Re: [PERFORM] pgbench to the MAXINT

From: Stephen Frost <sfrost(at)snowman(dot)net>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: Greg Smith <greg(at)2ndquadrant(dot)com>, Euler Taveira de Oliveira <euler(at)timbira(dot)com>, Pgsql Hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: [PERFORM] pgbench to the MAXINT
Date: 2011-02-11 13:35:51
Message-ID: 20110211133551.GE4116@tamriel.snowman.net
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Greg,

* Tom Lane (tgl(at)sss(dot)pgh(dot)pa(dot)us) wrote:
> Greg Smith <greg(at)2ndquadrant(dot)com> writes:
> > Poking around a bit more, I just discovered another possible approach is
> > to use erand48 instead of rand in pgbench, which is either provided by
> > the OS or emulated in src/port/erand48.c That's way more resolution
> > than needed here, given that 2^48 pgbench accounts would be a scale of
> > 2.8M, which makes for a database of about 42 petabytes.
>
> I think that might be a good idea --- it'd reduce the cross-platform
> variability of the results quite a bit, I suspect. random() is not
> to be trusted everywhere, but I think erand48 is pretty much the same
> wherever it exists at all (and src/port/ provides it elsewhere).

Works for me. Greg, will you be able to work on this change? If not, I
might be able to.

Thanks,

Stephen

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