Re: BUG #14952: COPY fails to fill in IDENTITY column default value

On Fri, Dec 8, 2017 at 2:13 AM, Peter Eisentraut
<peter(dot)eisentraut(at)2ndquadrant(dot)com> wrote:
> On 12/7/17 06:29, steven(dot)winfield(at)cantabcapital(dot)com wrote:
>> COPYing data to a table with an IDENTITY column, where the column's value
>> isn't specified in the copied input, fails because COPY attempts to insert a
>> NULL value for the column:
>
> That indeed appears to be a bug.

That's a bug. When doing a COPY with or without a list of columns, and
that a column is not listed and has a default expression, then this
expression is used. This is a role filled in by build_column_default()
but identity columns need to create a NextValueExpr expression
instead. As this expression is missing, the backend complains about a
NULL input for this column, which is logic without an expression.
Attached is a patch with a regression test.

Peter, what do you think?

Thanks,
--
Michael