Re: [PERFORM] pgbench to the MAXINT

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Greg Smith <greg(at)2ndquadrant(dot)com>
Cc: Stephen Frost <sfrost(at)snowman(dot)net>, 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 03:18:38
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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).

regards, tom lane

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