IT Management

At conferences and regional user group meetings, IBM has been leaking out details about the next version of DB2 for z/OS. This article provides a concise overview of some features and functions IBM has been touting. Remember, though, that this is merely an overview of some of the features you can expect in DB2 Version 8; more details will become available later this year.

Architecture

A major impact of V8 will be the requirement to run a zSeries machine and z/OS 1.3. DB2 V8 won’t support old hardware, nor will it support OS/390. Additionally, DB2 customers must migrate to V7 before converting to V8. There’ll be no IBM-supported capability to jump from V6 (or predecessors) directly to V8 without first migrating to V7.

Owing to these architectural requirements, DB2 will have the ability to support large virtual memory. This next version of DB2 will be able to surmount the limitation of two gigabytes (2GB) of real storage that was imposed due to S/390’s 31-bit addressing. Theoretically, with 64-bit addressing, DB2 could have up to 16 exabytes of virtual storage address support to be used by a single DB2 address space. Now there’s some room for growth!

Broader usage of Unicode is another architectural highlight of DB2 V8. V7 delivered support for Unicode-encoded data, but V8 forces its use. If you don’t use Unicode today, you will when you move to V8. The DB2 system catalog will be implemented using Unicode. In fact, the DB2 catalog has some dramatic changes, including some table spaces with larger page sizes and long names.

Actually, support of long DB2 object names is another significant architectural change in V8. DB2 V8 significantly increases the maximum length of most DB2 object names. For example, instead of being limited to 18-byte table names, you’ll be able to use up to 128 bytes to name your DB2 tables. The same limit applies to most DB2 objects and special registers, including views, aliases, indexes, collections, schemas, triggers, and distinct types. The limit for columns is 30 bytes, a table space is still 8 bytes, and packages are still 8 bytes, unless it’s a trigger package, which can be 128 bytes. This brings considerable flexibility, but also a lot of reworking of DB2 catalog tables.

One such reworking requires the use of table spaces with 8K, 16K, and 32K page sizes. So the system catalog in DB2 V8 will require use of the BP8K0, BP16K0, and BP32K buffer pools.

Administration

As with each new version, DB2 V8 offers new functionality that helps DBAs administer and manage their databases and subsystems. This release contains many enhancements to the DB2 objects DBAs must manage:

  • Sequence objects
  • Variable length index keys
  • Expanded partitions
  • New types of partitioned indexes
  • New partition management
  • Materialized query tables (also known as automated summary tables).

Also, index keys can comprise up to 2,000 bytes, so more data can be indexed using a single index. Each of these features delivers more functionality but also presents implementation and maintenance challenges.

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