diff options
| author | Guillermo Bonvehí <gbonvehi@gmail.com> | 2020-06-20 04:33:24 -0300 |
|---|---|---|
| committer | Mariusz Felisiak <felisiak.mariusz@gmail.com> | 2020-06-22 06:29:35 +0200 |
| commit | f386454d1302b66d0eb331ed0ae9e4811e2f3a15 (patch) | |
| tree | 49abd4e5637c83d2838b692e579b2f96082abaaa | |
| parent | 27c09043da52ca1f02605bf28600bfd5ace95ae4 (diff) | |
Fixed #31728 -- Fixed cache culling when no key is found for deletion.
DatabaseCache._cull implementation could fail if no key was found to
perform a deletion in the table. This prevented the new cache key/value
from being correctly added.
| -rw-r--r-- | django/core/cache/backends/db.py | 9 | ||||
| -rw-r--r-- | tests/cache/tests.py | 14 |
2 files changed, 20 insertions, 3 deletions
diff --git a/django/core/cache/backends/db.py b/django/core/cache/backends/db.py index 33c79c5a14..acbe702255 100644 --- a/django/core/cache/backends/db.py +++ b/django/core/cache/backends/db.py @@ -267,9 +267,12 @@ class DatabaseCache(BaseDatabaseCache): cursor.execute( connection.ops.cache_key_culling_sql() % table, [cull_num]) - cursor.execute("DELETE FROM %s " - "WHERE cache_key < %%s" % table, - [cursor.fetchone()[0]]) + last_cache_key = cursor.fetchone() + if last_cache_key: + cursor.execute( + 'DELETE FROM %s WHERE cache_key < %%s' % table, + [last_cache_key[0]], + ) def clear(self): db = router.db_for_write(self.cache_model_class) diff --git a/tests/cache/tests.py b/tests/cache/tests.py index d404475e16..dc4a221060 100644 --- a/tests/cache/tests.py +++ b/tests/cache/tests.py @@ -621,6 +621,20 @@ class BaseCacheTests: def test_zero_cull(self): self._perform_cull_test('zero_cull', 50, 19) + def test_cull_delete_when_store_empty(self): + try: + cull_cache = caches['cull'] + except InvalidCacheBackendError: + self.skipTest("Culling isn't implemented.") + old_max_entries = cull_cache._max_entries + # Force _cull to delete on first cached record. + cull_cache._max_entries = -1 + try: + cull_cache.set('force_cull_delete', 'value', 1000) + self.assertIs(cull_cache.has_key('force_cull_delete'), True) + finally: + cull_cache._max_entries = old_max_entries + def _perform_invalid_key_test(self, key, expected_warning): """ All the builtin backends should warn (except memcached that should |