| From: | "Kevin Grittner" <Kevin(dot)Grittner(at)wicourts(dot)gov> |
|---|---|
| To: | "fkater(at)googlemail(dot)com" <fkater(at)googlemail(dot)com> |
| Cc: | <pgsql-performance(at)postgresql(dot)org>, "Scott Carey" <scott(at)richrelevance(dot)com> |
| Subject: | Re: Inserting 8MB bytea: just 25% of disk perf used? |
| Date: | 2010-01-19 15:13:51 |
| Message-ID: | 4B5577CF020000250002E746@gw.wicourts.gov |
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| Thread: | |
| Lists: | pgsql-performance |
"fkater(at)googlemail(dot)com" <fkater(at)googlemail(dot)com> wrote:
> Scott Carey:
>
>> You are CPU bound.
>>
>> 30% of 4 cores is greater than 25%. 25% is one core fully
>> used.
>
> I have measured the cores separately. Some of them reached
> 30%. I am not CPU bound here.
If you have numbers like that when running one big query, or a
stream of queries one-at-a-time, you are CPU bound. A single
request only uses one CPU at a time although it could switch among a
number of them, if the OS doesn't make an effort to keep each
process with the same CPU.
-Kevin
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