A query is received which causes an initial data flow graph that includes a plurality of nodes that are used to execute the query is generated. Thereafter, the initial data flow graph is optimized using a model optimizer that includes an optimizer framework and an application programming interface (API). The optimizer framework provides logic to restructure the initial data flow graph and a rules engine for executing one or more optimization rules. The API allows for registration of new optimization rules to be executed by the rules engine. Execution of the query is then initiated using the optimized data flow graph. Related apparatus, systems, techniques and articles are also described.