Re: Extraordinarily slow!!

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: "Justin R(dot) Smith" <jsmith(at)drexel(dot)edu>
Cc: tony_caduto(at)amsoftwaredesign(dot)com, jd(at)commandprompt(dot)com, pfein(at)pobox(dot)com, pgsql-general(at)postgreSQL(dot)org
Subject: Re: Extraordinarily slow!!
Date: 2005-09-27 13:38:46
Message-ID: 10997.1127828326@sss.pgh.pa.us
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"Justin R. Smith" <jsmith(at)drexel(dot)edu> writes:
> I've solved the problem.

> I was accessing Postgres over an ssh connection and had enabled X
> forwarding in the sshd server (not the default configuration). For
> reasons that pass understanding, psql attempts to establish an X
> connection with EACH elementary operation it performs (unless no such
> connection is possible). It doesn't actually USE this X connection for
> anything as far as I know, but the attempt to make the connection over a
> slow communication line creates an enormous delay,

> Reconfiguring the sshd server to NOT forward X connections solved the
> problem. Database operations take fractions of a second now...

> Interestingly, it does NOT help to have X forwarding turned off only in
> the client: sshd itself must not do any forwarding.

[ scratches head... ] That makes no sense at all. psql doesn't even
know what X is, let alone try to open X connections for every database
operation.

Is it conceivable that the openssl library would do this? That would
seem pretty broken too.

How are you using ssh to access the database, exactly? Is psql running
through a tunnel port, or what? What versions of ssl/ssh at each end of
the connection?

regards, tom lane

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