Recently there has been a storm of bugs and problems in all variants of MySQL including MySQL, Percona Server, and MariaDB. To list a few:

• MySQL 5.5.25
  UPDATE on InnoDB table enters recursion, consumes all disk space
• All MariaDB and MySQL versions up to 5.1.61, 5.2.11, 5.3.5, 5.5.22
  Security vulnerability in MySQL/MariaDB sql/password.c
• MySQL 5.1.61
  DSA-2429-1 mysql-5.1 — several vulnerabilities
• MySQL 5.5.25a
  Slave crash regression
• Percona Server 5.5.27-28.0 regression
  …

I continue my benchmarks of Intel SSD 910, the raw IO results are available in my previous experiment. Now I want to test this card under MySQL workload to see if the card is suitable to use with MySQL.

• Server: Dell PowerEdge R710
• CPU: 2x Intel(R) Xeon(R) CPU E5-2660 0 @ 2.20GHz
• Memory: 192GB
• Storage: Fusion-io ioDrive 640GB, Intel SSD 910 (software RAID over 2x200GB devices)
• Filesystem: ext4

• OS: Ubuntu 12.04.1
• MySQL Version: Percona Server 5.5.27-28.1

• Benchmark name: tpcc-mysql
• Scale factor: 2500W (~250GB of data)
• Benchmark …

I wrote one week ago about how to find duplicate indexes. This time we’ll learn how to find unused indexes to continue improving our schema and the overall performance. There are different possibilites and we’ll explore the two most common here. User Statistics from Percona Server and pt-index-usage.

User Statistics

User Statistics is an improvement on Percona Server that adds some tables to Information Schema with useful information to understand the server activity and identify the source of the load. …

Having duplicate keys in our schemas can hurt the performance of our database:

• They make the optimizer phase slower because MySQL needs to examine more query plans.

• The storage engine needs to maintain, calculate and update more index statistics

• DML and even read queries can be slower because MySQL needs update fetch more data to Buffer Pool for the same load

• Our data needs more disk space so our backups will be bigger and slower

In this post I’m going to explain the different types of duplicate indexes and how to find and remove them.

Duplicate keys on the same column

This is the easiest one. You can create multiple indexes on the same column and MySQL won’t complain. Let’s see this example:

mysql> alter table t add index(name);
mysql> alter table t add index(name);
…

This post is a step-by-step guide to set up Percona XtraDB Cluster (PXC) in a virtualized test sandbox. I used Amazon EC2 micro instances, but the content here is applicable for any kind of virtualization technology (for example VirtualBox). The goal is to give step by step instructions, so the setup process is understandable and it could serve as a reference architecture.

You will need 4 virtual machines. 3 for PXC and 1 for the client, which will have HaProxy. I used CentOS 6 as the operating system, the instructions are similar for any Linux distribution.

The client node will have HaProxy installed and it will redirect requests to PXC nodes. This approach works well in real-world scenarios too. Running HaProxy on the application servers instead of having them as dedicated entities gives you benefits like you don’t need an extra network roundtrip because of a loadbalancer and scalability of PXC’s load balancing layer scales …

Contrary to initial reports here and here, further investigation has revealed that under some specific and limited circumstances, Percona Server and Percona XtraDB Cluster binaries, similar to other MySQL variants, are susceptible to the security vulnerability in MySQL/MariaDB sql/password.c:

• 64bit Ubuntu Oneiric (11.10) binaries are vulnerable in Percona Server ONLY on some hardware/virtualization platforms (confirmed on Amazon EC2 but not on HP Cloud).
• Neither older nor newer Ubuntu versions are affected.
• Oneiric is not a LTS distribution. Most …

Version 1.0.1 of the Percona Monitoring Plugins is released. This is a routine bug-fix release that addresses several minor issues.

The Percona Monitoring Plugins are high-quality components to add enterprise-grade MySQL monitoring and graphing capabilities to your existing in-house, on-premises monitoring solutions. The components are designed to integrate seamlessly with widely deployed solutions such as Nagios and Cacti, and are delivered in the form of templates, plugins, and scripts.

The plugins are fully supported for customers with a Percona Support contract, and free installation services are provided as part of some contracts. You can find links to downloads, …

The Percona Toolkit team is happy to announce the release of Percona Toolkit versions 2.0.5 and 2.1.2. These are bug-fix releases in the 2.0 and 2.1 series, respectively. These releases fix many dozens of bugs, and we suggest that users upgrade to the latest versions of the tools.

The complete list of changes is on Launchpad for 2.0.5 and 2.1.2. Here are some highlights of the changes in version 2.1.2, which is the current development focus:

• We fixed several bugs in pt-table-sync that prevented it from working properly, and disabled the –lock-and-rename feature when using it with MySQL versions that don’t support it reliably.
• We enhanced pt-table-checksum and pt-online-schema-change to add even more safety checks, and to detect and deal with …

Many of you heard of this nasty security vulnerability in MySQL, and as we are getting a lot of inquiries how does it affect Percona Server, I decided to address it in this post.

• The issue exists in the source code of MySQL 5.5.23 or earlier and MySQL 5.1.62 or earlier. The same is true for Percona Server, as we share the same code base.
• However binaries provided by Percona do not have this problem, as in our build process we do not use sse-optimized glibc memcmp. This is true for any version of Percona and all tar.gz, RPM and DEB packages. Once again, if you use binary builds, provided by Percona from our official download area, or from our repositories, you are safe.
• If you use your own or third-party binaries, …

I am happy to announce next version Percona XtraDB Cluster 5.5.24, which is mostly jump to the current version of Percona Server.

It includes an important bug fix:

• table with no PK but still having UK, can cause crash in slave using PA

Binaries are available from downloads area or from our repositories.

For this release we provide binaries for Ubuntu 12.04.

If you want to know more how to migrate to XtraDB Cluster, you can check our recent webinar Migrating To Percona XtraDB Cluster.

This is an General Availability release. We did our best to eliminate bugs and problems during alpha and …