From f386454d1302b66d0eb331ed0ae9e4811e2f3a15 Mon Sep 17 00:00:00 2001 From: Guillermo Bonvehí Date: Sat, 20 Jun 2020 04:33:24 -0300 Subject: 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. --- django/core/cache/backends/db.py | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) (limited to 'django/core/cache') 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) -- cgit v1.3