In MySQL 5, at the moment you can't write a recursive stored functions. It is forbidden.
Instead you can write a recursive stored procedure. That is not permitted by default but modifying a variable you can achieve such a recursion.
The variable is max_sp_recursion_depth.

SET GLOBAL max_sp_recursion_depth = 0.
A value of zero means: "no recursion" (the default value)

SET GLOBAL max_sp_recursion_depth=255
A value greater then zero means: the maximun number of nested recursion in a procedure. Max value is 255.

Pay attention to the variable named thread_stack, it is the amount of memory allocated for the stack of a thread. Writing a recursive routine the tipical error is to create an infinite recursion An infinite recursion leads very soon to fill up the stack. (the default value of the thread stack is less than 200K)
So, if you have …

Peter Zaitsev's blog entry on Duplicate indexes and redundant indexes certainly made a bit of a stir! It has already led to a new (mini) project by Baron Schwartz, the Duplicate index/foreign key finder which is publicly available on MySQLForge as a perl script. Daniel Schneller has entered the arena as well, devoting an entire blog to his own java implementation to tackle this and other index trouble.

I figured it would be fun …

I wonder how many people will attend a session at a tech conference where the start of the description reads as follows:

Hey You! Yes, You! Manager, marketeer, sales professional: are you tired of 98lb weaklings kicking silicon in your face?

I am thinking this way because my friends at MySQL AB are putting on another MySQL User Conference - this time from April 23 - 26 in Santa Clara, California.

The Call for Participation went live a few days ago and, as always, I am proposing a session. I don’t really need to go, but I definitely have a soft spot for the event, as I chaired the first two MySQL UCs. Also, I had a good deal of fun working on the …

Hello,

For those of you who are interested in learning more about MySQL Cluster, check out tomorrow's webinar presented by Vinay Joosery.

Info and registration:

http://www.mysql.com/news-and-events/web-seminars/mysql-ha-clustering.php

See you there,

Jimmy

I did a webinar for EMEA last week on tuning indexes and optimal SQL coding, and I had forgotten to publish the slides. Here they are in PDF format... Feel free to email me if you have any questions!

In other news, work on my new blog site is progressing. I should be done with this hideous beast of a website soon!

Zmanda has released their Recovery Manager for MySQL.  This is a great solution for DBAs seeking an easy-to-use backup and recovery solution.  Zmanda is based on the open source Amanda project started at the University of Maryland and the Zmanda team is a significant contributor to the Amanda project.  Zmanda offers support through their Zmanda Network subscription offering. 

Zmanda's has built on what was a rather generic backup project and now given it a much sharper focus by targeting the needs of DBAs.  The Zmanda Recovery Manager includes support for automatic backup scheduling, monitoring and reporting, backup analysis and granular recovery. Backup is a must-have capability for …

A few meetups ago, we had Jim Starkey come and speak. During that evening, he asked “Why is MVCC not serializable?” It was a “go and do your homework” kind of question.

So, in order to answer that question, let’s explore the concepts of isolation and concurrency, the “i” and “c” in ACID compliance. For this post, I will refer to “transactions”, by which I mean actual transactions, as well as statements where autocommit=0. In other words, every statement is its own transaction, unless it is within an explicit transaction, and for the purpose of this article, those statements are “transactions”. Of course, for many of the explanations below, if there’s only one statement in the transaction, there’s no problem. (As usual, if I make a mistake, please correct me. I will make sure all comments from all sources get to the article at …

Do you know the fine details of MySQL's transactional error handling with the InnoDB storage engine? If you're writing transactional SQL, you need to be prepared to handle errors appropriately, and to do that, you need to know how MySQL handles them. This article introduces you to the topic.

If you’ve been using the Event Scheduler that was introduced in MySQL 5.1.6, there are some changes in the workings of the event_scheduler server variable. These changes are fairly simple — but not trivial — and were just committed to the 5.1 tree a few days ago. They will definitely be part of the official 5.1.12 release — which should be out just about any day now — so you’ll want to be aware of them, and how they’ll affect the behaviour of the Event Scheduler, before you upgrade.

This variable determines whether the Event Scheduler is available, and whether it’s actually running. In MySQL 5.1.12, it can be used in either of two ways:

1. a server option that can be used from the command line (--event-scheduler), or in the …

We released Zimbra 4.0.2 today and there were a few extras that came along for the ride. First off the Fedora Core 5 build is now GA. We also added a new developer/preview release on Ubuntu. This has been a popular hack in our forums for sometime.

Here's a sample of some of the other changes/fixes in 4.0.2:

- perf improvements for IMAP (new MySQL indexes)
- > 2GB support in the Zimbra Outlook Connector
- i18n and some l10n for the Zimbra Outlook Connector
- disabling AS/AV causes mail deferral
- cursor fails to appear in Firefox
- mailbox quota page does not contain any entries
- several all day event and timezone bugs fixed