Hi Oleg
[EMAIL PROTECTED] schrieb am 05.07.2007
11:31:56:
> On Thu, Jul 05, 2007 at 11:22:36AM +0200, [EMAIL PROTECTED] wrote:
> > The accesses are made in different threads, to objects of the same
class
> > (MyClass in my example). One locks while resolving a ForeignKey in
> > _SO_foreignKey(), one locks in _SO_finishCreate() and the third one in
the
> > selectresult's __iter__().
>
> Can you do an experiment - create objects of OtherClass outside of
> _create() and assign them to foreign keys after the object has been fully
> created?
>
I've tried to produce an isolated example of my problem. I'm not yet sure
if everything's needed in here, I'm still trying to buil it further down.
Things I noticed so far:
- The _create seems not to have anything to do with it, as it locks even
without one.
- A higher number of threads increase the possibility for deadlocks.
- I need to have two classes, MyClass1 and MyClass2, in order for the
deadlock to occur.
To the code:
- On my machine, the code deadlocks after some 10s of objects created.
- The threadframe module may be downloaded here:
http://www.majid.info/mylos/stories/2004/06/10/threadframe.html. Maybe you
have some clever debugger that can do that for you... :-)
Thanks!
Bernhard
#****************************************************
import sqlobject
import threading
import time
sqlobject.sqlhub.processConnection =
sqlobject.connectionForURI('mysql://XXX')
class Attribute(sqlobject.SQLObject):
"""
Attribute class
"""
attributeSet = sqlobject.ForeignKey('AttributeSet')
name = sqlobject.StringCol(default = '')
value = sqlobject.StringCol(default = '')
class AttributeSet(sqlobject.SQLObject):
"""
Attribute set class, contains attributes
"""
attributes = sqlobject.SQLMultipleJoin('Attribute')
def _set_attributes(self, attrs):
# First clear...
for attr in self.attributes: attr.destroySelf()
# ... then set.
for k, v in attrs.items():
Attribute(attributeSet = self, name = k, value = v)
def _get_attributes(self):
attrs = {}
for attribute in list(self._SO_get_attributes()):
attrs[attribute.name] = attribute.value
return attrs
class MyClass1(sqlobject.SQLObject):
"""
First class that uses an attribute set.
"""
attrSet = sqlobject.ForeignKey('AttributeSet', default = None)
# I would want to create the attribute set here, but for
# Oleg's suggestion, I'm doing it from the calling class.
#def _create(self, *args, **kw):
#super(MyClass1, self)._create(*args, **kw)
#self.attrSet = AttributeSet()
#self.attrSet.attributes = dict(foo = 1, bar = 2)
class MyClass2(sqlobject.SQLObject):
"""
Second class that uses an attribute set.
"""
attrSet = sqlobject.ForeignKey('AttributeSet', default = None)
#def _create(self, *args, **kw):
#super(MyClass2, self)._create(*args, **kw)
#self.attrSet = AttributeSet()
#self.attrSet.attributes = dict(foo = 1, bar = 2)
# Create tables.
Attribute.createTable(ifNotExists = True)
AttributeSet.createTable(ifNotExists = True)
MyClass1.createTable(ifNotExists = True)
MyClass2.createTable(ifNotExists = True)
class MyThread(threading.Thread):
"""
A thread that produces instances of MyClass1 or Myclass2.
"""
def __init__(self, Klass):
super(MyThread, self).__init__()
self._Klass = Klass
def run(self):
print '%02d %02d %20s : Started' % (time.localtime().tm_min,
time.localtime().tm_sec, threading.currentThread().getName())
for i in range(100):
mc = self._Klass()
mc.attrSet = AttributeSet()
mc.attrSet.attributes = dict(foo = 1, bar = 2)
# Accessing these will result in a deadlock
for key, value in mc.attrSet.attributes.items():
pass
if i % 10 == 0:
print '%02d %02d %20s : %s' % (time.localtime().tm_min,
time.localtime().tm_sec, threading.currentThread().getName(), i)
# Create some threads
threads = [MyThread(MyClass1) for i in range(10)] + [MyThread(MyClass2) for
i in range(10)]
print 'Starting threads'
for t in threads: t.start()
time.sleep(10)
import threadframe, traceback, sys
frames = threadframe.threadframe()
print '-' * 72
for frame in frames:
print '-' * 72
print 'frame ref count = %d' % sys.getrefcount(frame)
traceback.print_stack(frame, file=sys.stdout)
for t in threads: t.join()
print 'Done'
#****************************************************
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