A method and apparatus for operating a database system is provided. One or more
partitions are identified from a data structure in the database system. An identifier
is assigned to at least one of the partitions. An external partition is identified
that is not one of the partitions that form the data structure. An identifier is
determined for the external partition. The first partition is removed from the
data structure by exchanging the identifier of the external partition with the
identifier of the first partition in the set of partitions.