[mapserver-dev] Mapserver issues with POST requests

[Jeff McKenna]

I'm curious also if you'd have the same issue with Apache (I know for 
MS4W builds, I've been using mod_fcgid for several years now 
successfully: http://httpd.apache.org/mod_fcgid/).

-jeff


-- 
Jeff McKenna
MapServer Consulting and Training Services
http://www.gatewaygeomatics.com/



On 2014-08-04 2:51 PM, Michel.Dastous at bentley.com wrote:
> All,
>
> Over the past few months we have been experiencing stability issue with
> our MapServer 6.4.1 windows builds running under IIS 7.5 (configured as
> FastCGI module).
>
> We discovered that IIS was restarting mapserv.exe instance after each
> request containing a POST body.    After investigation, I have found
> that other projects using libfcgi were suffering from the exact same
> behavior.  The problem is well documented on
> http://forums.iis.net/t/1150498.aspx?FastCGI+Error+Number+233+for+Ruby+on+Rails+Configuration
> and http://www.perlmonks.org/?node_id=862506.
>
> As suggested in the forum threads, I have applied the libfcgi patch
> available at:
> http://git.shadowcat.co.uk/gitweb/gitweb.cgi?p=catagits/fcgi2.git;a=commitdiff;h=c4d74207308dfafa652925306c6b2828843e0e97
>
> Once the patch applied,  Mapserv.exe was able to serve more than one
> request  before being recycled.  However, after performing stress tests
> with JMeter we were still getting an  error rate of ~10%.    So even
> with the libfcgi patch applied,  we keep having issues with POST requests.
>
> The problem is difficult to reproduce, but at some point Mapserver.exe
> instances start hanging and the instance finally get killed by IIS.  I’m
> convinced that issue is caused by a bad libfcgi communication/behavior:
> each time the process hang, the application seems to be blocked on a
> FCGI_Accept call, which let us think the Mapserver’s core code is not
> the root of the problem.
>
> Looking at libfcgi website, I can see that version is 2.4.6 and have not
> been updated since 2007 and their mailing list seems to be dead, so it
> looks like it will be very difficult to get support from that project.
>
> I’m interested in your thoughts and suggestion about this.
>
> thanks,
>
> Michel D’Astous