| From: | Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us> |
|---|---|
| To: | Magnus Hagander <mha(at)sollentuna(dot)net> |
| Cc: | Merlin Moncure <merlin(dot)moncure(at)rcsonline(dot)com>, Josh Berkus <josh(at)agliodbs(dot)com>, pgsql-performance(at)postgresql(dot)org |
| Subject: | Re: seq scan cache vs. index cache smackdown |
| Date: | 2005-02-19 04:11:08 |
| Message-ID: | 200502190411.j1J4B8T15005@candle.pha.pa.us |
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| Lists: | pgsql-performance |
Magnus Hagander wrote:
> I don't think that's correct either. Scatter/Gather I/O is used to SQL
> Server can issue reads for several blocks from disks into it's own
> buffer cache with a single syscall even if these buffers are not
> sequential. It did make significant performance improvements when they
> added it, though.
>
> (For those not knowing - it's ReadFile/WriteFile where you pass an array
> of "this many bytes to this address" as parameters)
Isn't that like the BSD writev()/readv() that Linux supports also? Is
that something we should be using on Unix if it is supported by the OS?
--
Bruce Momjian | http://candle.pha.pa.us
pgman(at)candle(dot)pha(dot)pa(dot)us | (610) 359-1001
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