Friday, January 20, 2012

DB2 and PL/SQL features

Today, I answered an email in which I was asked whether DB2 supports PL/SQL and such features as exception handling, the Oracle data dictionary (system catalog), triggers, etc. My response was that many features, especially the most important ones, are supported and that it has become fairly easy - compared to some years back - to move from Oracle to DB2. Many companies are considering this, often as a way to start a dual vendor strategy and to save money.

How do you find out what is supported and how do you find more information? Here are some links:
Happy reading and have a nice weekend...

Thursday, January 12, 2012

Hospitals - a place of extremes

A Happy New Year to everyone. The last week of 2011 was like the first week of 2011, I was in the hospital with one of my kids because of an epilepsy-related check-up (all is well). Hospitals are the place to be to experience life at its fullest extent.

It's the place where - for many people - life begins and/or ends. You will receive personalized treatment as long as it fits into the standard procedures (think of "customized" ERP software like SAP...). It is where absolute boredom and highest suspense and action meet. Hospitals are thoroughly organized through all kinds of processes, they are certified for quality, for hygiene, etc., but they can also be the most chaotic place. If you want to meet new kinds of viruses and bacteria, go to a hospital even though they have disinfection and sanitation processes much more than any other place.

Hospitals also have all kinds of technology which helps both efficiency and medical results, but the human is at the core and without highly experienced humans the technology does not help at all. And in terms of data management you will find traditional relational systems, content management, BI systems, image processing, video and sound processing, archiving, and so forth. And a lot of paper, all kinds of paper.

Health care is a very old profession and always at the edge of technology.


With all that in mind I wish you both a very interesting year full of action and a quiet, relaxed year. The right mix will do...

Wednesday, December 14, 2011

If you are late, just say you are super asynchronous... (HADR)

Well, not everybody is on time and waiting for them can hold up a meeting, important decisions, or completing tasks. The same waiting can happen in an IT environment for various reasons, e.g., a replication or synchronization process taking longer because of network congestion or temporarily overloaded hardware. But what can you do when other tasks are waiting for?

When using DB2 HADR (High Availability Disaster Recovery) some thoughts have to be put into the decision of what synchronization mode to use. Starting with DB2 9.7 FP 5 there are now 4 instead of 3 modes offered:
  • SYNC (synchronous): the transaction log has been written on both the primary and standby
  • NEARSYNC (nearly synchronous): the transaction log has been written on the primary and has been transferred to the standby
  • ASYNC (asynchronous): the transaction log has been written on the primary and is ready to be sent over to the standby
  • SUPERASYNC (super asynchronous): the transaction log has been written on the primay
The SYNC mode needs the most work before a transaction is considered committed the SUPERASYNC mode the least. On the reverse, the SUPERASYNC mode has the most potential for loss of a transaction in the case of a failure. It is the traditional battle between performance and consistency as we have with isolation levels in database systems.

If you want to learn more about HADR for DB2, take a look at the best practices section on developerWorks. In August a new paper on DB2 HADR has been added that focuses on the configuration and tuning of HADR environments. And remember, you are not reading the paper late. You are just super asynchronous with the news...

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