Data Warehousing on DB2 for z/OS

Not so long ago, a lot of people had the idea that if you wanted to do advanced, large-scale (multi-terabyte) data warehousing with DB2, your best bet, platform-wise, was DB2 for Linux, UNIX, and Windows (LUW). This widespread impression was based on several factors, including:

• IBM's own product marketing and packaging efforts, which emphasized DB2 for LUW as the data warehouse platform of choice.
• The absence on the z/OS platform of some product features that were very useful from a business intelligence perspective (including materialized query tables, better star-join query optimization, and 64-bit addressability).
• A richer SQL on the DB2 for LUW platform, including support for common table expressions (which enable powerful data manipulation via recursive SQL) and convenient result set comparisons via EXCEPT and INTERSECT operations.
• A perception that the mainframe platform was not a cost-effective data warehouse solution.

It's time now for people who have looked upon DB2 for z/OS as an also-ran BI platform to rethink their opinions, because the situation with respect to all of the factors cited above has changed:

• IBM is promoting DB2 for z/OS as well as DB2 for LUW as a prime-time data warehousing platform.
• DB2 for z/OS has materialized query tables (which can dramatically improve response times for queries that involve data aggregations and/or large-scale joins), advanced star-join query optimization (important for so-called dimensional data warehouses), and 64-bit addressing support (great for reducing I/O wait times via extra-large buffer pools).
• SQL on the DB2 for z/OS platform has been enriched with BI-friendly features such as common table expressions (enabling you to do with one SQL statement what might have taken several SQL statements and some user programming before), and (in V9) the INTERSECT and EXCEPT clauses of SELECT (both of which make the coding of result set comparisons much easier). Also available on System z now are advanced XML data management and query capabilities that were introduced with DB2 9 for LUW.
• The pricing story on Z keeps getting better and better. On top of the ongoing price-performance gains delivered with successive generations of System z microprocessors, IBM recently provided the DB2 for z/OS Value Unit Edition, making DB2 on System z available for a One-Time Charge for eligible net-new applications or workloads, including data warehousing applications. And another thing: at a time of historically high energy costs people are appreciating all the more the ability of System z servers to deliver maximum bang for your kilowatt expenditures.

It's actually a really exciting time for mainframers where data warehousing is concerned. Organizations are out there right now, running multi-terabyte data warehouse systems using dimensional databases and sophisticated front-end query and reporting tools, all on a DB2 for z/OS foundation. Not only is the technology first-class, the IBM support is first-rate, as a number of the best and brightest in IBM's DB2 for z/OS development organization are dedicated to helping companies achieve success with mainframe-based BI applications.

And what of DB2 for LUW? It's still an outstanding data warehouse platform, and it also gets additional BI goodies with each new release. That hasn't changed. What has changed is the choice between DB2 for z/OS and DB2 for LUW as a foundation for enterprise data warehouse solutions. That choice is now tougher -- in a good way.