Nginx double requests for my upstreams?

[Maxim Dounin]

Hello!

On Sun, Jun 07, 2009 at 03:35:41PM -0400, funkdoobiest wrote:

> Hi Maxim,
> 
> Maxim Dounin Wrote:
> -------------------------------------------------------
> > Hello!
> > 
> > On Fri, Jun 05, 2009 at 07:59:13AM -0400,
> > funkdoobiest wrote:
> > 
> > > Hi,
> > > 
> > > I have a strange behavior for my site load
> > balanced with nginx.
> > > I have 1 Loadbalancer with nginx and 3 servers
> > with apache.
> > > 
> > > sometimes a request  is doubled and send to 2 of
> > my apache webservers.
> > > this is a big problem for me, because this is
> > sometimes a requests that is doing a payement.
> > > I checked this behavior with doing a log of all
> > my payment transactions and there a some
> > transactions
> > > for the same person double at the same second!
> > (the user can't do this at the website, because I
> > send the form which is doing the request with JS
> > and ask the User if he really wants to pay and so
> > on)
> > 
> > http://wiki.nginx.org/NginxHttpProxyModule#proxy_n
> > ext_upstream
> > 
> > Maxim Dounin
> 
> Thank you for your help. I set proxy_next_upstream to off, but there are still double requests :-(

It doesn't looks like nginx problem.  Try checking logs (frontend 
and backend ones) - probably your javascript code just does 
something wrong.

Maxim Dounin