We think that whatever statements are there in a transaction can be rolled-back. Right? No! If by any chance you have statements that cause an implicit commit, then no. These statements commit the transaction mid-air. And if you think that these statements are only DDL, beware. There are many statements in MySQL that implicitly commit like LOAD DATA INFILE was an implicit commit statement for all storage engines until 5.1.12. Even now, if you are using NDB, this is still a implicit commit statement.

Say, we have statements like this:

1. START TRANSACTION
2. SOME INSERT STATEMENT
3. ONE MORE INSERT STATEMENT
4. ONE IMPLICIT COMMIT STATEMENT
5. ONE MORE INSERT STATEMENT
6. SOME MORE STATEMENTS
7. COMMIT

The implicit commit statement (statement number 4) commits the statements above it and aborts the transaction, as already mentioned. So, what happens to the statements 5 and 6. They run as …

In two blogs I follow, Andy Leonard's blog on SQLBlogs.com and Sheeri Kritzer's The MySQL She-BA, the question of what is a database administrator has come back up. Andy has posted twice on the topic, first with how DBAs are an enterprise requirement and then a follow-up to that post. In Sheeri's case, she was pointing out that a system administrator friend of hers considers the use of phpMyAdmin as a determining factor on whether or not one is DBA: he's not much of a DBA …

The only thing I like better than writing howtos for our software is reading howtos for our software written by someone else. Especially when they’re really really good. Mark Schoonover has written an excellent introduction to setting up Heartbeat with MySQL and DRBD.

Last week I received an email indicating that MySQL had made available an entry level certification, the Certified MySQL Associate. The idea is to provide a certification which shows a person has some basic knowledge of MySQL, but not at the level of a developer or DBA. That's a great idea.

Not everyone needs a developer's or DBA's knowledge of a product to make use of it. This is true whether we're talking about MySQL or SQL Server. After all, we don't expect an end user to know how to fully administer a Windows XP / Vista system, but the basics of how to use it, that's well within the bounds of expectations.

I haven't had time to pursue a MySQL certification, mainly …

(I am writing this as a note to myself, more then as a note to
others...)

The MySQL Engine API supports a concept of "discovery". Discovery
allows an engine to say "yes this table exists, and here is the
definition".

To implement this, you need to create the following function in your
engine:

int archive_discover(handlerton *hton, THD* thd, const char *db,
const char *name,
const void** frmblob,
uint* frmlen);

This is a function for the handlerton, and is not a method of the
handler class.

Table discovery flow of execution is simple. Whenever a table is
opened, MySQL looks for a corresponding table or view definition. If
neither exists then the discovery functions are called for each of
the engines that have registered a discovery function. In the
discovery an engine can return …

Introduction

It's 2 AM Saturday and the phone rings. You thought you were going to have a long holiday weekend. You've been informed by the NOC that there's no connection to the database server, and could you come down to see what's wrong with it. Remote access won't save you, there's no response at all from the server. We've all been there during our careers, and there's technology freely available to save your sanity, and allow you to take that long holiday weekend. Creating a MySQL high availability cluster using Distributed Replicated Block Device, DRBD and Heartbeat will save you from heading back to work at 2 AM.

During MySQL Conference 2007, I attended Storage Replication with DRBD: The Next Big Thing in Cluster Storage Management, which was very informative, but it left …

Matt has a good post on the recent push to make people use PHP 5. He makes several good points, and I’m just jumping on the same bandwagon.. forcing a version # change, just because the engine works better is pointless. Going into the political arena a little bit, making people switch to PHP 5 is like changing CAFE standards, it won’t do a thing for the billions of cars already out there, and it won’t change the basic dependence on crude oil. It’s just a lot of hot air to make the choir sing to themselves, again.

I’ve been running PHP 5 on my systems for the past 3 years, without any issues. Even some of the code I wrote in PHP 4, works flawlessly (with the same bugs) in PHP 5 as PHP4. Which brings me to the main point.. End Users don’t care or want to know what the engine is doing . If the application does something they want, they’ll use it. If …

Yes, even though MySQL 5.1 is in beta (soon to be RC), our surveys show that folks are using 5.1 already for production use.

If you’re using 5.1 for production apps, I’d appreciate it if you could drop me a line and let me know what motivated you to move up to 5.1. What 5.1 features made you take the plunge? As we’re in the midst of planning features for the upcoming server versions, knowing what you like about 5.1 and what improvements you’d like to see over what we did in 5.1 would be a great help. Shoot me a note at rschumacher@mysql.com.

Thanks!

OSCON, the Open Source Convention organized by O'Reilly is coming up next week (July 23rd-27th, Portland, OR).

MySQL AB will be present in the exhibition area and we will also be giving some talks:

• Brian Aker: Extending MySQL, Swiss Army Knife Approach
• Kaj Arnö: The MySQL Architecture of Participation
• Mårten Mickos: The Path to IPO …

I’m not quite sure how to feel about this but I feel today has been more productive than all of last week. hrrm..