Re: [PATCHES] Current-stream read for psql's \copy

Mark Feit wrote:
> This patch against 7.4.1's psql and the documentation adds the option
> of reading rows from the "current" input stream (standard input, -f
> xxx, \i xxx) during a "\copy ... from" operation in psql. The details
> were proposed and discussed (somewhat) here:
>
> http://archives.postgresql.org/pgsql-hackers/2003-12/msg00687.php
> http://archives.postgresql.org/pgsql-hackers/2004-01/msg00056.php
>
> After some consideration, I decided to stick with the
> originally-proposed syntax because I couldn't come up with anything
> that made as much sense.
>
> This patch also includes a change which makes the "enter data to be
> copied..." message appear for both \copy and COPY in an interactive
> setting.
>
> If there's interest, I can build a patch against the current
> development version.

[ Moved to hackers list.]

Actually, I am confused by our current \copy behavior. Given the
following file:

CREATE TABLE test(x INT);
\copy test FROM STDIN
444
\.
SELECT * FROM test;

'psql test </tmp/x' works fine, but 'psql -f /tmp/x test' hangs waiting
for input from stdin. Why would we want STDIN to read from the terminal
if all commands are being read from a file with -f?

Reading the second URL, I see:

> Peter Eisentraut declared that from that point on, stdin would be
> whatever stream the \copy command came from. I'd like to propose a
> variant on the "FROM" clause which makes good on Peter's declaration
> without breaking anything already using FROM STDIN and expecting it
> to really read from stdin. (I think this is for the better because
> there are lots of good uses for "psql -f foo.sql < foo.dat".)

I agree with Peter stdin should be where ever the commands are coming
from. I don't see any value to keeping backward compatibility for such
strange behavior, and adding another flag to give the reasonable
behavior seems wrong too.

I propose we just fix this and document it in the release notes. Heck,
COPY and \copy should behave the same in determining STDIN, and right
now they don't.

--
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