Earlier this month I wrote about vmstat iowait cpu numbers and some of the comments I got were advertising the use of util% as reported by the iostat tool instead. I find this number even more useless for MySQL performance tuning and capacity planning. Now let me start by saying this is a really tricky and deceptive number. Many […]
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The heartbleed bug was introduced in OpenSSL 1.0.1 and is present in 1.0.1 1.0.1a 1.0.1b 1.0.1c 1.0.1d 1.0.1e 1.0.1f The bug is not present in 1.0.1g, nor is it present in the 1.0.0 branch nor the 0.9.8 branch of OpenSSL some sources report 1.0.2-beta is also affected by this bug at the time of writing, […]
MySQL and Scaling-up (using more powerful hardware) was always a hot topic. Originally MySQL did not scale well with multiple CPUs; there were times when InnoDB performed poorer with more CPU cores than with less CPU cores. MySQL 5.6 can scale significantly better; however there is still 1 big limitation: 1 SQL query will eventually use only […]
This is part two on a two-part series on the performance implications of in-flight data encryption with MySQL. In the first part, I focused specifically on the impact of using MySQL’s built-in SSL support with some rather surprising results. Certainly it was expected that query throughput would be lower with SSL than without, but I […]
NOTE: This is part 1 of what will be a two-part series on the performance implications of using in-flight data encryption. Some of you may recall my security webinar from back in mid-August; one of the follow-up questions that I was asked was about the performance impact of enabling SSL connections. My answer was 25%, […]
Percona XtraDB Cluster (PXC) is different enough from async replication that it can be a bit of a puzzle how to do things the Galera way. This post will attempt to illustrate the basics of setting up 2 node PXC cluster from scratch. Requirements Two servers (could be VMs) that can talk to each other. […]
In preparing for this month’s Percona Live MySQL Conference and Expo, I’ve been reminiscing about the annual MySQL User Conference’s history – the 9 times it previously took place in its various reincarnations – and there are a lot of good things, fun things to remember. 2003 was the year that marked the first MySQL user conference […]
If you ever had a replication slave that is severely behind, you probably noticed that it’s not catching up with a busy master at a steady pace. Instead, the “Seconds behind master” is going up and down so you can’t really tell whether the replica is catching up or not by looking at just few […]
MariaDB 5.3/5.5 has introduced a new join type “Hash Joins” which is an implementation of a Classic Block-based Hash Join Algorithm. In this post we will see what the Hash Join is, how it works and for what types of queries would it be the right choice. I will show the results of executing benchmarks […]
I used to think one should never look at max_binlog_size, however last year I had a couple of interesting cases which showed that sometimes it may be very important variable to tune properly. I meant to write about it earlier but never really had a chance to do it. I have it now!