Re: pgsql: Increase upper limit for vacuum_cleanup_index_scale_factor - Mailing list pgsql-committers

From Tom Lane
Subject Re: pgsql: Increase upper limit for vacuum_cleanup_index_scale_factor
Date
Msg-id 22604.1530028829@sss.pgh.pa.us
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In response to Re: pgsql: Increase upper limit for vacuum_cleanup_index_scale_factor  (Alexander Korotkov <a.korotkov@postgrespro.ru>)
Responses Re: pgsql: Increase upper limit for vacuum_cleanup_index_scale_factor  (Alexander Korotkov <a.korotkov@postgrespro.ru>)
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Alexander Korotkov <a.korotkov@postgrespro.ru> writes:
> BTW, this line looks cumbersome.

> +DETAIL:  Valid values are between "0.000000" and
>
"179769313486231570814527423731704356798070567525844996598917476803157260780028538760589558632766878171540458953514382464234321326889464182768467546703537516986049910576551282076245490090389328944075868508455133942304583236903222948165808559332123348274797826204144723168738177180919299881250404026184124858368.000000".

> It's not something introduced by this patch, because other reloptions
> behave the same.  Should we change output format for real reloption
> boundaries to '%g' (as guc.c does).  It looks much better.
> ERROR:  -1 is outside the valid range for parameter "random_page_cost"
> (0 .. 1.79769e+308)

%g, unmodified, is a bad idea because it loses a lot of precision
in some cases (due to the assumption that nobody cares about more
than six digits).  Maybe you could fix that by using %.15g or some
such, but...

I think that the original patch to use DBL_MAX was itself a bad idea
and should be rethought.  It creates (what is in principle) a
platform-dependent limit, for no adequate justification.  Why not
just set it to 1e9 or 1e10 or some such?

            regards, tom lane


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