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References: <12436.1149087794@sss.pgh.pa.us>
Date: Thu, 1 Jun 2006 08:52:59 -0400 (EDT)
Subject: Re: Possible TODO item: copy to/from pipe
From: "Mark Woodward" <pgsql@mohawksoft.com>
To: "Tom Lane" <tgl@sss.pgh.pa.us>
Cc: pgsql-hackers@postgresql.org
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> After re-reading what I just wrote to Andreas about how compression of
> COPY data would be better done outside the backend than inside, it
> struck me that we are missing a feature that's fairly common in Unix
> programs.  Perhaps COPY ought to have the ability to pipe its output
> to a shell command, or read input from a shell command.  Maybe something
> like
>
> 	COPY mytable TO '| gzip >/home/tgl/mytable.dump.gz';
>
> (I'm not wedded to the above syntax, it's just an off-the-cuff thought.)
>
> Of course psql would need the same capability, since the server-side
> copy would still be restricted to superusers.
>
> You can accomplish COPY piping now through psql, but it's a bit awkward:
>
> 	psql -c "COPY mytable TO stdout" mydb | gzip ...
>
> Thoughts?  Is this worth doing, or is the psql -c approach good enough?


To be honest, I don't see much benefit in it. You can already accomplish
what you want to accomplish easily enough.

If you want to muck with COPY, I'd like to see it accept a query as:

psql -c "COPY select * from mytable where foo='bar' TO stdout" mydb | gzip
...