Percona is glad to announce the release of Percona XtraBackup 2.1.1 on May 15th 2013. 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 free as an open source solution, XtraBackup drives down backup costs while providing unique features for MySQL backup. The new 2.1.1 GA …

MySQL Community team is pleased to announce following events as the ones supported by us with a great MySQL staff attending. Find more details below (or at our Community wikis).

• NoSQL Roadshow, Berlin Germany, May 16, 2013
  
  • Talk: NoSQL & MySQL by Mario Beck
• Solutions Libres & Open Source, Paris, France, May 28-29, 2013
  • Talk: NoSQL & MySQL by Olivier Zemrag
  …

Recently someone asked my if it's possible to find the total free space within InnoDB. I thought this would be very easy as the INFORMATION_SCHEMA.TABLES table has a DATA_FREE column. So we could just use SELECT SUM(DATA_FREE) FROM INFORMATION_SCHEMA.TABLES couldn't we?
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So what does the DATA_FREE column tell us? It tells us the free data within InnoDB for that particular table. A table can share a tablespace with multiple other tables.
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The tablespace which is used by a table depends on whether the innodb_file_per_table was enabled during table creation and/or at the last time the table was rebuild (e.g. by OPTIMIZE TABLE).
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If innodb_file_per_table was always disabled then this query probably reports the correct free space:

SELECT DATA_FREE FROM INFORMATION_SCHEMA.TABLES WHERE ENGINE='InnoDB' LIMIT 1;

This is because all tables will share 1 …

Occasionally it is useful to know what a MySQL command is doing internally. Just looking into the MySQL source directory can be overwhelming. Knowing the basics of the handler interface and the sql parser can be a great start for reading the source code to understand what MySQL does under the hood. Here I will cover a little bit about how the SQL syntax is defined.

Everything starts with lex.h and sql_yacc.yy in the sql/ dir. lex.h contains all the functions and symbols used to make up the SQL syntax. The sql_yacc.yy file describes the relationships between these symbols and the C functions responsible for executing them. I’m not sure why some symbol definitions end in _SYM and others don’t. Looking in lex.h “FLUSH” is defined as FLUSH_SYM. To see all the places where flush is allowed in the SQL go back to sql_yacc.yy and grep for it.

The first important section looks like this:

/* flush things */ …

The Example storage engine is meant to serve mainly as a code example of the stub of a storage engine for example purposes only (or so the code comment at the start of ha_example.cc reads). In reality however, it’s not very useful. It likely was back in 2004 when it could be used as a starting point for starting some simple new engines (my guess would be that more than a few of the simpler engines started from ha_example.cc).

The sad reality is the complexity of the non-obviousness of the bits o the storage engine API you actually care about are documented in ha_ndbcluster.cc, ha_myisam.cc and ha_innodb.cc. If you’re doing something that isn’t already done by one of those three engines: good luck.

Whenever I looked at ha_example.cc I always wished there was something more behind it… basically hoping that InnoDB would get a better and cleaner API with the server and would use that rather than the layering violations it has to …

MySQL Thread Pool has now been updated for the MySQL 5.6 version. Obviously, with the much higher concurrency of the MySQL Server in 5.6 it's important that the thread pool doesn't add any new concurrency problem when scaling up to 60 CPU threads. The good news is that the thread pool works even better in MySQL 5.6 than in MySQL 5.5. MySQL 5.6 has fixed even more issues when it comes to execution of many concurrent queries and this means that the thread pool provides even more stable throughput almost independent of the number of queries sent to it in parallel.

Starting with MySQL 5.6, MySQL commercial-license builds use OpenSSL.  yaSSL – previously used as the default SSL library for all builds – remains the implementation for Community (GPL) builds, and users comfortable building from source can choose to build with OpenSSL instead.  Daniel van Eeden recently requested a global variable to indicate which SSL library was used to compile the server (bug#69226), and it’s a good request.  It’s something I’ve previously requested as well, having been fooled by the use of have_openssl as a synonym for …

I would like to invite everyone who is around Trondheim, Norway to the "MySQL mini-seminar" taking place on June 19, 2013 in Oracle office. Do not miss this great opportunity to meet great MySQL engineers who are looking forward to meeting you and talking about MySQL!!!

Please see the official invitation in English and Norwegian below.

Invitation to MySQL mini-seminar

Many people are unaware that a great number of the MySQL developers are located in Trondheim, Norway, and that we have a lot of competence we would love to share.

We therefore invite anyone in Trondheim who's interested in MySQL to a mini-seminar located the Oracle's offices on Lade, June 19 at 3 pm.

The agenda will be:

• Presentation: MySQL Query Optimizer: an overview, by Jørgen Løland, MySQL Optimizer team
• Q&A, discussions
• Suggestions for presentations on …

Last week we released MySQL Connector/Python v1.0.10. Release notes can be found in the MySQL Developver Zone.

A notable fix in Connector/Python v1.0.10 which might interest a few users is adding support for LOAD DATA LOCAL INFILE. It allows you to import CSV using a simple SQL statement.

Please use the MySQL Bugs website to report any problem.

Some useful links:

• Documentation: …

The third meeting for the MySQL User Group NL will be hosted by Snow B.V. in the Snow office in Geldermalsen.
 
The Agenda:

• Choosing the Best Sharding Policy - Doran Levari (ScaleBase, using a video link)
• Performance Monitoring with Statsd and Graphite - Art van Scheppingen (Spil Games)
• Basic MySQL performance tuning for sysadmins - Daniël van Eeden (Snow)

Please RSVP on the meetup.com page.

The user group now has more than 100 members!