The latest from the MySQL community

MySQL 5.6.26 was recently released (it is the latest MySQL 5.6, is GA), and is available for download here.

For this release, there are 3 “Functionality Added or Changed” items, 1 “Security Fix”, and 36 other bug fixes.

Out of those other 36 bugs, 13 are InnoDB, 1 Partitioning, 3 Replication, and 19 misc. (including 3 potentially crashing bug fixes, and 1 performance-related fix) Here are the ones of note:

• Functionality Added/Changed: Replication: When using a multi-threaded slave, each worker thread has its own queue of transactions to process. In previous MySQL versions, STOP SLAVE waited for all workers to process their entire queue. This logic has been changed so that STOP SLAVE first finds the newest transaction that was committed by any worker thread. Then, it waits for all workers to complete …

MySQL 5.5.45 was recently released (it is the latest MySQL 5.5, is GA), and is available for download here:

http://dev.mysql.com/downloads/mysql/5.5.html

This release, similar to the last 5.5 release, is mostly uneventful.

There were 0 “Functionality Added or Changed” items this time, 1 “Security Fix”, and just 9 bugs overall fixed.

Out of the 9 bugs, there were 3 InnoDB bugs, 1 security-related bug, and 1 potential crashing bug. Here are the ones worth noting:

• InnoDB: An index record was not found on rollback due to inconsistencies in the purge_node_t structure.
• InnoDB: An assertion was raised when InnoDB attempted to dereference a NULL foreign key object.
• InnoDB: On Unix-like platforms, os_file_create_simple_no_error_handling_func and …

Today I released version 1.1 of myoradump for download from sourceforge. If you don't know what myoradump is, this is a utility for exporting data from an Oracle database in some relevant text format so that it can be imported to some other database.

The main thing in version 1.1 is that I have added a whole bunch of new output formats, so make it even easier to get your data out of expensive Oracle and into something more effective. The new formats supported are:

• MySQL - The format of this is a bunch of INSERT statements that you get when you use mysqldump for example and is useful for import into MariaDB (and MySQL). INSERT arrays are supported as a bunch of more options.
• JSON - This format is rather obvious, the output is a file consisting of one JSON object per row. To support binary …

This is getting more and more common, so I wanted to provide the steps required to get LDAP authentication working with MariaDB PAM plugin.

Unless you’re already familiar with setting up the MariaDB PAM plugin, I’d first recommend getting this to work with a standard Linux user (steps 1-4), then once all is working fine, progress to the LDAP users (steps 5-10). (And if you do not want to test this for the Linux user account, then you may skip steps #2 and #3.)

1. Enable plugin by running the following from the command line client:

   INSTALL SONAME 'auth_pam';

   You should see an entry like this afterward in SHOW PLUGINS:

       | pam | ACTIVE | AUTHENTICATION | auth_pam.so | GPL |

2. Create the mysql user account (note it does not have a password, as it will obtain this from your Linux user, and eventually the LDAP account) and provide it with the GRANTS you want it to …

http://dom.as/2015/07/30/on-order-by-optimization/

An insightful exploration by Domas (Facebook) on how some of the MySQL optimiser’s decision logic is sometimes naive, in this case regarding ORDER BY optimisation.

Quite often, “simple” logic can work better than complex logic as chasing all the corner cases can just make things worse – but sometimes, logic can be too simple.

Everything must be made as simple as possible, but no simpler.
— Albert Einstein / Roger Sessions

Replication is the process that transfers data from an active master to a slave server, which reproduces the data stream to achieve, as best as possible, a faithful copy of the data in the master.

To check replication health, you may start with sampling the service, i.e. committing some Sentinel value in the master and retrieving it from the slave.

Sentinel data: Tap tap… Is this thing on?
If you want to make sure that replication is working, the easiest test is using replication itself to see if data is being copied across from the master to the slaves. The method is easy:

1. Make sure that the data you want to see is NOT in the master or in the slave. If you skip this step, you may think that replication is working, while in fact it may not.
2. Either create a table …

Download MariaDB 10.1.6

Release Notes Changelog What is MariaDB 10.1?

MariaDB APT and YUM Repository Configuration Generator

The MariaDB project is pleased to announce the immediate availability of MariaDB 10.1.6. This is a Beta release.

See the Release Notes and …

My latest post is online on the Booking.com blog: Evaluating MySQL Parallel Replication Part 3: Benchmarks in Production.  In this post, I present benchmark results on MariaDB 10.0 parallel replication on four Booking.com production workloads.

This post is also the opportunity to promote my two talks at Percona Live Europe, taking place in Amsterdam from September 21 to 23:

Binlog Servers at

Both MySQL and MariaDB have been busy, each introducing new features, sometimes creating the same feature, often with different syntax.

This is sometimes good for users, who have a wide choice. And sometimes it is bad, as once you are used to the deployment and syntax of one flavor, it is hard to switch to a different one. This problem is enhanced if you are dealing with an application, MySQL Sandbox, that needs to work well with all flavors.

The latest releases of MySQL Sandbox (3.0.51 to 3.0.55) have been necessary to solve minor and major troublesome points with MySQL 5.7.8 and MariaDB 10.1.

The current version (3.0.55) can install all the newest releases, including replication with MySQL 5.7.8 which suffers from a compatibility bug (better explored in a separate article). …

The schedule is out for Percona Live Europe: Amsterdam (September 21-23 2015), and you can see it at: https://www.percona.com/live/europe-amsterdam-2015/program.

From MariaDB Corporation/Foundation, we have 1 tutorial: Best Practices for MySQL High Availability – Colin Charles (MariaDB)

And 5 talks:

1. Using Docker for Fast and Easy Testing of MariaDB and MaxScale – Andrea Tosatto (Colt Engine s.r.l.) (I expect Maria Luisa is giving this talk together – …