Обсуждение: BUG #5647: COPY TO does not respect the [standard_conforming_strings] setting

The following bug has been logged online:

Bug reference:      5647
Logged by:          David Sahagian
Email address:      david.sahagian@gmail.com
PostgreSQL version: 9.0 beta4
Operating system:   win XP
Description:        COPY TO does not respect the
[standard_conforming_strings] setting
Details:

-
start the postgresql-9.0 service on my winXP laptop
-
verify that [standard_conforming_strings] = on
-
select a varchar(255) column from my table
using Query Tool of pgAdmin III
-
value displayed: my\n\m\\pq
this is expected by me
-
then do the COPY stmt
============
COPY( select mycol from silly_tbl )
TO $$c:\tmp\copy_to_bug.txt$$
WITH ( FORMAT text )
============
-
eyeball the output file using Notepad
value displayed: my\\n\\m\\\\pq
-

So all the backslash chars got "doubled".

My claim is . . .
if
  standard_conforming_strings = on
then
  COPY TO should NOT be modifying the data values
  with extra backslashes
.

Notes:
I want to use the output file as input to psql, for another db whose
[standard_conforming_strings] is also = on. The current behavior of COPY TO
makes that impossible.

Thanks,
-dvs-




-dvs-

"David Sahagian" <david.sahagian@gmail.com> writes:
> Description:        COPY TO does not respect the
> [standard_conforming_strings] setting

This is not a bug.  The COPY format is well defined and is not going to
be changed by standard_conforming_strings.

> I want to use the output file as input to psql, for another db whose
> [standard_conforming_strings] is also = on. The current behavior of COPY TO
> makes that impossible.

That's nonsense.  standard_conforming_strings won't affect the
interpretation of COPY data on either machine.  If we were to change it
as you suggest, then we *would* have a compatibility problem.

            regards, tom lane

Tom Lane wrote:
> "David Sahagian" <david.sahagian@gmail.com> writes:
> > Description:        COPY TO does not respect the
> > [standard_conforming_strings] setting
>
> This is not a bug.  The COPY format is well defined and is not going to
> be changed by standard_conforming_strings.

Yes, remember COPY data are not "strings", they are delimited data, so
there is no standard to match here.

--
  Bruce Momjian  <bruce@momjian.us>        http://momjian.us
  EnterpriseDB                             http://enterprisedb.com

  + It's impossible for everything to be true. +