On Mon, May 10, 2010 at 2:59 PM, Joshua D. Drake <j...@commandprompt.com>wrote:
> On Mon, 2010-05-10 at 17:33 +0000, Greg Sabino Mullane wrote: > > -----BEGIN PGP SIGNED MESSAGE----- > > Hash: RIPEMD160 > > > > > > > I would like to replicate the following Unix pipe within a Perl script, > > > perhaps using DBD::Pg: > > > > > > > > > % pg_dump -Z9 -Fc -U <DB_USER> <FROM_DB> | pg_restore -v -d <TO_DB> -p > > > <SSH_TUNNEL_PORT> -h localhost -U <DB_USER> > > > > > > Of course, I can try to use Perl's system, and the like, to run this > pipe > > > verbatim, but I this as a last-resort approach. > > > > > > Is there a more direct way? > > > > If you mean emulate the pg_dump, no. pg_dump does a *lot* of stuff behind > > the scenes, and trying to rewrite all that in Perl would be madness. And > I > > say that having written some serious madness into DBD::Pg already :). > Stick > > with the shell script, even if it means calling system. > > > > If you simply want to avoid the pipes, you can think about calling > pg_dump > > from the remote box, using a authorized_keys with a specific command in > it, > > and other tricks, but nothing will be as straightforward and error proof > > as the line you gave, I suspect. > > With one minor exception. I don't think he needs -Z9 since he is using > SSH which will compress anyway. > Actually, that was a mistake on my part. That should have been "-Ft" rather than "-Z9 -Fc", since I *don't* want compression (most of the data being transmitted consists of highly incompressible blobs anyway). Regarding SSH, my understanding is that to get compression one needs to pass to it the -C flag at the time of creating the tunnel. But my grasp of these details is tenuous as best. ~K
