May 19, 2013

MySQL 5.5 and MySQL 5.6 default variable values differences

As the part of analyzing surprising MySQL 5.5 vs MySQL 5.6 performance results I’ve been looking at changes to default variable values. To do that I’ve loaded the values from MySQL 5.5.30 and MySQL 5.6.10 to the different tables and ran the query:

Lets go over to see what are the most important changes [...]

Announcing Percona XtraDB Cluster 5.5.29-23.7.2

Percona is glad to announce the release of Percona XtraDB Cluster 5.5.29-23.7.2 on February 13th, 2013. Binaries are available from downloads area or from our software repositories. Bugs fixed: DML operations on temporary tables would try to append the key for provider library, which could cause a memory leak. Bug fixed for MyISAM temporary tables, [...]

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 [...]

MySQL Wish for 2013 – Better Memory Accounting

With Performance Schema improvements in MySQL 5.6 I think we’re in the good shape with insight on what is causing performance bottlenecks as well as where CPU resources are spent. (Performance Schema does not accounts CPU usage directly but it is something which can be relatively easily derived from wait and stage information). Where we’re [...]

Full table scan vs full index scan performance

Earlier this week, Cédric blogged about how easy we can get confused between a covering index and a full index scan in the EXPLAIN output. While a covering index (seen with EXPLAIN as Extra: Using index) is a very interesting performance optimization, a full index scan (type: index) is according to the documentation the 2nd [...]

Announcing Percona XtraDB Cluster 5.5.28-23.7

Percona is glad to announce the release of Percona XtraDB Cluster on November 15th, 2012. Binaries are available from downloads area or from our software repositories. Features: Percona XtraDB Cluster has ported Twitter’s MySQL NUMA patch. This patch implements improved NUMA support as it prevents imbalanced memory allocation across NUMA nodes. Number of binlog files [...]

What is the largest amount of data do you store in MySQL ?

My previous poll got a great response so I thought I should continue these series. The question of the day today is How much data do your store in your largest MySQL instance ? I’m interested about single instance not the total amount of data you have in MySQL in your Sharded replicated environment. Feel [...]

Review of MySQL 5.6 Defaults Changes

James Day just posted the great summary of defaults changes in MySQL 5.6 compared to MySQL 5.5 In general there are a lot of good changes and many defaults are now computed instead of hardcoded. Though some of changes are rather puzzling for me. Lets go over them: back_log = 50 + ( max_connections / [...]

Percona Server tree with support of Fusion-io atomic writes and DirectFS

Not so long ago Fusion-io announced an SDK which provides direct API access to Fusion ioMemory(tm) in addition to providing a native filesystem (directFS) with a goal to avoid overhead from kernel and regular Linux filesystems: ext4 and xfs. This requires a support from application, it should use special calls for IO. With help from [...]

A (prototype) lower impact slow query log

Yesterday, over at my personal blog, I blogged about the impact of the MySQL slow query log. Since we’re working on Percona Server 5.6, I did wonder if this was a good opportunity to re-examine how we could provide slow query log type functionality to our users. The slow query log code inside the MySQL [...]