May 24, 2013

MySQL and the SSB – Part 2 – MyISAM vs InnoDB low concurrency

May 22, 2013 By Leave a Comment

This blog post is part two in what is now a continuing series on the Star Schema Benchmark. In my previous blog post I compared MySQL 5.5.30 to MySQL 5.6.10, both with default settings using only the InnoDB storage engine.  In my testing I discovered that innodb_old_blocks_time had an effect on performance of the benchmark.  There was [...]

Filed Under: Benchmarks, MySQL Tagged With: , , , , , , ,

Disconnecting a replication slave is easier with MySQL 5.5+ (RESET SLAVE vs. RESET SLAVE ALL)

April 17, 2013 By 2 Comments

It’s not uncommon to promote a server from slave to master. One of the key things to protect your data integrity is to make sure that the promoted slave is permanently disconnected from its old master. If not, it may get writes from the old master, which can cause all kinds of data corruption. MySQL [...]

Filed Under: Insight for DBAs, MySQL Tagged With: , ,

InnoDB Full-text Search in MySQL 5.6 (part 1)

February 26, 2013 By 1 Comment

I’ve never been a very big fan of MyISAM; I would argue that in most situations, any possible advantages to using MyISAM are far outweighed by the potential disadvantages and the strengths of InnoDB. However, up until MySQL 5.6, MyISAM was the only storage engine with support for full-text search (FTS). And I’ve encountered many [...]

Filed Under: Insight for DBAs, Insight for Developers, MySQL Tagged With: , , , , ,

How to start a Percona XtraDB Cluster

January 29, 2013 By 10 Comments

Before version 5.5.28 of Percona XtraDB Cluster, the easiest way was to join the cluster using wsrep_urls in [mysqld_safe] section of my.cnf. So with a cluster of 3 nodes like this : node1 = 192.168.1.1 node2 = 192.168.1.2 node3 = 192.168.1.3 we defined the setting like this :

With that line above in my.cnf [...]

Filed Under: Percona Software, XtraDB Cluster

Profiling MySQL Memory Usage With Valgrind Massif

January 9, 2013 By 1 Comment

There are times where you need to know exactly how much memory the mysqld server (or any other program) is using, where (i.e. for what function) it was allocated, how it got there (a backtrace, please!), and at what point in time the allocation happened. For example; you may have noticed a sharp memory increase [...]

Filed Under: Insight for DBAs, Insight for Developers, MySQL, Quality Assurance

Get Me Some Query Logs!

November 22, 2012 By 14 Comments

One of my favorite tools in the Percona Toolkit is pt-query-digest.  This tool is indispensable for identifying your top SQL queries, and analyzing which queries are accounting for your database load. But the report you get from pt-query-digest is only as good as the log of queries you give it as input.  You need a large [...]

Filed Under: Events and Announcements, Insight for DBAs, MySQL Tagged With: , , ,

Debugging MySQL SSL problems

November 8, 2012 By Leave a Comment

This is not necessarily going to be a comprehensive post, but I learned somethings about MySQL SSL today that I thought would be worth sharing. I was setting up a PRM install for a customer and one of the requirements was SSL replication.  In this particular case, I had setup PRM first, and then was [...]

Filed Under: MySQL

Percona XtraDB Cluster – installation and setup webinar follow up Q&A

October 28, 2012 By 4 Comments

Thanks for all, who attended my webinar, I got many questions and I wanted to take this opportunity to answer them. Q: Even ntp has a delay of 0.3-0.4 between servers does that mean a 0.25 as from logs can be an issue ? A: My demo vms were running for a few hours before [...]

Filed Under: MySQL, XtraDB Cluster

Review of MySQL 5.6 Defaults Changes

October 8, 2012 By 10 Comments

James Day just posted the great summary of defaults changes in MySQL 5.6 compared to MySQL 5.5 In general there are a lot of good changes and many defaults are now computed instead of hardcoded. Though some of changes are rather puzzling for me. Lets go over them: back_log = 50 + ( max_connections / [...]

Filed Under: Insight for DBAs, MySQL

Percona XtraDB Cluster: Failure Scenarios with only 2 nodes

July 25, 2012 By 6 Comments

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 [...]

Filed Under: MySQL, XtraDB Cluster
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