Sometimes one has weird ideas, or am I the only one? - This specific one is at least a year old, now, during the Christmas days, waiting for New Year's Eve I had the time and mood to finally try it out: MySQL 5.1 has a plugin interface to easily add storage engines. PHP can easily embedded into other applications.  So why not combine these two things? - Writing a MySQL Storage Engine which reads data by calling a PHP script.

Let's start with a simple example first:

<?phpfunction create_table($table, $data) {
    return true;
}

function open_table($table) {
…

Sun has invited me to showcase Maatkit at the dot-org pavilion at the upcoming MySQL Conference and Expo 2009. At this time it’s really hard to say what I’ll be demoing! Development on Maatkit is accelerating and I don’t look for that to change, so who knows what we’ll have done by then. I’ll see you there.

I've created a Twitter for Drizzle at http://twitter.com/drizzlebugs

Follow it for announcements, bugs reports, and other Drizzle related stuff

Ok this isn’t very timely reporting, but about two weeks ago Batched Key Access feature has been pushed into MySQL 6.0. You can get it from the bazaar repo now (bzr branch lp:mysql-server/6.0), or wait several more weeks till MySQL 6.0.9 is released and get it from there.

Batched Key Access in a nutshell

BKA is about accessing tables in batches when running nested loop joins. The benefits of batching table accesses are that

• “Remote” engines save on number of roundtrips
• Disk-based engines do reads in disk order instead of randomly probing the table, which allows to be easier on disk cache and take advantage of prefetching

Batched Key Access only works if the used storage engine supports it. At the moment there is support for MyISAM, InnoDB, Maria, Falcon (these are disk-based) and NDB (this one is remote) engines.

Documentation

At the moment …

One of our customers gave me a chance to run some benchmarks on 24-core (intel cpu based) server, and I could not miss it and ran few CPU-bound tasks there.

The goal of benchmarks was investigation of InnoDB-plugin and XtraDB scalability in CPU-bound load.

CPU specification:

PLAIN TEXT CODE:

1. processor       : 23
2. vendor_id       : GenuineIntel
3. cpu family      : 6
4. model           : 29
5. model name      : Intel(R) Xeon(R) CPU           E7450  @ 2.40GHz
6. stepping        : 1
7. cpu MHz         : 2394.011
8. cache size    …

The other day, a client mentioned they were getting strange results when running ALTER TABLE. The episode involved modifying an existing primary key to add an auto_increment primary key: it was “shifting” values. Say what?!

As it turns out, it was a very special value getting changed: zero. Some fiddling revealed the underlying reason. Care to join me?

To understand what’s going on, follow the example below as we start with an empty database, create a table and insert a few rows:

mysql> use test;
Database changed
mysql> show tables;
Empty set (0.00 sec)

mysql> create table test_table (id int not null primary key) engine=innodb;
Query OK, 0 rows affected (0.01 sec)

mysql> desc test_table;
+-------+---------+------+-----+---------+-------+
| Field | Type    | Null | Key | Default | Extra |
+-------+---------+------+-----+---------+-------+
| id    | …

By now you have been looking at the UC’s upcoming schedule. On Tuesday @ 2pm Yves and I are currently scheduled to present our presentation on Waffle Grid entitled: “Distributed Innodb Caching with memcached “ . When we submitted this topic, we had not yet come up with a name for the project, So we are really hoping one of the conference gods allows us to change it to something like “The Waffle Grid Project: Distributed Innodb Caching with memcached”. Speaking of changes something, my other accepted proposal a talk on Solid State Disk scheduled for Wednesday @ 2pm Entitled “SAN Performance on a Internal Disk Budget: The coming Solid State Disk revolution” (http://en.oreilly.com/mysql2009/public/schedule/detail/5991) went horribly wrong in the formatting …

Laurel Ruma (@laurelatoreilly) just did a quick census of the number of O'Reilly employees on twitter. She came up with 74 twitter accounts out of about 300 employees worldwide, plus five people who were controlling departmental or project-based O'Reilly twitter accounts like the following:

Official O'Reilly account:
@oreillymedia: The top level O'Reilly Media site.


@oreilly_verlag: O'Reilly Germany

Number of O'Reilly products or divisions on Twitter: 8


@make: Make: Magazine and makezine blog

@craft: Craft: Magazine and craftzine blog
…

(This is a purely technical or at least semi-technical post about a database and Web20 architecural issue.)

I just noticed about 5-10 status updates from my friends on Facebook are duplicated. Reading from the top I get to "17 hours ago" and then it restarts with duplicate status update messages from "5 hours ago".

read more

Every hour, we saw the diskspace on our root partition go up from 45 %  to 90 % and come back to 45 %. Initially thought mysql was processing some temp tables and in the next hour we kept watching the temp location. In terms of files / diskspace usage using “du / ls” nothing changed. But lsof provided an interesting output.

Output 1 :

mysqld    31719   mysql    6u   REG                8,1          0   149240 /var/tmp/ibOLLuRa (deleted)
mysqld    31719   mysql    7u   REG                8,1        102   149243 /var/tmp/ibNuSvI9 (deleted)
mysqld    …