From: Greg Smith <greg@2ndquadrant.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Stephen Frost <sfrost@snowman.net>
Cc: Euler Taveira de Oliveira <euler@timbira.com>
Cc: Pgsql Hackers <pgsql-hackers@postgresql.org>
Subject: Re: [PERFORM] pgbench to the MAXINT
Date: Wed, 16 Feb 2011 08:15:41 -0500
Message-ID: <4D5BCDFD.2010703@2ndquadrant.com> (raw)
In-Reply-To: <12987.1297394318@sss.pgh.pa.us>
References: <4D27C4E5.5000609@2ndquadrant.com>
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<4D5017DE.90404@2ndquadrant.com>
<4D525281.1000201@2ndquadrant.com>
<20110209194008.GX4116@tamriel.snowman.net>
<4D549E92.4010709@2ndquadrant.com>
<12987.1297394318@sss.pgh.pa.us>
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
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To: pgsql-performance@postgresql.org
Cc: greg@2ndquadrant.com, tgl@sss.pgh.pa.us, sfrost@snowman.net, euler@timbira.com, pgsql-hackers@postgresql.org
Subject: Re: [PERFORM] pgbench to the MAXINT
In-Reply-To: <4D5BCDFD.2010703@2ndquadrant.com>
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