InnoDB allows you to dump information on its internal data dictionary out to stderr, by creating specific InnoDB monitor tables. Specifically the innodb_table_monitor and innodb_tablespace_monitor tables. This is covered to a limited extent in the MySQL Reference Manual at http://dev.mysql.com/doc/refman/5.0/en/innodb-monitor.html, however not to any great detail.

In the following I’ll use output created via these tables based upon the sample “sakila” database, and give details on how to attempt to correlate the information between the different outputs.

The output of SHOW INNODB STATUS is the output of the InnoDB Monitor, which is different than both the InnoDB Tablespace Monitor and the Innodb Table Monitor. You can also cause this information to be …

While developing mysql-proxy I sometimes have to step-by-step refactoring that usually result in unstable code for a while until the unit-tests are happy again.

When a unit-test fails I usually use gdb as a wrapper and let it create a stack-trace for me:

$ gdb --command=backtrace.gdb --args /path/to/my/testcase

The --command option is used to automate gdb:

run
thread apply all bt
quit

If the test finishes successfully, gdb will just quit, but on error we will get a nice, all-threads stack-trace.

In the end it looks like:

$ gdb --command=backtrace.gdb --args .../tests/unit/t_network_io
...
Program received signal SIGINT, Interrupt.
0x909f43ae in __semwait_signal ()

Thread 2 (process 49948 thread 0x1003):
#0  0x90a1d906 in kevent ()
#1  0x0006ee40 in kq_dispatch ()
#2  0x00062b26 in event_base_loop ()
#3  0x0000781a in mock_server (_udata=0x907dd0) …

This Thursday, we're continuing our series of sessions on MySQL performance measuring and improvements with Richard Smith's presentation titled Scalability by Design - Coding for Systems With Large CPU Counts. Richard works in the Performance and Applications Engineering department at Sun Microsystems, so again, expect to get some deep insights into the inner workings of the MySQL Server.

Richard is based in Australia, so note that this session will take place in the morning (Europe) or evening (APAC), respectively.

For MySQL University sessions, point your browser to this page. You need a browser with a working Flash plugin. …

These days I'm working with a customer who has an application based entirely on stored routines on MySQL side. Even though I haven't worked much with stored procedures, I though it's going to be a piece of cake. In the end - it was, but there's a catch.

My initial idea was - I'll just analyze queries in the slow query log generated by our mysql build running with long_query_time=0, get the slowest ones and work on them. It wasn't really all the way I expected..

For a showcase I have created a function "whatstheweatherlike". Let's call it and see what shows up in the slow query log:

PLAIN TEXT SQL:

1. mysql> SELECT whatstheweatherlike(5);
2. +----------------------------------------------------------+
3. | …

About one year ago, 400 MySQL employees were in Orlando, FL, for their company meeting. Their main worry was how to improve the business in view of the inevitable IPO that was coming soon. Nobody knew when, but there was expectation for Mårten Mickos keynote, on January 16, 2008, at 8:00. Possibly, everybody thought, he will announce a date for going public.

And public we went, but not the way we thought.

The evening before, I was among a group of about 25 people who were summoned to Mårten's suite, without a specific reason. At about 10pm, Mårten announced the $1B news, and for many of us there are only fuzzy memories after that. We weren't allowed to leave the suite before signing a NDA, to keep the news quiet until the following day at 8am.

Thus, having slept very little, with conflicting thoughts, I met my co-workers, and I couldn't tell anyone what was about to happen. We lined up for the keynote hall to open, and …

I’ll try to clear up possible confusion about dates and MySQL’s TO_DAYS() function. TO_DAYS() works, correctly. TO_DAYS() assumes a year 0, correctly. There are indeed bugs, but only if you use MySQL extensions with partitions.

First: TO_DAYS() works, correctly. The MySQL Reference Manual says we use a proleptic Gregorian calendar, and that’s all explained with terms anyone can follow, in section “11.7. What Calendar Is Used By MySQL?”
http://dev.mysql.com/doc/refman/5.1/en/mysql-calendar.html
So we follow the Gregorian rules, not the Julian ones, without concerning ourselves about what happened in 1582 — just like DB2, just like the standard, not like Oracle. To make sure it’s okay, I wrote and ran this stored procedure:

DELIMITER //
SET @@sql_mode=ansi//
DROP procedure IF EXISTS p//
CREATE PROCEDURE p ()
BEGIN
  DECLARE days_in_month INT DEFAULT 31;
  DECLARE months_in_year INT DEFAULT 12;
  DECLARE …

A year ago this past week (on January 16, 2008), Sun Microsystems announced a historic deal to acquire MySQL AB for a billion dollars. Since then, MySQL-ers (aka Sun Dolphins) have settled in with Sun folks. While Sun has had an influence on MySQL, MySQL has also had an influence on several projects within "Sun Classic". Over this week, we hope to explore some of the projects around Sun which use MySQL and how the acquisition has helped bring us all closer together.

Today we talk to Vince Carbone in Sun's Performance Technology Group about MySQL with DTrace, the dynamic tracing application that is part of Solaris and OpenSolaris and set to be a hot topic at the 2009 MySQL User Conference.

MySQL Replication is fairly simple to setup for the first time.  However over time maintenance can become troublesome.  At times errors show up in the error logs, or it can stop running altogether.  In fact MySQL Replication can fail in a much more insidious way, that is silently.  So what to do?

As it turns out there are specific reasons and causes for MySQL replication to get out of sync.  We’ll discuss what is and isn’t compliant in a MySQL Replicated environment, and then most importantly, we’ll discuss a tool that can help you verify your environment, and show you what is or isn’t in sync and why.

I’m presenting this webcast with O’Reilly on Thursday January 22.  If you’re interested, click here to register.

Greetings Planet MySQL readers,

I am new to Planet MySQL.. so I thought I should introduce myself.

I am Trent Lloyd (some may know me online as 'lathiat'), based in Perth, Western Australia and presently working for Sun Microsystems as a MySQL Support Engineer providing support to Sun's MySQL customers. I have been with Sun for 12 months, and previous to that was working for MySQL AB before it was acquired for 8 months. My background before that is in the ISP industry working for HostAway in a combination System/Network administration and support role.

I have also given a number of papers, often related to either Avahi or IPv6 at a few conferences.. mainly Linux.conf.au - you can view them on my web-site www.lathiat.net.

I have an open-source/free-software community background.. I co-authored …

About one year ago, 400 MySQL employees were in Orlando, FL, for their company meeting. Their main worry was how to improve the business in view of the inevitable IPO that was coming soon. Nobody knew when, but there was expectation for Mårten Mickos keynote, on January 16, 2008, at 8:00. Possibly, everybody thought, he will announce a date for going public.

And public we went, but not the way we thought.

The evening before, I was among a group of about 25 people who were summoned to Mårten's suite, without a specific reason. At about 10pm, Mårten announced the $1B news, and for many of us there are only fuzzy memories after that. We weren't allowed to leave the suite before signing a NDA, to keep the news quiet until the following day at 8am.

Thus, having slept very little, with conflicting thoughts, I met my co-workers, and I couldn't tell anyone what was about to happen. We lined up for the keynote hall to open, and …