Re: Postgres performance and the Linux scheduler - Mailing list pgsql-general

From Albe Laurenz
Subject Re: Postgres performance and the Linux scheduler
Date
Msg-id D960CB61B694CF459DCFB4B0128514C2068E5962@exadv11.host.magwien.gv.at
Whole thread Raw
In response to Postgres performance and the Linux scheduler  ("Simon Windsor" <simon.windsor@cornfield.me.uk>)
List pgsql-general
Simon Windsor wrote:
> Can the performance of Postgres be boosted, especially on busy
systems,  using the none default
> DEADLINE Scheduler?

I think that mostly depends on your storage.

I personally have made one experience where (after weeks of trying
everything
else) I changed the scheduler from CFQ to deadline and immediately got
about
four times better performance. The storage in this case was a SAN.

I don't have enough experience, but my guess is that the smarter your
storage
is, the less the kernel should try to optimize I/O. I assume that in my
case
the kernel's optimizations (which try to optimize things for a physical
hard drive)
and the SAN's optimizations got in each other's way.

As I think is the case for all performance questions, there cannot be a
certain
answer -- the best thing is for you to try it out and see if it does
something for you.

Yours,
Laurenz Albe

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