Another fall, another MySQL community conference. What's the point? Haven't we heard it all before? Same old RDBMS, same old problems, same old speakers, same old venue? What can we expect this year's European conference? Well for starters, the venue has been moved from London to Amsterdam so we have a new acronym; PLEU or PLAM or PLNL? You can decide and use it in your #tweets.

If you hid from all the announcements, Percona acquired Tokutek in April 2015. Tokutek are a company invested in both MySQL and MongoDB landscapes through their fractal tree based storage engines. What does this mean? Well this gave birth to a new scope to the traditionally MySQL-focussed event. Amongst the plethora of high profile company representations you'll see MongoDB, Elastic and Couchbase. So if you're seeking a heterogeneous data conference then you should be there. …

I recently helped a customer figure out why a minor version MySQL upgrade was indicating that some tables needed to be rebuilt. The mysql_upgrade program should be run for every upgrade, no matter how big or small the version difference is, but when only the minor version changes, I would normally not expect it to require tables to be rebuilt.

Turns out some of their tables were still marked with an older MySQL version, which could mean a few things… most likely that something went wrong with a previous upgrade, or that the tables were copied from a server with an older version.

In cases like this, did you know there is a fast, safe and simple way to check the version associated with a table? You can do this by reading the FRM file, following the format specification found here.

If you look at that page, you’ll see that the …

Sometimes I give parts of a solution to increase the play time to solve a problem. I didn’t anticipate a problem when showing how to perform a sort operation with a CASE statement. It’s a sweet solution when you need to sort something differently than a traditional ascending or descending sort.

I gave my students this ORDER BY clause as an example:

  CASE
    WHEN filter = 'Debit' THEN 1
    WHEN filter = 'Credit' THEN 2
    WHEN filter = 'Total' THEN 3
  END;

It raises the following error in MySQL for students:

      ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'ORDER BY
  CASE
    WHEN filter = 'Debit' THEN 1
    WHEN filter = 'Credit' THEN' at line 6

It raises the …

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 – …

The MySQL Enterprise Audit plug-in is part of the MySQL Enterprise Edition (available through a paid license). Basically, Enterprise Audit tracks everything that is happening on your MySQL server, and can be used to protect/detect the misuse of information, and to meet popular compliance regulations including HIPAA, Sarbanes-Oxley, and the PCI Data Security Standard.

MySQL Enterprise Audit uses the open MySQL Audit API to enable standard, policy-based monitoring and logging of connection and query activity executed on specific MySQL servers. Designed to meet the …

Thanks to everyone who joined us last week for this live session on backup strategies for MySQL and Galera clusters led by Krzysztof Książek, Senior Support Engineer at Severalnines. The replay and slides to the webinar are now available to watch and read online via the links below.

Watch the replay

Become a MySQL DBA - webinar series: Deciding on a relevant backup solution from Severalnines AB   Read the slides

Become a MySQL DBA - slides: Deciding on a relevant backup solution from …

Addition of support for Apache Cassandra and DataStax Enterprise extends Pythian’s leadership in extreme-scale database deployments and big data services

OTTAWA, Canada – July 8, 2015 – Pythian, a global IT services company specializing in helping companies leverage disruptive technologies to optimize revenue-generating systems, today announced the general availability of its consulting and follow-the-sun managed services support for both Apache™ Cassandra™ and DataStax®, the company that delivers Apache Cassandra to the enterprise. Cassandra is an open-source, distributed database management system designed to handle large amounts of data across many commodity servers, providing high availability with no single point of failure.

Pythian leverages an extensive suite of managed services, tools, and database experience to get organizations up and running in their Cassandra and …

There is nothing more to be said:

SELECT
gen.TABLE_SCHEMA
, gen.TABLE_NAME
, (select
count(TABLE_NAME) from information_schema.columns idx
where
idx.TABLE_SCHEMA = gen.TABLE_SCHEMA
and idx.TABLE_NAME=gen.TABLE_NAME
) as COLUMN_NUM
, (select
count(TABLE_NAME) from information_schema.columns idx
where
idx.TABLE_SCHEMA = gen.TABLE_SCHEMA
and idx.TABLE_NAME=gen.TABLE_NAME
and COLUMN_KEY != ""
) as INDEX_NUM_ALL
, (select
count(TABLE_NAME) from information_schema.columns idx
where
idx.TABLE_SCHEMA = gen.TABLE_SCHEMA
and idx.TABLE_NAME=gen.TABLE_NAME
and COLUMN_KEY = "PRI"
) as INDEX_NUM_PRI
, (select
count(TABLE_NAME) from information_schema.columns idx
where
idx.TABLE_SCHEMA = gen.TABLE_SCHEMA
and idx.TABLE_NAME=gen.TABLE_NAME
and COLUMN_KEY = "UNI"
) as INDEX_NUM_UNI
, (select
count(TABLE_NAME) from information_schema.columns idx
where
idx.TABLE_SCHEMA = gen.TABLE_SCHEMA
and idx.TABLE_NAME=gen.TABLE_NAME
and COLUMN_KEY = "MUL"
) as INDEX_NUM_MUL

from …

Way back in 2010, MySQL Bug 57241 was filed, pointing out that the “swap insanity” problem was getting serious on x86 systems – with NUMA being more and more common back then.

The swapping problem is due to running out of memory on a NUMA node and having to swap things to other nodes (see Jeremy Cole‘s blog entry also from 2010 on the topic of swap insanity). This was back when 64GB and dual quad core CPUs was big – in the past five years big systems have gotten bigger.

Back then there were two things you could do to have your system be usable: 1) numa=off as kernel boot parameter (this likely has other implications though) and 2) “numactl –interleave all” in mysqld_safe …

MySQL replication has been available for years, and even though a number of new clustering technologies showed up recently, replication is still very common among MySQL users. It is understandable as replication is a reliable way of moving your data between MySQL instances. Even if you use Galera or NDB cluster, you still may have to rely on MySQL replication to distribute your databases across WAN.

In this blog post we’d like to discuss one of the most common operations DBA has to handle - replication topology changes and planned failover. 

This is the fifth installment in the ‘Become a MySQL DBA’ blog series, and discusses one of the most common operations a DBA has to handle - replication topology changes and planned failover. Our previous posts in the DBA series include Schema Changes, …