Abstract: In a computer embodiment, in a polyglot database management system (DBMS) that contains a guest language runtime environment, a database buffer is configured that the guest language runtime environment does not manage. In the polyglot DBMS, logic that is defined in a guest language is invoked to retrieve, into the database buffer, a value stored in a database in the polyglot DBMS. Compiling the logic causes semantic analyzing the logic to detect that usage of the retrieved value cannot occur after the retrieved value is overwritten in the database buffer. When detecting that such usage of the retrieved value cannot occur, the logic is executed without, after the retrieved value is overwritten in the database buffer, retaining a copy of the retrieved value in a memory region that the guest language runtime environment manages.