What is the Spider engine, then? In short, it's an extension to the partitioning engine with the ability of connecting to remote servers. Basically, partitions + federated, except that Federated is explicitly removed during the …

Last week I gave a presentation titled "Predicting Performance with Queuing Models" at the MySQL Camp section of the MySQL User Conference. I have uploaded the slides for a longer version of the presentation than could have been covered in the 45 minute time slot, for anyone who would like a copy. I've also uploaded a version that includes speaker notes.

Presentation slides:

• Predicting Performance with Queuing Models
• version with speaker notes

We announce next beta version of our xtrabackup tool.

Changelist includes:

- set innodb_fast_shutdown=1 on xtrabackup shutdown
- set innodb_write_io_threads=10 by default for fast buffer_pool flushing during recovery
- build xtrabackup with --with-extra-charsets=complex
Bug #357653: innobackupex-1.5.1 --copy-back fails
Bug #358194: 2nd-phase is very slow
Bug #358266: xtrabackup-0.5 dies with SEGV on bad command line arguments
Bug #359341: innobackupex still does not read defaults-file

You can download current binaries RPM for RHEL4 and RHEL5 (compatible with CentOS also), DEB for Debian/Ubuntu and tar.gz for Mac OS / Intel 64bit there:
http://www.percona.com/mysql/xtrabackup/0.6/.
By the same link you can find general .tar.gz with binaries which can be run on any modern Linux distribution.
…

Migrating from Oracle to MySQL is not easy. A few weeks ago Baron Schwartz summarized the culture shock in 50 things to know before migrating Oracle to MySQL. It's a great article but as you read through the comments it's easy to forget that culture shock can run the other way.

For example, try building horizontally scaled systems. Oracle has excellent "small" database editions like SE and SE1. However, they lack built-in replication of the type provided by MySQL. Even simple and effective deployment patterns like master-master replication do not exist. The usual approach in the Oracle world is to use RAC + Enterprise Edition features like Streams and DataGuard. That's great for large enterprises, but it's not a good method for smaller businesses and start-ups.

We have been working for some time on a …

In the Apache world, you might be familiar with tweaking your config file(s) and then running

$ apachectl configtest

to see if the config parses. We've been discussing this on the drizzle mailing list and talking in general about configuration handling and management. Well, it turns out that you can fake it in MySQL and Drizzle too.

If you have a new configuration in /tmp/new.cnf, try this:

$ mysqld --defaults-file=/tmp/new.cnf --verbose --help

And it'll run mysqld (or drizzled), parse the config, report any problems, print help, and exit without initializing storage engines or trying to grab a port.

Neat trick!

Thanks to Baron Schwartz, Arjen Lentz, and Sheeri …

At MySQL Conference and Expo 2009, I explained how Linux I/O scheduler queue size affects MyISAM insert performance.

It is well known that Linux implemented four types of I/O schedulers (noop/deadline/anticipatory/cfq) in Linux kernel 2.6.10. The default is cfq in most distributions including RHEL, which is not so good then noop normally outperforms, but I'll talk this in other posts.

Linux I/O scheduler also has a functionality to sort incoming I/O requests in its request-queue for optimization. Queue size is configurable. Queue size is defined as "/sys/block/sdX/queue/nr_requests" then you can change queue length as follows.

# cat /sys/block/sda/queue/nr_requests
128
# echo 100000 > /sys/block/sda/queue/nr_requests

Changing queue size is even effective for noop …

Last week I gave a presentation titled "Predicting Performance with Queuing Models" at the MySQL Camp section of the MySQL User Conference. I have uploaded the slides for a longer version of the presentation than could have been covered in the 45 minute time slot, for anyone who would like a copy. I've also uploaded a version that includes speaker notes.

Presentation slides:

• Predicting Performance with Queuing Models
• version with speaker notes

Last week I gave a presentation titled "Predicting Performance with Queuing Models" at the MySQL Camp section of the MySQL User Conference. I have uploaded the slides for a longer version of the presentation than could have been covered in the 45 minute time slot, for anyone who would like a copy. I've also uploaded a version that includes speaker notes.

Presentation slides:

• Predicting Performance with Queuing Models
• version with speaker notes

Assume you have a table with about 300 000 rows, and an indexed column ‘col1′ with only 9 distinct values. Now you got a query like ’select * from t1 where col1 = const’. The questions are

- when the index is faster to full table scan and vice versa?
- does MySQL use the optimal plan by default?

These questions became very relevant now that QOT got server access and is able to gather various table metrics including selectivity. Besides index selectivity the threshold value obviously depends on the storage engine used, so for me it is also interesting to see how our PBXT engine compares to others in this aspect. Namely to InnoDB - an engine with similar transactional properties and MyISAM - a very fast engine for read-only scenarios.

For the test I took the …

Peter wrote about this recently, but I don’t know if it was really clear what was going on.

Point One: Sphinx can be contacted by the MySQL protocol. Not “as a MySQL storage engine.” Not “from MySQL.” It understands the MySQL protocol itself. So from the protocol point of view, the Sphinx search daemon can look just like a MySQL server.

Point Two: Sphinx understands a SQL-like query language. Don’t be fooled. You’re not writing SQL. It just looks like you are.

Point Three: Because of point One and point Two, you can use the mysql command-line client program to talk directly to Sphinx, with absolutely no MySQL server anywhere in sight. This also means you can connect …