From: Bruce Momjian <bruce@momjian.us>
To: Aleksey Tsalolikhin <atsaloli.tech@gmail.com>
Cc: pgsql-docs@postgresql.org
Subject: Re: what is a "working set" ?
Date: Mon, 23 Apr 2012 19:48:50 -0400
Message-ID: <20120423234850.GA22081@momjian.us> (raw)
In-Reply-To: <CA+jMWofRNWaOX0W3p_X_wsX+dUgDTsUPWbR3st8unSSmzqOLJg@mail.gmail.com>
References: <CA+jMWofRNWaOX0W3p_X_wsX+dUgDTsUPWbR3st8unSSmzqOLJg@mail.gmail.com>
On Mon, Apr 23, 2012 at 04:43:25PM -0700, Aleksey Tsalolikhin wrote:
> Hi. I'm trying to find a definition of "working set", it seems
> important for performance tuning, but I cannot find a PostgreSQL
> document defining it.
That is a great question, and I plan to write a blog about it soon.
Working set is from the mainframe days and tries to represent how much
data you "touch" during a specified period of time, e.g. a 5-minute
working set is the amount of data you typically access (and maybe write)
in a 5-minute period. It is _very_ hard to get that information right
now from Postgres, and getting that information for a typical Unix
process isn't easy either.
--
Bruce Momjian <bruce@momjian.us> http://momjian.us
EnterpriseDB http://enterprisedb.com
+ It's impossible for everything to be true. +
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To: pgsql-docs@postgresql.org
Cc: bruce@momjian.us, atsaloli.tech@gmail.com
Subject: Re: what is a "working set" ?
In-Reply-To: <20120423234850.GA22081@momjian.us>
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