1. In a parallel database management system including a request reception server for receiving a request from a user, and a plurality of execution servers for parallelly executing database processing appropriate to the request from the user, said request reception server and said plurality of execution servers each having a function of executing a plug-in program module incorporated by the user in a database system, a database management system method performing a database execution control comprising the steps of: when said request reception server creates an execution procedure code for instructing a procedure for executing the database processing appropriate to the request from the user, said request reception server recognizing that another plug-in module is executed on said request reception server to acquire information to be passed to the plug-in module as an input when an plug-in module is executed on each said execution server; executing said other plug-in module on said request reception server in accordance with said recognition to acquire said information to be passed as an input; and said request reception server editing said execution procedure code such that the information acquired at the preceding step is passed as an input when said plug-in module is executed on each said execution server.