I'm presenting during MySQL Performance Session in Paris which will take place on 24th November in our office building - Sun Solution Center, 32 rue Monceau, 75008 Paris. I did not blog about to avoid to increase frustration for all people who cannot attend it.. Because even we reserved for this even the biggest conference hall in the building there is still not enough place to accept everybody.. As well we did not expect so high interest - the first invitations were sent in priority to MySQL customers, and in few days there was already no more place..

So, why I'm writing now? ;-) Just because I'm pretty sure there will be a second session! :-) I cannot say you date & place yet because it'll directly depend on the number of persons willing to attend. And if you have a such willing, please, right now express it by email to Olivier.Beutels(at)sun.com !

List of topics covered during Performance Session:

…

Hello again.

After I left Pythian I was looking at a couple of other places to begin working with, but finally settled on staying in the mediterranean region, however with a small relocation.

Thus, this post is now long overdue, but I am working for a spanish company called Tuenti, which is the largest social network in spain. I am quite excited and have now settled down in Madrid, so I will be using this website in order to blog about challenges, problems, solutions and everything that comes with running a large scale deployment of MySQL.

Stay tuned for the first technical post, it’s on its way already!

When I developed partitioning for MySQL the main goal was
to make it easier for MySQL users to manage large tables
by enabling them to easily add and drop partitions.

It turns out that partitioning can also be used as a manner
to make MySQL more scalable. The reason is that in some
cases the storage engine have internal locks per table or
per index (one such example is the btr_search_latch in InnoDB).

So in this case adding a
PARTITION BY KEY (key_part)
PARTITIONS 4
to the table definition makes a very hot table into 4 tables
from the storage engine point of view.

This would mostly be beneficial in cases where the main
operation is primary key lookups on the table. Dividing the
indexes in cases of scans can be both positive and negative.
So this solution is definitely not a winner for all situations.

I haven't …

There is the rare bug which I ran into every so often. Last time I've seen it about 3 years ago on MySQL 4.1 and I hoped it is long fixed since... but it looks like it is not. I now get to see MySQL 5.4.2 in the funny state.

When you see bug happening you would see MySQL log flooded with error messages like this:

091119 23:03:34 [ERROR] Error in accept: Resource temporarily unavailable
091119 23:03:34 [ERROR] Error in accept: Resource temporarily unavailable
091119 23:03:34 [ERROR] Error in accept: Resource temporarily unavailable
091119 23:03:34 [ERROR] Error in accept: Resource temporarily unavailable

filling out disk space

Depending on the case you may be able to connect to MySQL through Unix Socket or TCP/IP or neither.
It also looks like there is a correlation between having a lot of tables and such condition.

Previously I was unlucky with seeing this issue in …

My benchmark scripts was upgraded once more today.
I fixed all issues pertaining to full automation
of DBT2 runs. So now it is as easy to start a
DBT2 test run as it previously was to start a
sysbench run. Obviously DBT2 was already earlier
supported in the benchmark scripts, so what I did
now was add the final steps to make it fully
automated. This includes also generating the DBT2
load files needed to load the DBT2 database.

See the download section on www.iclaustron.com
for the tarball including some description of
how to configure sysbench and DBT2 test runs.

New in this release:
External PHP based binary log consumer. It wraps 'mysqlbinlog' and reads settings from an .ini file.
The consumer must be running in order to refresh views and collect table change logs.
MIN/MAX and COUNT(DISTINCT) are now supported, experimentally.
Many other improvements.

Ever been around a group of people discussing some technology and heard Cool-Whip phrases like this?

It’s not about MySQL versus PostgreSQL, it’s about using the right tool for the job.

Or how about this one?

You need to take the important factors into account before you decide whether [hot new fad] or [trusty old solution] is best suited for your application.

Both are signs that someone might be trying to sound important. In situations like this, I’ve noticed that the people I look up to usually don’t make weighty-sounding statements about other people’s systems. They talk about what they are qualified to talk about: either they say something about their own systems, or if it’s warranted and invited, they ask intelligent questions about other people’s systems.

People who only have vacuous generalities to contribute don’t talk about their own systems, because if they actually worked on …

For those of you interested in the open source database world, you will get a good in-depth look at Kontrollbase this month in the OSDB Magazine. Keith Murphy has been kind enough to give me pages 37 through 50 to tell you all about the history, current features, and plans for the future. It’s a [...]

It’s been hectic to find a good provider even with all of the choices out there these days but I’m happy to let you know that we settled on ServerBeach for the demo server and are back online. The page load testing is positive and quick, and all features are available for you to try. [...]

I am working with a client that is using managed hosting on dedicated servers. This has presented new challenges in obtaining the right permissions to undertake MySQL tasks but not have either ‘root’ or ‘mysql’ access and not have to involve a third party everytime.

Adding the following to the /etc/sudoers file enabled the ability to restart MySQL.

User_Alias      DBA = rbradfor, user2, etc
Host_Alias      DB_SERVERS = server1.example.com, server2.example.com, etc
Cmnd_Alias      MYSQL = /etc/init.d/mysqld, /usr/sbin/tcpdump

DBA DB_SERVERS = MYSQL

As you can see I also got tcpdump, which I find valuable to monitor via mk-query-digest.

Next, permissions for log files.