Re: Making hash indexes worthwhile - Mailing list pgsql-hackers

From Tom Lane
Subject Re: Making hash indexes worthwhile
Date
Msg-id 6429.1254750583@sss.pgh.pa.us
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In response to Re: Making hash indexes worthwhile  (Jeff Janes <jeff.janes@gmail.com>)
Responses Re: Making hash indexes worthwhile
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Jeff Janes <jeff.janes@gmail.com> writes:
> Do you know why that should be?  I've done some work with gprof, and
> the results are pretty suspect, because the total gprof time adds up
> to only about 1/3 of the total time the backend spends on CPU
> (according to "top"), and I don't know where the unaccounted for time
> is going.

Are you sure that gprof is delivering trustworthy numbers at all?
I've seen cases where it was consistently mis-timing things.
https://bugzilla.redhat.com/show_bug.cgi?id=151763
Admittedly that was an old Linux version, but ...
        regards, tom lane


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