Message-ID: <4D5BCDFD.2010703@2ndquadrant.com>
Date: Wed, 16 Feb 2011 08:15:41 -0500
From: Greg Smith <greg@2ndquadrant.com>
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To: Tom Lane <tgl@sss.pgh.pa.us>
CC: Stephen Frost <sfrost@snowman.net>,
	Euler Taveira de Oliveira <euler@timbira.com>,
	Pgsql Hackers <pgsql-hackers@postgresql.org>
Subject: Re: [PERFORM] pgbench to the MAXINT
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	<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>
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Tom Lane wrote:
> 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).
>   

Given that pgbench will run with threads in some multi-worker 
configurations, after some more portability research I think odds are 
good we'd get nailed by 
http://sourceware.org/bugzilla/show_bug.cgi?id=10320 : "erand48 
implementation not thread safe but POSIX says it should be".  The AIX 
docs have a similar warning on them, so who knows how many versions of 
that library have the same issue.

Maybe we could make sure the one in src/port/ is thread safe and make 
sure pgbench only uses it.  This whole area continues to be messy enough 
that I think the patch needs to brew for another CF before it will all 
be sorted out properly.  I'll mark it accordingly and can pick this back 
up later.

-- 
Greg Smith   2ndQuadrant US    greg@2ndQuadrant.com   Baltimore, MD