Hello all
I'm experiencing frequent deadlocks in my cherrypy/sqlobject multithreaded
server application. I'm unable to reproduce the error in a small-scale
example yet, but one thing I noticed is, that it might be related to me
creating other sqlobjects in an overwritten _create() function.
What I see is that various threads try to acquire a threadSafeMethod
decorator's lock, originating from various places:
...
File "/usr/lib/python2.4/site-packages/sqlobject/sresults.py", line 165,
in __iter__
return iter(list(self.lazyIter()))
File "/usr/lib/python2.4/site-packages/sqlobject/dbconnection.py", line
804, in next
obj = self.select.sourceClass.get(result[0], selectResults=result[1:],
connection=self.dbconn)
File "/usr/lib/python2.4/site-packages/sqlobject/main.py", line 915, in
get
val = cls(_SO_fetch_no_create=1)
File "/usr/lib/python2.4/site-packages/sqlobject/declarative.py", line
92, in _wrapper
lock.acquire()
File "threading.py", line 100, in acquire
rc = self.__block.acquire(blocking)
And one thread is pending on the cache's lock:
...
File "/usr/lib/python2.4/site-packages/sqlobject/declarative.py", line
94, in _wrapper
return fn(self, *args, **kwargs)
File "/usr/lib/python2.4/site-packages/sqlobject/main.py", line 1214, in
__init__
self._create(id, **kw)
File "/usr/lib/python2.4/site-packages/sqlobject/main.py", line 1245, in
_create
self._SO_finishCreate(id)
File "/usr/lib/python2.4/site-packages/sqlobject/main.py", line 1271, in
_SO_finishCreate
cache.created(id, self.__class__, self)
File "/usr/lib/python2.4/site-packages/sqlobject/cache.py", line 300, in
created
self.caches[cls.__name__].created(id, obj)
File "/usr/lib/python2.4/site-packages/sqlobject/cache.py", line 177, in
created
self.cull()
File "/usr/lib/python2.4/site-packages/sqlobject/cache.py", line 190, in
cull
self.lock.acquire()
.. originating from a certain _create function (hence my assumption).
My create() is looking quite straight-forward, something like this:
class MyClass(sqlobject):
foo = ForeignKey('OtherClass', default=None)
bar = ForeignKey('OtherClass', default=None)
def _create(self, *args, **kw):
# Create the object
super(MyClass, self)._create(*args, **kw)
# Create other object
self.foo = OtherClass()
self.bar = OtherClass()
So, my question is: is this problematic, and, if yes, what other ways are
there to do it?
Thanks a million
Bernhard
... and, sorry for the mess:
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