How does Buffer Pool size affects Innodb Performance ? I always expected the effect to be positive, Innodb with large buffer pool to performing better. Including Recovery of course. I even blogged about it.

It turns out it is not always the case. Last week I was called to help with Innodb crash recovery on box with large amount of memory (64GB) with Innodb Buffer pool configured to be just a bit over 20GB. Innodb recovery was taking long hours with reasonably sized Innodb log files (256M) gradually progressing slower and slower so it was just about 50% after 3 hours with very little disk IO and one CPU 100% busy.

I took oprofile to see what exactly CPU is being spent for and saw the following picture:

samples % app name symbol name
1345161 95.2609 mysqld …

OK, so you have a nice replication setup, but how do you know it is actually working, and what do you do when it stops? This short article shows how to check and quickly fix replication that has stopped. This procedure takes 2 minutes and can be done remotely on the command line.

Tell me what’s wrong with the picture:

Anyways, Ubuntu Live looks like a great conference. The session line-up looks more like a conference than the one-day FUDCon’s, and with the tracks (there are 4 concurrent tracks), I am truly impressed. A big part of me wishes I was there… Some interesting tech bloggers like Stephen O’Grady of Redmonk fame, and Matt Asay are keynoting.

Of course, MySQL’s very own CEO, Mårten Mickos is also giving a keynote on Monday July 23, at 9:20-9.40am.

One caveat with Ubuntu Live: its cost. FUDCon is free, and true to its nature, really does spread community love (with about two tracks). Its USD$895 to attend Ubuntu Live - very troublesome to the pocketbook.

…

After some consideration I have decided to move the BLOB repository from PBXT to MyBS (§). This has the advantage that any engine that does not have its own BLOB repository (or is otherwise not suitable for storing large amounts of BLOB data) can reference BLOBs in the MyBS BLOB repository.

(§) MyBS stands for "BLOB Streaming for MySQL". The BLOB Streaming engine is a new storage engine for MySQL which allows you to stream media data directly in and out of the database. More info at www.blobstreaming.org.

Lets look at an example of this. Assume my standard example table:

CREATE TABLE notes_tab (
  n_id    int PRIMARY KEY,
  n_text  longblob
) ENGINE=PBXT;

And assume we have a file called blob_eg.txt with the contents "This is a BLOB Streaming upload test".

Firstly, I can upload a BLOB to the MyBS BLOB …

The good people at Unwired are looking for basically a MySQL DBA, although you'd also have the opportunity to do some coding, work on other projects and with additional technologies. You'll need to have decent experience with MySQL 4 and 5, understanding of replication and backup/recovery methods, query and server performance tuning.

You don't need to be a guru on all of these topics, but show you have a clue level, work smart, and pick up new stuff quickly. Unwired offers a salary package of around 90K, which seems fairly reasonable.
This looks like an excellent opportunity for a MySQL-ish person in Australia.

If you're interested, you can contact me (I have some additional info here too) and I can put you in touch with the right people. (my email is my first name @ my last name dot com dot au)

As the Google Summer of Code mid-term mentor surveys have been completed, we’ve got a strong nine projects in the MySQL front, from what I can tell. Its an exciting time, as there’s code available from some of the projects, and the students have got interesting blog entries as well. What I’d consider as the one-stop resource for all would be the Participants in the Summer of Code 2007 page.

Milos Prodanovic deserves special mention as he’s just posted code to the internals list, with his IPv6 data type patch. Also, from what I can tell, Charles Cahoon is currently in the Top 30 active bloggers on Planet MySQL, so kudos to him too. To the rest, continue working hard and cutting …

Simple idea; I've blogged about this before.

Make a wearable computer with a camera. Create an online service,
something like Twitter or Pounce, for "guys" to share real time
photos of the bottom in front of them. Each member of the buddy list
who gets to see the photo, gets to rate the photo.

Best photo of the week goes on the front page of the site.

It will sell wearable computers like hot cakes...

...Or just create a cell phone that lets you take discreet photos and
at the same time reads you your monthly telephone bill so that your
face doesn't acquire that grin that betrays the action of taking the
photo.

Seriously, somewhere out there, there is a fortune to be made.

I'm reminded of buddy cam because of all of the blogs entries I am
seeing on how cool Twitter and Pounce are.

I'd like a …

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.