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Good Migrations

Six compelling reasons for migrating to DB2 UDB Version 8 for z/OS

DB2* Universal Database* Version 8 (DB2 UDB V8) for z/OS* offers significant opportunities for improvement in six key areas without a lot of added effort. They are:

• High availability
• Scalability and benefits for very large databases
• Increased productivity of Java* and Web applications
• Query optimization and benefits for data warehouses
• Compatibility for migrating or porting applications from other platforms
• Improvements and certification for application packages

If you need improvement in any of these areas, you may benefit from moving to V8 soon.

High Availability
One of the biggest steps toward continuous availability for database administrators is the ability to make schema changes dynamically-on demand-without losing availability. DB2 UDB V8 offers several enhancements and additions that can help improve availability.

Enhancements to the ALTER TABLE statement let you redefine a table or the partitioning of a table space without dropping and recreating the table. These enhancements include the ability to:

• Add, rotate or rebalance partitions in a table space
• Change column types and lengths
• Change the partitioning and clustering of data in tables

Enhancements to the ALTER INDEX statement also let you add columns to an index.

Two new utilities, BACKUP SYSTEM and RESTORE SYSTEM, provide system-level, point-in-time recovery. These utilities let you recover data to any point in time, regardless of whether you have uncommitted units of work. Consequently, data-recovery time can improve significantly for large DB2 subsystems that contain more than 30,000 table spaces and indexes, which means that the downtime for the subsystem can be decreased considerably.

Scalability and Performance
Availability and optimization improvements are critical for very large databases. DB2 UDB V8 provides many important scalability and performance benefits for customers that rely on very large databases.

One key for scalability is 64-bit virtual storage, which provides the flexibility to use more memory more effectively. The 64-bit architecture allows DB2 UDB for z/OS to use two large address spaces of up to 264 bytes (16 exabytes) each, which is 8 billion times larger than the address space available in Version 7. Two-dimensional clustering with more efficient I/O is made possible through enhancements to CREATE INDEX and ALTER INDEX statements that let you:

• Define a clustering order that's different from the partitioning order
• Create a partition without an index, which eliminates the overhead that accompanies an unnecessary index
• Drop a partitioning index or create a table without a partitioning index
• Alter the clustering index

Version 8 also gives you the flexibility to use an index in more situations for improved scalability and more efficient access. Improvements include:

• The capability to index predicates that have mismatched data types
• Support for varying-length index keys, which allows index-only access for indexes that have varying-length index keys and reduces storage requirements
• The capability to scan and index backwards to avoid an unnecessary sort operation

 

The 64-bit architecture allows DB2 UDB for z/OS to use large address spaces of up to 264 bytes (16 exabytes) each, which is 8 billion times larger than the address space available in Version 7.

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