| From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
|---|---|
| To: | Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us> |
| Cc: | Curt Sampson <cjs(at)cynic(dot)net>, nickf(at)ontko(dot)com, PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org>, Ray Ontko <rayo(at)ontko(dot)com> |
| Subject: | Re: Script to compute random page cost |
| Date: | 2002-09-10 14:09:14 |
| Message-ID: | 19229.1031666954@sss.pgh.pa.us |
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| Lists: | pgsql-hackers |
Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us> writes:
> I will run it some more tomorrow but clearly we are
> seeing reasonable numbers now.
... which still have no provable relationship to the ratio we need to
measure. See my previous comments to Curt; I don't think you can
possibly get trustworthy results out of a shell script + dd approach,
because we do not implement Postgres using dd.
If you implemented a C testbed and then proved by experiment that the
shell script got comparable numbers, then I'd believe its results.
Without that confirmation, these are just meaningless numbers.
regards, tom lane
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