About

VSQL_PLAN contains the actual execution plan information for each child cursor loaded in the library cache.

A child cursor is a data result created from the same query (parent). The same query execution will create several child cursors in the library cache.

Join Column Equality Predicate Join Table In order to add
ADDRESS and HASH_VALUE VSQLAREA cursor-specific information
ADDRESS, HASH_VALUE, and CHILD_NUMBER VSQL child cursor-specific information

Documentation / Reference