[PATCH] Fix drain logic for small number of connections

[Maxim Dounin]

Hello!

On Tue, Jan 17, 2017 at 09:37:58AM -0600, Joel Cunningham wrote:

> Maxim,
> 
> > On Dec 30, 2016, at 8:04 PM, Maxim Dounin <mdounin at mdounin.ru> wrote:
> > 
> > Hello!
> > 
> > On Fri, Dec 30, 2016 at 12:13:01PM -0600, Joel Cunningham wrote:
> > 
> >>> On Dec 29, 2016, at 1:13 PM, Maxim Dounin <mdounin at mdounin.ru> wrote:
> > 
> > [...]
> > 
> >>> I agree though that if connection shortage is occasional the 
> >>> current behaviour might not be optimal with worker_connections set 
> >>> to a small value, or there are only a few connections can be 
> >>> reused.  Instead of gradually reducing keepalive (and post accept) 
> >>> timeout to a smaller value it closes all keepalive connections 
> >>> from time to time.
> >>> 
> >>> Probably optimal solution would be to close no more than some 
> >>> fraction of reusable connections at once.  Patch series below.
> >> 
> >> I tested out the patch series and I did run into a problem.  
> >> Looks like the reusable_connections_n increment and decrement 
> >> are swapped.  The first call to ngx_reusable_connection causes 
> >> unsigned integer wrap around.  I swapped the increment/decrement 
> >> and the patch gives the expected behavior of only freeing 1/8 
> >> (or at least 1) of the reusable connections.
> > 
> > Thanks for noticing this, fixed.
> > 
> 
> Was your patch series going to be comitted?  I didn’t see anything in the commit history yet

It is expected to be committed in a couple of days.

-- 
Maxim Dounin
http://nginx.org/