I recently posted a blog entry on clustering indexes, which are good for speeding up queries.  Eric Day brought up the concern that clustering indexes might degrade update performance. This is often true, since any update will require updating the clustering index as well.

However, there are some cases in TokuDB for MySQL, where the opposite is true: clustering indexes can drastically improve the performance of updates and deletions.  Consider the following analysis and example.

Updates and deletions generally have two steps. First, a query is done to find the necessary rows (the where clause in the statement), and then the rows are modified: they are deleted or updated, as the case may be. So the total time to do a deletion or an update is

T_total = T_query + T_change

Eric noted that …

ScienceLogic embeds MySQL in its EM7 network management appliances. An installation of EM7 can perform over half a billion database queries daily, storing massive amounts of data for both real-time and trended performance reporting.

Michael McFadden, senior software architect with ScienceLogic, will discuss all this in an upcoming MySQL webinar.

I am reading SQL and Relational Theory by C. J. Date. Baron Schwartz wrote a nice review for it. I am reading the online version, about half way through, so am not sure if it has an accompanying CD with source code. In any case, if you want to play with some SQL code listed in the book, here is the script to generate the tables and rows (or should I say relations at a certain point in time with tuples?)

CREATE TABLE S
   ( SNO    VARCHAR(5)   NOT NULL ,
     SNAME  VARCHAR(25)  NOT NULL ,
     STATUS INTEGER      NOT NULL ,
     CITY   VARCHAR(20)  NOT NULL ,
     UNIQUE ( SNO ) ) ;

 CREATE TABLE P
   ( PNO    VARCHAR(6)   NOT NULL ,
     PNAME  VARCHAR(25)  NOT NULL ,
     COLOR  CHAR(10)     NOT NULL ,
     WEIGHT NUMERIC(5,1) NOT NULL ,
     CITY   VARCHAR(20)  NOT NULL ,
     UNIQUE ( PNO ) ) ;

 CREATE TABLE SP
   ( SNO …

Early Registration has been extended to June 23. Save up to $250!Enter my friends-of-speaker discount code "os09fos" when you register, and save an additional 20%! Just because you read my blog.Practical Object-Oriented Models in SQLWednesday July 22, 5:20pm.SQL is from Mars, Objects are from Venus.This talk is for software developers who know SQL but are stuck trying to implement common

At MySQL Conference in Santa Clara this April the idea was brought up, now we do it:

a MySQL Proxy hackathon this summer in Sun Office in Hamburg, Germany.

We want bring together everyone who is interested in

• hacking on MySQL Proxy,
• sharing ideas how it is used and
• how it should develop.

More at http://forge.mysql.com/wiki/MySQL_Proxy_Hackathon_2009

At MySQL Conference in Santa Clara this April the idea was brought up, now we do it:

a MySQL Proxy hackathon this summer in Sun Office in Hamburg, Germany.

We want bring together everyone who is interested in hacking on MySQL Proxy, sharing ideas how it is used and * how it should develop.

More at http://forge.mysql.com/wiki/MySQL_Proxy_Hackathon_2009

"An ecosystem is a unit of interdependent organisms which share the same habitat." - Definition: Ecosystem on Wikipedia .

Software comprises a symbiotic ecosystem that functions in much the same way as ecosystems found in nature. The various elements interact with one another, thereby providing a complete solution to users. ISVs and SaaS companies are part of the ecosystem of open source software (OSS), yet some of these companies are referred to as vampires, leeches, parasites and freeloaders because they don’t give back code to the community software.

Pardon my quick digression, but parasites are valuable members of any ecosystem. They do the dirty work of cleaning the ecosystem and turning waste into valuable food and fertilizer for the ecosystem. Consider, for example how your neighborhood …

No! There is no error in the topic. You can see yourself:

Testing, Testing, Testing...

I've gotten a number of questions about how we are doing testing, and even how our methodology for accepting code works :)

A lot of this comes from running open source projects for almost a couple of decades (hell, if I toss in uploading public domain to software to BBS'es for the Commodore 64 it is a bit longer!).

One of the most important rules I have learned over the years is that anything that is not automated and not required, will get skipped.

Today Drizzle runs 213 tests, the entire MySQL test suite minus tests that are for features we don't have. We don't allow for any regression, meaning that no one is allowed to disable a test in order to get their code pushed. Our test suite was also modified so that we can run all of the tests against a particular engine. Today we do this with both Innodb and PBXT. So instead of having "engine specific" tests, we …