For those of you on the O’Reilly MySQL conference list you will no doubt see this email, but for readers here is the important bits.

Oracle Executive Will Speak at O’Reilly MySQL Conference & Expo
Edward Screven to Answer Questions re: Future of MySQL

Sebastopol, CA, February 24, 2010—Wonder about the future of MySQL? Curious about what Oracle plans for the open source database software? Expect answers when Edward Screven, Oracle’s chief corporate architect and leader of the MySQL business, speaks at the O’Reilly MySQL Conference & Expo, scheduled for April 12-15, at the Santa Clara Convention Center and the Hyatt Regency Santa Clara.

Edward Screven reports to CEO Larry Ellison, and he drives technology and architecture decisions across all Oracle products to ensure that product directions are consistent with Oracle’s overall strategy. He’ll discuss the current and future state of …

It is a pleasure to announce that Kontrollbase – the MySQL analytics and performance monitoring webapp for MySQL servers – has a new sponsor. Network Redux is located in Portland, Oregon and offers enterprise quality dedicated and managed hosting as well as cloud services. Thomas Brenneke contacted me to discuss his interest in utilizing the [...]

In MySQL significant performance improvements can be achieved by the correct use of indexes. It is important to understand different MySQL index implementations and one key improvement on indexes defined on single columns is to use multiple column or more commonly known concatenated indexes.

However it’s also possible to define ineffective indexes. This example shows you how to identify a concatenated index that is ineffective.

CREATE TABLE example (
  id INT UNSIGNED NOT NULL AUTO_INCREMENT,
  a  INT UNSIGNED NOT NULL,
  b  INT UNSIGNED NOT NULL,
  c  INT UNSIGNED NOT NULL,
  d  INT UNSIGNED NOT NULL,
  x  VARCHAR(10),
  y  VARCHAR(10),
  z  VARCHAR(10),
PRIMARY KEY (id),
UNIQUE INDEX (a,b,c,d)
) ENGINE=InnoDB;

INSERT INTO example(a,b,c,d) VALUES
(1,0,1,1),(1,0,1,2), (1,0,2,3), (1,0,4,5),
(2,0,2,1),(2,0,2,2), …

With the motivation from today’s public news on Twitter’s move from MySQL to Cassandra, my own skills desire following in-depth discussions at last November’s Open SQL Camp to consider Cassandra and yesterday’s discussion with a new client on persistent key-value store products, today I download installed and configured for the first time. Not that today’s news was unexpected, if you follow the Twitter Engineering Open Source projects you would have seen Cassandra as well as other products being used or evaluated by Twitter.

So I went from nothing to a …

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’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.

Continuing on from preparation in our MySQL latin1 to utf8 migration let us first understand where MySQL uses character sets. MySQL defines the character set at 4 different levels for the structure of data.

• Instance
• Schema
• Table
• Column

In MySQL 5.1, the default character set is latin1. If not specified, this is what you will get. For example.

mysql> create table test1(c1 varchar(10) not null);
mysql> show create table test1\G
Create Table: CREATE TABLE `test1` (
  `c1` varchar(10) NOT NULL
) ENGINE=MyISAM DEFAULT CHARSET=latin1

If you want all tables in your instance to always be a default of utf8, you can changed the server variable character_set_server. This can be set dynamically.

mysql> set global …

I'll approach this topic from another direction.
I had to perform a task which required moving tables between schemas on the same MySQL server. One way of doing this would be:

1. Dumping the original table to disk.
2. Creating new empty table on the target schema.
3. Importing table from disk into the target schema.

But, a simpler way exists! The manual entry for RENAME TABLE casually describes this feature: As long as two databases are on the same file system, you can use RENAME TABLE to move a table from one database to another:

RENAME TABLE current_db.tbl_name TO other_db.tbl_name;

Which works almost instantaneously and does what it is supposed …

I sound like a broken record with every client when I talk to about the resilience of their production environments. It’s very simple in theory, however in practice many organizations fail.

Ask yourself these checklist questions for your MySQL backup and recovery process?

1. Do you have MySQL backups in place?
2. Do you backup ALL your MySQL data?
3. Do you have consistent MySQL backups?
4. Do you have backups that include both static snapshot and point in time transactions?
5. Do you review your backup logs EVERY SINGLE day or have tested backup monitoring in place?
6. Do you perform a test recovery of your static backup?
7. Do you perform a test recovery to point in time?
8. Do you time your backup and recovery process and review over time?
9. Do you have off-site copies of your backups?
10. Do you backup your primary binary logs?
…

At the recent FOSDEM 2010 event, I presented in my keynote Dolphins, now and beyond a option which I termed the “Blue Pill” or the “Red Pill”. The following slide produced noticed interest in a packed room, and subsequent conversation.

While the ownership of MySQL has changed, the option between MySQL and Oracle as a product for use still remains. While MySQL is the most popular for modern online applications, Oracle continues to have the widely used enterprise database product and has a large number of Oracle DBAs in the IT marketplace.

Over the past 5 years I have presented a number of topics on MySQL for Oracle DBA’s. At the upcoming MySQL Users Conference 2010 I will be presenting …