Re: single session I/O bandwidth
- From: Tanel Poder <tanel@xxxxxxxxxxxxxx>
- To: Ls Cheng <exriscer@xxxxxxxxx>
- Date: Wed, 13 Mar 2013 15:19:08 +0200
Google for Frits Hoogland's multiblock reads slides to get useful extra
info about this ...
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*Tanel Poder*
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On Wed, Mar 13, 2013 at 3:17 PM, Tanel Poder <tanel@xxxxxxxxxxxxxx> wrote:
> what's the wait profile for this single session? 90% on CPU or 90%
> waiting? (run snapper :)
>
> if it's a buffered scan (db file scattered reads) then you will do an IO
> operation, wait, process on CPU, do another IO operation, wait again etc...
> so you'll be wasting a lot of time on waiting for the synchronous IO
> operations to complete. So it's about the latency. Easily measurable.
>
>
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