Re: TCP network cost

From: Ross J. Reedstrom
Subject: Re: TCP network cost
Date: ,
Msg-id: 20090224170201.GA25420@cooker
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In response to: Re: TCP network cost  (Tom Lane)
Responses: Re: TCP network cost  (Linos)
List: pgsql-performance

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TCP network cost  ("Ross J. Reedstrom", )
 Re: TCP network cost  (Rusty Conover, )
  Re: TCP network cost  (, )
  Re: TCP network cost  ("Ross J. Reedstrom", )
   Re: TCP network cost  (Rusty Conover, )
    Re: TCP network cost  ("Ross J. Reedstrom", )
     Re: TCP network cost  ("Ross J. Reedstrom", )
      Re: TCP network cost  (Aaron Turner, )
     Re: TCP network cost  (PFC, )
      Re: TCP network cost  ("Ross J. Reedstrom", )
   Re: TCP network cost  (Gregory Stark, )
    Re: TCP network cost  ("Ross J. Reedstrom", )
     Re: TCP network cost  (Tom Lane, )
      Re: TCP network cost  ("Ross J. Reedstrom", )
       Re: TCP network cost  (Linos, )
        Re: TCP network cost  (Tom Lane, )
         Re: TCP network cost  (Linos, )
          Re: TCP network cost  (Tom Lane, )
           Re: TCP network cost  (Linos, )
            Re: TCP network cost  (Tom Lane, )
             Re: TCP network cost  (Magnus Hagander, )
              Re: TCP network cost  (Linos, )
 Re: TCP network cost  (Aaron Turner, )

Excellent. I'll take a look at this and report back here.

Ross


On Mon, Feb 23, 2009 at 04:17:00PM -0500, Tom Lane wrote:
> "Ross J. Reedstrom" <> writes:
> > Summary: C client and large-object API python both send bits in
> > reasonable time, but I suspect there's still room for improvement in
> > libpq over TCP: I'm suspicious of the 6x difference. Detailed analysis
> > will probably find it's all down to memory allocation and extra copying
> > of bits around (client side)
>
> I wonder if the backend isn't contributing to the problem too.  It chops
> its sends up into 8K units, which doesn't seem to create huge overhead
> in my environment but maybe it does in yours.  It'd be interesting to see
> what results you get from the attached quick-and-dirty patch (against
> HEAD, but it should apply back to at least 8.1).
>
>             regards, tom lane


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