GENERATION OF QUERY EXECUTION PLANS

A query is received at a database execution engine. A query plan is generated by the database execution engine and for execution of the query. The query plan includes a first operator including computer executable instructions that upon execution queries a data structure of a database, determines whether the data structure satisfies a precondition for execution of a second operator of the query plan, and generates a signal indicating that the precondition is not satisfied. Execution of the query plan is initiated. A new query plan is generated by the database execution engine and in response to receiving the signal indicating that the precondition is not satisfied. Related systems, methods, and articles of manufacture are also described.