feat(celery): set msgpack as default serializer and drop json_ext as it's actually slower

rhodecode/lib/celerylib/loader.py

@@ -40,7 +40,6 b' from celery import Celery'
 from celery import signals
 from celery import Task
 from celery import exceptions  # noqa
-from kombu.serialization import register
 
 import rhodecode
 
@@ -51,11 +50,6 b' from rhodecode.lib.pyramid_utils import '
 from rhodecode.lib.utils2 import str2bool
 from rhodecode.model import meta
 
-
-register('json_ext', json.dumps, json.loads,
-         content_type='application/x-json-ext',
-         content_encoding='utf-8')
-
 log = logging.getLogger('celery.rhodecode.loader')
 
 
@@ -75,9 +69,10 b' base_celery_config = {'
     'result_persistent': True,
     'imports': imports,
     'worker_max_tasks_per_child': 20,
-    'accept_content': ['json_ext', 'json'],
-    'task_serializer': 'json_ext',
-    'result_serializer': 'json_ext',
+    'task_serializer': 'msgpack',
+    'accept_content': ['json', 'msgpack'],
+    'result_serializer': 'msgpack',
+    'result_accept_content': ['json', 'msgpack'],
     'worker_hijack_root_logger': False,
     'broker_connection_retry_on_startup': True,
     'database_table_names': {