Customizing data distribution with DB2® Multisystem

 

Because the system is responsible for placing the data, you do not need to know where the records actually reside. However, if you want to guarantee that certain records are always stored on a particular system, you can use the Change Node Group Attributes (CHGNODGRPA) command to specify where those records reside.

As an example, suppose you want all the records for the 55902 ZIP code to reside on your system in Minneapolis, Minnesota. When you issue the CHGNODGRPA command, you should specify the 55902 ZIP code and the system node number of the local node in Minneapolis.

At this point, the 55902 ZIP has changed node groups, but the data is still distributed as it was previously. The CHGNODGRPA command does not affect the existing files. When a partitioned file is created, the partitioned file keeps a copy of the information from the node group at that time. The node group can be changed or deleted without affecting the partitioned file. For the changes to the records that are to be redistributed to take effect, either you can re-create the distributed file using the new node group, or you can use the Change Physical File (CHGPF) command and specify the new or updated node group.

Using the CHGPF command, you can:

You must also use the CHGNODGRPA command to redistribute an already partitioned file. The CHGNODGRPA command can be optionally used with the CHGPF command to do any of the other tasks.

In the Redistribution issues for adding systems to a network topic, you can find information on changing a local file to a distributed file or a distributed file to a local file.

 

Parent topic:

Distributed files with DB2 Multisystem

 

Related concepts


Change Node Group Attributes command
Planning for partitioning with DB2 Multisystem
Redistribution issues for adding systems to a network