1. A system comprising: at least one processor; non-transitory computer-readable storage medium including instructions executable by the at least one processor, the instructions configured to implement, a request handler configured to determine a query of a Data Stream Management System (DSMS), the query using original stream data stored in a buffer associated with the query, the stored original stream data being obtained from stream data received from at least one data source and being removed from the buffer in association with new stream data being received, wherein the query includes at least one operator being configured to execute the query within the DSMS; a duplication manager configured to duplicate the at least one operator to obtain at least one duplicated operator, and configured to duplicate the stored original stream data to obtain duplicated stream data for storage within a duplication buffer; a modification manager configured to modify the at least one duplicated operator to obtain at least one modified operator and to obtain a modified query; an execution manager configured to determine original results based on execution of the at least one operator, and configured to determine modified results based on execution of the at least one modified operator, the execution manager configured to determine the original results and the modified results in parallel for at least a portion of time; and an integration manager configured to replace the at least one operator and the original stream data with the at least one duplicated operator and the duplicated stream data, respectively, based on the modified results and the original results, to obtain an integrated query for execution within the DSMS.