Mapserver caching and map generation

[Ed McNierney]

Emmanuel -

Each map request generates a unique image, and the URL for that image is
returned to the client browser requesting that image.  Since your Web
server can process several HTTP requests at one time, there can be
several MapServer instances all running at the same time.

There will be some interaction with the disk subsystem on which the
temporary images are written, and from which they are read by the client
browsers.  Some disk systems can handle multiple simultaneous read/write
requests better than others.  Nothing will break - but some disk
subsystems will take longer than others to respond when multiple reads
and writes are happening.

In case you haven't discovered it yet, using MapServer as a WMS server
or in the CGI "mode=map" mode, the output image is written directly to
the client and no temporary files are written to disk.

     - Ed

Ed McNierney
President and Chief Mapmaker
TopoZone.com / Maps a la carte, Inc.
73 Princeton Street, Suite 305
North Chelmsford, MA  01863
ed at topozone.com
(978) 251-4242  

-----Original Message-----
From: UMN MapServer Users List [mailto:MAPSERVER-USERS at LISTS.UMN.EDU] On
Behalf Of Emmanuel BELO
Sent: Wednesday, March 01, 2006 12:26 PM
To: MAPSERVER-USERS at LISTS.UMN.EDU
Subject: [UMN_MAPSERVER-USERS] Mapserver caching and map generation

Hello,

after cleaning the cache, mapserver generates the new images on request.

What happens if 10 users ask for the same map during the generation of
the first map? Are their request delayed or will 10 processes in
parallel be initiated?

Best regards,

Emmanuel BELO
emmanuel.belo at microgis.ch