1. A system comprising: a first computing node configured to operate a first execution engine, the first execution engine comprising a first partition of a partitioned data set; the first computing node configured to operate a first query optimizer operable to determine a first plan of executing a query on the first execution engine, the query directed to the partitioned data set; a second computing node configured to operate a second execution engine, the second execution engine comprising a second partition of the partitioned data set; the second computing node configured to operate a second query optimizer operable to determine a second plan of executing the query on the second execution engine; and an optimizer configured to determine whether the first plan of executing the query or the second plan of executing the query should be used to execute the query on the first and second execution engine.