Re: equal operator for _int4 (array of int4)

Oleg Bartunov <oleg@sai.msu.su> writes:
> this call produces core when one of the PointerGetDatum(ev0p->pred)
> or PointerGetDatum(datum) is NULL
> We use internal postgres function for array comparison -
>  &giststate->equalFn is references to array_eq

array_eq is marked strict, so it's not expecting to get a NULL input.

It's impossible to pass a true SQL NULL through FunctionCall3() anyway
--- no, a null pointer is not an SQL null.  So if you want to use
a coding convention that equates null pointer with SQL null, you'll
have to implement that within your own code and avoid calling array_eq
when you have a null.

IIRC, the rtree and/or gist index types are fairly sloppy about this
point at the moment.  I do not like that, because I do not think an
index type should depend on the assumption that all datatypes it can
handle are pass-by-reference.  If you're going to support nulls then
there needs to be a separate isnull flag for each datum, *not* an
assumption that all-zero-bits can't be a valid datum value.  But I
didn't get around to changing the code yet.
        regards, tom lane