[SQL-CVS] [ sqlobject-Patches-1407684 ] object initialization threading issue

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Patches item #1407684, was opened at 2006-01-16 13:35
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Category: None
Group: None
Status: Open
Resolution: None
Priority: 5
Submitted By: Nobody/Anonymous (nobody)
Assigned to: Nobody/Anonymous (nobody)
Summary: object initialization threading issue

Initial Comment:
The creation of SQL objects is not threadsafe. After stressing a 
TurboGears app with ab2 with multiple concurrent connections to a 
threaded server, the log gets filled with tracebacks like these:

15/Jan/2006:22:05:00 HTTP INFO Traceback (most recent call last): 
  File 
"/usr/lib/python2.4/site-packages/CherryPy-2.2.0beta-py2.4.egg/
cherrypy/_cp httptools.py", 
line 96, in _run 
    applyFilters('before_main') 
  File 
"/usr/lib/python2.4/site-packages/CherryPy-2.2.0beta-py2.4.egg/
cherrypy/fil ters/__init__.py", 
line 131, in applyFilters 
    method() 
  File "/home/alberto/turbogears/turbogears/visit.py", line 99, in
beforeMain 
    visit=self.get_visit() 
  File "/home/alberto/turbogears/turbogears/visit.py", line 139, in 
get_visit 
    return self.new_visit() 
  File "/home/alberto/turbogears/turbogears/visit.py", line 122, in 
new_visit 
    visit= TG_Visit( visit_key=visit_key, expiry=now+self.timeout ) 
  File 
"/usr/lib/python2.4/site-packages/SQLObject-0.7.1dev_r1500-
py2.4.egg/sqlobj ect/main.py", 
line 1197, in __init__ 
    self._create(id, **kw) 
  File 
"/usr/lib/python2.4/site-packages/SQLObject-0.7.1dev_r1500-
py2.4.egg/sqlobj ect/main.py", 
line 1221, in _create 
    self.set(**kw) 
  File 
"/usr/lib/python2.4/site-packages/SQLObject-0.7.1dev_r1500-
py2.4.egg/sqlobj ect/main.py", 
line 1142, in set 
    self._connection._SO_update(self, args) 
  File 
"/usr/lib/python2.4/site-packages/SQLObject-0.7.1dev_r1500-
py2.4.egg/sqlobj ect/dbconnection.py", 
line 561, in _SO_update 
    self.query("UPDATE %s SET %s WHERE %s = %s" % 
AttributeError: 'TG_Visit' object has no attribute 'id' 

15/Jan/2006:22:05:00 HTTP INFO Traceback (most recent call last): 
  File 
"/usr/lib/python2.4/site-packages/CherryPy-2.2.0beta-py2.4.egg/
cherrypy/_cp httptools.py", 
line 96, in _run 
    applyFilters('before_main') 
  File 
"/usr/lib/python2.4/site-packages/CherryPy-2.2.0beta-py2.4.egg/
cherrypy/fil ters/__init__.py", 
line 131, in applyFilters 
    method() 
  File "/home/alberto/turbogears/turbogears/visit.py", line 99, in
beforeMain 
    visit=self.get_visit() 
  File "/home/alberto/turbogears/turbogears/visit.py", line 139, in 
get_visit 
    return self.new_visit() 
  File "/home/alberto/turbogears/turbogears/visit.py", line 122, in 
new_visit 
    visit= TG_Visit( visit_key=visit_key, expiry=now+self.timeout ) 
  File 
"/usr/lib/python2.4/site-packages/SQLObject-0.7.1dev_r1500-
py2.4.egg/sqlobj ect/main.py", 
line 1197, in __init__ 
    self._create(id, **kw) 
  File 
"/usr/lib/python2.4/site-packages/SQLObject-0.7.1dev_r1500-
py2.4.egg/sqlobj ect/main.py", 
line 1224, in _create 
    self._SO_finishCreate(id) 
  File 
"/usr/lib/python2.4/site-packages/SQLObject-0.7.1dev_r1500-
py2.4.egg/sqlobj ect/main.py", 
line 1242, in _SO_finishCreate 
    del self.sqlmeta._creating 
AttributeError: _creating 

I've found at http://pythonpaste.org/archives/message/
20051202.223718.a3adcfaa.en.html a solution to the problem, which 
is overriding __init__ on SQLObject subclasses by wrapping 
SQLObject.__init__ with a mutex acquisition and release.

I've made a patch for main.py which generalizes this approach and 
wraps __init__ for every SQLObject created. Tested under my 
environment and works fine.

The patch is also posted at the turbogears Trac at http://
trac.turbogears.org/turbogears/attachment/ticket/397/
sqlobject_threading.patch

Cheers,
Alberto Valverde
al...@to...

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