Re: pgbench internal contention

On Tue, Aug 2, 2011 at 8:44 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> Robert Haas <robertmhaas(at)gmail(dot)com> writes:
>>> If you want erand48_r, best to provide that API, not kluge up some
>>> other functions.
>
>> ...because erand48() is a GNU extension with a stupid API.
>
> I assume you mean erand48_r, there, because erand48 is pretty standard.

Yes.

>> I don't
>> see much value in supporting that, on both counts.  We're going to end
>> up with the built-in erand48_r() on precisely those systems that use
>> glibc, and our own everywhere else.  For the 25 SLOCs it's going cost
>> us, I'd rather use the same code everywhere.
>
> Maybe.  But if that's the approach we want to use, let's just call it
> pg_erand48 in the code, and dispense with the alias macros as well as
> all vestiges of configure support.

Works for me. Just to confirm, that means we'd also change GEQO to
use pg_erand48().

> BTW, as far as the original plan of using random_r is concerned, how
> did you manage to not run into this?
> http://sourceware.org/bugzilla/show_bug.cgi?id=3662
> I just wasted half an hour on that stupidity in an unrelated context...

Good grief. It's hard to imagine a more user-hostile attitude than
the one taken there. I did run into that precise issue, but managed
to stumble on what is apparently the officially sanctioned method of
working around it - viz, zeroing the state array. However, that bug
report is a pretty compelling argument for the position that expecting
any of the GNU blah_r() functions to behave halfway sanely or be
properly documented is a pipe dream.

--
Robert Haas
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