diff --git a/swh/scheduler/backend.py b/swh/scheduler/backend.py
--- a/swh/scheduler/backend.py
+++ b/swh/scheduler/backend.py
@@ -8,6 +8,7 @@
 from functools import wraps
 import json
 import tempfile
+import logging
 
 from arrow import Arrow, utcnow
 import psycopg2
@@ -17,6 +18,9 @@
 from swh.core.config import SWHConfig
 
 
+logger = logging.getLogger(__name__)
+
+
 def adapt_arrow(arrow):
     return AsIs("'%s'::timestamptz" % arrow.isoformat())
 
@@ -185,6 +189,7 @@
         self.db = None
         self.db_conn_dsn = self.config['scheduling_db']
         self.reconnect()
+        logger.debug('SchedulerBackend config=%s' % self.config)
 
     task_type_keys = [
         'type', 'description', 'backend_name', 'default_interval',
@@ -333,7 +338,7 @@
                 %s, %s, %s :: bigint, %s :: bigint)''',
             (task_type, timestamp, num_tasks, num_tasks_priority)
         )
-
+        logger.debug('PEEK %s => %s' % (task_type, cursor.rowcount))
         return cursor.fetchall()
 
     @autocommit
@@ -355,13 +360,12 @@
         """
         if timestamp is None:
             timestamp = utcnow()
-
         cursor.execute(
             '''select * from swh_scheduler_grab_ready_tasks(
                  %s, %s, %s :: bigint, %s :: bigint)''',
             (task_type, timestamp, num_tasks, num_tasks_priority)
         )
-
+        logger.debug('GRAB %s => %s' % (task_type, cursor.rowcount))
         return cursor.fetchall()
 
     task_run_create_keys = ['task', 'backend_id', 'scheduled', 'metadata']