[Qgis-developer] qgis-server will crash on a specific project

[Marco Hugentobler]

>char* maxLayerEnv = getenv( "MAX_CACHE_LAYERS" )

This is a short-time workaround for users.

Regards,
Marco

On 22.06.2014 12:12, Andrea Peri wrote:
> Hi,
> thx for response.
>
> meanwhile,
> I notice that the max allowed layers is exactly 101.
> This mean (knowing C/C++) an array of 100 elements.
>
> Searching for this particular value,
> i find in the file "mapserver/qgsmslayercache.cpp"
> is defined
>          mDefaultMaxLayers = 100;
>
> if not defined the environment variable "MAX_CACHE_LAYERS"
>
> char* maxLayerEnv = getenv( "MAX_CACHE_LAYERS" );
>    if ( maxLayerEnv )
>
>
> So a possible solution could be to set this environment variable.
>
> I try and report.
>
> Regards,
>
> Andrea.
>
>
> 2014-06-22 12:07 GMT+02:00 Marco Hugentobler <marco.hugentobler at sourcepole.ch>:
>> It is a problem with the layer cache. Will provide a fix for that soon.
>>
>> Regards,
>> Marco
>>
>>
>> On 22.06.2014 11:49, Andrea Peri wrote:
>>> Hi,
>>>
>>> I confirm.
>>>
>>> There is a layer limit in QGIS-Server
>>>
>>> I do a huge test removing one by one all the layers from my project.
>>> And after the removing of every single layer I retest the working.
>>>
>>> Aftr a while of time. I reach the limit.
>>>
>>> And the project begin to run.
>>>
>>> I do other test to exclude that was the number of layer inside a single
>>> group.
>>> All the test give the response that seem to be the max number of
>>> layers in a project.
>>>
>>> So the question is:
>>>
>>> QGIS desktop allow to put more layers rather than how many are
>>> accepted from qgis-server.
>>>
>>> This not good for a WYSIWYG system.
>>>
>>> Ok, I will try to patch my server when found exactly where is the problem.
>>>
>>> Meanwhile,
>>> Now the question is on what structure is this limit ?
>>>
>>> I don't guess it is simply a layer limit but perhaps a more specific
>>> structure.
>>>
>>> Now I have a project that crash , and a project with a one less layer that
>>> work.
>>>
>>>
>>> Doing a DIFF beetween the two projects I see the possible structure
>>> breakable are:
>>>
>>> layer-tree-canvas -> custom-order -> item
>>> maplayer
>>> Digitizing -> LayerSnappingList -> value   (type QStringList)
>>> Digitizing -> LayerSnappingEnabledList -> value   (type QStringList)
>>> Digitizing -> LayerSnapToList -> value   (type QStringList)
>>> Digitizing -> LayerSnappingToleranceList -> value   (type QStringList)
>>>
>>> I check if in the code there is a limited array dimension for this
>>> objects.
>>>
>>> Regards,
>>>
>>> Andrea.
>>>
>>>
>>> 2014-06-22 7:29 GMT+02:00 Andrea Peri <aperi2007 at gmail.com>:
>>>> Hi,
>>>>
>>>> I do some other tests.
>>>>
>>>> I take my project that give QG crash and split it in two compementary
>>>> projects.
>>>> Of course I do this using qgis desktop to avoid unvolontary errors.
>>>>
>>>> Testing both of them on QS there is no crash !
>>>>
>>>> So:
>>>> The first plausible theory I can give is that Qgis-Server has a LIMIT
>>>> to the number of Groups or Layers it can have in a project.
>>>> A limit different (and less) than qgis desktop (osgeo4w version).
>>>>
>>>> Is this a plausible theory ?
>>>>
>>>> Thx,
>>>>
>>>> Andrea.
>>>>
>>>>
>>>> 2014-06-21 22:04 GMT+02:00 Andrea Peri <aperi2007 at gmail.com>:
>>>>> Hi,
>>>>> I have a qgis-server that will crash on a specific project.
>>>>>
>>>>> The qgis-server will run correctly with another project that seem
>>>>> almost similar (both use the SVG symbols).
>>>>>
>>>>> The project that crash my QG  run correctly and smootly on a qgis
>>>>> desktop (qgis-dev) on a windows system.
>>>>> The project use SVG symbols, but also the other project I test on
>>>>> QSused SVG symbol
>>>>> so I suppose the SVG engine is ok.
>>>>> Also I check t have set correctly the SVG paths.
>>>>> Also I update to the very last (about 4 hours ago) master version.
>>>>>
>>>>> After all this check the qgis-server still crash.
>>>>>
>>>>> So I try to set the logfile, but the log is always empty.
>>>>> This mean that the cgi qgis-server will crash almost immediatly.
>>>>>
>>>>> So I set an environment shell to run it manually and to test the cgi
>>>>> with a gdb session.
>>>>>
>>>>> The results are this:
>>>>>
>>>>> ..................
>>>>> [Thread debugging using libthread_db enabled]
>>>>> Using host libthread_db library
>>>>> "/lib/x86_64-linux-gnu/libthread_db.so.1".
>>>>> Warning 1: Unable to find driver ECW to unload from GDAL_SKIP
>>>>> environment variable.
>>>>> Warning 1: Unable to find driver ECW to unload from GDAL_SKIP
>>>>> environment variable.
>>>>> Warning 1: Unable to find driver JP2ECW to unload from GDAL_SKIP
>>>>> environment variable.
>>>>> Warning 1: Unable to find driver ECW to unload from GDAL_SKIP
>>>>> environment variable.
>>>>> Warning 1: Unable to find driver JP2ECW to unload from GDAL_SKIP
>>>>> environment variable.
>>>>> [New Thread 0x7fffe307c700 (LWP 1844)]
>>>>> [New Thread 0x7fffe27ea700 (LWP 1845)]
>>>>>
>>>>> Program received signal SIGSEGV, Segmentation fault.
>>>>> 0x00007ffff4fc06da in qHash(QString const&) ()
>>>>>      from /usr/lib/x86_64-linux-gnu/libQtCore.so.4
>>>>> (gdb)
>>>>> ............................
>>>>>
>>>>> The version of libQtCore.so.4 I run on the linux is 4.8.2.
>>>>>
>>>>> Perhaps the 4.8.2 is too old for qgis-server ?
>>>>> :/
>>>>> But another project will run without any apparent problem.
>>>>> ?
>>>>>
>>>>> Many thx for every hint.
>>>>>
>>>>> --
>>>>> -----------------
>>>>> Andrea Peri
>>>>> . . . . . . . . .
>>>>> qwerty àèìòù
>>>>> -----------------
>>>>
>>>>
>>>> --
>>>> -----------------
>>>> Andrea Peri
>>>> . . . . . . . . .
>>>> qwerty àèìòù
>>>> -----------------
>>>
>>>
>>
>> --
>> Dr. Marco Hugentobler
>> Sourcepole -  Linux & Open Source Solutions
>> Weberstrasse 5, CH-8004 Zürich, Switzerland
>> marco.hugentobler at sourcepole.ch http://www.sourcepole.ch
>> Technical Advisor QGIS Project Steering Committee
>>
>> _______________________________________________
>> Qgis-developer mailing list
>> Qgis-developer at lists.osgeo.org
>> http://lists.osgeo.org/mailman/listinfo/qgis-developer
>
>


-- 
Dr. Marco Hugentobler
Sourcepole -  Linux & Open Source Solutions
Weberstrasse 5, CH-8004 Zürich, Switzerland
marco.hugentobler at sourcepole.ch http://www.sourcepole.ch
Technical Advisor QGIS Project Steering Committee