5. The method of claim 1 , wherein performing the predefined action comprises: interrupting the iterative execution of the query against the samples of the database; and notifying the requesting entity that the predefined condition is not satisfied.
5. The method of claim 1 , wherein performing the predefined action comprises: interrupting the iterative execution of the query against the samples of the database; and notifying the requesting entity that the predefined condition is not satisfied. 7. The method of claim 5 , further comprising: in response to notifying the requesting entity, receiving a modified predefined condition from the requesting entity; resuming the iterative execution of the query against one or more samples of the database; determining whether the query result obtained for each subsequent iterative execution of the query satisfies the modified condition; and if the modified condition is not satisfied, performing the predefined action.