As shown in , btree defines
- one required and three optional support functions. The four
+ one required and four optional support functions. The five
user-defined methods are:
There are five user-defined methods that an index operator class for
-
SP-GiST must provide, and
one is optional. All five
+
SP-GiST must provide, and
two are optional. All five
mandatory methods follow the convention of accepting two internal
arguments, the first of which is a pointer to a C struct containing input
values for the support method, while the second argument is a pointer to a
cases, the output struct is initialized to zeroes before calling the
user-defined method. The optional sixth method compress
accepts datum to be indexed as the only argument and returns a value suitable
- for physical storage in a leaf tuple.
+ for physical storage in a leaf tuple. The optional seventh method
+ options accepts internal pointer to a C struct, where
+ opclass-specific parameters should be placed, and returns void.