[mapserver-dev] python mapscript and msCleanup issues

[Umberto Nicoletti]

I have pushed a modified version of mapserver to:

https://github.com/unicolet/mapserver/tree/WxS_threadsafety

could you give it a try?

Regards,
Umberto

On Tue, Jul 3, 2012 at 7:25 AM, Umberto Nicoletti <
umberto.nicoletti at gmail.com> wrote:

>
>
> On Monday, July 2, 2012, Stephan Meißl wrote:
>
>> Hi Umberto,
>>
>> many thanks for your help. I tried both suggestions but without an
>> optimal result.
>>
>> Using msIO_resetHandlers() instead of msCleanup() gives me, after using
>> a fairly big amount of memory, quite strange results. In fact sometimes
>> results from previous requests are present in responses. It seems, that
>> not everything gets cleared. Any suggestion how to investigate this?
>
>
> msIO_resetHandlers should probably be invoked after the response has been
> commited, could you take a look at this page:
>
> http://code.google.com/p/modwsgi/wiki/RegisteringCleanupCode
>
> and implement the cleanup hook as described?
>
>
>>
>> Using msIO_getStdoutBufferString() seems to work for text responses only
>> but not for images.
>>
>> Thanks,
>> Stephan
>>
>>
>> On Sun, 2012-07-01 at 12:06 +0200, Umberto Nicoletti wrote:
>> > Before we turn on debugging mode let's try a couple of simple changes
>> > to your script:
>> >
>> >
>> > http://pastebin.ca/2165984
>> >
>> >
>> > I have replaced the call to msCleanup with a call to
>> > msIO_resetHandlers which clears all buffers.
>> >
>> >
>> > http://pastebin.ca/2165986
>> >
>> >
>> > same as before but with the buffer accessed as a string rather than a
>> > byte array (string is not copied inside mapscript, array is).
>> >
>> >
>> > Let us now how this goes.
>> >
>> >
>> > Umberto
>> >
>> > On Thu, Jun 28, 2012 at 8:02 PM, Stephan Meißl <stephan at meissl.name>
>> > wrote:
>> >         Thomas, Umberto,
>> >
>> >         we created a simple (at least as simple as possible) test
>> >         case. Here is
>> >         a basic Python script: http://pastebin.ca/2165345 which we
>> >         deployed in
>> >         Apache using mod_wsgi with this config:
>> >         http://pastebin.ca/2165346
>> >
>> >         There is also a basic mapfile using the "road" data in
>> >         "msautotets/wxs"
>> >         http://pastebin.ca/2165329 but I suspect you can use whatever
>> >         mapfile
>> >         you have at hand.
>> >
>> >         When we issue multiple simultaneous requests e.g. using this
>> >         script
>> >         http://pastebin.ca/2165348 (note the "&" at the end of the
>> >         curl call)
>> >         some of the requests result in errors.
>> >
>> >         Either removing the call to msCleanup() or extending the
>> >         Apache config
>> >         to limit the number of threads to 1
>> >         (http://pastebin.ca/2165347) seems
>> >         to resolve the issues but of course with limitations.
>> >
>> >         Are we missing anything essential? How should we free
>> >         request/map
>> >         objects without using msCleanup() in Python?
>> >
>> >         Thanks for any hint,
>> >         Stephan
>> >
>> >
>> >         On Thu, 2012-06-28 at 14:15 +0200, Umberto Nicoletti wrote:
>> >         > Fabian,
>> >         > if you could put together a test case that I can run to
>> >         reproduce the
>> >         > problem I will take a look into it.
>> >         >
>> >         >
>> >         > Regards,
>> >         > Umberto
>> >         >
>> >         > On Thu, Jun 28, 2012 at 1:44 PM, thomas bonfort
>> >         > <thomas.bonfort at gmail.com> wrote:
>> >         >         Fabian,
>> >         >         can you get a backtrace of the segfaults?
>> >         >
>> >         >         Aside from that, I would personally refrain from
>> >         using threads
>> >         >         with
>> >         >         mapscript and stick to a prefork mpm in apache to
>> >         accomplish
>> >         >         this. It
>> >         >         is also my understanding that calling m
>
>
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