| From: | Bruno Wolff III <bruno(at)wolff(dot)to> |
|---|---|
| To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
| Cc: | Manfred Koizar <mkoi-pg(at)aon(dot)at>, pgsql-patches(at)postgresql(dot)org |
| Subject: | Re: Tuple sampling |
| Date: | 2004-05-24 03:57:43 |
| Message-ID: | 20040524035743.GA337@wolff.to |
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| Lists: | pgsql-patches |
On Sun, May 23, 2004 at 17:32:36 -0400,
Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>
> slower. (The datatype conversions induced inside get_next_S are likely
> to outweigh any savings from counting by ints, on most modern hardware.)
You aren't even guarenteed that integer operations are faster. On the Cray
XMP integer math was often done using floating point operations because
they were faster. This limited them to 48 bits instead of instead of 64,
but normally 48 bits was enough. I don't remember if just multiplication
was faster or if all operations were faster.
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