I had a customer recently who needed to reduce their database size on disk quickly without a lot of messy schema redesign and application recoding. They didn’t want to drop any actual data, and their index usage was fairly high, so we decided to look for unused indexes that could be removed. Collecting data It’s [...]
Realtime stats to pay attention to in Percona XtraDB Cluster and Galera
November 26, 2012 By 4 Comments
I learn more and more about Galera every day. As I learn more, I try to keep my myq_gadgets toolkit up to date with what I consider is important to keep any eye on on a PXC node. In that spirit, I just today pushed some changes to the ‘wsrep’ report, and I thought I’d go over [...]
Percona XtraDB Cluster – installation and setup webinar follow up Q&A
October 28, 2012 By 4 Comments
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 [...]
Logging Foreign Key errors
September 27, 2012 By Leave a Comment
In the last blog post I wrote about how to log deadlock errors using Percona Toolkit. Foreign key errors have the same problems. InnoDB only logs the last error in the output of SHOW ENGINE INNODB STATUS, so we need another similar tool in order to have historical data. pt-fk-error-logger This is a tool very [...]
What attendees are saying about Percona Live NYC ?
September 19, 2012 By Leave a Comment
With Percona Live NYC right around the corner I decide some of attendees what did they like on the last year event and what they are looking forward to in 2012. Here are some responses I got. If you’ve attended in 2011 or planning to join us in 2012 please feel free to comment with [...]
How to obtain the “LES” (Last Executed Statement) from an Optimized Core Dump?
September 9, 2012 By 9 Comments
Ever ran into a situation where you saw “some important variable you really needed to know about=<optimized out>” while debugging?
Where to get a BZR tree of the latest MySQL releases
August 16, 2012 By 1 Comment
I just posted this to the MySQL Internals mailing list: Hi all, Like many of you, I’m disappointed that the bzr trees for MySQL are out of sync with the tarball source and binary releases from Oracle. Since Oracle has been silent on this, and this is a recurring problem, I’ve decided to attempt to [...]
Percona XtraDB Cluster: Failure Scenarios with only 2 nodes
July 25, 2012 By 6 Comments
During the design period of a new cluster, it is always advised to have at least 3 nodes (this is the case with PXC but it’s also the same with PRM). But why and what are the risks ? The goal of having more than 2 nodes, in fact an odd number is recommended in [...]
Index Condition Pushdown in MySQL 5.6 and MariaDB 5.5 and its performance impact
March 12, 2012 By 12 Comments
I have been working with Peter in preparation for the talk comparing the optimizer enhancements in MySQL 5.6 and MariaDB 5.5. We are taking a look at and benchmarking optimizer enhancements one by one. So in the same way this blog post is aimed at a new optimizer enhancement Index Condition Pushdown (ICP). Its available [...]
The relationship between Innodb Log checkpointing and dirty Buffer pool pages
February 17, 2012 By 10 Comments
This is a time-honored topic, and there’s no shortage of articles on the topic on this blog. I wanted to write a post trying to condense and clarify those posts, as it has taken me a while to really understand this relationship. Some basic facts Most of us know that writing into Innodb updates buffer [...]
