There will be big changes for those taking certification exams at the MySQL Users Conference. Once again we are offering $25 MySQL exams which is a big discount from the regular $200 price.

Last year we ran the exams as a drop-in service and it was well received. So we will continue to run it as a drop-in service. No need for an appointment. We will be in the Magnolia Room from 8:30 AM to about 4:00 PM but will not let anyone start an exam later than 3:00PM.

Be sure to bring your WiFi enabled laptop! Last year we killed a lot of trees and got a big workout printing thousands of exams and moving them around. This year the exams will be online. We will be reserving some hard lines for those taking the hands-on DBA 5.1 exam as they need to connect to the virtual servers in Colorado (that is if the O'Reilly folks can get the network gear) but everyone else will be using the wireless connections. Last year the wireless was …

Continuing on from CPU, we turn our attention to Memory. One of the first steps when addressing a MySQL performance tuning problem is to perform a system audit of the physical hardware resources, then identify any obvious bottlenecks in these resources.

In auditing, I start with the ‘free’ command, the already used ‘vmstat’ command, the /proc/meminfo and /proc/sys/vm/swappiness files to get an indication of memory and swap resources. While we are looking at the Memory, the configuration of Swap is also very important. I will discuss this in more detail later.

$ free -m
             total       used       free     shared    buffers     cached
Mem:          3955       3838        117          0        402       2366
-/+ buffers/cache:       1069       2886
Swap:         1027          0 …

Amazon today launched a beta of it's Elastic MapReduce (hosted hadoop). This is exciting and just in time for my upcoming, Hadoop and MySQL: Friends with benefits, session at the MySQL Conference & Expo.

I can't wait to try it out!

There are two problems with the CAST function in all versions of MySQL:

bug#43774CAST(CAST(value) as TIME as DATETIME ) returns the wrong value.

example:
mysql> select '0000-00-00 21:00:00' expected, cast(cast('21:00:00' as time) as datetime) actual;
+---------------------+---------------------+
| expected | actual |
+---------------------+---------------------+
| 0000-00-00 21:00:00 | 2021-00-00 00:00:00 |
+---------------------+---------------------+
1 row in set (0.00 sec)

bug#43865CAST( -1.0 as UNSIGNED) yields 0 instead of MAXINT and returns a warning.

example:
create table t1(c1 int signed,
c2 decimal(5,2),
c3 float(5,2)
);

insert into t1 values …

MySQL Connector/Net 6.0.1, a new version of the all-managed .NET driver for MySQL has been released. This is a beta release and is intended to introduce you to the new features and enhancements we are planning. This release should not be used in a production environment.

We had three major goals with this release. Speed, Entity Framework support, and a better Visual Studio experience. I'm happy to report that we have met all three. Please see the complete list of changes below.

It is now available in source and binary form from [http://dev.mysql.com/downloads/connector/net/6.0.html] and mirror sites (note that not all mirror sites may be up to date at this point of time - if you can't find this version on some mirror, please try again later or choose another download site.)

• Massive speedups. We have increased the speed of the provider. In many situations it now matches or exceeds the speed of the native C connector. …

I just learned that there will be a Webinar “What’s New in the Next Generation of MySQL Cluster?”, April 30th. From what I know, the webinar is supposed to be at a good technical level, it is not a marketing like introduction. If you are interested, just register at: http://www.mysql.com/news-and-events/web-seminars/display-320.html

Why should a performance engineer care about SSDs

There has a been lot of buzz regarding SSDs lately. SSDs change the dynamics of the IO subsystem. You are no longer limited by rotational latency and vibration effects. For a performance engineer this has many implications. Since performance engineers care mostly about performance, the first thought that comes to mind is "Are we going to see a big impact in benchmarks?".

The answer is really easy for IO bound benchmarks. How about CPU bound benchmarks? Many database benchmarks are CPU limited. Does a faster disk really change anything?

So what does an SSD really give you?

• Faster IOPS
• Decreased Latency for an IO

Faster IOPS

SSD's have a huge random IO capability. During a recent experiment with a SSD, I got around 12,000 random IO operations per second! I have seen SSDs where you can get more. If you have ever …

Spreading the word about Jay’s awesome findings on the libdrizzle benchmark against the original library inherited from MySQL. For those that aren’t familiar with libdrizzle, it is a fresh new (modern implementation) MySQL compatible client library for Drizzle that leverages asynchronous I/O and smarter memory usage founded by Eric Day.

You can read how this library came to life in this thread:

• https://lists.launchpad.net/drizzle-discuss/msg00472.html

As you can see in Jay’s findings with sysbench, libdrizzle outperforms the original library in all concurrency …

...is that truth is stranger than fiction. Reality does not appear any more plausible than plain nonsense.

We were discussing this yesterday on #ourdelta (Freenode IRC) in the context of How MySQL really executes a query by Baron. Antony Curtis noted that if he'd write a truthful post on that topic, people would think it was made-up regardless of the day of the year!

Another proof of the premise: Baron has now put a giant banner above/below his post, explaining that it was a joke. Apparently that's necessary?

I tend to come up with neat ideas for April Fools throughout the year, neglect to write them down, and come the day I have a blank. But, given the above, there's another option: you just write a truthful story, still leaving people …

…is that truth is stranger than fiction. Reality does not appear any more plausible than plain nonsense.

We were discussing this yesterday on #ourdelta (Freenode IRC) in the context of How MySQL really executes a query by Baron. Antony Curtis noted that if he’d write a truthful post on that topic, people would think it was made-up regardless of the day of the year!

Another proof of the premise: Baron has now put a giant banner above/below his post, explaining that it was a joke. Apparently that’s necessary?

I tend to come up with neat ideas for April Fools throughout the year, neglect to write them down, and come the day I have a blank. But, given the above, there’s another option: you just write a truthful story, still leaving people wondering …