Various techniques are described for improving the performance of a
shared-nothing database system in which at least two of the nodes that
are running the shared-nothing database system have shared access to a
disk. Specifically, techniques are provided for changing the ownership of
data in a shared-nothing database dynamically, based on factors such as
which node would be the most efficient owner relative to the performance
of a particular operation. Once determined, the ownership of the data may
be changed permanently to the new owner, or temporarily for the duration
of the particular operation.