Re: WIP patch: add (PRE|POST)PROCESSOR options to COPY

I wrote:
> "Etsuro Fujita" <fujita.etsuro@lab.ntt.co.jp> writes:
>> I have a question.  I think it would be also better to extend the syntax for the
>> SQL COPY command in the same way, ie,
>> COPY foo from '/home/pgsql/decompress.sh /home/pgsql/foo.csv.gz |' with format
>> 'csv'

> Yeah, sure --- that case is already superuser-only, so why not give it
> the option of being a popen instead of just fopen.

BTW, one thought that comes to mind is that such an operation is
extremely likely to fail under environments such as SELinux.  That's
not necessarily a reason not to do it, but we should be wary of
promising that it will work everywhere.  Probably a documentation note
about this would be enough.
        regards, tom lane