proxy_cache_background_update leads to 200 ms delay

[Valentin V. Bartenev]

On Friday, 6 July 2018 15:32:07 MSK stephan13360 wrote:
> I recently set proxy_cache_valid 200 to 1 second, down from 15 minutes to
> refresh the content more often (With proxy_cache_background_update on;
> already activated long before that).
> Our Web monitoring, checking our site every minute, showed an increase in
> response time following this change.
> 
> After some investigating I pinned it down to a ~200 ms delay coming from
> using proxy_cache_background_update.
> 
[..]

I assume you have tcp_nopush directive enabled, then please try switching it off.

  wbr, Valentin V. Bartenev