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 [...]
read_buffer_size can break your replication
There are some variables that can affect the replication behavior and sometimes cause some big troubles. In this post I’m going to talk about read_buffer_size and how this variable together with max_allowed_packet can break your replication. The setup is a master-master replication with the following values: max_allowed_packet = 32M read_buffer_size = 100M To break the [...]
Aligning IO on a hard disk RAID – the Benchmarks
In the first part of this article I have showed how I align IO, now I want to share results of the benchmark that I have been running to see how much benefit can we get from a proper IO alignment on a 4-disk RAID1+0 with 64k stripe element. I haven’t been running any benchmarks [...]
How InnoDB handles REDO logging
Xaprb (Baron) recently blogged about how InnoDB performs a checkpoint , I thought it might be useful to explain another important mechanism that affects both response time and throughput – The transaction log.
MySQL 5.5.8 – in search of stability
A couple of days ago, Dimitri published a blog post, Analyzing Percona’s TPCC-like Workload on MySQL 5.5, which was a response to my post, MySQL 5.5.8 and Percona Server: being adaptive. I will refer to Dimitri’s article as article [1]. As always, Dimitri has provided a very detailed and thoughtful article, and I strongly recommend reading if [...]
Impact of the number of idle connections in MySQL
Be careful with my findings, I appear to have compile in debug mode, I am redoing the benchmarks. Updated version here. I recently had to work with many customers having large number of connections opened in MySQL and although I told them this was not optimal, I had no solid arguments to present. More than [...]
table_cache negative scalability
Couple of months ago there was a post by FreshBooks on getting great performance improvements by lowering table_cache variable. So I decided to investigate what is really happening here. The “common sense” approach to tuning caches is to get them as large as you can if you have enough resources (such as memory). With MySQL [...]
MySQL-Memcached or NOSQL Tokyo Tyrant – part 3
This is part 3 of our series. In part 1 we talked about boosting performance with memcached on top of MySQL, in Part 2 we talked about running 100% outside the data with memcached, and now in Part 3 we are going to look at a possible solution to free you from the database. The [...]
MySQL-Memcached or NOSQL Tokyo Tyrant – part 2
Part 1 of our series set-up our “test” application and looked at boosting performance of the application by buffer MySQL with memcached. Our test application is simple and requires only 3 basic operations per transaction 2 reads and 1 write. Using memcached combined with MySQL we ended up nearly getting a 10X performance boost from [...]
Adjusting Innodb for Memory resident workload
As larger and larger amount of memory become common (512GB is something you can fit into relatively commodity server this day) many customers select to build their application so all or most of their database (frequently Innodb) fits into memory. If all tables fit in Innodb buffer pool the performance for reads will be quite [...]

