METHOD FOR FAST AND CONSISTENT INVOCATION OF CONCURRENTLY MODIFIABLE USER-DEFINED FUNCTIONS

Database techniques are provided that use state machines to manage polyglot subroutine bindings for database commands. In an embodiment, a computer receives a database command that contains call sites (CSs). Each CS is associated with a user defined logic (UDL). The computer associates an initial operational state with each of the CSs. During a first invocation of a particular CS, the CS becomes initialized and transitions to an optimized state that is configured for streamlined invocation of the UDL. The UDL is invoked to contribute data to a partial result for the database command. Eventually, command execution stalls and causes the CS to transition to an unready state, which entails releasing shared resources. Later execution resumes and during another invocation of the CS, resources are reacquired, the CS is made ready and transitioned back to the optimized state. The CS may again be repeatedly invoked while revisiting the optimized state.