October 1, 2014

XtraDB feature: save / restore buffer pool

We recently released XtraDB-9, and while we did not highlight it in announcement, the release-making feature is ability to save and restore InnoDB buffer pool. The idea is not new and was originally developed by Jeremy Cole (sorry, I do not have the link on hands) some time ago, and now we implemented it in […]

How innodb_open_files affects performance

Recently I looked at table_cache sizing which showed larger table cache does not always provides the best performance. So I decided to look at yet another similar variable – innodb_open_files which defines how many files Innodb will keep open while working in innodb_file_per_table mode. Unlike MyISAM Innodb does not have to keep open file descriptor […]

Profiling MySQL stored routines

These days I’m working with a customer who has an application based entirely on stored routines on MySQL side. Even though I haven’t worked much with stored procedures, I though it’s going to be a piece of cake. In the end – it was, but there’s a catch.

Real-Life Use Case for “Barracuda” InnoDB File Format

In one of his recent posts Vadim already gave some information about possible benefits from using new InnoDB file format but in this post I’d like to share some real-life example how compression in InnoDB plugin could be useful for large warehousing tasks.

MySQL File System Fragmentation Benchmarks

Few days ago I wrote about testing writing to many files and seeing how this affects sequential read performance. I was very interested to see how it shows itself with real tables so I’ve got the script and ran tests for MyISAM and Innodb tables on ext3 filesystem. Here is what I found:

MySQL Stored Procedures problems and use practices

To be honest I’m not a big fan of Stored Procedures, At least not in the form they are currently implemented in MySQL 5.0 Only SQL as a Language Which is ancient ugly for algorithmic programming and slow. It is also forces you to use a lot of foreign constructs to “original” MySQL style – […]

PHP Sessions – Files vs Database Based

One may think changing PHP session handler from file based to database driven is fully transparent. In many cases it is, sometimes however it may cause some unexpected problems as happened to one of our customers. If you use file based sessions PHP will lock session file for whole script execution duration, which means all […]

Recovery after DROP [ TABLE | DATABASE ]

In your recovery practice we often face the problem when data lost by execution DROP TABLE or DROP DATABASE statement. In this case even our InnoDB Data Recovery tool can’t help, as table / directory with files was deleted (if you have innodb-file-per-table). And the same for MyISAM, all .MYD / .MYI / .frm – […]

Percona XtraBackup 2.2.4 is now available

Percona is glad to announce the release of Percona XtraBackup 2.2.4 on September 12th 2014. Downloads are available from our download site here and Percona Software Repositories. Percona XtraBackup enables backups without blocking user queries, making it ideal for companies with large data sets and mission-critical applications that cannot tolerate long periods of downtime. Offered […]

How to calculate the correct size of Percona XtraDB Cluster’s gcache

When a write query is sent to Percona XtraDB Cluster all the nodes store the writeset on a file called gcache. By default the name of that file is galera.cache and it is stored in the MySQL datadir. This is a very important file, and as usual with the most important variables in MySQL, the […]