Re: Shouldn't "WHEN (OLD.* IS DISTINCT FROM NEW.*)" clause be independent from data type? - Mailing list pgsql-general

On 09/17/2015 07:51 AM, Tom Lane wrote:
> Adrian Klaver <adrian.klaver@aklaver.com> writes:
>> On 09/17/2015 07:34 AM, Tom Lane wrote:
>>> Ah, sorry, actually what IS [NOT] DISTINCT FROM looks up is the "="
>>> operator.
>
>> So the docs should be changed?
>> As they stand now:
>> http://www.postgresql.org/docs/9.4/interactive/functions-comparison.html
>> "For non-null inputs, IS DISTINCT FROM is the same as the <> operator."
>
> Well, it's an oversimplification to begin with.  Do we want to try to
> cram all of these implementation details in there?

No, just that IS DISTINCT ON is dependent on '=' and will not work on
data types that do not have that operator. That would also cover the IS
NOT DISTINCT FROM case where '=' is the operator 'alias'.

>
>             regards, tom lane
>


--
Adrian Klaver
adrian.klaver@aklaver.com