AW: [mapserver-users] MapServer and fastcgi-benefits?

[Eichner, Andreas - SID-NLK]

Hello Kai,

fast-cgi is intented to make the handling of _multiple_ requests faster. A normal CGI call involves several steps for every request, mainly
  + do a fork()
  + seed all intended variables into the environment
  + prepare stdin to point to a buffer (or directly to the network socket)
  + exec() the CGI script
  + clean up after all that

Normally this is time consuming so fast-cgi tries to accomplish that by giving a CGI program the possibility to not only handle a single request but to run into a request-handling loop to handle multiple requests. So setup/cleanup time is consumed only once for all those request.
The problem is that "mapserv" opens and parses the mapfile for every request from the ground up which introduces a lot of overhead...

AFAIK, for shapefiles the processing directive "CLOSE_CONNECTION" is simply ignored or has at least no singificant effect. It is intended for databases where the cost for establishing a connection over a network _is_ significant compared to the time required for a query.

You may want to read the "Optimizing raster/vector data sources" howtos from the mapserver website to optimize your data.


Good luck!

-----Ursprüngliche Nachricht-----
Von: mapserver-users-bounces at lists.osgeo.org [mailto:mapserver-users-bounces at lists.osgeo.org] Im Auftrag von Kai Behncke
Gesendet: Montag, 17. März 2008 22:49
An: mapserver-users at lists.osgeo.org
Betreff: [mapserver-users] MapServer and fastcgi-benefits?

Hello list,

I`m testing MapServer with fast-cgi to see if there`s a benefit in performance.

I succesfully compiled MapServer with fast-cgi, in my Apache 2.2 at Debian Etch the mod_fastcgi is activated, the httpd.conf has the needed entries and in my mapfile I set 
PROCESSING "CLOSE_CONNECTION=DEFER"
to a very "expensive" Layer (the data are shapefiles).

But if I check the performance with "siege"
(siege -c 4 -r 10 http://localhost/cgi-bin/mapserv?map=/var/www/wms_ogc/wms_server.map)
I don`t see any performance benefits in comparison to MapServer without fastcgi??

Am I do something wrong??
What is the benefit of fast-cgi?
Should`t it be faster than "normal"-cgi?

Thank you very much in advance, Kai
-- 
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