[Django] #20470: Querying crashes with RuntimeError (dictionary changed size during iteration)
Django
iteration)
----------------------------------------------+--------------------
Reporter: jpaalasm | Owner: nobody
Type: Bug | Status: new
Component: Database layer (models, ORM) | Version: 1.5
Severity: Normal | Keywords:
Triage Stage: Unreviewed | Has patch: 0
Easy pickings: 0 | UI/UX: 0
----------------------------------------------+--------------------
We have defined the following model.
{{{
class SignalAnalysisTask(models.Model):
continuous_signal = models.ForeignKey(ContinuousSignal,
related_name='signal_analysis_tasks')
closed = models.BooleanField(default=False, db_index=True)
ticket = models.OneToOneField(AnalysisTicket, null=True, blank=True,
related_name='analysis_task')
latest_fragment = models.ForeignKey(SignalFragment, null=True,
blank=True, related_name='analysis_task_latest_fragments')
}}}
When the below query is performed with the model, Django crashes with
"RuntimeError: dictionary changed size during iteration". See the full
traceback. Django is configured to run with Apache and mod_wsgi on Linux.
{{{
open_tasks = SignalAnalysisTask.objects.filter(closed=False)
open_tasks_with_new_data =
open_tasks.exclude(latest_fragment=F('continuous_signal__last_signal_fragment'))
open_tasks_with_new_data =
open_tasks_with_new_data.order_by("continuous_signal__start_time")
}}}
Traceback:
{{{
Traceback (most recent call last):
File "/usr/lib/finsor/virtualenvs/signalstorage/local/lib/python2.7
/site-packages/django/core/handlers/base.py", line 115, in get_response
response = callback(request, *callback_args, **callback_kwargs)
File "/usr/lib/finsor/virtualenvs/signalstorage/local/lib/python2.7
/site-packages/bedsenseweb/utils/viewutils.py", line 27, in check
return view_func(request, *args, **kwargs)
File "/usr/lib/finsor/virtualenvs/signalstorage/local/lib/python2.7
/site-packages/bedsenseweb/tickets/views.py", line 21, in acquire
ticket = models.create_new_ticket()
File "/usr/lib/finsor/virtualenvs/signalstorage/local/lib/python2.7
/site-packages/bedsenseweb/tickets/models.py", line 41, in
create_new_ticket
open_tasks_with_new_data =
open_tasks_with_new_data.order_by("continuous_signal__start_time")
File "/usr/lib/finsor/virtualenvs/signalstorage/local/lib/python2.7
/site-packages/django/db/models/query.py", line 791, in order_by
obj = self._clone()
File "/usr/lib/finsor/virtualenvs/signalstorage/local/lib/python2.7
/site-packages/django/db/models/query.py", line 907, in _clone
query = self.query.clone()
File "/usr/lib/finsor/virtualenvs/signalstorage/local/lib/python2.7
/site-packages/django/db/models/sql/query.py", line 264, in clone
obj.where = copy.deepcopy(self.where, memo=memo)
File "/usr/lib/python2.7/copy.py", line 174, in deepcopy
y = copier(memo)
File "/usr/lib/finsor/virtualenvs/signalstorage/local/lib/python2.7
/site-packages/django/utils/tree.py", line 61, in __deepcopy__
obj.children = copy.deepcopy(self.children, memodict)
File "/usr/lib/python2.7/copy.py", line 163, in deepcopy
y = copier(x, memo)
File "/usr/lib/python2.7/copy.py", line 230, in _deepcopy_list
y.append(deepcopy(a, memo))
File "/usr/lib/python2.7/copy.py", line 174, in deepcopy
y = copier(memo)
File "/usr/lib/finsor/virtualenvs/signalstorage/local/lib/python2.7
/site-packages/django/utils/tree.py", line 61, in __deepcopy__
obj.children = copy.deepcopy(self.children, memodict)
File "/usr/lib/python2.7/copy.py", line 163, in deepcopy
y = copier(x, memo)
File "/usr/lib/python2.7/copy.py", line 230, in _deepcopy_list
y.append(deepcopy(a, memo))
File "/usr/lib/python2.7/copy.py", line 174, in deepcopy
y = copier(memo)
File "/usr/lib/finsor/virtualenvs/signalstorage/local/lib/python2.7
/site-packages/django/utils/tree.py", line 61, in __deepcopy__
obj.children = copy.deepcopy(self.children, memodict)
File "/usr/lib/python2.7/copy.py", line 163, in deepcopy
y = copier(x, memo)
File "/usr/lib/python2.7/copy.py", line 230, in _deepcopy_list
y.append(deepcopy(a, memo))
File "/usr/lib/python2.7/copy.py", line 174, in deepcopy
y = copier(memo)
File "/usr/lib/finsor/virtualenvs/signalstorage/local/lib/python2.7
/site-packages/django/utils/tree.py", line 61, in __deepcopy__
obj.children = copy.deepcopy(self.children, memodict)
File "/usr/lib/python2.7/copy.py", line 163, in deepcopy
y = copier(x, memo)
File "/usr/lib/python2.7/copy.py", line 230, in _deepcopy_list
y.append(deepcopy(a, memo))
File "/usr/lib/python2.7/copy.py", line 163, in deepcopy
y = copier(x, memo)
File "/usr/lib/python2.7/copy.py", line 237, in _deepcopy_tuple
y.append(deepcopy(a, memo))
File "/usr/lib/python2.7/copy.py", line 190, in deepcopy
y = _reconstruct(x, rv, 1, memo)
File "/usr/lib/python2.7/copy.py", line 334, in _reconstruct
state = deepcopy(state, memo)
File "/usr/lib/python2.7/copy.py", line 163, in deepcopy
y = copier(x, memo)
File "/usr/lib/python2.7/copy.py", line 257, in _deepcopy_dict
y[deepcopy(key, memo)] = deepcopy(value, memo)
File "/usr/lib/python2.7/copy.py", line 190, in deepcopy
y = _reconstruct(x, rv, 1, memo)
File "/usr/lib/python2.7/copy.py", line 334, in _reconstruct
state = deepcopy(state, memo)
File "/usr/lib/python2.7/copy.py", line 163, in deepcopy
y = copier(x, memo)
File "/usr/lib/python2.7/copy.py", line 257, in _deepcopy_dict
y[deepcopy(key, memo)] = deepcopy(value, memo)
File "/usr/lib/python2.7/copy.py", line 163, in deepcopy
y = copier(x, memo)
File "/usr/lib/python2.7/copy.py", line 256, in _deepcopy_dict
for key, value in x.iteritems():
RuntimeError: dictionary changed size during iteration
}}}
--
Ticket URL: <https://code.djangoproject.com/ticket/20470>
Django <https://code.djangoproject.com/>
The Web framework for perfectionists with deadlines.
Django
iteration)
Reporter: jpaalasm | Owner: nobody
Type: Bug | Status: new
(models, ORM) | Resolution:
Severity: Normal | Triage Stage:
Keywords: | Unreviewed
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
Changes (by svisser):
* needs_better_patch: => 0
* needs_tests: => 0
* needs_docs: => 0
Comment:
Some observations:
- I couldn't reproduce this today on master with the given model and a few
sample instances that I could think of.
- The line `obj.where = copy.deepcopy(self.where, memo=memo)` (line 264 in
`clone`) is present in Django 1.5 but no longer in master as it was
rewritten for ticket #16759 (commit:
https://github.com/django/django/commit/23ca3a01940c63942885df4709712cebf4df79ec).
So I think the problem isn't there anymore but if the bug can be
demonstrated using a small test case then further investigation is needed.
--
Ticket URL: <https://code.djangoproject.com/ticket/20470#comment:1>
Django
iteration)
Reporter: jpaalasm | Owner: nobody
Type: Bug | Status: new
(models, ORM) | Resolution:
Severity: Normal | Triage Stage:
Keywords: | Unreviewed
Has patch: 0 | Needs documentation: 0
Easy pickings: 0 | UI/UX: 0
Comment (by DrMeers):
Thanks @svisser.
@jpaalasm are you able to confirm whether using the development version of
Django fixes your problem?
If so, I wonder whether the fix for #16759 can be backported (or even
partially, since there seem to be some backwards compatibility concerns
which were debatably "internal"), or if we need to address the issue
specifically in 1.5.
--
Ticket URL: <https://code.djangoproject.com/ticket/20470#comment:2>
Django
iteration)
Reporter: jpaalasm | Owner: nobody
Type: Bug | Status: closed
Component: Database layer | Version: 1.5
Severity: Normal | Triage Stage:
Keywords: | Unreviewed
Has patch: 0 | Needs documentation: 0
Easy pickings: 0 | UI/UX: 0
Changes (by bmispelon):
* cc: bmispelon@… (added)
* status: new => closed
* resolution: => needsinfo
Comment:
I also tried reproducing the issue without any success.
Your example is missing the definition of the models you use in the
ForeignKeys, so I had to improvise. Here's what I used:
{{{#!python
class SignalFragment(models.Model):
pass
class ContinuousSignal(models.Model):
last_signal_fragment = models.ForeignKey(SignalFragment)
class AnalysisTicket(models.Model):
pass
class SignalAnalysisTask(models.Model):
continuous_signal = models.ForeignKey(ContinuousSignal,
related_name='signal_analysis_tasks')
closed = models.BooleanField(default=False, db_index=True)
ticket = models.OneToOneField(AnalysisTicket, null=True, blank=True,
related_name='analysis_task')
latest_fragment = models.ForeignKey(SignalFragment, null=True,
blank=True, related_name='analysis_task_latest_fragments')
}}}
I tried running the example you gave with master, 1.5, and even with 1.4
but none of them raised any exception.
In consequence, I'm marking this as `needsinfo`.
Please re-open with more information on how to reproduce the issue.
Thanks.
--
Ticket URL: <https://code.djangoproject.com/ticket/20470#comment:3>
Django
iteration)
Reporter: jpaalasm | Owner: nobody
Type: Bug | Status: new
(models, ORM) | Resolution:
Keywords: | Unreviewed
Has patch: 0 | Needs documentation: 0
Easy pickings: 0 | UI/UX: 0
Changes (by jpaalasm):
* status: closed => new
* resolution: needsinfo =>
Comment:
Here's more information about the issue.
This crash occurs in about 0.3% of all requests, in a view that gets some
hundreds of requests per minute.
I think that installing the development version is not currently possible,
because we seem to be using some removed functionality (e.g. importing
django.conf.urls.defaults fails).
--
Ticket URL: <https://code.djangoproject.com/ticket/20470#comment:4>
Django
iteration)
Reporter: jpaalasm | Owner: nobody
Type: Bug | Status: closed
Component: Database layer | Version: 1.5
Severity: Normal | Triage Stage:
Keywords: | Unreviewed
Has patch: 0 | Needs documentation: 0
Easy pickings: 0 | UI/UX: 0
Changes (by akaariai):
* status: new => closed
* resolution: => needsinfo
Comment:
I think this is data-dependant and trying to fix this in 1.5 is impossible
without getting a reproducible test case. Also, this is very likely fixed
in master as `__deepcopy__` isn't used any more for cloning the query.
Backpatching the `__deepcopy__` removal can't be done, it is just too big
of a change and has a real possibility for nasty regressions.
I don't see any other option as to close this as needsinfo. This doesn't
mean at all that we don't trust the issue exists, just that there is no
way to fix this unless we can reproduce the issue.
--
Ticket URL: <https://code.djangoproject.com/ticket/20470#comment:5>