Re: Script to compute random page cost - Mailing list pgsql-hackers

From Tom Lane
Subject Re: Script to compute random page cost
Date
Msg-id 19229.1031666954@sss.pgh.pa.us
Whole thread Raw
In response to Re: Script to compute random page cost  (Bruce Momjian <pgman@candle.pha.pa.us>)
List pgsql-hackers
Bruce Momjian <pgman@candle.pha.pa.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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