There are a few interesting learning resources recently created by activists in the MySQL community. I just wanted to link to them to spread the word. They are free and if you've been looking for a way to learn more about MySQL, you should have a look at these.

MySQL Marinate

This is something I haven't really seen done before (for MySQL): a virtual self study group. It is based on the idea of everyone reading the same book, and I assume Sheeri will then facilitate some commentary on what your read. Sheeri mentioned this in a blog post earlier, but yesterday I went to check the signup page and wow - there are already 117 (or 76, depending on whether you look to the left or to the right) students registered!

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In my ongoing efforts to migrate my fun side projects and coding experiments from SVN to Git I’ve come across some of my favorite Python based apps – which are all available in their respective repos on BitBucket, as follows:

IRC Bot Commander

• What it does: it’s an IRC bot that takes commands and does your bidding on whichever remote server the bot is installed on.
• How it does it: the bot runs on whatever server you install it on, then it connects to the IRC server and channel you configured it to connect to and it waits for you to give it commands, then it execs the commands and returns the output to your IRC chat window.

MacroBase – MySQL Analytics

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MySQL has once again won the Linux Journal Readers Choice Award for Best Database 2012. Thanks to all who votes and all who use MySQL.

It's a well-know fact that InnoDB secondary keys contain both user defined columns and the primary key columns. For example, if a table has PRIMARY KEY(pk) and secondary key k1(f1), then index k1 is internally stored as k1(f1,pk).

Prior to version 5.6.9, the MySQL optimizer could only partially use these extended primary key columns: they could be used for sorting and to provide index only access. Starting from MySQL 5.6.9, the optimizer makes full use of the extended columns. This means that 'ref' access, range access, MIN/MAX optimizations, index_merge, loose index scan etc all works as if you had created the index with all primary key columns in all secondary keys. The new feature is turned on and off by optimizer switch 'use_index_extensions' and is on by default.

Consider we have following table:

CREATE TABLE t1
(
  f1 INT NOT NULL DEFAULT '0',
  f2 INT NOT NULL DEFAULT …

I would like to thank you again for all positive feedbacks I got on MyXplain.
This project has just begun but I am glad he has already affected many of you, it is a very pleasant surprise for us.

We are already working on very exciting features that I hope will emerge in the first quarter of 2013, stay tuned!

Now, if you would like to contribute to MyXplain, several options are available :

Of course you can propose a link, a slide or a book via the box available on website.
Feel free to leave comments on the options that you have some experience or expertise.

To go further, you can also provide a link to your blog or website and even make a donation, Christmas is coming soon, enjoy!
Only $10 can allow MyXplain to run for 1 more …

How easy is it to identify and debug Percona XtraDB Cluster replication problem ?

If you are using PXC, you may have already seen in your datadirectory several log files starting with GRA_

Those files correspond to a replication failure. That means the slave thread was not able to apply one transaction. For each of those file, a corresponding warning or error message is present in the mysql error log file.

Those error can also be false positive like a bad DDL statement (DROP a table that doesn’t exists for example) and therefore nothing to worry about. However it’s always recommended to understand what’s is happening.

As the GRA files contain binlog events in ROW format representing the failed transaction this post explains how to proceed.

The first step to be able to analyze your GRA files is to add a binlog header to the file.
You can download one here : …

Every time I visit my family for the holidays, as the date approaches, I find myself filled with dread. It’s nothing sinister, my family’s great, and the season is nice. The reason is simple:

I hate packing.

In fact, I hate both kinds of packing: trip packing, and bit packing. Let me tell you a story about bit packing.

Bit packing

If you’ve ever browsed around the available type attributes in GCC, you may have noticed the entry for “packed”. It seems straightforward enough, and if you’re trying to cram a lot of data in a system (like we do), it can be pretty attractive.

There are plenty …

We are really getting into the Christmas spirit this year, so we are offering 25% flat discount on all your purchases in the run-up to the big day. Time to go shopping again and buy yourself a gift, and make super savings of the year.

It’s a limited period offer, so head right away to the Online Shop and apply the coupon code save25.

Cheers,
Team Webyog

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There have been several reports (1,2,3) describing Percona’s stance regarding the MariaDB Foundation that are not totally accurate so I though it would be worth it to describe where we stand on this and related matters.

First, let me say the creation of theMariaDB Foundation is a good thing for the MariaDB Community and I’m very pleased to be in the group of those select people Monty chose to brief and seek feedback from before it was announced publicly. A Foundation is a form of governance for many mature open source projects, such as …

A week or two ago I heard second hand about someone saying "they can't use Galera because they use SAN for everything". Well, just so there is no doubt: You can perfectly well use Galera together with SAN. Galera is quite agnostic about the disks used.

In fact, Galera might be a great option together with SAN. Often SAN means slightly worse latency for disk writes, in particular when used with iSCSI. If the network path to the SAN is poor, it might mean a big performance hit, actually. Galera is in fact a good fit here, because the default/recommended setting for a Galera cluster is to relax the durability settings for InnoDB (innodb_flush_log_at_trx_commit), since durability is primarily guaranteed by the syncrhonous nature of the replication. (Same philosophy as is applied in the architecture for MySQL NDB Cluster.) This reduced stress on the disk can actually improve your experience with a SAN. A case in point is …