[mapserver-users] Java MapScript and Tomcat6 Hanging

[Umberto Nicoletti]

I'm totally clueless as to why it happens. As for the what happens a
trace of the java process with
http://technet.microsoft.com/en-us/sysinternals/bb896645.aspx Procmon
should give us a hint.

Regards,
Umberto


On Thu, Jul 22, 2010 at 4:34 PM, Gilbertson, Paul <paulbe at ceh.ac.uk> wrote:
> I've left it to run for 5 minutes, still no response. Usual response time ~2s and lower. No processor, no drive activity, just hangs.
>
> Regards,
> Paul Gilbertson
>
>
>> -----Original Message-----
>> From: Umberto Nicoletti [mailto:umberto.nicoletti at gmail.com]
>> Sent: 22 July 2010 15:16
>> To: Gilbertson, Paul
>> Subject: Re: [mapserver-users] Java MapScript and Tomcat6 Hanging
>>
>> That's pretty weird...will Tomcat respond eventually or does it stay
>> locked forever? Is cpu or disk usage high while stalled?
>>
>> On Thu, Jul 22, 2010 at 4:07 PM, Gilbertson, Paul <paulbe at ceh.ac.uk>
>> wrote:
>> > Umberto,
>> >
>> > Absolute lock up. Process is running, but never responds to requests.
>> Tomcat creates threads for new requests, and accepts them, they just
>> never return data. Tomcat/JVM never crashes.
>> >
>> > The synchronized keyword was an attempt to fix this, symptoms are the
>> same with or without it.
>> >
>> > Regards,
>> > Paul Gilbertson
>> >
>> >
>> >> -----Original Message-----
>> >> From: Umberto Nicoletti [mailto:umberto.nicoletti at gmail.com]
>> >> Sent: 22 July 2010 15:04
>> >> To: Gilbertson, Paul
>> >> Cc: mapserver-users at lists.osgeo.org
>> >> Subject: Re: [mapserver-users] Java MapScript and Tomcat6 Hanging
>> >>
>> >> Hi Paul,
>> >> please define hang: is it a crash or simply a momentary stall?
>> >>
>> >> In the case it is the latter I see the synchronized keyword in the
>> >> definition of the doLogic method and by looking at the code you have
>> >> posted it seems superflous, but there might be some other code that
>> >> you didn't post that makes it necessary. Anyway I would start
>> looking
>> >> there.
>> >>
>> >> HTH,
>> >> Umberto
>> >>
>> >> On Wed, Jul 21, 2010 at 4:41 PM, Gilbertson, Paul <paulbe at ceh.ac.uk>
>> >> wrote:
>> >> > Good folks,
>> >> >
>> >> > I am somewhat new to MapServer and MapScript, and I'm trying to do
>> a
>> >> few experiments with Java Mapscript in order to scope out
>> MapServer's
>> >> feasibility for a large project.
>> >> >
>> >> > I've downloaded and installed MS4W 3.0 beta 11, and Netbeans 6.9
>> with
>> >> Tomcat 6.0.29 in order to test out Java Mapscript. I created a most
>> >> basic servlet to serve up simple map tiles, and it works for serial
>> >> requests. When I try to serve two requests at the same time Tomcat
>> >> hangs hard.
>> >> >
>> >> > My map file and Java classes are below:
>> >> >
>> >> > MAP
>> >> >  IMAGETYPE      PNG24
>> >> >  NAME           "nbndemo"
>> >> >  STATUS         ON
>> >> >  EXTENT         -12.5 12.5 700000 1300012.5
>> >> >  SIZE           800 800
>> >> >  IMAGECOLOR     226 245 255
>> >> >  CONFIG         "MS_ERRORFILE" "/ms4w/apps/nbndemo/error.txt"
>> >> >  DEBUG          5
>> >> >
>> >> >  PROJECTION
>> >> >    "init=epsg:27700"
>> >> >  END
>> >> >
>> >> >  LAYER
>> >> >    NAME         os250k
>> >> >    STATUS       ON
>> >> >    TILEINDEX    "/OSRasterTiles/os_250k/os250k_tindex_srs.shp"
>> >> >    TILEITEM     "Location"
>> >> >    TYPE         RASTER
>> >> >    OFFSITE      71 74 65
>> >> >
>> >> >    PROJECTION
>> >> >      "init=epsg:27700"
>> >> >    END
>> >> >    EXTENT         -12.5 12.5 700000 1300012.5
>> >> >  END
>> >> > END
>> >> >
>> >> > public class SPRewriter {
>> >> >    public synchronized void doLogic(HttpServletRequest request,
>> >> HttpServletResponse response) throws Exception
>> >> >    {
>> >> >        ServletOutputStream out = response.getOutputStream();
>> >> >        edu.umn.gis.mapscript.mapObj mo = new
>> >> mapObj("/ms4w/apps/nbndemo/mapfiles/test.map");
>> >> >
>> >> >        imageObj image = mo.draw();
>> >> >        response.setContentType(image.getFormat().getMimetype());
>> >> >        out.write(image.getBytes());
>> >> >        image.delete();
>> >> >        mo.delete();
>> >> >    }
>> >> > }
>> >> >
>> >> >    protected void processRequest(HttpServletRequest request,
>> >> HttpServletResponse response) throws ServletException, IOException {
>> >> >        try {
>> >> >            SPRewriter spr = new SPRewriter();
>> >> >            spr.doLogic(request, response);
>> >> >        }  catch (Exception e) {
>> >> >            e.printStackTrace();
>> >> >        }
>> >> >    }
>> >> >
>> >> > Any thoughts why this would hang the moment I try to run parallel
>> >> requests?
>> >> >
>> >> > Regards,
>> >> > Paul Gilbertson
>> >> >
>> >> >
>> >> >
>> >> > --
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>> >> >
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>
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