Date: Wed, 31 May 2006 08:28:33 -0700
From: David Fetter <david@fetter.org>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: pgsql-hackers@postgreSQL.org
Subject: Re: Possible TODO item: copy to/from pipe
Message-ID: <20060531152832.GB27220@fetter.org>
References: <12436.1149087794@sss.pgh.pa.us>
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On Wed, May 31, 2006 at 11:03:14AM -0400, Tom Lane wrote:
> 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';

That's a great syntax :)

Similarly,

COPY mytable FROM 'create_sample_data --table mytable --rows 10000000 |';

would be cool.

> (I'm not wedded to the above syntax, it's just an off-the-cuff
> thought.)

It will be familiar to Perl users, for better or worse.  Come to that,
should the prefixes > and >> also mean their corresponding shell
things?

> Of course psql would need the same capability, since the server-side
> copy would still be restricted to superusers.

Roight.

> 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?

I think it's worth doing :)

Cheers,
D
-- 
David Fetter <david@fetter.org> http://fetter.org/
phone: +1 415 235 3778        AIM: dfetter666
                              Skype: davidfetter

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