Dear Community,

We are pleased to present the 20th build of MySQL server with Percona patches.

Comparing to the previous release it has following new features:

• The build is based on MySQL-5.0.87
• innodb_rw_lock.patch is ported from InnoDB Plugin 1.0.3
• To be compatible with RedHat RPM repository, the naming scheme has changed to

      <rpm name>-<mysql version>-<percona build version>.<buildnumber>.<redhat version>.<architecture>.rpm

  Example:

  MySQL-server-percona-5.0.87-b20.29.rhel5.x86_64.rpm

See release notes for earlier changes.

Since the build 20 MySQL server with Percona patches is available in …

This Thursday (November 19th, 14:00 UTC), Patrick Galbraith will present memcached Functions for MySQL (UDFs). This session is about a suite of functions available to use with MySQL that allow you to store, retrieve and delete data, as well as most of the functions and operations that are available with libmemcached, such as server connectivity to the client, server status, client behaviors, and more. You can combine the fetching of data from one or more tables with the fetching of data from memcached and be able to apply any SQL operations on that result set such as LIMIT, sorting and other conditional operations.

For MySQL University sessions, point your browser to this …

Over the weekend, I experienced a strange issue (even though its not new) with the InnoDB tablespace (ibdata) corruption. When in general InnoDB crashes, it automatically recovers during the next start by rolling back/forward based on what was pending and un-flushed/un-committed changes at the time of crash.

But for some reason, one of the server; we ran out of disk space (yeah, no alerts) on data directory; where we store everything (tablespace, logs and data); and server was running for few hours in this mode (disk full); and it became un-available and not responding after a while. Only option left was to kill the server process and its PID along with cleaning the stuff to get the space back. After I (re)started the server; server failed to start with the following error..

      InnoDB: Error: trying to access page number 1098759810 in space 0,
InnoDB: space name /data/ibdata1,
InnoDB: which is outside …

There are a lot of tutorial out there describing how to use PHP's classic MySQL extension to store and retrieve blobs. There are also many tutorials how to use PHP's MySQLi extension to use prepared statements to fight SQL injections in your web application. But there are no tutorials about using MySQLi with any blob data at all.

Until today... ;)

Preparing the database

Okay, first I need a table to store my blobs. In this example I'll store images in my database because images usually look better in a tutorial than some random raw data.

mysql> CREATE TABLE images (
       id INT(10) UNSIGNED NOT NULL AUTO_INCREMENT,
       image MEDIUMBLOB NOT NULL,
       PRIMARY KEY (id)
       );
Query OK, 0 rows affected (0.02 sec)

In general you don't want to store images in a relational database. But that's another discussion for …

There are a lot of tutorial out there describing how to use PHP's classic MySQL extension to store and retrieve blobs. There are also many tutorials how to use PHP's MySQLi extension to use prepared statements to fight SQL injections in your web application. But there are no tutorials about using MySQLi with any blob data at all.

Until today... ;)

Preparing the database

Okay, first I need a table to store my blobs. In this example I'll store images in my database because images usually look better in a tutorial than some random raw data.

mysql> CREATE TABLE images (
       id INT(10) UNSIGNED NOT NULL AUTO_INCREMENT,
       image MEDIUMBLOB NOT NULL,
       PRIMARY KEY (id)
       );
Query OK, 0 rows affected (0.02 sec)

In general you don't want to store images in a relational database. But that's another discussion for …

This Thursday (November 19th, 14:00 UTC), Patrick Galbraith will present memcached Functions for MySQL (UDFs). This session is about a suite of functions available to use with MySQL that allow you to store, retrieve and delete data, as well as most of the functions and operations that are available with libmemcached, such as server connectivity to the client, server status, client behaviors, and more. You can combine the fetching of data from one or more tables with the fetching of data from memcached and be able to apply any SQL operations on that result set such as LIMIT, sorting and other conditional operations.

For MySQL University sessions, point your browser to …

This Thursday (November 19th, 14:00 UTC), Patrick Galbraith will present memcached Functions for MySQL (UDFs). This session is about a suite of functions available to use with MySQL that allow you to store, retrieve and delete data, as well as most of the functions and operations that are available with libmemcached, such as server connectivity to the client, server status, client behaviors, and more. You can combine the fetching of data from one or more tables with the fetching of data from memcached and be able to apply any SQL operations on that result set such as LIMIT, sorting and other conditional operations.

For MySQL University sessions, point your browser to this …

At today's Web 2.0 Expo keynote with Kevin Rose and Jay Adelson they mentioned they'd done a lot of architecture work on Digg including moving things from MySQL to Cassandra.

I guess something like this was on the table in 2006, mentioned in this O'Reilly article, but the comments clear it up as more of a "we've thought about it and are sticking with MySQL."

This whole idea of NoSQL, and that developers would rank performance over normalization and ability to use joins is interesting. At today's NoSQL talk there was a good Q/A where …

I’ve been messing around with the Kontrollbase schema for the last couple of days, writing various queries for the daily reporting scripts that will eventually be an automated pdf report. I’ll give you examples of two of the queries, the first being overall environment stats, and the second being single-host growth over time.

Overall environment stats
select ((((MAX(os_mem_used)) / 1024 ) / 1024) / 1024) max_os_mem_used, ((((MIN(os_mem_used)) / 1024 ) / 1024) / 1024) min_os_mem_used, ((((AVG(os_mem_used)) / 1024 ) / 1024) / 1024) avg_os_mem_used, ((((STDDEV_POP(os_mem_used)) / 1024 ) / 1024) / 1024) stdev_os_mem_used, ((((MAX(length_data + length_index)) / 1024 ) / 1024) / 1024) max_size, ((((MIN(length_data + length_index)) / 1024 ) / 1024) / 1024) min_size, ((((AVG(length_data + length_index)) / 1024 ) / 1024) / 1024) avg_size, ((((STDDEV_POP(length_data + length_index)) / 1024 ) / 1024) / 1024) …

Last spring, we added a feature that allows the user to see the progress of writes in a statement. Vadim liked it. In 2.2.0, in “show processlist”, we add progress information on reads.

Here is an example of what “show processlist” displays on an update:

mysql> show processlist \G
*************************** 1. row ***************************
Id: 1
User: root
Host: localhost
db: test
Command: Query
Time: 7
State: Queried about 1576008 rows, Updated about 197000 rows
Info: update foo set a=9 where a=8

Here is an example of what “show processlist” displays on an insert that requires a query:

mysql> show processlist \G
*************************** 1. row ***************************
Id: 1
User: root
Host: localhost
db: test
Command: Query
Time: 6
State: Queried about 1542001 rows, Inserted about 771000 …