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From: Tomas Vondra <tomas.vondra@2ndquadrant.com>
To: Fabien COELHO <coelho@cri.ensmp.fr>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Georgios Kokolatos <gkokolatos@pm.me>
Cc: PostgreSQL Developers <pgsql-hackers@lists.postgresql.org>
Subject: Re: CPU costs of random_zipfian in pgbench
Date: Sun, 24 Mar 2019 04:06:08 +0100
Message-ID: <7fe3b752-e204-6735-e6ef-2c54b56b024d@2ndquadrant.com> (raw)
In-Reply-To: <alpine.DEB.2.21.1903231944420.18811@lancre>
References: <b5e172e9-ad22-48a3-86a3-589afa20e8f7@2ndquadrant.com>
	<alpine.DEB.2.21.1902221716430.4182@lancre>
	<155246731010.16480.15850913449923768119.pgcf@coridan.postgresql.org>
	<alpine.DEB.2.21.1903131048290.4059@lancre>
	<3703.1553360483@sss.pgh.pa.us>
	<alpine.DEB.2.21.1903231802440.18811@lancre>
	<alpine.DEB.2.21.1903231910020.18811@lancre>
	<alpine.DEB.2.21.1903231944420.18811@lancre>



On 3/23/19 7:45 PM, Fabien COELHO wrote:
> 
>>>> What is the point of that, and if there is a point, why is it nowhere
>>>> mentioned in pgbench.sgml?
>>
>> The attached patch simplifies the code by erroring on cache overflow,
>> instead of the LRU replacement strategy and unhelpful final report.
>> The above lines are removed.
> 

Eh? Do I understand correctly that pgbench might start failing after
some random amount of time, instead of reporting the overflow at the
end? I'm not sure that's really an improvement ...

Why is the cache fixed-size at all?

regards

-- 
Tomas Vondra                  http://www.2ndQuadrant.com
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services




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