The headline is flame-bait, don’t take it. I just wanted to point something out about character sets and collations in MySQL.

To the uninitiated, it may seem overwhelming. Everything has a character set! Everything has a collation! And they act weirdly! The server has one. The database has one (oh, and it changes magically as I USE different databases.) Every table has one, and columns too. Is that all? NO! My connection has one! Kill me now!

Relax. In truth, only one kind of thing actually has a charset/collation. That is values. And values are stored in columns. The only thing that really has a charset/collation is a column.[1]

What about all the rest of those things — connection, database, server, table? Those are just defaults, which determine what charset/collation a value gets if it isn’t overridden. So if the table’s default charset is utf8, and you add a column without saying what …

I say correct because there are several incorrect approaches to managing MySQL logs. In MySQL you have two important log files, the MySQL error log (configured with –log-error) and the MySQL slow query log (configured with –log-slow-queries or –slow-query-log and –slow-query-log-file which is available …

I’ll be helping Morgan Tocker deliver the second half of his training course for MySQL Developers/DBAs in New York City in a few days (more Percona training). It was a snap decision at the last minute, but I’m hoping I’ll still get to meet some folks there. If we’ve corresponded over email or blog comments and you would like to get together, ping me in the comments here! If you’re in the New York City area and you use MySQL, you should consider attending this course, too.

Cary Millsap has a concise, readable paper on performance. Anyone involved in database performance optimization should read it. Cary’s writing has heavily influenced the mk-query-digest tool for analyzing MySQL/PostgreSQL/Memcached/HTTP query performance, and I think you’ll get a lot more from mk-query-digest if you read this paper — and you should also read his book, reviewed here. It’s one of the top books on my Essential Books List.

Related posts:

1. …

I'll be giving 2 talks this year. Here's a quick description:


Want Faster Queries?
Fixing slow queries is often very easy if you know what to look for and it can give huge performance gains. In this talk I'll cover common SQL mistakes, how to identify "bad" queries, indexing techniques, using EXPLAIN to verify execution plan, etc.


Get your Replication on: Advanced Techniques, Tips and Tricks
I'll be co-speaking with Chris Schneider for this one! We have lots of interesting uses for replication and some best practices up our sleeves. Warning: we won't be covering how to set up basic replication - that's a prerequisite for this talk.

It was asked in the previous post whether or not there would be better async support in MySQLdb-2.0. The answer is a qualified yes.
libmysqlclient (the MySQL C client library) has blocking calls, and doesn't have a true async interface. In a nutshell, the three blocking calls that are most important are mysql_query(), mysql_store_result() or mysql_use_result(), and mysql_fetch_row() (sometimes).
The original design of MySQLdb uses mysql_store_result(), which stores the entire result set in a MYSQL_RESULT structure; in this case, mysql_fetch_row() does not block. To save memory, the result is immediately converted to Python types and then freed.
An alternative cursor implementation (SSCursor) uses mysql_use_result(), which does not internally buffer the result set; this does cause mysql_fetch_row() to block, however. A further complication is that no new queries can be issued on the connection until the entire result set has been …

I spent my Saturday at the SCALE conference down in LA. Most conferences I find have a meme and for this conference that was "MySQL's longterm influence on the GPL".

MySQL was the company that had the most influence on how companies and investors viewed the GPL.

When MySQL said "we will only take contributions via a contributor agreement", this translated into investors expecting everyone to do this (though requiring contributor agreements destroyed outside MySQL development to the kernel, and left MySQL in a position where no substantial, or many, contributions ever occurred).

When MySQL pushed dual licensing, investors looked for this hook in every business model. I remember standing outside of a conference room in SF a couple of years ago and talking to one of the Mozilla Foundation people. Their question to me was "Is the nonsense …

Kyle Vanderbeek is going to take over as release manager for MySQLdb-1.2. We should have one more release candidate of 1.2.3 first, followed quickly by the final release.
Development on MySQLdb-2.0 has been progressing, and has recently moved to a Mercurial repository on SourceForge. This was imported from the SVN trunk. If you pull from the SVN trunk in the future, you may be disappointed.
2.0 is turning into a very major rewrite. I should have an alpha release soon. For now, the hg repository builds and passes all tests, but there are probably a few things that aren't thoroughly tested yet, particularly scrolling on cursors. I'll post more detail along with the alpha release.
Python3 support is not immediately in the works, and I probably won't work on it until I am close to a beta. At this point, I would target Python-3.1, maybe 3.2. 3.0 would probably work too.

Just the facts:
What: MySQL user community dinner
Who: me, you, and many MySQL community members
When: Monday, April 12th – Meet at 6:30 at the Hyatt Santa Clara or at 7 pm at the restaurant
Where: Pedro’s Restaurant and Cantina – 3935 Freedom Circle, Santa Clara, CA 95054
How: Comment on this blog post to add your name to the list of probable attendees

I was sad that last year there was no community dinner, and I missed the one the year before when Jonathan Schwartz and Rich Green made an appearance. This year I am determined not to miss it, and so I am calling for a community (pay-your-own-way) dinner on Monday, April 12th, at Pedro’s – a Mexican restaurant that has vegetarian and vegan options. I think Monday is a better time because many folks arrive …

I’ve heard that the mechanic’s wife always has a car that needs repair or tuneup, the painter’s wife always had walls of peeling paint, you get the picture. What about MySQL DBA’s and their own databases? While I have many versions of MySQL for testing including for example the latest 5.1.44 which I was using for my previous post, what is running on my production server? Let’s see:

mysql> select version();
+-----------+
| version() |
+-----------+
| 5.1.25-rc |
+-----------+

That’s really old. And yes, to prove my point that we can be our own worst enemy, the previous version before 5.1.25 was 5.1.6. Yes, .6 which worked just fine, and never crashed once for my 20+ websites. While I have downloaded onto my production server several versions ready for upgrade including versions 5.1.30, 5.1,38, and 5.4.1 I’ve never actually gone through the upgrade process.