One of the very frequent cases with performance problems with MySQL is what they happen every so often or certain times. Investigating them we find out what the cause is some batch jobs, reports and other non response time critical activities are overloading the system causing user experience to degrade. The first thing you need […]
The problem of MySQL Replication unable to catch up is quite common in MySQL world and in fact I already wrote about it. There are many aspects of managing mysql replication lag such as using proper hardware and configuring it properly. In this post I will just look at couple of query design mistakes which […]
The question I often get is how far MySQL may fall behind and how to keep replication from lagging. The lag you will see will vary a lot from application to the application and from load to load. Plus what is the most important within same application the lag will likely have spikes – most […]
On many web sites you would see a counter how many time given object – blog post, forum thread, image, movie etc was viewed. This is sometimes handy feature but it can be rather expensive from performance point of view. The nasty thing with counters as they are implemented the most trivial way – they […]
Brian Aker recently published good write up about using MySQL replication. The piece I find missing however is good description of warning about limits of this approach as well as things you need to watch out for. You can call me person with negative mind but I tend to think about limits as well. So […]
Just yesterday I wrote about math of automatic failover today I’ll share my thoughts about what makes MySQL failover different from many other components and why asynchronous nature of standard replication solution is causing problems with it. Lets first think about properties of simple components we fail over – web servers, application servers etc. We […]
There are number of people recently blogging about MySQL automated failover, based on production incident which GitHub disclosed. Here is my take on it. When we look at systems providing high availability we can identify 2 cases of system breaking down. First is when the system itself has a bug or limitations which does not […]
First time I heard about Galera on Percona Performance Conference 2009, Seppo Jaakola was presenting “Galera: Multi-Master Synchronous MySQL Replication Clusters”. It was impressed as I personally always wanted it for InnoDB, but we had it in plans at the bottom of the list, as this is very hard to implement properly. The idea by […]
Note: This blog post is part 1 of 4 on building our training workshop.
The Percona training workshop will not cover sharding. If you follow our blog, you’ll notice we don’t talk much about the subject; in some cases it makes sense, but in many we’ve seen that it causes architectures to be prematurely complicated.
So let me state it: You don’t want to shard.
Optimize everything else first, and then if performance still isn’t good enough, it’s time to take a very bitter medicine. The reason you need to shard basically comes down to one of these two reasons