Every so often you need to perform sort results retrieved from MySQL when your WHERE clause goes beyound col=const values which would allow MySQL to still use second portion of the index for the order by. Ranges as well as IN lists make this optimization impossible, not even speaking about index merge optimization. Lets look at this example:

PLAIN TEXT SQL:

1. CREATE TABLE `utest` (
2.   `c1` int(10) UNSIGNED NOT NULL,
3.   `c2` int(10) UNSIGNED NOT NULL,
4.   `ord` int(10) UNSIGNED NOT NULL,
5.   KEY `c1` (`c1`,`ord`),
6.   KEY `c2` (`c2`,`ord`)
7. ) ENGINE=MyISAM DEFAULT CHARSET=latin1
8.  
9. mysql> EXPLAIN SELECT * FROM utest WHERE c1=5 OR c2=5 ORDER BY ord DESC LIMIT 10 \G
10. *************************** 1. row ***************************
11.           …

(whoops - Movable Type 4 decided to mess up the permalink from the index page on this entry earlier; it should be fixed now. Darn bugs in run-periodic-tasks, grrh).

One of the NTP Pool server operators emailed recently and told that his server was unavailable for a few hours because he had changed some firewall rules remotely and managed to lock everyone out. Oops!

There's an easy way to do safe remote firewall changes.

He should have used the at daemon to automatically recover! If you don't have a console server then you absolutely must get in the habit of using it before doing anything that can lock you out of your server.

The basic concept is to setup something that in say 5 minutes will undo whatever you're about to do. So if you are messing with the …

We are currently working on Cool Stack 1.1.1 which will have the following components updated, in addition to fixing known bugs :

• Apache 2.2.6 : Add mod_proxy, mod_fcgid, SMF support
  
• PHP 5.2.4      : Add dtrace extension, add new fastcgi version for use with non-Apache webservers
• APC 3.0.14
  
• Suhosin 0.9.20
  
• MySQL 5.0.45: Add SMF support
  
• Perl 5.8.8       : Add Sys:Syslog, DBI, DBD-mysql extensions
• memcached 1.2.2
• squid 2.6
• tomcat 5.5.23

I would love to get feedback on this. Is your favorite module/extension missing ? Are there bugs/issues you have run into that haven't been reported on the forum ?

We are currently working on Cool Stack 1.1.1 which will have the following components updated, in addition to fixing known bugs :

• Apache 2.2.6 : Add mod_proxy, mod_fcgid, SMF support
  
• PHP 5.2.4      : Add dtrace extension, add new fastcgi version for use with non-Apache webservers
• APC 3.0.14
  
• Suhosin 0.9.20
  
• MySQL 5.0.45: Add SMF support
  
• Perl 5.8.8       : Add Sys:Syslog, DBI, DBD-mysql extensions
• memcached 1.2.2
• squid 2.6
• tomcat 5.5.23

I would love to get feedback on this. Is your favorite module/extension missing ? Are there bugs/issues you have run into that haven't been reported on the forum ?

Its exciting to see Zimbra being purchased for USD$350 million, by Yahoo!. Exciting because its a great product, exciting because I use it daily, and I guess Satish & team (of over 100 employees) deserve a big pat on the back. The other exciting thing to note is that its got MySQL in its core, and if they’re pushing it out farther and wider now thanks to the Yahoo! purchase, all the better.

There are a few things that are unclear, though, even from their FAQ:

• They mention commitment to Zimbra 5, but I’m still waiting for 4.5.7 :P (My Series 60 phone still …

PDO is a PHP extension providing a data-access abstraction layer that can be used with a variety of databases. This gives you the flexibility of changing the database backend without having to alter your access methods. Even if you use MySQL exclusively, PDO can provide advantages; you can use the same data-access methods regardless of the MySQL version. This does away with the need for using the standard MySQL extension with older versions of MySQL and using the MySQLi extension for later versions. An additional advantage is the ability to use object-oriented code regardless of the version of MySQL.

The phrase "security vulnerability" gives most of us the creeps. We are afraid of them. Looking at them rationally, they share a trait with other bugs: All are a pain, but some are a bigger pain than others. And instead of trying to avoid the evil by not talking about it, let's take a look at MySQL's security vulnerability track record over the years, and explain the rationale behind our actions using actual cases from past years.

The Falcon transactional storage engine uses the concept of user-defined tablespaces that are more in line with what one would find in Oracle (tablespaces) or SQL Server (filegroups). Let?s take a quick look at how tablespaces are used within Falcon and what you can and can?t do with them.

This article shows you how to use a little-known InnoDB feature to find out what is holding the lock for which an InnoDB transaction is waiting. I then show you how to use an undocumented feature to make this even easier with innotop. Background One of the most common complaints I’ve heard from DBAs used to other database servers is “I can’t find out who holds the locks that are blocking all these connections and making them time out.

Community version 1.2.1 of Zmanda Recovery Manager (ZRM) for MySQL, a robust and intelligent solution for backup and recovery of MySQL databases is available for download at Zmanda downloads page.

Changes in this release:

1. Bug fixes
2. Source tar ball (including debian package files)
3. Help from ZRM online sites

For documentation see, ZRM for MySQL users manual. Please use bugzilla to report bugs and feature requests. If you have questions or feedback, please post them in forums.