Re: Can PostgreSQL create new WAL files instead of reusing old ones?

On Wed, Jun 20, 2018 at 10:35 AM, Jerry Jelinek <jerry(dot)jelinek(at)joyent(dot)com>
wrote:

> As Dave described in his original email on this topic, we'd like to avoid
> recycling WAL files since that can cause performance issues when we have a
> read-modify-write on a file that has dropped out of the cache.
>
> I have implemented a small change to allow WAL recycling to be disabled.
> It is visible at:
> https://cr.joyent.us/#/c/4263/
>
> I'd appreciate getting any feedback on this.
>
> Thanks,
> Jerry
>
>

For reference, there's more context in this thread from several months ago:
https://www.postgresql.org/message-id/flat/CACukRjO7DJvub8e2AijOayj8BfKK3XXBTwu3KKARiTr67M3E3w%40mail(dot)gmail(dot)com#CACukRjO7DJvub8e2AijOayj8BfKK3XXBTwu3KKARiTr67M3E3w(at)mail(dot)gmail(dot)com

I'll repeat the relevant summary here:

tl;dr: We've found that under many conditions, PostgreSQL's re-use of old
> WAL files appears to significantly degrade query latency on ZFS. The
> reason is
> complicated and I have details below. Has it been considered to make this
> behavior tunable, to cause PostgreSQL to always create new WAL files
> instead of re-using old ones?

Thanks,
Dave