As some of you may or may not know, I’ve maintained a list of all InnoDB Plugin versions as they’ve historically contained a different version (entirely different numbering scheme) than the MySQL distribution they were included with.

This list was most helpful for troubleshooting various InnoDB issues when the plugin may (or may not) have been involved, and/or for benchmarking, etc. And it’s fair to say it was more useful when the InnoDB plugin was not the mainstream, which it is now.

However, with the latest releases, in MySQL and MariaDB, the “InnoDB Version” simply matches the “MySQL Version”. These “latest releases” include: MySQL 5.6.10, MySQL 5.5.30, MySQL 5.1.68, and MariaDB 5.5.30

Of course this isn’t the most newsworthy story, but having maintained this “list” the past couple/few years, I was happy to see the change, …

I just wrote an article about “Troubleshooting ‘Waiting for table metadata lock’ Errors for both MyISAM and InnoDB Tables” and then ran into a new, different metadata locking issue right after I posted it, and so I thought I’d share that too, just in case anyone ever encounters a similar situation.

In this case, mysqld kept crashing on restart, reporting “out of memory” errors:

/opt/app/mysql/product/mysql/bin//mysqld: Out of memory (Needed 840 bytes)
stack_bottom = 7fb4ebaeae58 thread_stack 0x40000
mysqld: /mysql/mysys/my_new.cc:52: int __cxa_pure_virtual():
  Assertion `! "Aborted: pure virtual method called."' failed.
mysqld: /mysql/mysys/my_new.cc:52: int __cxa_pure_virtual():
  Assertion `! "Aborted: pure virtual method called."' failed.
Fatal signal 6 while backtracing

There is a …

With the introduction of metadata locking in MySQL 5.5, it is much more common to see queries stuck in the “Waiting for table metadata lock” state.

If you see a query stuck in the “Waiting for table metadata lock” state, waiting for a MyISAM table, then it is because this table has been included as part of some uncommitted transaction (whether intentionally or not).

In fact, it could be as simple as issuing SET AUTOCOMMIT=0 followed by a SELECT against a MyISAM table (a transaction can be started 3 ways: START TRANSACTION, BEGIN, and SET AUTOCOMMIT=0). After that, the table will be locked to other DDL statements until the transaction is committed (or ended).

This metadata lock is meant for DDL statements, and so that is what it blocks. However, once a DDL statement is blocked and waiting, then all queries …

Ever see an error like this in your console or error log, respectively, and wonder where it originated from?

Console (5.5.30):

ERROR 1017 (HY000): Can't find file:
'.\test\select@0020@002a@0020from@0020t1.frm' (errno: 22)

Error Log (5.5.30):

130307 23:22:04 [ERROR] C:\Program Files\MySQL\MySQL Server 5.5\bin\mysqld: 
Can't find file: '.\test\select@0020@002a@0020from@0020t1.frm' (errno: 22)

(Fwiw, they are harmless, unless it is indicative of some sql injection – but you may want to sanitize your data better, unless it’s just a one-time user error. Also, if you’re seeing it from the command line, then you’ll likely realize what you did immediately, and thus no need to ‘figure out’ what happened. However, when you *only* see this entry in the error log, and you want to know how that happened after the fact, then this is more relevant.)

At any rate, after searching the code, one can see …

The last MySQL User Group NL meeting was last Friday. It's always nice to learn about MySQL and meet other MySQL users. There were two presentations: one about MySQL User Defined Functions (UDF's) and one about MySQL TCO. The slides are available from the meetup page.

There are already a number of MySQL events announced for the next few months. I'll only list events in the Netherlands and Virtual events.

MySQL Virtual Developer Days
This is a virtual event which will take place on March 19 (EMEA region, NA event is on March 12). There are many interesting topics: Performance Schema, New 5.6 Features, Replication, MySQL Enterprise Monitor
The eVite

SkySQL and MariaDB roadshow
21 March 2013 in Amsterdam
This event  have …

Latest training events calendar & class schedule now available

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SkySQL and Monty Program are on the road with our joint Meetup in Amsterdam where Monty Widenius - the origninal creator of MySQL - will unveil his vision of the future of the MySQL database via MariaDB.

Seppo Jaakola from Codership will give a presentation about Galera Cluster for MySQL and MariaDB.

In addition we will have speakers from Booking.com as well as Anders Karlsson from SkySQL who will talk about Big Data.

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Le 27 mars de 14h à 19h à l'Atelier du France, Paris

SkySQL et Monty Program organisent une demie journée de conférences consacrées aux bonnes pratiques et retours d'expériences autour des bases de données MySQL®et MariaDB, l'objectif étant de répondre aux préoccupations actuelles des administrateurs de bases de données.

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A high-level comparative overview of the features

With the recent GA release of MySQL 5.6, there have been a lot of questions about where MariaDB stands with regards to MySQL 5.6.  SkySQL will of course support both as Patrik explained in his recent blog post, but there are many questions about the technical differences. Rasmus from Monty Program gave a detailed view on MariaDB 10.0 here but I thought it would be beneficial to share a comparison table of the two. MariaDB recently released a benchmark including various versions of both MariaDB and MySQL (as did DmitriK from Oracle), but this post will focus solely on features (not …

It’s time to unveil the winners of the [Plus] readers choice awards!
Thank you again for your votes, remember that the real winner was the community, again.

I asked you to vote for what you used in 2012 and you’ve voted with your heart.
Here are the final results, congrats to the lucky guys and teams :

The most useful blogs in 2012 :

1. MySQL Performance Blog
2. The MariaDB Blog
3. SkySQL Blog

Ok, the Percona team members provides the best technical blog about MySQL (and more), this year again. Of course, this blog is very useful and interesting, I recommend to read the comments too, they are often very informative.
There is a …