From: Alvaro Herrera <alvherre@2ndquadrant.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Fabien COELHO <coelho@cri.ensmp.fr>
Cc: Tomas Vondra <tomas.vondra@2ndquadrant.com>
Cc: Georgios Kokolatos <gkokolatos@pm.me>
Cc: PostgreSQL Developers <pgsql-hackers@lists.postgresql.org>
Subject: Re: CPU costs of random_zipfian in pgbench
Date: Mon, 1 Apr 2019 18:51:35 -0300
Message-ID: <20190401215135.GA31141@alvherre.pgsql> (raw)
In-Reply-To: <19055.1554154745@sss.pgh.pa.us>
On 2019-Apr-01, Tom Lane wrote:
> Fabien COELHO <coelho@cri.ensmp.fr> writes:
> >> I was wondering about that too. It seems like it'd be a wise idea to
> >> further constrain s and/or n to ensure that the s > 1 code path doesn't do
> >> anything too awful ...
>
> > Yep. The attached version enforces s >= 1.001, which avoids the worse cost
> > of iterating, according to my small tests.
>
> Seems reasonable. Pushed with minor documentation editing.
Ah, so we now we can get rid of the TState * being passed around
separately for expression execution, too?
--
Álvaro Herrera https://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
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To: pgsql-hackers@postgresql.org
Cc: alvherre@2ndquadrant.com, tgl@sss.pgh.pa.us, coelho@cri.ensmp.fr, tomas.vondra@2ndquadrant.com, gkokolatos@pm.me, pgsql-hackers@lists.postgresql.org
Subject: Re: CPU costs of random_zipfian in pgbench
In-Reply-To: <20190401215135.GA31141@alvherre.pgsql>
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