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Re: CPU bound

From: Mladen Gogala <mladen(dot)gogala(at)vmsinfo(dot)com>
To: James Cloos <cloos(at)jhcloos(dot)com>
Cc: Royce Ausburn <royce(at)inomial(dot)com>, "pgsql-performance(at)postgresql(dot)org" <pgsql-performance(at)postgresql(dot)org>
Subject: Re: CPU bound
Date: 2010-12-20 06:47:30
Message-ID: 4D0EFC02.7040004@vmsinfo.com (view raw or flat)
Thread:
Lists: pgsql-performance
On 12/19/2010 7:57 PM, James Cloos wrote:
>>>>>> "RA" == Royce Ausburn<royce(at)inomial(dot)com>  writes:
> RA>  I notice that when restoring a DB on a laptop with an SDD,
> RA>  typically postgres is maxing out a CPU - even during a COPY.
>
> The time the CPUs spend waiting on system RAM shows up as CPU
> time, not as Wait time.  It could be just that the SSD is fast
> enough that the RAM is now the bottleneck, although parsing
> and text<=>binary conversions (especially for integers, reals
> and anything stored as an integer) also can be CPU-intensive.
>
> -JimC

Good time accounting is the most compelling reason for having a wait 
event interface, like Oracle. Without the wait event interface, one 
cannot really tell where the time is spent, at least not without 
profiling the database code, which is not an option for a production 
database.

-- 
Mladen Gogala
Sr. Oracle DBA
1500 Broadway
New York, NY 10036
(212) 329-5251
www.vmsinfo.com


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