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

"Etsuro Fujita" <fujita(dot)etsuro(at)lab(dot)ntt(dot)co(dot)jp> writes:
> I'd like to add the following options to the SQL COPY command and the psql \copy
> instruction:

> * PREPROCESSOR: Specifies the user-supplied program for COPY IN. The data
> from an input file is preprocessed by the program before the data is loaded into
> a postgres table.
> * POSTPROCESSOR: Specifies the user-supplied program for COPY OUT. The data
> from a postgres table is postprocessed by the program before the data is stored
> in an output file.

The proposed patch causes the external processor programs to execute
with the privileges of the database server, which seems like a pretty
horrid idea. At the very least this would imply limiting use of the
feature to superusers, which greatly restricts its use-case.

I think it would be a lot better if this were designed so that the
processor programs executed on client side. Which would probably make
it not a COPY patch at all, but something in psql.

regards, tom lane