I have previously written about the new replication protocol that comes with GTIDs in MySQL 5.6. Because of this new replication protocol, you can inadvertently create errant transactions that may turn any failover to a nightmare. Let’s see the problems and the potential solutions.

In short

• Errant transactions may cause all kinds of data corruption/replication errors when failing over.
• Detection of errant transactions can be done with the GTID_SUBSET() and GTID_SUBTRACT() functions.
• If you find an errant transaction on one …

Github user Adrianlzt provided a python-twisted alternative version of pyclustercheck per discussion on issue 7.

Due to sporadic performance issues noted with the original implementation in SimpleHTTPserver, the benchmarks which I’ve included as part of the project on github use mutli-mechanize library,

• cache time 1 sec
• 2 x 100 thread pools
• 60s ramp up time
• 600s total duration
• testing simulated node fail (always returns 503, rechecks mysql node on cache expiry)
• AMD FX(tm)-8350 Eight-Core Processor
• Intel 330 SSD
• local loop back test (127.0.0.1)

The SimpleHTTPServer instance faired as follows:

…

In our previous post, we introduced the MySQL Fabric utility and said we would dig deeper into it. This post is the first part of our test of MySQL Fabric’s High Availability (HA) functionality.

Today, we’ll review MySQL Fabric’s HA concepts, and then walk you through the setup of a 3-node cluster with one Primary and two Secondaries, doing a few basic tests with it. In a second post, we will spend more time generating failure scenarios and documenting how Fabric handles them. (MySQL Fabric is an extensible framework to manage large farms of MySQL servers, with support for high-availability and sharding.)

Before we begin, we recommend you read this post by Oracle’s …

Some of us Perconians are at OpenStack summit this week in Atlanta. Matt Griffin, our director of product management, tweeted about the turbo-hipster CI talk about their experience of ALTER TABLEs running faster on Percona Server. Oracle’s Morgan Tocker then tweeted in response, asking why this was the case. I decided that the simplest way to answer that was here in this post.

The reason for this is the …

The combination of max_allowed_packet variable and replication in MySQL is a common source of headaches. In a nutshell, max_allowed_packet is the maximum size of a MySQL network protocol packet that the server can create or read. It has a default value of 1MB (<= 5.6.5) or 4MB (>= 5.6.6) and a maximum size of 1GB. This adds some constraints in our replication environment:

• The master server shouldn’t write events to the binary log larger than max_allowed_packet

• All the slaves in the replication chain should have the same max_allowed_packet as the master server

Sometimes, even following those two basic rules we can have problems.

For example, there are situations (also called bugs) where the master writes more data than the max_allowed_packet …

Achieving the best possible MySQL Performance doesn’t have to be complicated. It’s all about knowing which tools are designed for the task at hand – along with some basic (yet often overlooked) best practices.

Join me Wednesday, May 14 at 10 a.m. Pacific for a free webinar titled, “Practical MySQL performance optimization.” I’ll be sharing the main areas for improving MySQL performance – along with what to specifically focus on in each. These will include:

• Hardware
• MySQL Configuration
• Schema and Queries
• Application Architecture

And as I mentioned earlier, I’ll also show you the best tools for the job and how …

One of the MySQL 5.6 features many people are interested in is Global Transactions IDs (GTIDs). This is for a good reason: Reconnecting a slave to a new master has always been a challenge while it is so trivial when GTIDs are enabled. However, using GTIDs is not only about replacing good old binlog file/position with unique identifiers, it is also using a new replication protocol. And if you are not aware of it, it can bite.

Replication protocols: old vs new

The old protocol is pretty straightforward: the slave connects to a given binary log file at a specific offset, and the master sends all the transactions from there.

The new protocol is slightly different: the slave first sends the range of GTIDs it has executed, and then the master sends every missing transaction. It also guarantees that a transaction with a given …

The new Percona Server 5.5.37-35.0 and Percona Server 5.6.17-65.0-56, announced yesterday (May 6), both include the open source version of the MySQL Audit Plugin. The MySQL Audit Plugin is used to log all queries or connections (“audit” MySQL usage). Until yesterday’s release, the MySQL Audit Plugin was only available in MySQL Enterprise.

EDIT:  Just to be clear, this implementation is alternative to the MySQL …

Tools for MySQL are a vital part of any deployment, so it’s important to use ones that are reliable and well-designed. Percona Toolkit is a collection of more than 30 command-line tools for MySQL, Percona Server, and MariaDB that can help database administrators automate a variety of database and system tasks. With so many available tools, however, it can be difficult knowing where to start.

For this reason I invite you to join me on Wednesday, May 7 at 10 a.m. Pacific time for a free webinar titled, “The top 9 Percona Toolkit tools that can make your job easier.” You can register directly …

Here on the Percona MySQL Support team, we often see issues where a customer is complaining about replication delays – and many times the problem ends up being tied to MySQL replication slave lag. This of course is nothing new for MySQL users and we’ve had a few posts here on the MySQL Performance Blog on this topic over the years (two particularly popular post in the past were: “Reasons for MySQL Replication Lag” and “Managing Slave Lag with MySQL Replication,” both by Percona CEO Peter Zaitsev).

In …