Re: [PERFORM] pgbench to the MAXINT

Tom Lane <tgl@sss.pgh.pa.us>

From: Tom Lane <tgl@sss.pgh.pa.us>
To: Greg Smith <greg@2ndquadrant.com>
Cc: Stephen Frost <sfrost@snowman.net>, Euler Taveira de Oliveira <euler@timbira.com>, Pgsql Hackers <pgsql-hackers@postgresql.org>
Date: 2011-02-11T03:18:38Z
Lists: pgsql-hackers, pgsql-performance
Greg Smith <greg@2ndquadrant.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