Re: Custom Operators Cannot be Found for Composite Type Values

On 03/08/2012 02:16 PM, Tom Lane wrote:
> "David E. Wheeler"<david(at)justatheory(dot)com> writes:
>> CREATE OPERATOR CLASS json_ops
>> DEFAULT FOR TYPE JSON USING btree AS
>> OPERATOR 3 = (json, json),
>> FUNCTION 1 json_cmp(json, json);
>> This seems to work.
> Urk. You really ought to provide the whole opclass (all 5 operators).
> I'm not sure what will blow up if you leave it like that, but it won't
> be pretty.

Yeah. Note too that this is at best dubious:

CREATE OR REPLACE FUNCTION json_cmp(
json,
json
) RETURNS INTEGER LANGUAGE SQL STRICT IMMUTABLE AS $$
SELECT bttextcmp($1::text, $2::text);
$$;

Two pieces of JSON might well be textually different but semantically
identical (e.g. by one having additional non-semantic whitespace).

cheers

andrew