UPDATE:
* s/Using join cache/Using join buffer/, changed to show the final variants of EXPLAIN output as described here
* s/join_buff_size/join_buffer_size/

Starting from 5.1.18, EXPLAIN output may show "Using join cache", like in this example:

mysql> explain select * from t1, t2 where t1.col < 10 and t2.col < 'bar';
+----+-------------+-------+-------+-...-+--------------------------------+
| id | select_type | table | type  |     | Extra                          |
+----+-------------+-------+-------+-...-+--------------------------------+
|  1 | SIMPLE      | t1    | range |     | Using where                    |
|  1 | SIMPLE      | t2    | range |     | Using where; Using join buffer |
+----+-------------+-------+-------+-...-+--------------------------------+

The join cache is actually not a new feature. It has been …

MySQL Table Checksum 1.1.5 adds a some useful features and fixes a couple of bugs. Now you can checksum tables in chunks, and there is an option to pause between chunks as well. This has already helped me recover a very large table that got out of sync on the replicas, and many of you have also requested this feature. You can read the full release notes and documentation for the details, but here’s an overview:

In a world in which many developers (myself included) use web search as their first avenue of inquiry when they run into a technical problem, it's important for platform providers to have technical content that is thorough, well-organized, and discoverable from web search engines. (This means that you should apply the principles of search engine optimization to your entire site, not just the marketing bits.)

Way too many technology products expect third party developers to flock to their platforms on the strength of the product alone, without providing any documentation to help them get started. Documentation isn't an amenity, it's a requirement.

If your documentation isn't easily searchable, then 10-70% of current and prospective developers aren't going to be able to find your documentation when they need it.

Keeping your developer content up to date as your platform evolves is another big challenge. Microsoft does a …

It’s no surprise, MySQL users want more scalability and better manageability. Heavy use of Web, e-commerce and other applications calls for higher availability and capability, according to a recent survey sponsored by MySQL storage engine provider Solid Information Technology. We covered MySQL AB’s efforts to improve scalability in our February 2007 report on Falcon, the company’s own storage engine for high-end customers needing transactional speed and reliability. Thanks to open source, MySQL is not alone in responding, and all MySQL database users should eventually benefit from Google enhancements for better manageability and reliability. These patches are free and open source, available from Google, and will eventually make their way into official MySQL …

In the two years since we first created opentaps, we've had the opportunity to work with a number of companies large and small on implementing open source ERP and CRM solutions. In the process, we realized that most companies want the same things:

1. Bring together all the people in the organization
2. Automate their business processes
3. Record all the transactions taking place in the organization, both internal and external
4. Analyze that data to help make better decisions

As we had to the 1.0 release of opentaps, we've made a lot of progress in making this a reality. From Apache OFBIZ we have a very rich (and complex) data model and a scalable and stable framework for record enterprise data in large volume. We also now have a suite of opentaps modules which are designed around the way business users work, whether they are in sales, marketing, customer service, finance, warehouse, or …

Recently I have seen storage companies being evaluated at various occasions. I have talked to various vendors and their customers to get an idea of experiences, frustrations and most importantly, sustained performance. At this month's New York MySQL Meetup Marc Simony brought up something I hadn't heard of: SATA Beast. On a quick glance it seems it has some impressive features at what seems to be an amazingly low cost.

Update: To clarify, SATA Beast was of interest to me for storage solutions where sequential IO is needed, vs. random IO that is generated by databases such as MySQL. I was working on finding storage solution for our media, not databases. Using something like SATA Beast for our non-db storage will allow us to use 3Par solely for database purposes, the IO of which can then be further optimized.

Thank you, …

I'm not sure how I forgot this classic ditty from Bill Gates, but it does show a certain consistency in Microsoft's thinking...stretching over the last 31 years:As the majority of hobbyists [open source developers] must be aware, most of you steal your software...[Y]ou...prevent good software from being written. Who can afford to do professional work for nothing? What hobbyist can put 3-man years into programming, finding all bugs, documenting his product and distribute for free? [Red Hat, MySQL, JBoss, Alfresco, Zenoss, etc. etc.]...I would appreciate letters from any one who wants to pay up...Nothing would please me more than being... READ MORE

I manage /etc/my.cnf from a template id. Since I use servers in pairs, all master-master setups, I need to ensure that the server id is unique and consistent for the server mysql is running on. Managing the id's is a pain in the ass, especially when servers change roles. For instance rotating a server in from another cluster, or recovering a server from backup.

So, I create a my.cnf.tmpl file and that is deployed to all database instances.

The /etc/init.d/mysql script executes a perl script to generate my.cnf from my.cnf.tmpl right before a start executes.

!/usr/bin/perl -w 
#
#

use strict;


my $HOSTNAME = `hostname`;
chomp($HOSTNAME);

my ($name,$alias,$addrtype,$length,@addrs) = gethostbyname($HOSTNAME);

my ($a,$b,$c,$d) = unpack('C4',$addrs[0]);

my $cnfContents ='';
while(<>) {
    $cnfContents .= $_; …

Just a quick reminder for those of you located near Hamburg, Germany: on Monday, June 4th at 19:00 there will be our 7th MySQL Meetup. As usual, we will gather at the Chinese Restaurant "Ni Hao". This time, Sönke Ruempler will give a talk about the PHP-ORM-Framework "Propel". If you'd like to join, don't hesitate to RSVP via meetup.com or Xing.com right away! Thanks - see you there!

Since my last post I have been working on Pre-fetching relay binlogs to speed up MySQL replication. While I will be writing more and eventually posting my script, I wanted to mention that I am extremely satisfied with the results I am seeing. Very soon I will be posting a before and after graph so stay tuned.