  We allow database user to script a parallel relational database engine with a
procedural language. Procedural language code is executed as a user defined
relational query operator called transducer. Transducer is tightly integrated
with relation engine, including query optimizer, query executor and can be
executed in parallel like other query operators. With transducer, we can
efficiently execute queries that are very difficult to express in SQL. As
example, we show how to run time series and graph queries, etc, within a
parallel relational database.
