Partitioning ownership of a database among different database servers to control access to the database

A method for managing data, the method comprising the steps of:

• maintaining a plurality of persistent data items on persistent storage accessible to a plurality of nodes;
• assigning ownership of each of the persistent data items to at least one of the plurality of nodes;
• shipping an operation that involves a particular data item of said plurality of persistent data items to a particular node assigned to the particular data item to cause the particular node to perform the operation on the particular data item, wherein said particular data item resides at a particular location on said persistent storage;
• while the first node continues to operate, reassigning ownership of the particular data item from the particular node to another node without moving the particular data item from said particular location on said persistent storage;
• after the reassignment, when any node wants an operation performed that involves said particular data item, the node that desires the operation to be performed ships the operation to said other node for the other node to perform the operation on the particular data item as said particular data item resides at said particular location.