster for data analytics

In my previous post about Hadoop and Impala I benchmarked performance of analytical queries in Impala. This time I’ve tried InfiniDB for Hadoop (open-source version) on the modern hardware with an 8-node Hadoop cluster. One of the main advantages (at least for me) of InifiniDB for Hadoop is that it stores the data inside the Hadoop cluster but uses the […]

Percona XtraDB Cluster: How to run a 2-node cluster on a single server

I reckon there’s little sense in running 2 or more Percona XtraDB Cluster (PXC) nodes in a single physical server other than for educational and testing purposes – but doing so is still useful in those cases. The most popular way of achieving this seems to be with server virtualization, such as making use of Vagrant boxes. […]

MySQL ring replication: Why it is a bad option

I’ve recently worked with customers using replication rings with 4+ servers; several servers accepting writes. The idea behind this design is always the same: by having multiple servers, you get high availability and by having multiple writer nodes, you get write scalability. Alas, this is simply not true. Here is why. High Availability Having several […]

Percona Toolkit 2.2.11 for MySQL is now available

Percona is pleased to announce the availability of Percona Toolkit 2.2.11.  Released on Sept. 25, Percona Toolkit is a collection of advanced command-line tools to perform a variety of MySQL server and system tasks that are too difficult or complex for DBAs to perform manually. Percona Toolkit, like all Percona software, is free and open source. This release contains […]

MySQL & OpenStack: How to overcome issues as your dataset grows

MySQL is the database of choice for most OpenStack components (Ceilometer is a notable exception). If you start with a small deployment, it will probably run like a charm. But as soon as the dataset grows, you will suddenly face several challenges. We will write a series of blog posts explaining the issues you may […]

Should you migrate to Percona XtraDB Cluster?

Interest in Percona XtraDB Cluster / Galera has been high ever since we introduced the product in 2012.  I typically have a conversation about Galera and Percona XtraDB Cluster (PXC) at least once a week with a consulting customer who wants to know if it will be a good fit for their application.  Last week […]

OpenStack users shed light on Percona XtraDB Cluster deadlock issues

I was fortunate to attend an Ops discussion about databases at the OpenStack Summit Atlanta this past May as one of the panelists. The discussion was about deadlock issues OpenStack operators see with Percona XtraDB Cluster (of course this is applicable to any Galera-based solution). I asked to describe what they are seeing, and as […]

Multi-Valued INSERTs, AUTO_INCREMENT & Percona XtraDB Cluster

A common migration path from standalone MySQL/Percona Server to a Percona XtraDB Cluster (PXC) environment involves some measure of time where one node in the new cluster has been configured as a slave of the production master that the cluster is slated to replace. In this way, the new cluster acts as a slave of […]

How to calculate the correct size of Percona XtraDB Cluster’s gcache

When a write query is sent to Percona XtraDB Cluster all the nodes store the writeset on a file called gcache. By default the name of that file is galera.cache and it is stored in the MySQL datadir. This is a very important file, and as usual with the most important variables in MySQL, the […]