From: Linos <info@linos.es>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Ross J. Reedstrom <reedstrm@rice.edu>
Cc: pgsql-performance@postgresql.org
Subject: Re: TCP network cost
Date: Sun, 01 Mar 2009 18:57:03 +0100
Message-ID: <49AACC6F.7080809@linos.es> (raw)
In-Reply-To: <13121.1235929398@sss.pgh.pa.us>
References: <1ca1c1410902171013q478f2620n13fcd68cb8b3d911@mail.gmail.com>
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<3FAF940B-9B0B-4DBA-8728-6096022129DF@infogears.com>
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<13121.1235929398@sss.pgh.pa.us>
Tom Lane escribió:
> Linos <info@linos.es> writes:
>> Hello, i have been having a problem like this in debian machines and i have
>> discovered that (almost in my case), the problem only arises when i am using
>> "ssl = true" in postgresql.conf although i am using clear tcp connections to
>> localhost to perform my query, if i disable ssl in configuration my localhost
>> query times goes from 4200ms to 110ms,
>
> Does that number include connection startup overhead? (If it doesn't,
> it'd be pretty strange.) Ross's problem is not about startup overhead,
> unless I've misread him completely.
>
> regards, tom lane
This difference it is from the runtime of the query, i get this with \timing
parameter in psql, it is from a table that have 300 small png (one for every row
in table) on a bytea column but the problem grows with any large result anyway,
i have attacted pcap files in general list but the differences are like this:
ssl enabled:
`psql -d database`: SELECT * FROM TABLE (110 ms with \timing)
`psql -d database -h localhost`: SELECT * FROM TABLE (4200 ms with \timing)
ssl disabled:
`psql -d database`: SELECT * FROM TABLE (110 ms with \timing)
`psql -d database -h localhost`: SELECT * FROM TABLE (120 ~ 130 ms with \timing)
Anyway i dont know if this apply to Ross problem but reading his post and after
see that he is using debian and have problem with speed on tcp localhost i
suppose that maybe have the same problem.
Regards,
Miguel Angel
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To: pgsql-performance@postgresql.org
Cc: info@linos.es, tgl@sss.pgh.pa.us, reedstrm@rice.edu
Subject: Re: TCP network cost
In-Reply-To: <49AACC6F.7080809@linos.es>
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