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Code Issues 25 Releases Wiki Activity

Fixed #32772 -- Made database cache count size once per set.

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Michael Lissner 2021-05-25 09:31:26 -07:00 committed by Mariusz Felisiak
parent 12b19a1d76
commit 5a8e8f80bb
3 changed files with 20 additions and 6 deletions
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1
AUTHORS
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@ -641,6 +641,7 @@ answer newbie questions, and generally made Django that much better:
Michael S. Brown <michael@msbrown.net> Michael S. Brown <michael@msbrown.net>
Michael Hall <mhall1@ualberta.ca> Michael Hall <mhall1@ualberta.ca>
Michael Josephson <http://www.sdjournal.com/> Michael Josephson <http://www.sdjournal.com/>
Michael Lissner <mike@free.law>
Michael Manfre <mmanfre@gmail.com> Michael Manfre <mmanfre@gmail.com>
michael.mcewan@gmail.com michael.mcewan@gmail.com
Michael Placentra II <someone@michaelplacentra2.net> Michael Placentra II <someone@michaelplacentra2.net>

12
django/core/cache/backends/db.py vendored
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@ -128,7 +128,7 @@ class DatabaseCache(BaseDatabaseCache):
exp = datetime.fromtimestamp(timeout, tz=tz) exp = datetime.fromtimestamp(timeout, tz=tz)
exp = exp.replace(microsecond=0) exp = exp.replace(microsecond=0)
if num > self._max_entries: if num > self._max_entries:
self._cull(db, cursor, now) self._cull(db, cursor, now, num)
pickled = pickle.dumps(value, self.pickle_protocol) pickled = pickle.dumps(value, self.pickle_protocol)
# The DB column is expecting a string, so make sure the value is a # The DB column is expecting a string, so make sure the value is a
# string, not bytes. Refs #19274. # string, not bytes. Refs #19274.
@ -247,7 +247,7 @@ class DatabaseCache(BaseDatabaseCache):
) )
return cursor.fetchone() is not None return cursor.fetchone() is not None
def _cull(self, db, cursor, now): def _cull(self, db, cursor, now, num):
if self._cull_frequency == 0: if self._cull_frequency == 0:
self.clear() self.clear()
else: else:
@ -255,10 +255,10 @@ class DatabaseCache(BaseDatabaseCache):
table = connection.ops.quote_name(self._table) table = connection.ops.quote_name(self._table)
cursor.execute("DELETE FROM %s WHERE expires < %%s" % table, cursor.execute("DELETE FROM %s WHERE expires < %%s" % table,
[connection.ops.adapt_datetimefield_value(now)]) [connection.ops.adapt_datetimefield_value(now)])
cursor.execute("SELECT COUNT(*) FROM %s" % table) deleted_count = cursor.rowcount
num = cursor.fetchone()[0] remaining_num = num - deleted_count
if num > self._max_entries: if remaining_num > self._max_entries:
cull_num = num // self._cull_frequency cull_num = remaining_num // self._cull_frequency
cursor.execute( cursor.execute(
connection.ops.cache_key_culling_sql() % table, connection.ops.cache_key_culling_sql() % table,
[cull_num]) [cull_num])

13
tests/cache/tests.py vendored
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@ -40,6 +40,7 @@ from django.test import (
ignore_warnings, override_settings, ignore_warnings, override_settings,
) )
from django.test.signals import setting_changed from django.test.signals import setting_changed
from django.test.utils import CaptureQueriesContext
from django.utils import timezone, translation from django.utils import timezone, translation
from django.utils.cache import ( from django.utils.cache import (
get_cache_key, learn_cache_key, patch_cache_control, patch_vary_headers, get_cache_key, learn_cache_key, patch_cache_control, patch_vary_headers,
@ -1117,6 +1118,18 @@ class DBCacheTests(BaseCacheTests, TransactionTestCase):
with self.assertNumQueries(1): with self.assertNumQueries(1):
cache.delete_many(['a', 'b', 'c']) cache.delete_many(['a', 'b', 'c'])
def test_cull_count_queries(self):
old_max_entries = cache._max_entries
# Force _cull to delete on first cached record.
cache._max_entries = -1
with CaptureQueriesContext(connection) as captured_queries:
try:
cache.set('force_cull', 'value', 1000)
finally:
cache._max_entries = old_max_entries
num_count_queries = sum('COUNT' in query['sql'] for query in captured_queries)
self.assertEqual(num_count_queries, 1)
def test_delete_cursor_rowcount(self): def test_delete_cursor_rowcount(self):
""" """
The rowcount attribute should not be checked on a closed cursor. The rowcount attribute should not be checked on a closed cursor.