Messages in this thread | | | Date | Tue, 27 Feb 2007 09:02:12 -0500 | From | Rik van Riel <> | Subject | Re: SMP performance degradation with sysbench |
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J.A. Magallón wrote: > On Mon, 26 Feb 2007 23:31:29 -0500, Rik van Riel <riel@redhat.com> wrote: > >> Hiro Yoshioka wrote:
>>> Another question. When the number of threads exceeds the number of >>> CPU cores, we may get a lot of idle time. Then a workaround of >>> MySQL is that do not creat threads which exceeds the number >>> of CPU cores. Is it right? >> Not really, that would make it impossible for MySQL to >> handle more simultaneous database queries than the system >> has CPUs. >> > > I don't know myqsl internals, but you assume one thread per query. > If its more like Apache, one long living thread for several connections ?
Yes, they are longer lived client connections. One thread per connection, just like Apache.
> Its the same to answer 4+4 queries than 8 at half the speed, isn't it ?
That still doesn't fix the potential Linux problem that this benchmark identified.
To clarify: I don't care as much about MySQL performance as I care about identifying and fixing this potential bug in Linux.
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