It’s strange what articles on one’s site become “popular.” I wrote Non-technical Guide to Isolating Slow MySQL Queries some time ago when I was an internal system admin at a data center. I wasn’t “customer-facing” but I still got requests from customers who wanted me to look at their MySQL server. Since that wasn’t my primary responsibility, I had to enlist their help to save me time. Hence, I wrote this article to help not-technically-inclined customers through the first few steps.

My webstats have shown this page to be hit more often than I would have expected. Consequently, I felt that I should update it, so I did.

SciBit is proud to announce the first release of MyLook's Webclient, MyLook Web 1.5.

It includes:
* 'Almost' all of the thick client technology
* Supports browsing of multiple diverse webservices
* Browser independent
* PHP based and therefore very portable
* As with the thick GUI, it is free and open source.

For more information and downloads, see: http://www.scibit.com/mylook
For an online demo, see: http://mylook.scibit.com/client/

It's been a long time coming, but we've finally managed to get the first alpha release of Connector/J 5.1 out the door. The key thing in this release is support for JDBC-4.0, including:

Ease-of-development features including auto-registration with the DriverManager via the service provider mechanism, standardized Connection validity checks and categorized SQLExceptions based on recoverability/retry-ability and class of the underlying error.

Unwrapping to interfaces that include vendor extensions

Support for XML processing via JAXP interfaces to DOM, SAX and StAX

Support for setting per-connection client information (which can be viewed in the comments section of a query via "SHOW PROCESSLIST" on a MySQL server, or can be extended to support custom persistence of the information via a public interface)

Support for JDBC-4.0 NCHAR, NVARCHAR and NCLOB types

It's available for download now at …

It's been a long time coming, but we've finally managed to get the first alpha release of Connector/J 5.1 out the door. The key thing in this release is support for JDBC-4.0, including:

Ease-of-development features including auto-registration with the DriverManager via the service provider mechanism, standardized Connection validity checks and categorized SQLExceptions based on recoverability/retry-ability and class of the underlying error.

Unwrapping to interfaces that include vendor extensions

Support for XML processing via JAXP interfaces to DOM, SAX and StAX

Support for setting per-connection client information (which can be viewed in the comments section of a query via "SHOW PROCESSLIST" on a MySQL server, or can be extended to support custom persistence of the information via a public interface)

Support for JDBC-4.0 NCHAR, NVARCHAR and NCLOB types

It's available for download now at …

It's been a long time coming, but we've finally managed to get the first alpha release of Connector/J 5.1 out the door. The key thing in this release is support for JDBC-4.0, including:

Ease-of-development features including auto-registration with the DriverManager via the service provider mechanism, standardized Connection validity checks and categorized SQLExceptions based on recoverability/retry-ability and class of the underlying error.

Unwrapping to interfaces that include vendor extensions

Support for XML processing via JAXP interfaces to DOM, SAX and StAX

Support for setting per-connection client information (which can be viewed in the comments section of a query via "SHOW PROCESSLIST" on a MySQL server, or can be extended to support custom persistence of the information via a public interface)

Support for JDBC-4.0 NCHAR, NVARCHAR and NCLOB types

It's available for download now at …

MySQL-Storage-Engines für memcached und Amazon S3

Neue Storage-Engine-Architektur animiert Entwickler

Mit seiner neuen "Pluggable Storage Engine Architecture" bietet MySQL 5.1 eine neue Flexibilität in Sachen Storage-Engines und einige Entwickler zeigen, was sich mit diesem System anfangen lässt: Mark Atwood arbeitet beispielsweise an einer Storage-Engine, mit der sich über MySQl auf Amazons Webspeicherdienst S3 zugreifen lässt, und Brian Aker bietet Zugriff auf Dankas memcached via MySQL.

Mit seinen verschiedenen Storage-Engines und deren unterschiedlichem Funktionsumfang hebt sich MySQL von manch anderem Datenbank-Management-System ab. Während eine Storage-Engine mit Volltext-Indizes aufwartet, bringt eine andere Transaktionsunterstützung mit. Was manche als Schwäche des Systems sehen, versucht MySQL zu einer Stärke zu machen und führt mit MySQL …

So a few things happened in the last few weeks or will be happening that I find worth sharing. First up Pagenello, the biggest Ultimate Frisbee tournament in Europe, was blast. Plenty of sun while playing 10 beach Frisbee matches in 4 days with some quality time chilling in Rimini before and after the tournament.

Yesterday I also held a slightly updated version of my "Explaining Explain" talk (now called "Finding Order in Execution") at the webtuesday usergroup meeting here in Zurich. As always you can find a pdf with the slides in the slides section of my blog.

Speaking of speaking I will be giving a talk on PHP6 at MySQL User …

MySQL stored procedures can use SELECT statements in their body, returning a data set to the caller. The manual also explains that multiple data sets can be returned from such a stored procedure.
For example, assume you have this stored procedure:

CREATE PROCEDURE p1(x INT, y INT)
    DETERMINISTIC
    BEGIN
        SELECT 
            x ;
        SELECT 
            x AS first_param, 
            y AS second_param;
        SELECT 
            x, 
            y, 
            x + y AS sum_xy, 
            x * y AS prod_xy; 
        SELECT *  FROM t1;
    END

There are four SELECT statements, with different headers, and a variable number of rows returned.
Early versions of …

I've got an interesting comment the other day saying "I've heard Jay Pipes saying indexes with cardinality lower than 30% are worthless, true?"

That is interesting question and it has different answers depending on who is asking. A lot of people want to hear simple answers to the questions because they would be overwhelmed by complete answer, it is like children being taught math first taught simple division skills like you can divide 10 by 2 but not by 3. As we grow up we learn the truth is much more complex than that and if you Major in math you will find there is a lot of stuff out where far beyond basic stuff we use in every day life.

Answering such question you can say yes it is true and for clueless person it will be helpful answer because it will allow him to avoid creation indexes on the column containing just one value which is good idea.

If you start to explain it in details, a lot of variables add in - covering …

I have put together a list of the sessions that are of interest to me this year at the MySQL Conference. Again, there is some overlap in sessions I would like to do, particularly with some certification exams in there as well! :)

• Building Scalable OLAP Applications with Mondrian and MySQL - Because I have been working with this and want to learn more.
• Building a Vertical Search Engine in a Day - Because I like to compare search engines.
• InnoDB Performance Potential in High-end Environments - Because I am always interested in high-end environments and performance.