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Displaying posts with tag: Hibernate (reset)
451 CAOS Links 2008.12.19

Red Hat increases its service levels. Linux Foundation appoints Ted Ts’o CTO. Sun delivers VirtualBox update. Novell cancels BrainShare. BBC enables iPlayer for Linux. And more.

Note: This is the last 451 CAOS Links post of 2008. We’ll be back with a bumper holiday special on January 2. Happy holidays!

Official announcements
Red Hat Increases Service Levels and Reduces Costs for Customers with Extended Update Support Red Hat

Linux Foundation Appoints Ted Ts’o to Position of Chief Technology Officer Linux Foundation

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Hibernate Query Cache: A Dirty Little Secret

You Mean, Memory Is Not Infinite? We're working hard getting MySQL Enterprise Monitor 2.0, featuring Query Analyzer, ready for release. As part of that, we started really ramping up the number of MySQL servers reporting in query data to see how we could scale. Not surprising (to me, anyway), the first efforts did not go so well. My old friend OutOfMemoryError reared its ugly head once again.
Query Cache -- It's More Than Just Results! We're big (ab)users of hibernate query caching, and more importantly to us the natural id optimized query cache. Firing up the profiler, I was not shocked to see that the second level (let's call it L2) and query caches were hogging the majority of memory. But, something didn't smell right...

What I was seeing was tons of …

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Hibernate: Cache Queries the Natural Id Way

I work on the MySQL Enterprise Tools team, formerly of MySQL and now with Sun Microsystems. The 2.0 version of the Enterprise Monitor is well under way. As part of this, the Java server backend has been refactored to utilize Spring and Hibernate. Honestly, I didn't know either one of those technologies before starting this project. Oh, what a fun road it has been...

A big draw for using an off-the-shelf ORM was so that we didn't have to write our own (kind of bad and slightly wrong -- those darn transactions) caching implementations for the custom one-off ORM that existed previously. A lot of our internal meta-model is very static, so …

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Getting Hibernate and MySQL's "ON DUPLICATE KEY UPDATE" Feature to Play Nice Together...

MySQL has a handy feature, that allows you to turn an INSERT into an UPDATE if a unique or primary key duplication is detected:

http://dev.mysql.com/doc/refman/5.1/en/insert-on-duplicate.html

A common usage pattern for this is “lazy initialization“ of a row in a database, which is exactly what my team was using it for yesterday to solve a problem in the backend for version 2.0 of the MySQL Enterprise Monitor. However, we ran into an issue where Hibernate would throw an exception complaining that when the INSERT was turned into an UPDATE, it couldn‘t retrieve the generated primary key value (we are using auto increments on this particular table, as it‘s not a high insertion-rate table).

To understand why this happens, you have to know a little bit about how Statement.getGeneratedKeys() works with MySQL‘s JDBC driver. …

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PostgreSQL Conference East 2008

As a I wrote a couple of days ago, I went to the second day of PostgreSQL Conference East 2008 last Sunday. I had a good time and really enjoyed meeting everyone, listening, learning, and occasionally talking. I asked a number of fearless-newbie questions that paid off handsomely: people were very willing to humor me. I also left with a beautiful t-shirt, mug, and bag combo thanks to EnterpriseDB. The bag has already been put to use for a grocery shopping trip.

Note to conference/website organizers: I can’t link to anything but the front page, so I assume my link above will someday point to the 2009 conference, or the 2008 West conference. It would be good to give each event a permalink right from the start…

One thing that surprised me was the distance …

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Guice and Hibernate with GlassFish, MySQL and NetBeans

More GlassFish blogging from Munich. This time Siegfried has written a two parter on how to use Guice (the Resource Injection framework Google developed for AdWords) and Hibernate.

part I introduces a simple Hibernate Application using GlassFish and MySQL, while …

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