MySQL Connect Conference --  September 29 and 30, 2012
Learn about the latest MySQL features, discuss product roadmaps, and ask questions directly to the Oracle engineers behind the latest MySQL code this year at the MySQL Connect Conference.

While you will see some Oracle OpenWorld umbrella branding around it, MySQL Connect is a different event. It is taking place just before Oracle OpenWorld and will have a separate pricing. Registration will open on April 16.

The Call for Papers will also be opening April 16th and the MySQL Community is encouraged to submit. It will only be open for approximately three weeks.

The …

When an application runs a query in MySQL, from time to time, it may receive various errors. Some are related to syntax errors in the query text itself, some occur because the statement attempted an illegal operation such as for example writing a duplicate value into a column with unique constraint. But there are a few that are not as easy to figure out, because they have no direct relationship with the actual work being done. One of such error messages reads “Lost connection to MySQL server during query”. What does it actually mean? If it appears frequently, how to diagnose what the problem may be?

The first thing to know about the “Lost connection to MySQL server during query” message is that this is not a MySQL error. It is a MySQL client error. The difference may seem subtle, but it is significant. A MySQL error would be a problem reported by database server, i.e. handling a query did not succeed, because the …

I’m proud to announce the GA release of version 2.1 of Percona Toolkit. Percona Toolkit is the essential suite of administrative tools for MySQL.

With this release we introduce a new version of pt-online-schema-change, a tool that enables you to ALTER large tables with no blocking or downtime. As you know, MySQL locks tables for most ALTER operations, but pt-online-schema-change performs the ALTER without any locking. Client applications can continue reading and writing the table with no interruption.

With this new version of the tool, one of the most painful things anyone experiences with MySQL is significantly alleviated. If you’ve ever delayed a project’s schedule because the release involved an ALTER, which …

mysqlslap is native mysql utility to check client load in MySQL server. It’s introduced in MySQl 5.1. It seems very useful as it has lots of options to check load of your server by running different kind of queries with specific iterations, specific concurrency. Output will give you how much max/min/avg  time has been taken … Continue Reading …

Oracle today announced that it will hold the MySQL Connect Conference on September 29 and 30 in San Francisco! You can read the Press Release here.

MySQL Connect will be jam-packed with technical sessions, hands-on labs and Birds of a Feather (BOF) sessions delivered by MySQL community members, users, customers and MySQL engineers from Oracle.

The event is a unique opportunity to learn about the latest MySQL features, discuss product roadmaps, and connect directly with the engineers behind the latest MySQL code.

The conference will include six tracks: Performance and Scalability, High Availability, Cloud Computing, Architecture and Design, Database Administration, and Application Development.

The call for papers will open on April 16, 2012 for approximately three weeks. MySQL users and community members are encouraged to submit …

This is the third blog post in the series of blog posts leading up to the talk comparing the optimizer enhancements in MySQL 5.6 and MariaDB 5.5. This blog post is targeted at the join related optimizations introduced in the optimizer. These optimizations are available in both MySQL 5.6 and MariaDB 5.5, and MariaDB 5.5 has introduced some additional optimizations which we will also look at, in this post.

Now let me briefly explain these optimizations.

Batched Key Access

Traditionally, MySQL always uses Nested Loop Join to join two or more tables. What this means is that, select rows from first table participating in the joins are read, and then for each of these rows an index lookup is performed on the second table. This means many point queries, say for example if table1 yields 1000 …

How important a primary key design can be for MySQL performance? The answer is: Extremely! If tables use InnoDB storage engine, that is.

It all begins with the specific way InnoDB organizes data internally. There are two major pieces of information that anyone should know:

1. It physically stores rows together with and in the order of primary key values. It means that a primary key does not only uniquely identify a row, it is also part of it. Or perhaps rather, a physical row is part of table’s primary key.
2. A secondary index entry does not point to the actual row position, which is how it works in MyISAM. Instead, every single index entry is concatenated with a value of the corresponding primary key. When a query reads a row through a secondary index, this added value is used in additional implicit lookup by the primary key, to locate the actual row.

What could be a “rule of the thumb” for …

When evaluating queries, Mondrian sometimes needs to make decisions about how to proceed, and in particular, what SQL to generate. One decision is which aggregate table to use for a query (or whether to stick with the fact table), and another is whether to "round out" a cell request for, say, 48 states and 10 months of 2011 to the full segment of 50 states and 12 months.

These decisions are informed by the volume actual data in the database. The first decision uses row counts (the numbers of rows in the fact and aggregate tables) and the second uses column cardinalities (the number of distinct values in the "month" and "state" columns).

Gathering statistical information is an imperfect science. The obvious way to get the information is to execute some SQL queries:

-- row count of the fact table
select count(*) from sales_fact_1997;

-- count rows in an aggregate table
select count(*) …

If you cannot make next week’s Percona Live: MySQL Conference and Expo, I am proud to announce that Mozilla will be live-streaming on Air Mozilla the events on Wednesday, April 11th. The events are (at the very least) the MySQL Community Awards and the Lightning Talks. The MySQL Community Awards are happening at 6:00 pm Pacific Time and the Lightning Talks are happening at 6:30 pm Pacific Time. (If the times change, I’ll let you know)
To watch the events on Air Mozilla, go to https://air.mozilla.org/ at the appropriate time. I will try to remember to post a reminder, and if for some reason the tech doesn’t work out, I’ll let you know by

Early bird registration for the International PHP Conference might be over but Oracle has just received discounts. 
If you register for a 2 days with the code "Oracle 1" it will only cost you 499€ instead of 699€ +VAT. If you register for a 3 days with the code "Oracle 2" it will only cost you 699€ instead of 899€ +VAT.
Ulf Wendel from Oracle is going to be presenting 2 different sessions on MySQL:

• MySQL DB Cluster Usage made easy: mysqlnd_ms
• …