Date: Fri, 11 Oct 2019 16:38:41 +0200
From: Albert Shih <Albert.Shih@obspm.fr>
To: pgsql-admin@postgresql.org
Subject: Strange behavior over WAN
Message-ID: <20191011143841.GH14404@io.chezmoi.fr>
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Hi


We got a postgresql server with a very small database ( ~few Mo) and do
a extract with a ruby (sequel) client.

If I do the extract on the same server the speed is correct (10-30 sec)

If I do the extract on the same LAN the speed is correct. (10-30 sec)

If I do the extract from the wan the speed goes from slow to ultra-slow
(reach the TTL and sometime the connection are close) (1 minutes -> 8
minutes)

When this happen I try to see if they are some bandwith problem, and they
don't have any bandwith problem ( ~10-20Mbytes/s 120-180Mbits/s), the size
of the extraction (with tcpdump) are small (~2Mo).

I also check the fragmentation of the tcp flow, when I'm on the wan they
are x2 packets so I can understand they are slower than over the LAN but I
can see how it's possible to go 50-60x slower.

Any idea ? ....or solution ?

Regards
--
Albert SHIH
Observatoire de Paris
France
xmpp: jas@obspm.fr
Heure local/Local time:
Fri 11 Oct 2019 04:27:48 PM CEST