[mapserver-users] Using Fast CGI with MapServer to alleviate poorperformance

[Paul Ramsey]

Intriguing stuff!

I found this generic-ish article about perl:
http://www.perlmonks.org/?node_id=83791

The implication is that unless/until Mapserver starts sending
Content-Length along with returned images, browsers won't do
keep-alive for us.

More performance!

P.

On Wed, Sep 17, 2008 at 10:26 AM, Jim Klassen
<Jim.Klassen at ci.stpaul.mn.us> wrote:
> I have found there is a fairly large overhead inherent in the HTTP request (per tile) especially if the network round trip times are an issue. Using HTTP keep-alive helped a lot with this.
>
> Awhile ago we did some tests at the city when we were looking to go to a tiled interface. What we found was along the lines of a 100x100px tile request takes much more than 1/4 of the time of a 200x200px request so the overall map load time was slowed by using more tiles when getting the tiles from mapserver. This would probably be different if we had used a tilecache. In the end we found not tiling (a.k.a. 1 tile per map) worked best for us from a speed/flexibility focus.
>
> JimK
>
>>>> "Paul Ramsey" <pramsey at cleverelephant.ca> 09/17/08 11:14 AM >>>
> John,
>
> The idea that CGI is naturally a much slower situation than a
> long-running process is a bit of a red herring in the case of
> Mapserver, and I say that as someone who is anal retentive about these
> things.  Unless your Mapserver installation has some naturally latent
> components (database connections, primarily) you'll find that moving
> from CGI to FastCGI is worth about 15ms per request.
>
> On Wed, Sep 17, 2008 at 8:40 AM, John Westwood <John.Westwood at port.ac.uk> wrote:
>
>> The reason I am trying to get MapServer to work with fast_cgi is because I am experiencing poor performance with OpenLayers. I believe that OpenLayers starts a new MapServer instance for each tile request, thus causing an unnecessary overhead. Am I correct?
>
> Yes and no. If you are experiencing noticeably poor performance (you
> can actually *see* it being slow) the only place that the CGI overhead
> could be the cause is if you're connecting to Oracle or SDE for some
> of your layers. If that's not the case, look elsewhere first, the very
> small gains you will receive from moving to FastCGI will not change
> your underlying problem.
>
> Paul
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