| From: | Claudio Freire <klaussfreire(at)gmail(dot)com> |
|---|---|
| To: | Metin Doslu <metin(at)citusdata(dot)com> |
| Cc: | Amit Kapila <amit(dot)kapila16(at)gmail(dot)com>, pgsql-hackers <pgsql-hackers(at)postgresql(dot)org>, postgres performance list <pgsql-performance(at)postgresql(dot)org> |
| Subject: | Re: [HACKERS] Parallel Select query performance and shared buffers |
| Date: | 2013-12-04 16:27:10 |
| Message-ID: | CAGTBQpbRNt7oK9Z9dJpN_ChV4TqBZpYD+634Zm1wg4NjC_Zx2w@mail.gmail.com |
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| Lists: | pgsql-hackers pgsql-performance |
On Wed, Dec 4, 2013 at 9:19 AM, Metin Doslu <metin(at)citusdata(dot)com> wrote:
>
> Here are the results of "vmstat 1" while running 8 parallel TPC-H Simple
> (#6) queries: Although there is no need for I/O, "wa" fluctuates between 0
> and 1.
>
> procs -----------memory---------- ---swap-- -----io---- --system--
> -----cpu-----
> r b swpd free buff cache si so bi bo in cs us sy id wa st
> 0 0 0 30093568 84892 38723896 0 0 0 0 22 14 0 0 100 0 0
> 8 1 0 30043056 84892 38723896 0 0 0 0 27080 52708 16 14 70 0 0
> 8 1 0 30006600 84892 38723896 0 0 0 0 44952 118286 43 44 12 1 0
> 8 0 0 29986264 84900 38723896 0 0 0 20 28043 95934 49 42 8 1 0
> 7 0 0 29991976 84900 38723896 0 0 0 0 8308 73641 52 42 6 0 0
> 0 0 0 30091828 84900 38723896 0 0 0 0 3996 30978 23 24 53 0 0
> 0 0 0 30091968 84900 38723896 0 0 0 0 17 23 0 0 100 0 0
Notice the huge %sy
What kind of VM are you using? HVM or paravirtual?
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