Collaborate 2012 started on Sunday but for me I began on Monday. I enjoyed Bob Burgess, SalesForce, presentation on shell scripting for MySQL Administration today. It preceded my presentation in the same room, which I thought was an interesting coincidence since we got our conference credentials together.

I presented on portable SQL between Oracle and MySQL. The presentation went well. Before I took questions, I got to ask them because I had three copies of my new Oracle Press book to give away: Oracle Database 11g and MySQL 5.6 Developer Handbook. Handing out the books served as a nice ice breaker for the audience to ask questions about the presentation.

My favorite …

I came across an interesting error reported on #mysql the other day. When I went through it with the reporter it looks like we uncovered up to two bugs in InnoDB (or rather XtraDB as it was Percona Server). I thought it might be useful to go through the error message, including the stack trace, to show that you don't need to be a developer to track down some useful information.

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The MySQL sessions at Collaborate started strong after an amazing keynote by former astronaut Mark Kelly about working to become a naval aviator, astronaut, and helping his wife — Congresswoman Gabrielle Giffords — after an assassination attempt on her life last year.

A rare moment when the Oracle demo pods where not wall to wall people.

First up was Set up MySQL in Five Minutes by Bob Burgess of Radian6. Most of the attendees to these sessions seem to be long time Oracle DBAs looking to add more MySQL skills or long time Oracle AND MySQL DBAs. Bob then had a second session and covered Shell Scripting for MySQL Administration where most of the crowd of twenty had already had lots of shell programming experience.

BYU’s Dr. Mike McLaughin …

This is a sneak peek of an exciting new data management technology. linq4j (short for "Language-Integrated Query for Java") is inspired by Microsoft's LINQ technology, previously only available on the .NET platform, and adapted for Java. (It also builds upon ideas I had in my earlier Saffron project.)



I launched the linq4j project less than a week ago, but already you can do select, filter, join and groupBy operations on in-memory and SQL data.

In this demo, I write and execute sample code against the working system, and explain the differences between the key interfaces …

LinkedIn has what they call "inDays" where employees may so something interesting which may not be directly related to their day job. I spent my inDay by porting my old WL820 project (External Language Stored Procedures) to MariaDB 5.3.

The code, as usual, is available on LaunchPad ... To get the branch, simply do:

bzr branch lp:~atcurtis/maria/5.3-wl820 The test cases pass... I haven't tested

Cleaning DataDuplicate keys happen.  I see it most when you feed data into a database and the source data is dirty.
Source data is usually dirty, that's why they want it in a database.
The UNIQUE constraint clause in SQL prevents duplicate keys from ever getting into your pristine database--at least in theory.  Sometimes a plain old attribute just needs to be turned into a key for some "practical" reason.
A common data cleaning need is finding and removing duplicate keys.  Don't forget to turn on unique constraints for your newly clean keys when you are ready.  You never know when you might get hit by a drive-by data sludger.
Finding Duplicate KeysSELECT my_key, count(*) FROM my_table GROUP BY my_key HAVING count(*) > 1; 

Remove Duplicate KeysDELETE
FROM     tableA
WHERE uniquekey NOT IN
    (SELECT …

I don’t think there is a single good-quality MySQL init script for a Unix-like operating system. On Windows, there is the service facility, and I used to write Windows services. Based on that, I believe Windows has a pretty good claim to better reliability for start/stop services with MySQL. What’s wrong with the init scripts? Well, let me count the reasons! Wait, I’m out of fingers and toes. I’ll just mention the two annoying ones that I’ve run into most recently.

A good day for MySQL at COLLABORATE 12. Most of the sessions had good attendance.  Dave and I also got the pleasure of meeting Michael McLaughlin of BYU. He is also an Oracle ACE in Database App Development.

Michael is a support of Oracle and MySQL and I have just recently added his blog to the Planet site.

This is an important feature and security release.

Bugfixes:

• merged with upstream MySQL 5.5.23 (security bugs fixed in 5.5.22 and 5.5.23)
• IO cache was not reset on trx cleanup if the writeset was empty
• ALTER TABLE RENAME and row deletion could conflict on slave
• slave applier can fail for exceeded max_allowed_packet size
• clustered index not included in key set
• locking session can deadlock multi-master

New experimental features:

• Runtime consistency check support.
• Hard crash recovery support (global transaction ID can be recovered by running 'mysqld --wsrep-recover')
• MyISAM storage engine support (non-deterministic functions unsupported, use wsrep_replicate_myisam to enable)
• Solaris 11 x86 build support (see …

A few weeks ago I blogged about the HTTP JSON api in Drizzle. (See also a small demo app using it.) In this post I want to elaborate a little on the design decisions taken. (One reason to do this is to provide a foundation for future work, especially in the form of a GSoC project.)

Looking around: MongoDB, CouchDB, Metabase

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