PostgreSQL, Second Edition

Extending the PostgreSQL Server with Custom Functions

An extension function is loaded into a running PostgreSQL server process as needed. If you don't actually use an extension, it will not be loaded. Extension functions must be created in the form of a dynamically loadable object module. In the Windows world, an extension is contained within a DLL. In the Linux/Unix environment, an extension is contained within a shared object module.

There are two phases to the process of adding an extension function to the PostgreSQL server. First, you create the extension function in the language of your choice, compiling it into a dynamic object module (.dll or .so). Next, tell the PostgreSQL server about the function. The CREATE FUNCTION command adds a ...