April 17, 2014

Taking backups on Percona XtraDB Cluster (without stalls!)

I occasionally see customers who are taking backups from their PXC clusters that complain that the cluster “stalls” during the backup.  As I wrote about in a previous blog post, often these stalls are really just Flow Control.  But why would a backup cause Flow control? Most backups I know of (even Percona XtraBackup) take […]

Percona XtraDB Cluster 5.5.33-23.7.6 is now available

Percona is glad to announce the release of Percona XtraDB Cluster 5.5.33-23.7.6 on September 18, 2013. Binaries are available from the downloads area or from our software repositories. New Features: Default State Snapshot Transfer method, defined in wsrep_sst_method variable has been changed from mysqldump to rsync. New wsrep_reject_queries variable has been implemented that can be […]

Read/Write Splitting with PHP Webinar Questions Followup

Today I gave a presentation on “Read/Write Splitting with PHP” for Percona Webinars.  If you missed it, you can still register to view the recording and my slides. Thanks to everyone who attended, and especially to folks who asked the great questions.  I answered as many as I could during the session, but here are […]

Percona XtraDB Cluster – installation and setup webinar follow up Q&A

Thanks for all, who attended my webinar, I got many questions and I wanted to take this opportunity to answer them. Q: Even ntp has a delay of 0.3-0.4 between servers does that mean a 0.25 as from logs can be an issue ? A: My demo vms were running for a few hours before […]

Automation: A case for synchronous replication

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 […]

Announcing Percona XtraDB Cluster 5.5.27-23.6

Percona is glad to announce the release of Percona XtraDB Cluster on September 7th, 2012. Binaries are available from downloads area or from our software repositories. Features: Percona XtraDB Cluster supports tunable buffer size for fast index creation in InnoDB. This value was calculated based on the merge block size (which was hardcoded to 1 […]

Percona XtraDB Cluster: Multi-node writing and Unexpected deadlocks

Percona XtraDB Cluster (PXC) and the technology it uses (Galera) is an exciting alternative to traditional MySQL replication.  For those who don’t know, it gives you: Fully Synchronous replication with a write latency increase equivalent to a ping RTT to the furthest node Automatic cluster synchronization, both incremental and full restores The ability to read […]

Migrating to XtraDB Cluster Webinar follow up questions

Thanks to all who attended my webinar today. The session was recorded and will be available to watch for free soon here. There were a lot of great questions asked during the session, so I’d like to take this opportunity to try to answer a few of them: Q: Is there an easy way to […]

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 […]

How (not) to find unused indexes

I’ve seen a few people link to an INFORMATION_SCHEMA query to be able to find any indexes that have low cardinality, in an effort to find out what indexes should be removed.  This method is flawed – here’s the first reason why:

The cardinality of status index is woeful, but provided that the application […]