Indexes to improves stats for service query

migrations/versions/0050_index_for_stats.py

@@ -0,0 +1,31 @@
+"""empty message
+
+Revision ID: 0050_index_for_stats
+Revises: 0048_job_scheduled_time
+Create Date: 2016-08-24 13:21:51.744526
+
+"""
+
+# revision identifiers, used by Alembic.
+revision = '0050_index_for_stats'
+down_revision = '0048_job_scheduled_time'
+
+from alembic import op
+import sqlalchemy as sa
+
+
+def upgrade():
+    op.create_index(
+        'ix_notifications_service_id_created_at',
+        'notifications',
+        ['service_id', sa.text("date(created_at)")]
+    )
+    op.create_index(
+        'ix_notification_history_service_id_created_at',
+        'notification_history',
+        ['service_id', sa.text("date(created_at)")]
+    )
+
+def downgrade():
+    op.drop_index(op.f('ix_notifications_service_id_created_at'), table_name='notifications')
+    op.drop_index(op.f('ix_notification_history_service_id_created_at'), table_name='notification_history')