DB2 for Mainframes Gets Native XML with V9.1 Release

Published: March 6, 2007

by Timothy Prickett Morgan

Having divulged its plans for the improvement of its three key operating system platforms for the mainframe, IBM this week completed the hat trick by getting the "Viper" edition of its database management system, sold as DB2 9.1, up and running on its mainframes. Like the Viper release for Windows, Unix, and Linux servers--which is a code base that is distinct from the DB2 that runs on mainframes--DB2 9.1 for z/OS supports native XML document as well as relational data formats.

IBM calls the native XML capability PureXML, and unlike past approaches, including prior releases and versions of DB2 for the mainframe, PureXML allows XML documents to be stored without losing the hierarchical information that is inherent in them and still allows the elements of the XML documents to be queried. This technology has been in development for five years, and was first released in the DB2 V9 releases for Windows, Unix, and Linux in July 2006. IBM holds a patent on the PureXML approach, by the way.

According to Bernie Spang, director of data servers at IBM--data server being the new-fangled name for a database management system at Big Blue these days and not to be confused with a database hardware appliance--past approaches to dealing with XML data were not exactly ideal. The approach, he explained, is to store a whole XML document inside of a database field; while this works, SQL queries only work across cells, not within them, which means you could not easily index XML documents for fast searches and queries.

The other approach, which is called shredding, takes the XML document and parses it up into chunks and then stores the chunks inside different columns within the same row in the relational database management system. This approach allows for the elements of the XML document to be queried, but it is no longer a hierarchical XML document that can be used in production. Recomposing it on the fly out of the database obviously takes a lot more resources than hitting a single cell in the database to retrieve the whole XML document, as can be done in the other approach.

With PureXML, IBM has figured out a way to store the XML document, index the data within documents and across documents, and allow a single SQL query to scan documents. This capability is clearly important for the services oriented architecture (SOA) approach to application development, which uses XML as a kind of superglue between disparate and often incompatible systems and applications to create individual services and then composite applications built from those services.

"With SOA, you can't just say, 'Whatever. I just need an SQL data server,'" says Spang. "The decision about what data server you use is every bit as important as the application server you choose."

Various industries are standardizing the XML documents they intend to use for services--ACCORD in financial services, HIPPA in healthcare, ARTS in retail, and so forth--and this PureXML capability is something they are looking for--especially since the same DB2 database can store plain old row and column data used to traditional transaction processing systems. But, perhaps more importantly, the DB2 Viper family of products is showing that it can handle XML data with anywhere from three to right times the performance of prior DB2 versions, which were using the two other methods mentioned above to cope with XML documents.

In addition to the PureXML support, DB2 V9.1 for z/OS allows remote native SQL procedures to be passed to the zIIP co-processors in mainframes. The zIIP co-processors, which IBM added to the mainframe last year, are discounted mainframe engines that are restricted to running DB2 routines. The idea behind the zIIP is to boost the performance and price/performance of mainframes running DB2 databases without cutting prices on the DB2 licenses. The DB2 Query Management Facility has also been given a new Web interface using Eclipse tools (IBM does eat its own dog food, eventually), and various DB2-related tools, such as DataQuadrant, DB2 Optimization Expert, and the DB2 Utilities Suite, have all been tweaked to support the new DV2 V9.1 for z/OS.

In addition to the PureXML support, DB2 V9.1 for z/OS allows remote native SQL procedures to be passed to the zIIP co-processors in mainframes. The zIIP co-processors, which IBM added to the mainframe last year, are discounted mainframe engines that are restricted to running DB2 routines. The idea behind the zIIP is to boost the performance and price/performance of mainframes running DB2 databases without cutting prices on the DB2 licenses. The DB2 Query Management Facility has also been given a new Web interface using Eclipse tools (IBM does eat its own dog food, eventually), and various DB2-related tools, such as DataQuadrant, DB2 Optimization Expert, and the DB2 Utilities Suite, have all been tweaked to support the new DV2 V9.1 for z/OS.

Just in case you are wondering, the DB2 Viper database for Linux does run on a mainframe's logical partition with a Linux instance inside of it.

DB2 V9.1 for z/OS will be available on March 16.

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