Re: Renice on Postgresql process

On 2018-05-07 11:04:31 -0700, Ben Chobot wrote:
> On May 7, 2018, at 7:46 AM, Ayappan P2 <ayappap2(at)in(dot)ibm(dot)com> wrote:
> We are using Postgresql in AIX. Unlike some other databases, Postgresql has
> lot of other process running in the background along with the main process.
>
> We do "renice" only on the Postgres main process. Is it sufficient to have
> higher priority only for the main process or we have to do "renice" for all
> the Postgresql related process ( like wal writer, logger , checkpointer
> etc.,) ?
>
>
> What do you hope to achieve with your renicing? There is a compelling school of
> thought which holds that nice database processes take longer to relinquish
> their resources, which doesn't end up helping anything at all.

I think you misunderstood Ayappan. He doesn't want to make the database
processes nicer, he wants to make them less nice ("higher priority").

So in theory, they should be able to complete requests faster because
they aren't interrupted by other processes so often.

Whether that is true, depends on whether the processes are cpu or disk
bound and what exactly the "nice value" affects. The best way to find
out is probably to try it.

hp

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