Inter-Db2 interest and GBP-dependency

For Db2 data sharing environments, the concepts of inter-Db2 read/write interest and group buffer pool dependency (GBP-dependency) are closely related.

Whenever inter-Db2 read/write interest exists on a page set or partition, that object is GBP-dependent. Conversely, if no inter-Db2 read/write interest exists on a page set or partition, the object is usually not GBP-dependent. Sometimes an object still has pages cached in the group buffer pool, and it can remain GBP-dependent even after the inter-Db2 read/write interest has gone away. The following table shows you how to determine if a page set is GBP-dependent based on the inter-Db2 interest of one member and all other members.

Table 1. Determining group buffer pool dependency
One member's interest Other members' interest Is page set GBP-dependent?
Read-only None, Read-only No
Read-only Read/Write Yes
Read/Write None No 1
Read/Write Read-only Yes
Read/Write Read/Write Yes
Exception:
  1. The page set remains GBP-dependent for some time before Db2 removes the dependency. Db2 might not be able to remove the GBP-dependency if applications update the page set without issuing periodic commits.