Last week at Percona Live, I delivered a six-hour tutorial about Percona XtraDB Cluster (PXC) for MySQL. I actually had more material than I covered (by design), but one thing I regret we didn’t cover was Flow control. So, I thought I’d write a post covering flow control because it is important to understand. What [...]
Replication checksums in MySQL 5.6
MySQL 5.6 has an impressive list of improvements. Among them, replication checksums caught my attention as it seems that many people misunderstand the real added value of this new feature. I heard people think that with replication checksums, data integrity between the master and its replicas is now enforced. As we’ll see, it’s not that [...]
Percona XtraDB Cluster reference architecture with HaProxy
This post is a step-by-step guide to set up Percona XtraDB Cluster (PXC) in a virtualized test sandbox. I used Amazon EC2 micro instances, but the content here is applicable for any kind of virtualization technology (for example VirtualBox). The goal is to give step by step instructions, so the setup process is understandable and [...]
Comparing Percona XtraDB Cluster with Semi-Sync replication Cross-WAN
I have a customer who is considering Percona XtraDB Cluster (PXC) in a two colo WAN environment. They wanted me to do a test comparing PXC against semi-synchronous replication to see how they stack up against each other. Test Environment The test environment included AWS EC2 nodes in US-East and US-West (Oregon). The ping RTT latency [...]
Statement based replication with Stored Functions, Triggers and Events
Statement based replication writes the queries that modify data in the Binary Log to replicate them on the slave or to use it as a PITR recovery. Here we will see what is the behavior of the MySQL when it needs to log “not usual” queries like Events, Functions, Stored Procedures, Local Variables, etc. We’ll [...]
Infinite Replication Loop
Last week I helped 2 different customers with infinite replication loops. I decided to write a blog post about these infinite loop of binary log statements in MySQL Replication. To explain what they are, how to identify them… and how to fix them.
Battery Learning still problem many years after
The performance problems caused by battery auto learning go many years back. We wrote about it, other people from MySQL Community too. The situation did not get better, at least not with Dell RAID controllers, H700 and H800 have the same problem too. At the same time situation got worse as a lot more people [...]
Updated msl (microslow) patch, installation walk-through!
For a couple of months there have been no updates to our msl patch, however recently I managed some time to change this. The functionality was extended a little bit and what’s even more important the patch is available for all the recent MySQL releases. To remind anyone who has not yet come across this [...]
Filtered MySQL Replication
To get this straight – I’m not a big fan of filtered or partial MySQL Replication (as of version MySQL 5.0) – there is enough gotchas with replication itself and getting things right with filtering can get quite bumpy road. In some applications however it is very helpful so lets see what one should do [...]
Managing Slave Lag with MySQL Replication
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 [...]

