July 25, 2014

Database problems in MySQL/PHP Applications

Article about database design problems is being discussed by Kristian. Both article itself and responce cause mixed feellings so I decided it is worth commenting: 1. Using mysql_* functions directly This is probably bad but I do not like solutions proposed by original article ether. PEAR is slow as well as other complex conectors. I […]

Intel Woodcrest vs AMD Opteron for MySQL

AnandTech published Intel Woodcrest preview benchmarks which have some numbers for MySQL as well. From these numbers performance looks great and it looks like finally Intel has something to respond to AMD Opterons on Server market. Now competition heats up and we’ll see what AMD will have to respond. As Opteron did not have serious […]

Exploring message brokers

Message brokers are not regularly covered here but are, nonetheless, important web-related technologies. Some time ago, I was asked by one of our customer to review a selection of OSS message brokers and propose a couple of good candidates. The requirements were fairly simple: behave well when there’s a large backlog of messages, be able […]

Percona XtraDB Cluster 5.6 GA release now available

Percona is pleased to announce the first General Availability release of the leading open source High Availability solution for MySQL, Percona XtraDB Cluster 5.6 on January 30, 2014. Binaries are available from downloads area or from our software repositories. Percona XtraDB Cluster 5.6 Percona XtraDB Cluster 5.6 is an active/active cluster solution for High Availability (HA) MySQL […]

InnoDB performance optimization basics (redux)

I recently stumbled upon a post that Peter Zaitsev published back in 2007 titled “Innodb Performance Optimization Basics.” It’s a great post and reading it inspired me to examine what’s changed in the nearly six years that have followed in terms of MySQL, Percona Server – as well as in all of the other now-available […]

Hidden columns of query_review_history table

You can use pt-query-digest to process a MySQL slow query log and store historical values for review trend analysis into query_review_history table. According to its official documentation you can populate many columns in that table but there are other important ones such as ‘user’, ‘host’, ‘db’ which are not included by default. I will explain […]

A case for MariaDB’s Hash Joins

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 […]

Percona Testing: Innodb crash / recovery tests available

Not everyone may know this, but there are precious few innodb crash recovery tests available. Some folks have noticed this and asked for something to be done about it, but unfortunately, no tests have been created for the main MySQL branch. The MySQL at Facebook branch has a number of tests that are quite interesting.  […]

Using any general purpose computer as a special purpose SIMD computer

Often times, from a computing perspective, one must run a function on a large amount of input. Often times, the same function must be run on many pieces of input, and this is a very expensive process unless the work can be done in parallel. Shard-Query introduces set based processing, which on the surface appears […]

Cache Miss Storm

I worked on the problem recently which showed itself as rather low MySQL load (probably 5% CPU usage and close to zero IO) would spike to have hundreds instances of threads running at the same time, causing intense utilization spike and server very unresponsive for anywhere from half a minute to ten minutes until everything […]