IBM is continuing to play the role of liberator, allowing users who thought they were locked-in to another DBMS vendor to switch to DB2. Last year, IBM added support to DB2 for syntax and features that make it easy for users to switch from Oracle Database to DB2 (See PL/SQL Support in DB2 for more information). Today, IBM is announcing a new product feature that makes it easy for users to switch from Sybase ASE to DB2.

So, you don’t need to feel locked into Sybase ASE any more… you can now easily switch to IBM DB2.

The first thing I should point out is that the features that make it easy to move from Oracle Database are different from the features that make it easy to move from Sybase ASE. For Oracle Database, we built native support for the syntax and features that make it easy to move deep into the DB2 engine. Whereas, with Sybase ASE, we are using an emulation layer. I’ve got to admit that my first reaction to this approach was skepticism. I wasn’t sure how using an emulation layer would affect performance. However, the performance numbers that I have seen from clients are quite impressive. At one insurance company, they saw that DB2 outperformed Sybase ASE in all tests. The speed up ranged from taking half as much time at the low end to taking a small fraction of the time. It was quite startling. Although I must say that their move from Sun Servers to IBM Power Systems at the same time probably also had an impact on performance.

This new “SQL Skin for Sybase ASE” feature is based on technology developed by ANTs, who have a lot of expertise in off-Sybase migrations. This is the third generation of their technology. IBM is OEMing it, and selling it as an optional feature for DB2. And naturally, as it is an IBM product, IBM is offering support for the product.

So how does this work? Well, on the database client machines, IBM replaces the Sybase ASE client with a compatibility services client. And, on the database server, a compatibility services module runs in DB2. The new client hides the fact that the database, triggers, and stored procedures are now running on DB2 instead of Sybase ASE. Our experience thus far is that, for the most part, the application code remains unchanged. I am not saying there will be no changes needed. But, I can say that—from what I have seen of the Beta testing—such changes are relatively minor in scope. In the press release mentioned above, you can see that Tom Holdener of BJC HealthCare said that they migrated with “virtually no changes” and Jim Ofalt of The Pep Boys enjoyed “a seamless move to DB2 requiring no changes to the application.”

Sybase ASE uses T-SQL. For T-SQL that is immediately recognizable by DB2, the compatibility services will simply pass it through. For T-SQL that is not immediately recognizable by DB2, the compatibility services will “convert” it into an equivalent call that DB2 can run. Then it will call DB2, get the output, and send it back to the application in the format that the application expects.

For more information about this feature, see DB2 SQL Skin feature for applications compatible with Sybase ASE.