From: Stephen Frost <sfrost@snowman.net>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Greg Smith <greg@2ndquadrant.com>
Cc: Euler Taveira de Oliveira <euler@timbira.com>
Cc: Pgsql Hackers <pgsql-hackers@postgresql.org>
Subject: Re: [PERFORM] pgbench to the MAXINT
Date: Fri, 11 Feb 2011 08:35:51 -0500
Message-ID: <20110211133551.GE4116@tamriel.snowman.net> (raw)
In-Reply-To: <12987.1297394318@sss.pgh.pa.us>
References: <4D27C4E5.5000609@2ndquadrant.com>
<4D2A965A.3000603@timbira.com>
<4D2AC273.3010709@2ndquadrant.com>
<4D2CCCD9.802@timbira.com>
<4D35DF33.6060901@2ndquadrant.com>
<4D5017DE.90404@2ndquadrant.com>
<4D525281.1000201@2ndquadrant.com>
<20110209194008.GX4116@tamriel.snowman.net>
<4D549E92.4010709@2ndquadrant.com>
<12987.1297394318@sss.pgh.pa.us>
Greg,
* Tom Lane (tgl@sss.pgh.pa.us) wrote:
> 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).
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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To: pgsql-performance@postgresql.org
Cc: sfrost@snowman.net, tgl@sss.pgh.pa.us, greg@2ndquadrant.com, euler@timbira.com, pgsql-hackers@postgresql.org
Subject: Re: [PERFORM] pgbench to the MAXINT
In-Reply-To: <20110211133551.GE4116@tamriel.snowman.net>
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