What's New

Parallel Features

DB2 Version 5 includes parallel features as described in the following sections:

• "DB2 Version 5 Parallel Features"

• "Symmetric Multi-Processor (SMP) Enhancements"

DB2 Version 5 Parallel Features

The features of DB2 Parallel Edition Version 1.2 are now available in DB2 Version 5.

DB2 Universal Database Extended Enterprise Edition, the new name for DB2 Parallel Edition, extends the ability of the database to be partitioned across multiple, independent computers connected by a LAN. To the end-user and application developer, the database still appears as a single database on a single computer. There are two main benefits that this provides. First, this enables an application to use a database that is simply too large for a single computer to handle efficiently. Second, SQL operations can operate in parallel on the individual database partitions, thereby speeding up the execution time of a single query or utility.

While enhancements to SQL commands and DB2 application programming interfaces (APIs) have been made and new commands and APIs have been added to support the parallel environment, most Data Manipulation Language (DML) commands are unchanged and users need not change their programs or SQL statements to run in the parallel environment. In addition, a new graphical administration tool is now available. DB2 Extended Enterprise Edition Quick Beginnings provides installing and configuring information.

The DB2 Parallel Edition Version 1.2 features that are now available in DB2 Version 5 are documented in the DB2 Version 5 product documentation.

Some restrictions apply to the DB2 Parallel Edition Version 1.2 features that are available in DB2 Version 5. They are documented in the following manuals:

• Administration Guide

• SQL Reference

• API Reference

• Command Reference

• System Monitor Guide and Reference

Symmetric Multi-Processor (SMP) Enhancements

Version 5 has the following SMP enhancements:

SMP Intra-Query Parallelism

I/O parallelism already provided in DB2 Version 2 has been enhanced. It now exploits CPU parallelism in a single SQL query. Technology is introduced which exploits multiple processors of a symmetric multiprocessor (SMP) to speed up the execution of a single SQL query. Prior to this work, SMP exploitation was limited to that between multiple queries and to parallel I/O. A key purpose of this technology is to exploit the fact that disks, memory, and processors can be shared uniformly by multiple processors in an SMP system. This provides two important benefits:

• It allows workload to be divided more evenly among the processors, thereby achieving better scalability. This is possible since all processors have the choice to work on all data. This is analogous to a single queue serviced by multiple bank tellers.

• It provides flexibility in designing query execution strategies that is not possible with a shared nothing approach. For example, a correlated subquery can be executed by the same processor that executes the parent query.

See the Administration Guide for more information.

LOAD Utility

Support now exists for the LOAD utility to exploit multiple processors in SMP machines.

While loading data into a table in a multinode nodegroup, the data files must have been processed by the splitter utility db2split), which writes a header to each file. Only ASC and DEL files may be used to load in a table that exists on a multi-node nodegroup. In addition, you now have the option to pick a set of partitions, which may be the same or different from the partitions being loaded, to participate in the parallel split process. See the Command Reference for more information.

As well, you can specify the degree of LOAD parallelism desired for CPU and disk I/O. See the Command Reference and the API Reference for more information.

Index Generation

Multiple processors of an SMP are now used to speed up the process of generating an index. An index can be generated via the CREATE INDEX statement, the addition of a primary key or unique constraint to a table, or the REORG TABLE command.

See the Command Reference for more information.

BACKUP and RESTORE Utilities

Backup and restore of multiple table spaces on SMP machines are performed in parallel.

See the Command Reference for more information.

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