November 27, 2014

Innodb transaction history often hides dangerous ‘debt’

In many write-intensive workloads Innodb/XtraDB storage engines you may see hidden and dangerous “debt” being accumulated – unpurged transaction “history” which if not kept in check over time will cause serve performance regression or will take all free space and cause an outage. Let’s talk about where it comes from and what can you do […]

Percona Server: Thread Pool Improvements for Transactional Workloads

In a previous thread pool post, I mentioned that in Percona Server we used an open source implementation of MariaDB’s thread pool, and enhanced/improved it further. Below I would like to describe some of these improvements for transactional workloads. When we were evaluating MariaDB’s thread pool implementation, we observed that it improves scalability for AUTOCOMMIT […]

Crash-resistant replication: How to avoid MySQL replication errors

Percona Server’s “crash-resistant replication” feature is useful in versions 5.1 through 5.5. However, in Percona Server 5.6 it’s replaced with Oracle MySQL 5.6’s “crash safe replication” feature, which has it’s own implementation (you can read more about it here). A MySQL slave normally stores its position in files master.info and relay-log.info which are updated by […]

Percona Server 5.6.11-60.3 first Release Candidate now available

Percona is glad to announce the first Release Candidate release of Percona Server 5.6.11-60.3 on June 3rd, 2013 (Downloads are available here and from the Percona Software Repositories). Based on MySQL 5.6.11, including all the bug fixes in it, Percona Server 5.6.11-60.3 is the first RC release in the Percona Server 5.6 series. All of […]

Replication in MySQL 5.6: GTIDs benefits and limitations – Part 1

Global Transactions Identifiers are one of the new features regarding replication in MySQL 5.6. They open up a lot of opportunities to make the life of DBAs much easier when having to maintain servers under a specific replication topology. However you should keep in mind some limitations of the current implementation. This post is the […]

Virident vCache vs. FlashCache: Part 2

This is the second part in a two-part series comparing Virident’s vCache to FlashCache. The first part was focused on usability and feature comparison; in this post, we’ll look at some sysbench test results. Disclosure: The research and testing conducted for this post were sponsored by Virident. First, some background information. All tests were conducted […]

Percona XtraDB Cluster: Failure Scenarios with only 2 nodes

During the design period of a new cluster, it is always advised to have at least 3 nodes (this is the case with PXC but it’s also the same with PRM). But why and what are the risks ? The goal of having more than 2 nodes, in fact an odd number is recommended in […]

How to Monitor MySQL with Percona’s Nagios Plugins

In this post, I’ll cover the new MySQL monitoring plugins we created for Nagios, and explain their features and intended purpose. I want to add a little context. What problem were we trying to solve with these plugins? Why yet another set of MySQL monitoring plugins? The typical problem with Nagios monitoring (and indeed with […]

Multiple purge threads in Percona Server 5.1.56 and MySQL 5.6.2

Part of the InnoDB duties, being an MVCC-implementing storage engine, is to get rid of–purge–the old versions of the records as they become obsolete.  In MySQL 5.1 this is done by the master InnoDB thread.  Since then, InnoDB has been moving towards the parallelized purge: in MySQL 5.5 there is an option to have a […]

When does Innodb Start Transaction ?

When does Innodb Start Transaction ? The answer looks obvious – when you issue “BEGIN” command. This is however wrong answer from engine point of you. Run “SHOW INNODB STATUS” and you will see “not started” status in transaction list. It is only when you read (or write) to INNODB table you can see transaction […]