CREATE ACCESS METHOD creates a new access method.
The access method name must be unique within the database.
Only superusers can define new access methods.
The name of the access method to be created.
This clause specifies the type of access method to define. Only INDEX is supported at present.
handler_function is the name (possibly schema-qualified) of a previously registered function that represents the access method. The handler function must be declared to take a single argument of type internal, and its return type depends on the type of access method; for INDEX access methods, it must be index_am_handler. The C-level API that the handler function must implement varies depending on the type of access method. The index access method API is described in Chapter 59.
Create an index access method heptree with handler function heptree_handler:
CREATE ACCESS METHOD heptree TYPE INDEX HANDLER heptree_handler;