1. A computer-implemented method for processing a database statement in a multi-server system, the method comprising: receiving the database statement at a first database server; within the first database server, generating a master plan about how to execute the database statement, and a set of one or more hints that represent directives that specify statements that are to govern construction of an execution plan generated for the database statement; within a second database server, generating a remote plan about how to execute the database statement, based at least in part on the statements specified by directives represented in the set of one or more hints; and if the remote plan is equivalent to the master plan, then one or more slaves on the second database server using said remote plan to participate in parallel execution of at least one operation required by the database statement; wherein the remote plan is equivalent to the master plan if and only if use of the remote plan by the one or more slaves, while the one or more slaves participate in parallel execution of the at least one operation, will produce correct results for said at least one operation.