diff --git a/swh/indexer/orchestrator.py b/swh/indexer/orchestrator.py
index 9f6e5de..4cdb5b1 100644
--- a/swh/indexer/orchestrator.py
+++ b/swh/indexer/orchestrator.py
@@ -1,45 +1,48 @@
 # Copyright (C) 2016  The Software Heritage developers
 # See the AUTHORS file at the top-level directory of this distribution
 # License: GNU General Public License version 3, or any later version
 # See top-level LICENSE file for more information
 
 import random
 
 from swh.core.config import SWHConfig
 from swh.scheduler.celery_backend.config import app
 
 from . import TASK_NAMES, INDEXER_CLASSES
 
 
 class OrchestratorIndexer(SWHConfig):
     """The indexer orchestrator is in charge of:
     - reading messages (list of sha1s as bytes)
     - according to its configuration, broadcast those messages to indexers
     - by eventually filtering by indexers
 
     """
     CONFIG_BASE_FILENAME = 'indexer/orchestrator'
 
     DEFAULT_CONFIG = {
         'indexers': ('[str]', ['mimetype']),
     }
 
     def __init__(self):
         super().__init__()
         self.config = self.parse_config_file()
         indexer_names = self.config['indexers']
         random.shuffle(indexer_names)
         self.indexers = {
             TASK_NAMES[name]: INDEXER_CLASSES[name]
             for name in indexer_names
         }
 
     def run(self, sha1s):
         for task_name, indexer_class in self.indexers.items():
             indexer = indexer_class()
 
             # first filter the contents per indexers
             sha1s_filtered = list(indexer.filter_contents(sha1s))
 
+            if not sha1s_filtered:
+                continue
+
             # now send the message for the indexer to compute and store results
             app.tasks[task_name].delay(sha1s_filtered)