Decision support has always been in DB2’s genetic makeup; it’s just been a bit recessive for a while. It’s been evolving over time, so suggesting DB2 for z/OS for your database warehousing shouldn’t be a surprise. Today, DB2 for z/OS is a real warehouse contender and you should be giving it some serious consideration—again. Recall the original DB2 announcement materials from June 7, 1983, which said: “DB2 offers a powerful new data base management system for use where business and application requirements and data structures are subject to frequent changes. … As such, DB2 may be used to address decision support systems as well as traditional application areas.”

Decision Support Systems (DSS) are still actively used today; they contributed to the need for a data warehouse.

When DB2 became generally available in 1985, it was initially difficult to convince customers to use it for Online Transaction Processing (OLTP). At that point, many customers thought DB2’s only purpose was decision support and information centers. Decision support prompted talk about warehousing and Business Intelligence (BI). It took a few years for DB2 to evolve into the transactional support database manager it is today. DB2 is more ready for your data warehouse today than ever before.

DB2’s recently renewed presence in the warehouse world isn’t coincidental, nor is it just DB2 trying to re-establish itself. Warehousing has been changing. Instead of determining what happened in the past, customers want to use all that information to make immediate decisions today. Instead of making information kept in the warehouse available to just a few, it’s being leveraged by larger numbers of customers, including their customers. The focus is getting the information to the correct person when that person needs it. Information must arrive rapidly and accurately. It’s starting to sound a lot like OLTP, isn’t it? What better DBMS than DB2 for z/OS to satisfy these modern challenges.

Before evaluating DB2’s usefulness for warehousing, let’s establish some terms. Webster’s New Millennium Dictionary defines a data warehouse as “a computer system that collects, stores, and manages large amounts of data for a company, to be used for business analysis and strategy.” DB2 for z/OS definitely satisfies this definition. That same dictionary defines BI as “a broad range of applications and technologies for gathering, storing, analyzing, and providing access to data to help make business decisions.” DB2 helps with BI, but needs additional application support for this area and gets it from Cognos (an IBM company), IBM DataQuant, and DB2 Alphablox.

Your data warehouse is how you store the data; BI is how the data is analyzed. Both are integral parts of a comprehensive solution. BI applications serve no purpose if they have nothing to analyze and a data warehouse is of little use without the tools to interrogate the information it contains.

Finally, this article assumes that the terms data mart, Operational Data Store (ODS), and DSS are all similar to the data warehouse concept and are sometimes used in conjunction with, and sometimes in place of, the term data warehouse.

DB2’s Effect on your Warehouse

Enhancements in DB2 Version 8 support data warehousing and associated analytics. DB2 9 for z/OS could improve your warehouse experience even more. The latest version continues a tradition of progress that’s worth briefly reviewing.

DSS support has been improved in some way with every release of DB2. Here are some highlights: • DB2 V2.1 introduced Resource Limit Facility (RLF), which lets you control the amount of CPU that a resource, in this case a query, can actually use. This is for dynamic SQL that will probably make up most of the warehouse SQL workload. This can be critical in controlling system resources, and RLF also can help you control the degree of parallelism obtained by a query.

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