A system for generating a query plan is provided. In some implementations, the system performs operations comprising: translating, into corresponding code, a query operation in a query plan comprising a sequence of query operations; determining a context for the translating of the query operation, the context corresponding to whether the query operation comprises a pre-compiled query operation or a code-generating query operation; and inserting adaptor code between code for the query operation and code for one or more previous query operations in the sequence of query operations, when a change in context is detected between the translating of the query operation and a translation of the one or more previous query operations. Related methods and articles of manufacture are also described.