Re: POC PATCH: copy from ... exceptions to: (was Re: VLDB Features)

Andres Freund <andres@anarazel.de> writes:
> On February 5, 2023 9:12:17 PM PST, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> Damir Belyalov <dam.bel07@gmail.com> writes:
>>> InputFunctionCallSafe() is good for detecting errors from input-functions
>>> but there are such errors from NextCopyFrom () that can not be detected
>>> with InputFunctionCallSafe(), e.g. "wrong number of columns in row''.

>> If you want to deal with those, then there's more work to be done to make
>> those bits non-error-throwing.  But there's a very finite amount of code
>> involved and no obvious reason why it couldn't be done.

> I'm not even sure it makes sense to avoid that kind of error. And
> invalid column count or such is something quite different than failing
> some data type input routine, or falling a constraint.

I think it could be reasonable to put COPY's overall-line-format
requirements on the same level as datatype input format violations.
I agree that trying to trap every kind of error is a bad idea,
for largely the same reason that the soft-input-errors patches
only trap certain kinds of errors: it's too hard to tell whether
an error is an "internal" error that it's scary to continue past.

            regards, tom lane