Re: Sysbench tests on PG12

Thanks Laurenz, will try these flags.

Regards,
Subhrajyoti

On Fri, Oct 1, 2021 at 5:19 PM Laurenz Albe <laurenz(dot)albe(at)cybertec(dot)at>
wrote:

> On Fri, 2021-10-01 at 14:22 +0530, Subhrajyoti Senapati wrote:
> > Was running a few sysbench tests in Postgres12.
> > Sysbench Test Config
> > oltp-readwrite-custom
> > Threads - 500
> > Machine: 16 core 64G
> >
> > In PG server:
> > shared_buffers: 16GB
> > maintenance_work_memory: 16GB
> > checkpoint_timeout: 1h
> > max_wal_size: 10GB
> > wal_sync_method: 'open_sync'
> > effective_cache_size: 32GB
> > wal_buffers: -1
> > wal_compression: on
> >
> > Got some qps dips.
> >
> > Changed fsync and full_page_rewrite to 'off'.
> > Which helped in avoiding these many long dips in performance:
> >
> > But fsync ensures DBMS consistency. So, instead of that can I change a
> few other configurations to avoid these inconsistent performance dips ?
>
> Try playing with "bgwriter_flush_after", "checkpoint_flush_after" and
> "wal_writer_flush_after"
> and see if that influences the behavior.
>
> Yours,
> Laurenz Albe
> --
> Cybertec | https://www.cybertec-postgresql.com
>
>