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 [...]
MySQL 5.6 Compatible Percona XtraBackup 2.0.6 Released
March 20, 2013 By 2 Comments
Percona is glad to announce the release of Percona XtraBackup 2.0.6 for MySQL 5.6 on March 20, 2013. Downloads are available from our download site here and Percona Software Repositories. This release is the current GA (Generally Available) stable release in the 2.0 series. New Features: XtraBackup 2.0.6 has implemented basic support for MySQL 5.6, Percona Server 5.6 [...]
Analyzing Slow Query Table in MySQL 5.6
February 18, 2013 By 1 Comment
Next week I’m teaching an online Percona Training class, called Analyzing SQL Queries with Percona Toolkit. This is a guided tour of best practices for pt-query-digest, the best tool for evaluating where your database response time is being spent. This month we saw the GA release of MySQL 5.6, and I wanted to check if any [...]
Quickly finding unused indexes (and estimating their size)
December 5, 2012 By 2 Comments
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 [...]
Best kept MySQLDump Secret
March 23, 2012 By 13 Comments
Many people use mysqldump –single-transaction to get consistent backup for their Innodb tables without making database read only. In most cases it works, but did you know there are some cases when you can get table entirely missing from the backup if you use this technique ? The problem comes from the fact how MySQL’s [...]
dbqp and Xtrabackup testing
November 16, 2011 By Leave a Comment
So I’m back from the Percona dev team’s recent meeting. While there, we spent a fair bit of time discussing Xtrabackup development. One of our challenges is that as we add richer features to the tool, we need equivalent testing capabilities. However, it seems a constant in the MySQL world that available QA tools often [...]
Improved InnoDB fast index creation
November 6, 2011 By 4 Comments
One of the serious limitations in the fast index creation feature introduced in the InnoDB plugin is that it only works when indexes are explicitly created using ALTER TABLE or CREATE INDEX. Peter has already blogged about it before, here I’ll just briefly reiterate other cases that might benefit from that feature: when ALTER TABLE [...]
How to use tcpdump on very busy hosts
April 18, 2011 By 17 Comments
Often I run into problems when trying to use mk-query-digest with tcpdump on “very” busy hosts. You might be thinking, “very busy is a relative and unquantifiable term,” and you’d be right, so I’ll phrase this differently. Let me give a little background to the problem first. Mk-query-digest tries to handle dropped or missing packets [...]
How to debug long-running transactions in MySQL
March 8, 2011 By 6 Comments
Among the many things that can cause a “server stall” is a long-running transaction. If a transaction remains open for a very long time without committing, and has modified data, then other transactions could block and fail with a lock wait timeout. The problem is, it can be very difficult to find the offending code [...]
Thinking about running OPTIMIZE on your Innodb Table ? Stop!
December 9, 2010 By 18 Comments
Innodb/XtraDB tables do benefit from being reorganized often. You can get data physically laid out in primary key order as well as get better feel for primary key and index pages and so using less space, it is just OPTIMIZE TABLE might not be best way to do it. If you’re running Innodb Plugin on [...]
