Re: Why it is not possible to create custom AM which behaves similar to btree?

Konstantin Knizhnik <k(dot)knizhnik(at)postgrespro(dot)ru> writes:
> But then I get error for btfloat48cmp and btfloat84cmp functions:
> ERROR: associated data types must be specified for index support function

You need to specify the amproclefttype and amprocrighttype types you
want the function to be registered under. The core code knows that
for btree, those are the same as the actual parameter types of the
function; but there's no reason to make such an assumption for other AMs.
So you have to write it out; perhaps

...
FUNCTION 1(float4,float8) btfloat48cmp(float4,float8),
...

regards, tom lane