From: Brian Hurt <bhurt@janestcapital.com>
To: pgsql-performance@postgresql.org
Subject: Re: RES: Priority to a mission critical transaction
Date: Wed, 29 Nov 2006 08:25:57 -0500
Message-ID: <456D8A65.3080400@janestcapital.com> (raw)
In-Reply-To: <456CE066.50803@cheapcomplexdevices.com>
References: <4939.1164740825@sss.pgh.pa.us>
<200611282344.kASNijt09203@momjian.us>
<456CE066.50803@cheapcomplexdevices.com>
Ron Mayer wrote:
>Before asking them to remove it, are we sure priority inversion
>is really a problem?
>
>I thought this paper: http://www.cs.cmu.edu/~bianca/icde04.pdf
>did a pretty good job at studying priority inversion on RDBMs's
>including PostgreSQL on various workloads (TCP-W and TCP-C) and
>found that the benefits of setting priorities vastly outweighed
>the penalties of priority inversion across all the databases and
>all the workloads they tested.
>
>
>
I have the same question. I've done some embedded real-time
programming, so my innate reaction to priority inversions is that
they're evil. But, especially given priority inheritance, is there any
situation where priority inversion provides *worse* performance than
running everything at the same priority? I can easily come up with
situations where it devolves to that case- where all processes get
promoted to the same high priority. But I can't think of one where
using priorities makes things worse, and I can think of plenty where it
makes things better.
Brian
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To: pgsql-performance@postgresql.org
Cc: bhurt@janestcapital.com
Subject: Re: RES: Priority to a mission critical transaction
In-Reply-To: <456D8A65.3080400@janestcapital.com>
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