Here’s a sneak peek at a video matrix — this is all the videos that include Pythian Group employees at the MySQL conference. I hope to have all the rest of the videos processed and uploaded within 24 hours, with a matrix similar to the one below (but of course with many more sessions).

I think most developers are able to cache database queries by now. But what about DML queries? Every query, connection - or in the general case - ressource needs time. So I thought a lot about how to write data as efficiently as possible into the database - in my case MySQL. Hmm...We have to take a closer look at the details and we can't choose the same asynchronously writing method for every kind of query. With kind of query I mean that it depends on what storage engine we use, the complexity of the query, should more than one record be written at once, are triggers involved and so on. Sure, the one or the other query MUST be written instantly, but most of the writing querys are stackable with no need to check if the request has succeed.

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A few weeks ago, we had a query optimization request from one of our customer.

The query was very simple like:

PLAIN TEXT CODE:

1. SELECT * FROM `table` WHERE (col1='A'||col1='B') ORDER BY id DESC LIMIT 20 OFFSET 0

This column in the table is looks like this:

PLAIN TEXT CODE:

1. `col1` enum('A','B','C','CD','DE','F','G','HI') default NULL

The table have 549252 rows and of course, there is an index on the col1. MySQL estimated the cardinality of that index as 87, though what was of course misleading as index cardinality in this case can't be over 9, as there is only 8(+ NULL) different possible values for this column.

PLAIN TEXT CODE:

1. …

There are those that are very adamant about letting people know that using INFORMATION_SCHEMA can crash your database. For example, in making changes to many tables at once Baron writes:

“querying the INFORMATION_SCHEMA database on MySQL can completely lock a busy server for a long time. It can even crash it. It is very dangerous.”

Though Baron is telling the truth here, he left out one extremely important piece of information: you can actually figure out how dangerous your INFORMATION_SCHEMA query will be, ahead of time, using EXPLAIN.

In MySQL 5.1.21 and higher, not only were optimizations made to the INFORMATION_SCHEMA, but new values were added so that EXPLAIN had better visibility into what MySQL is actually doing. As per …

First of all, I'd like to thank everyone who read and gave their 2 cents about the [WordPress Plugin Development] How To Include CSS and JavaScript Conditionally And Only When Needed By The Posts post. The article was well received and will hopefully spark some optimizations around loading styles and scripts.

Here are some discussions and mentions around the web:

• an article on Weblog Tools Collection
• a forum post on WP Tavern
• …

MySQL Cluster Performance Tuning Best Practices

Are you experiencing current performance bottlenecks in your high availability applications ? Are you designing a new mission-critical application and want to know how best to structure your schema and index strategy for optimal performance? Interested in how to transform your SQL into faster, more efficient queries?

Then this free web presentation is for you! You will get expert insight and learn best practices to help you identify those areas of database and application design that will give you the greatest benefits for performance when using MySQL Cluster.

We will discuss guidelines and best practices covering the following areas:

• General Design Concepts and Guidelines
• Schema Optimization
  • BLOB/Text vs VARBINARY/VARCHAR
  • Partition by Key
• Index Selection and Tuning
…

This time, I’m talking about indexes for string typed columns. In particular, I’ll show a procedure I find useful while looking for good index length values for these columns. I’ll use a sample table called people. Here’s what it looks like: mysql> desc people; +————+——————+——+—–+———+—————-+ | Field | Type | Null | Key | Default … Continue reading Indexing text columns in MySQL →

Related posts:

1. Using MySQL Proxy to benchmark query performance By transparently sitting between client and server on each request,...
2. Making use of …

This is the 150th edition of Log Buffer, the weekly review of database blogs. Someone accidentally left Dave Edwards‘ cage unlocked, and he escaped, thus leaving me with the pleasurable duty of compiling the 150th weekly Log Buffer.

Many people other than Dave are finding release this week. Giuseppe Maxia explains some details of MySQL’s New Release Model. Andrew Morgan announces a New MySQL Cluster Maintenance Release. Aleksandr Kuzminsky of the MySQL Performance …

In addition to being practical, …

In addition to being practical, …