Administration Guide

Nodegroups and Data Partitioning

You can define named subsets of one or more database partitions in a database. Each subset you define is known as a nodegroup. Each subset that contains more than one database partition is known as a multi-partition nodegroup. Multi-partition nodegroups can only be defined with database partitions that belong to the same instance.

Figure 21 shows an example of a database with five partitions in which:

• A nodegroup spans all but one of the database partitions (Nodegroup 1).
• A nodegroup contains one database partition (Nodegroup 2).
• A nodegroup contains two database partitions.
• The database partition within Nodegroup 2 is shared (and overlaps) with Nodegroup 1.
• There is a single database partition within Nodegroup 3 that is shared (and overlaps) with Nodegroup 1.

Figure 21. Nodegroups in a Database

You create a new nodegroup using the CREATE NODEGROUP statement. Refer to the SQL Reference for more information. Data is divided across all the partitions in a nodegroup. If you are using a multi-partition nodegroup, you must look at several nodegroup design considerations. For more information, see Designing Nodegroups.