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';
(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.
Won't help too much, until gzip's output is piped back too, so a replacement for COPY .. TO STDOUT COMPRESSED would be COPY ... TO '| /bin/gzip |' STDOUT, to enable clients to receive the reduced stuff. But clients should be agnostic of server side installed tools, and probably not be able to address them directly. Sounds like a potential security issue.
Regards, Andreas