For those of you who miss what Maatkit’s mk-audit tool (now retired) gave you, there’s a pair of tools in Aspersa that more than replaces it. I wrote previously about the summary tool. I don’t think I have mentioned the mysql-summary tool. It has been under development for a while, and at this point it has quite a lot of functionality. You can see a sample of the output on its manual page.

Over the last little while I've come across quite a few XML feed generators written in PHP, with varying degrees of 'correctness'. Even though generating XML should be very simple, there's still quite a bit of pitfalls I feel every PHP or (insert your language)-developer should know about.

1. You are better off using an XML library

This is the first and foremost rule. Most people end up generating their xml using simple string concatenation, while there are many dedicated tools out there that really help you generate your own XML.

In PHP land the best example is XMLWriter. It is actually quite easy to use:

1. <?php
2.  
3. $xmlWriter = new XMLWriter();
4. $xmlWriter->openMemory();
5. $xmlWriter->startDocument('1.0','UTF-8');
6. $xmlWriter->startElement('root'); …

The Dallas Oracle Users Group has voted unanimously to accept the North Texas MySQL Users Group as a special interest group within their organization. This will give us wide exposure to the local DBA world, provide more venues for presentation (Irving and Plano), and the ability to have food & drink at meetings.

New presentations are being worked on for presentations including 'No SQL -- is traditional row based SQL in trouble'? Watch here for meeting information.

This month on Database Journal we talk about multi-master MySQL using circular replication to achieve high availability.

Read more at DatabaseJournal – Intro to Multi-Master MySQL

Mat Keep and I will be presenting this free webinar on Wednesday 14 July.

The MEMORY storage engine has been widely adopted by MySQL users to provide near-instant responsiveness with use cases such as caching and web session management. As these services evolve to support more users, so the scalability and availability demands can start to exceed the capabilities of the MEMORY storage engine.

The MySQL Cluster database, which itself can be implemented as a MySQL storage engine, is a viable alternative to address these evolving web service demands. MySQL Cluster can be configured and run in the same way as the MEMORY storage engine (ie on a single host with no replication and no persistence). As web services evolve, any of these attributes can then be added in any combination to deliver higher levels of scalability, …

Thanks to Martin Loschwitz, official Linux cluster stack Debian packages are now available for Debian lenny. Check out the the lenny-backports repository on backports.org (and your favorite local mirror).

When upgrading from Heartbeat 2.1.3, this webinar recording may come in handy. The webinar covers an upgrade to squeeze, but the upgrade procedure is identical if you’re staying on lenny.

…

When examining the execution plan of troublesome queries in MySQL, most users are aware of using EXPLAIN. However, an often overlooked, yet very helpful extension of EXPLAIN, is EXPLAIN EXTENDED coupled with the SHOW WARNINGS command.

The reason being is because it provides a little more information about how the optimizer processes the query, and thus it could help to quickly identify a problem that you might not otherwise recognize with just EXPLAIN.

For instance, here is a common query which could be inefficient:

SELECT id FROM t WHERE id='1';

And here is the CREATE TABLE output:

mysql> show create table tG
*************************** 1. row …

Senior Database Administrator Position: Senior Database Administrator
Job Type: Full-Time
Department: Engineering
Location: San Jose, CA
Responsibilities

• Manage MySQL in production/QA/development environments including installation, configuration, backup, recovery, upgrades, schema changes, etc.

• Perform database health monitoring and diagnostics

• Implement monitoring, auditing and alert systems for MySQL databases

• Troubleshoot and resolve problems with MySQL

• Design, implement, maintain and automate the appropriate backup and recovery architecture required

• Work with various teams for performance tuning and optimization, query optimization, index tuning, caching, buffer tuning, etc.

• Perform capacity planning exercises to properly identify required hardware, software, database configuration/architecture necessary to support …

Working on a new set of replication APIs in MariaDB, I have given some thought to the generation of replication events on the master server.

But there is another side of the equation: to apply the generated events on a slave server. This is something that most replication setups will need (unless they replicate to non-MySQL/MariaDB slaves). So it will be good to provide a generic interface for this, otherwise every binlog-like plugin implementation will have to re-invent this themselves.

A central idea in the current design for generating events is that we do not enforce a specific content of events. Instead, the API provides accessors for a lot of different information related to each event, allowing the plugin flexibility in choosing what to include in a …

Every month or so a node randomly dies

EQX root@cass01:/opt/cassandra/bin# ./nodeprobe -host localhost -port 8181 ring
Address       Status     Load          Range                                      Ring
                                       facebook_1301003235_1301003235             
10.129.28.22  Down       15.77 GB      9ZehBzpHHwnxiPJU                           |<--|
10.129.28.23  Up         7.59 GB       facebook_100000471858343_1514390063        |   |
10.129.28.14  Up         4.59 GB       facebook_100000846936312                   |   |
10.129.28.20  Up         12.94 GB      facebook_1301003235_1301003235             |-->|

Trying to get info from the host, the reads timeout.
java.net.SocketTimeoutException: Read timed out


Doing an lsof -p on the java proc I see that it is holding open a bunch of sockets. So the node itself is hanging on …