For Finnish or Northern European readers of this blog, I just wanted to advertise that there is a great MySQL training coming up in Helsinki on the 3rd week of August. The trainer will be Oli Sennhauser from Switzerland. Oli is a former collague of mine from MySQL AB and is now an independent MySQL consultant - one of the best in Europe! The curriculum is targeted at developers (more dev than ops) that are already familiar with using MySQL, and will help you get a deeper understanding of InnoDB internals, high availability, caching and other advanced topics.

You can check it out or register at the Citrus website.

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OSCON is coming up again: July 25th-29th in wonderful Portland, OR. If you come to OSCON, not only will you be at OSCON, but you’ll be in Portland in July – which is just lovely. We’ll also have other people from Percona there and it should be a great lot of fun.

So come along and talk interesting technology – I’ll be speaking on “Dropping ACID: Eating Data in a Web 2.0 Cloud World“. If you know my love of reliable software with known failure modes, you’ll probably enjoy this one – especially if you saw my “Eat My Data: How everybody gets POSIX file I/O Wrong” which when given at OSCON 2008 was given to a packed room with people in the aisles and out the door.

Speaking has its pluses and minuses of course. It takes a very, very …

Oracle VM Template for MySQL Enterprise Edition

Oracle today announced the release of the “Oracle VM Template for MySQL Enterprise Edition” – you can read the press-release here.

There are a couple of ways to look at the benefits:

• Provides a simple alternate High Availability solution for MySQL (i.e. rather than MySQL Replication or MySQL Cluster – although you can still set up replication to/from a MySQL Server installed this way)
• A new, very simple way to get up and running with MySQL Enterprise – running on a complete stack that Oracle can provide support for

As the focus of this blog is normally MySQL Cluster and Replication, the HA attributes of this solution are probably those …

Three years ago MySQL has got @@optimizer_switch variable. It was introduced in MySQL 5.1.34, that is, we needed it so much that we’ve added it into the stable release.

In a nutshell,@@optimizer_switch held a comma-separated list of optimizer controls:

mysq> > select @@optimizer_switch;
+------------------------------------------------------------------------------------------+
| @@optimizer_switch                                                                       |
+------------------------------------------------------------------------------------------+
| index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on|
+------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)

One could set all settings at once:

mysql> set …

In a small environment, there's very little reason to rely on DNS resolution inside MySQL. You can disable it by adding skip-name-resolve to your my.cnf or by using the --skip-name-resolve command line argument. Remember that if you disable DNS lookups, you will need to set permissions using IP addresses rather than host names!

Performance schema performance tuning One of the most important question users ask before deciding to use the performance schema is: what is the overhead ? The underlying concern of course is to make sure deploying the performance schema does not negatively impact production ("First, do no harm").
The question is simple, and yet the answer is not so simple, as it depends on so many things.
As seen in some benchmarks done already, the overhead when using the performance schema can vary a lot, and in some cases really causes degradations.
A lot of time has been spent investigating the root causes (note the plural form) for the performance schema overhead in general, so I think it is a good time to share current findings.

Server workload Analysing performances, and testing the effects of different code or configuration changes, can hardly be done in a vacuum. That's where benchmarks come in.
The problem with …

Performance Monitoring of MySQL Server: Following are the command which we can use for session or server level performance for MySQL server. SHOW GLOBAL STATUS – shows global server status SHOW LOCAL STATUS  - This is used for session level server status Have to check following values to know how server works. Aborted_clients : Usually

If the table has a multiple-column index, any leftmost prefix of the index can be used by the optimizer to find rows. For example, if you have a three-column index on (col1, col2, col3), you have indexed search capabilities on (col1), (col1, col2), and (col1, col2, col3). MySQL cannot use an index if the columns do not form a leftmost prefix of the index. Suppose that you have the SELECT statements shown here: SELECT * FROM tbl_name WHERE col1=val1;SELECT * FROM tbl_name WHERE col1=val1 AND col2=val2;
SELECT * FROM tbl_name WHERE col2=val2;SELECT * FROM tbl_name WHERE col2=val2 AND col3=val3;If an index exists on (col1, col2, col3), only the first two queries use the index. The third and fourth queries do involve indexed columns, but (col2) and …

In your hands, the new edition of Log Buffer is smiling and it wants your undivided attention, because it is full of selected simmering yet cool blog posts from around the blogistan of database arena. Enjoy the Log Buffer #226.

Oracle:

Kyle Hailey is exploring I/O histogram values in Automatic Workload Repository.

Charles Hopper tells us what is wrong with the quote – Addressing TM Enqueue Contention

…

This year I set myself a target to get back to my pre-marital weight. Back in 2001 I was 90kg, but over the past decade I’d steadily gone up and for quite a few years had hovered around 100kg.

I’m a bit of a perfectionist, and like shiny graphs, so from Jan 1st this year I weighed myself every day on the Wii Fit, and kept a record of my progress. This morning I was finally under 90kg. Here’s how things have gone thus far:

And for the geeks, my gnuplot script, assuming an input file named weight.txt containing lines of the format "%Y-%m-%d <weight>":

set terminal png size 640, 400
set output "weight-jun11.png"
set xdata time
set timefmt "%Y-%m-%d"
set format x "%b"
set xlabel 'Date'
set ytics 2
set ylabel 'Weight (kg)'
set multiplot
plot 'weight.txt' using 1:2 title 'Weight' with lines linecolor 2

My three step plan for losing weight

The interwebs are awash …