Author: Alex
Date: 2011-01-19 08:39:54 -0600 (Wed, 19 Jan 2011)
New Revision: 15243
Modified:
django/trunk/django/db/models/deletion.py
Log:
Avoid doing quadratic amounts of work during object deletion.
Modified: django/trunk/django/db/models/deletion.py
===================================================================
--- django/trunk/django/db/models/deletion.py 2011-01-18 23:25:38 UTC (rev
15242)
+++ django/trunk/django/db/models/deletion.py 2011-01-19 14:39:54 UTC (rev
15243)
@@ -58,7 +58,8 @@
class Collector(object):
def __init__(self, using):
self.using = using
- self.data = {} # {model: [instances]}
+ # Initially, {model: set([instances])}, later values become lists.
+ self.data = {}
self.batches = {} # {model: {field: set([instances])}}
self.field_updates = {} # {model: {(field, value): set([instances])}}
self.dependencies = {} # {model: set([models])}
@@ -75,11 +76,11 @@
return []
new_objs = []
model = objs[0].__class__
- instances = self.data.setdefault(model, [])
+ instances = self.data.setdefault(model, set())
for obj in objs:
if obj not in instances:
new_objs.append(obj)
- instances.extend(new_objs)
+ instances.update(new_objs)
# Nullable relationships can be ignored -- they are nulled out before
# deleting, and therefore do not affect the order in which objects have
# to be deleted.
@@ -190,8 +191,8 @@
@force_managed
def delete(self):
# sort instance collections
- for instances in self.data.itervalues():
- instances.sort(key=attrgetter("pk"))
+ for model, instances in self.data.items():
+ self.data[model] = sorted(instances, key=attrgetter("pk"))
# if possible, bring the models in an order suitable for databases that
# don't support transactions or cannot defer contraint checks until the
--
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