Re: Priorities for users or queries?

Hard to argue with that.

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Ron Mayer wrote:
> Magnus Hagander wrote:
> > Most likely, you do not want to do this. You *can* do it, but you are
> > quite likely to suffer from priority inversion
>
> Papers I've read suggest that the benefits of priorities
> vastly outweigh the penalties of priority inversion for
> virtually all workloads on most all RDBMs's including
> PostgreSQL.
>
> This CMU paper in particular tested PostgreSQL (and DB2)
> on TPC-C and TPC-W workloads and found that indirectly
> influencing I/O scheduling through CPU priorities
> is a big win for postgresql.
>
> http://www.cs.cmu.edu/~bianca/icde04.pdf
>
> "For TPC-C running on PostgreSQL,
>  the simplest CPU scheduling policy (CPU-Prio) provides
>  a factor of 2 improvement for high-priority transactions,
>  while adding priority  inheritance (CPU-Prio-Inherit)
>  provides a factor of 6 improvement while hardly
>  penalizing low-priority transactions."
>
>
> Have you heard of any workload on any RDBMS where priority inversion
> causes more harm than benefit?
>
>     Ron Mayer
>
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  Bruce Momjian  <bruce@momjian.us>          http://momjian.us
  EnterpriseDB                               http://www.enterprisedb.com

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