Re: pg_get_constraintdef failing with cache lookup error

On Mon, Apr 27, 2015 at 11:16 AM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> Michael Paquier <michael.paquier@gmail.com> writes:
>> pg_get_constraintdef() fails rather easily:
>> =# select pg_get_constraintdef(1);
>> ERROR:  cache lookup failed for constraint 1
>
> It's expected that the caller will supply a valid pg_constraint OID.
> I don't think it's necessary to go out of our way to throw a friendlier
> error message if the OID isn't found.

It's clearly at least a bug in the comment to complain that it can't
happen if in fact it can.  But I would argue that we should never hit
an elog just because of bad user input.

--
Robert Haas
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