Re: High context switches occurring

From: Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: Anjan Dave <adave(at)vantage(dot)com>, Vivek Khera <vivek(at)khera(dot)org>, Postgresql Performance <pgsql-performance(at)postgresql(dot)org>
Subject: Re: High context switches occurring
Date: 2005-12-07 04:34:04
Message-ID: 200512070434.jB74Y4o20004@candle.pha.pa.us
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Tom Lane wrote:
> "Anjan Dave" <adave(at)vantage(dot)com> writes:
> > -bash-3.00$ time pgbench -c 1000 -t 30 pgbench
> > starting vacuum...end.
> > transaction type: TPC-B (sort of)
> > scaling factor: 1
> > number of clients: 1000
> > number of transactions per client: 30
> > number of transactions actually processed: 30000/30000
> > tps = 45.871234 (including connections establishing)
> > tps = 46.092629 (excluding connections establishing)
>
> I can hardly think of a worse way to run pgbench :-(. These numbers are
> about meaningless, for two reasons:
>
> 1. You don't want number of clients (-c) much higher than scaling factor
> (-s in the initialization step). The number of rows in the "branches"
> table will equal -s, and since every transaction updates one

Should we throw a warning when someone runs the test this way?

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