| From: | Laurenz Albe <laurenz(dot)albe(at)cybertec(dot)at> |
|---|---|
| To: | Subhrajyoti Senapati <ssubhrajyoti(at)google(dot)com>, pgsql-general(at)lists(dot)postgresql(dot)org |
| Subject: | Re: Sysbench tests on PG12 |
| Date: | 2021-10-01 11:49:19 |
| Message-ID: | d9be2f9b77f69aad81d845c50badbe6abe059e8e.camel@cybertec.at |
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| Lists: | pgsql-general |
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
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