threads in mapserv

[tim]

On Thu, 2006-03-02 at 22:28 -0800, Paul Ramsey wrote:
> Tim,
> FastCGI does not require thread-safety.  You will find your SDE tests  
> work much much better with fcgi: in fact, the fcgi support got  
> finished precisely because of an SDE contract we were working on that  
> needed to get decent performance.  Don't forget to defer connection  
> closing in your map file, otherwise you'll get no benefit from the  
> fcgi connection pool.  

Thanks Paul, that's just what I needed to hear!

> We found that 2-3 mapserver fcgi processes per  
> CPU was the sweet spot.

Can you elaborate on what you mean here?  Does this mean having more
than 1 instance of apache on each machine or have I missed something?

>   The fcgi module queues up requests if all  
> the child processes are busy, which is actually preferable to running  
> them all concurrently (and making them all finish slower).  It is a  
> nice way to smooth out bursts of load so they don't simply drop the  
> machine to it's knees by firing up 10 concurrent mapservers.
> Paul
> 
Bringing the server to its knees is easy!  We are setting up wms/wfs to
serve data from 15 different govt departments and agencies (for stage 1)
with over 150 data sets.  All we have to do is try and suck the entire
cadastre for Western Australia through wfs and the server can do nothing
else for 5 mins.  We are working on some ideas to try and filter the
requests by data volume rather than bbox size or scale or number of
layers as there can be large discrepancies between rural and urban data
densities.

Regards,
Tim Bowden

> 
> On Mar 2, 2006, at 9:36 PM, tim wrote:
> 
> > anks Frank.  Does 'normal' cgi use include --with-fastcgi?  the
> > mapserver I am building gets almost all its data from a variety of sde
> > servers (think large state govt depts).  In our testing so far (4.6.2
> > and 4.8.1) we keep hitting the limit of sde's connections before we  
> > hit
> > mapservers limits (though we do have good hardware: Dell 3ghz dual  
> > xeons
> > with 4gb ram), hence our decision to re-do testing with fastcgi.
> >
> > Thanks,
> > Tim
> > -- 
> > Mapforge Geospatial
> > Level 3/ 267 St Georges Tce
> > Perth 6000
> > Western Australia
-- 
Mapforge Geospatial
Level 3/ 267 St Georges Tce
Perth 6000
Western Australia