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Graham Dumpleton
graham.dumpleton at gmail.com
Tue Apr 10 21:00:29 EDT 2007
Try rebuilding dbxml but ensure that compiler option: -DSWIG_PYTHON_NO_USE_GIL is used. I don't know when SWIG changed, it certainly didn't generate these PyGILState calls the last time I played with it, which wasn't that long ago, but it isn't going to work under mod_python the way they now do it as the default. I'll have to look into this further when I get a chance as this new behaviour of SWIG is going to cause all my Apache API SWIG bindings to break. :-( Graham On 11/04/07, David Schachter <ds at bittorrent.com> wrote: > > Folks-- > > I'm having a problem embedding Berkeley DB XML into Apache with mod_python. > The first attempt to create an XmlManager causes a lockup in Python--the > Global Interpreter Lock is deadlocked, I think. (Stack trace below.) Any > ideas of how to debug? Is there a BDB XML Python expert? I checked Google > without success. > > The code to demonstrate the problem is simple and shown below. When the > line "xmlManager = dbxml.XmlManager()" is commented out, the code runs ok. > Commented in, Apache locks up. > > The most recent mod_python has this comment at > http://www.modpython.org/live/mod_python-3.3.1/doc-html/app-changes.html: > > > Third party C modules that use the simplified API for the Global Interpreter > Lock (GIL), as described in PEP 311, can now be used. The only requirement > is that such modules can only be used in the context of the > "main_interpreter". (More info at > http://issues.apache.org/jira/browse/MODPYTHON-77.) > The documentation for mod_python at > http://www.modpython.org/live/current/doc-html/pyapi-interps.html > says: > > > Note that if any third party module is being used which has a C code > component that uses the simplified API for access to the Global Interpreter > Lock (GIL) for Python extension modules, then the interpreter name must be > forcibly set to be "main_interpreter". This is necessary as such a module > will only work correctly if run within the context of the first Python > interpreter created by the process. > Conforming to this, I set the interpreter name in the httpd.conf file using > the directive "PythonInterpreter main_interpreter" and I verified this by > printing the interpreter name from my Python code. > > In dbxml-2.3.10/dbxml/src/python, there's some code relating to the GIL in > dbxml_python_wrap.cpp. If someone else has already beaten this problem into > submission, I'd rather not duplicate the effort. > > -- David Schachter > > #! /usr/bin/python > > import dbxml > from mod_python import apache > import os > > > def handler(req): > id = "pid %d, interpreter '%s'" % (os.getpid(), req.interpreter) > > apache.log_error("About to start BDB XML from %s." % id) > xmlManager = dbxml.XmlManager() > apache.log_error("Started BDB XML.") > > req.write("Hi from %s." % id) > return apache.OK > > > STACK TRACE IS: > > (gdb) bt > #0 0xffffe410 in __kernel_vsyscall () > #1 0xb7e97af0 in sem_wait at GLIBC_2.0 () from > /lib/tls/i686/cmov/libpthread.so.0 > #2 0x00000004 in ?? () > #3 0xb7ce7a00 in PyThread_acquire_lock (lock=0x0, waitflag=1) at > thread_pthread.h:298 > #4 0xb7cb5689 in PyEval_RestoreThread (tstate=0x810f888) at > Python/ceval.c:305 > #5 0xb7ce16e7 in PyGILState_Ensure () at Python/pystate.c:512 > #6 0xb78282f9 in _wrap_new_XmlManager (self=0x0, args=0xb7b9102c) at > dbxml_python_wrap.cpp:898 > (The reference to line 898 is correct but surprising, the result of a > macro expansion at line 4195. --D.S.) > #7 0xb7c65967 in PyObject_Call (func=0x0, arg=0xfffffffc, kw=0xfffffffc) > at Objects/abstract.c:1795 > #8 0xb7cb9e1d in PyEval_EvalFrame (f=0x822cdbc) at Python/ceval.c:3845 > #9 0xb7cbd719 in PyEval_EvalCodeEx (co=0xb6b12e20, globals=0xfffffffc, > locals=0x0, args=0x0, argcount=1, > kws=0x0, kwcount=0, defs=0x0, defcount=0, closure=0x0) at > Python/ceval.c:2741 > #10 0xb7d0d6be in function_call (func=0xb6b0902c, arg=0xb6b892ac, kw=0x0) > at Objects/funcobject.c:548 > #11 0xb7c65967 in PyObject_Call (func=0x0, arg=0xfffffffc, kw=0xfffffffc) > at Objects/abstract.c:1795 > #12 0xb7c6e389 in instancemethod_call (func=0xfffffffc, arg=0xb6b892ac, > kw=0xfffffffc) > at Objects/classobject.c:2532 > #13 0xb7c65967 in PyObject_Call (func=0x0, arg=0xfffffffc, kw=0xfffffffc) > at Objects/abstract.c:1795 > #14 0xb7c99728 in slot_tp_init (self=0xb6af1fac, args=0xfffffffc, > kwds=0xfffffffc) > at Objects/typeobject.c:4774 > #15 0xb7c91ad4 in type_call (type=0xb7c99675, args=0xb7b9102c, kwds=0x0) at > Objects/typeobject.c:435 > #16 0xb7c65967 in PyObject_Call (func=0x0, arg=0xfffffffc, kw=0xfffffffc) > at Objects/abstract.c:1795 > #17 0xb7cba239 in PyEval_EvalFrame (f=0x820f224) at Python/ceval.c:3776 > #18 0xb7cbd0eb in PyEval_EvalFrame (f=0x8195854) at Python/ceval.c:3651 > #19 0xb7cbd0eb in PyEval_EvalFrame (f=0x81c9ac4) at Python/ceval.c:3651 > #20 0xb7cbd719 in PyEval_EvalCodeEx (co=0xb6b87e20, globals=0xfffffffc, > locals=0x0, args=0x7, argcount=0, > kws=0x8282440, kwcount=7, defs=0x0, defcount=0, closure=0x0) at > Python/ceval.c:2741 > #21 0xb7cbb46a in PyEval_EvalFrame (f=0x82822a4) at Python/ceval.c:3660 > #22 0xb7cbd719 in PyEval_EvalCodeEx (co=0xb6b87ee0, globals=0xfffffffc, > locals=0x0, args=0x0, argcount=2, > kws=0x0, kwcount=0, defs=0x0, defcount=0, closure=0x0) at > Python/ceval.c:2741 > #23 0xb7d0d6be in function_call (func=0xb6af3a74, arg=0xb6b7c78c, kw=0x0) > at Objects/funcobject.c:548 > #24 0xb7c65967 in PyObject_Call (func=0x0, arg=0xfffffffc, kw=0xfffffffc) > at Objects/abstract.c:1795 > #25 0xb7c6e389 in instancemethod_call (func=0xfffffffc, arg=0xb6b7c78c, > kw=0xfffffffc) > at Objects/classobject.c:2532 > #26 0xb7c65bf6 in PyObject_CallMethod (o=0x0, name=0xb6b891ec "\001", > format=0xb6b891ec "\001") > at Objects/abstract.c:1795 > #27 0xb7c5f505 in python_handler (req=0x828a7b8, phase=0xb7d16e59 > "PythonHandler") at mod_python.c:1652 > #28 0x08073daf in ap_run_handler (r=0x828a7b8) at config.c:157 > #29 0x080741b1 in ap_invoke_handler (r=0x828a7b8) at config.c:372 > ---Type <return> to continue, or q <return> to quit--- > #30 0x0808ba77 in ap_process_request (r=0x828a7b8) at http_request.c:258 > #31 0x0808929b in ap_process_http_connection (c=0x8185638) at > http_core.c:184 > #32 0x0807a599 in ap_run_process_connection (c=0x8185638) at > connection.c:43 > #33 0x0809e55a in child_main (child_num_arg=-4) at prefork.c:640 > #34 0x0809e7a8 in make_child (s=0x80c9c80, slot=0) at prefork.c:680 > #35 0x0809ee53 in ap_mpm_run (_pconf=0xbf86d6f0, plog=0x81031a0, > s=0xbf86d6f4) at prefork.c:956 > #36 0x080622c8 in main (argc=2, argv=0xbf86d8b4) at main.c:717 > (gdb) > > > > > _______________________________________________ > Mod_python mailing list > Mod_python at modpython.org > http://mailman.modpython.org/mailman/listinfo/mod_python > >
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