On Wednesday, September 17 there will be a web based seminar on MySQL 5.1. 

Seminar will be in Italian and anyone who is interested is invited to join us!

You can find details here.

If you are a database administrator or a developer and you are courious about new features coming with MySQL 5.1 then this is the right webinar to attend. In the meantime, to better understand MySQL 5.1, take have a look at "Inside MySQL 5.1" white paper.

See you soon! 

On Wednesday, September 17 there will be a web based seminar on MySQL 5.1. 

Seminar will be in Italian and anyone who is interested is invited to join us!

You can find details here.

If you are a database administrator or a developer and you are courious about new features coming with MySQL 5.1 then this is the right webinar to attend. In the meantime, to better understand MySQL 5.1, take have a look at "Inside MySQL 5.1" white paper.

See you soon! 

Finally the on-demand version of the web based seminar is online. You can find recording here and you can also download presentation slides.

Please note that due to a technical problem in the time span  11:10 - 13:20 slides are not visible, but audio is good. Sorry for the inconvenience and thanks to everyone who attended!

Finally the on-demand version of the web based seminar is online. You can find recording here and you can also download presentation slides.

Please note that due to a technical problem in the time span  11:10 - 13:20 slides are not visible, but audio is good. Sorry for the inconvenience and thanks to everyone who attended!

I have never, ever seen this before. I don’t even know how the table was created with a different collation. However, I had all my other tables created with the character set utf8, no collation specified.

I had to convert the second table to match the character set. This probably wouldn’t have been a problem if I wasn’t joining on a character field.

alter table exclusion CONVERT TO CHARACTER SET utf8;

First time I’ve ever seen that one.

One common question I guess is how much should I see performance improved in case I increase memory say from 16GB to 32GB. The benefit indeed can be very application dependent - if you have working set of say 30GB with uniform data access raising memory from 16GB to 32GB can improve performance order of magnitude by converting very IO bound load to CPU bound, it is well possible to see limited gains - if your working set already fits in 16GB you may not see any significant gains upgrading memory to 32GB. Interesting enough similar can happen for very large working set - for example if your main queries do full table scan of 100GB table it does not matter if you have 16GB or 32GB the load is going to be way too much IO bound anyway.

Interesting enough because of MySQL scaling issues it is also possible to see performance to go down as you increase buffer pool size. Some threads which would be safely sleeping waiting on IO completion are now …

For those unfamiliar with SQL Server clustering let me give you a quick blurb.  Microsoft markets SQL Server as having active-active clustering.  When most people hear active/active or clustering in the database they generally immediately think of features like Oracle Rac.  SQL Servers implementation of Active-Acitve clustering ( as of 2005 anyways ) is really a HA setup with one instance active on the A side, and a seperate unrelated instance active on the B Side.  These servers hove different ports, install directories,  and share nothing at the DB level.  A san is used with its disk presented to each node in the cluster.  Microsoft Clustering Services (MCS) is used to manage the IP take over,  handle resource transitions, etc.   The setup is really active-passive, passive-active.  This ends up confusing and even mis-leading people who are both technical and in management positions.

Why …

From LinuxWorld this week in San Francisco, me, Tux and Larry Augustin...

And then some time later...

I think someone spiked my drink!

Matt Asay writes today about the prospects for open source vendors going public or, more likely, being acquired, and wonders whether open source vendors should “hold out for an IPO” or “capitulate” and be acquired.

The latter seems far more likely, especially in the current economic climate. We have written before about the open source vendors most likely to go public in the next couple of years.

Looking at the list of contenders again it is easy to imagine that they could all be snapped up before they make it public thanks to the fact that 1) open source vendors are very attractive investments 2) it is difficult for open source vendors to build the momentum to do so.

I spoke recently with …

I recently spent 3 hours pulling my hair out trying to fix a MySQL stored procedure that wasn’t working as expected. I’ve boiled the ultimate problem down to a simple example below. Can you spot the problem?

# First, let's create some sample data
CREATE TABLE TrendicsTest (
DateTime DATETIME NOT NULL,
Value INT NOT NULL,
UNIQUE KEY DateTime (DateTime)
);
INSERT INTO TrendicsTest VALUES ('2008-01-01 01:00', 1);
INSERT INTO TrendicsTest VALUES ('2008-01-01 02:00', 2);

# Next, lets' define a stored procedure to query the sample data
DELIMITER |
DROP PROCEDURE IF EXISTS summarizeTrendicsTest|
CREATE PROCEDURE summarizeTrendicsTest(dateTime DATETIME)
BEGIN
SELECT @endDateTime := DATE_ADD(dateTime, INTERVAL 1 HOUR);
SELECT * FROM TrendicsTest WHERE DateTime=@endDateTime;
END;
|
DELIMITER ;

…