diff --git a/addons/mrp/models/mrp_workorder.py b/addons/mrp/models/mrp_workorder.py
index e445b40389b..6f3fe4b77c8 100644
--- a/addons/mrp/models/mrp_workorder.py
+++ b/addons/mrp/models/mrp_workorder.py
@@ -33,7 +33,7 @@ class MrpWorkorder(models.Model):
     product_id = fields.Many2one(related='production_id.product_id', readonly=True, store=True, check_company=True)
     product_tracking = fields.Selection(related="product_id.tracking")
     product_uom_id = fields.Many2one('uom.uom', 'Unit of Measure', required=True, readonly=True)
-    production_id = fields.Many2one('mrp.production', 'Manufacturing Order', required=True, check_company=True, readonly=True)
+    production_id = fields.Many2one('mrp.production', 'Manufacturing Order', required=True, check_company=True, readonly=True, index='btree')
     production_availability = fields.Selection(
         string='Stock Availability', readonly=True,
         related='production_id.reservation_state', store=True) # Technical: used in views and domains only
diff --git a/addons/mrp/models/stock_move.py b/addons/mrp/models/stock_move.py
index d310ad45e52..f2e82cfcba6 100644
--- a/addons/mrp/models/stock_move.py
+++ b/addons/mrp/models/stock_move.py
@@ -135,7 +135,7 @@ class StockMove(models.Model):
         'mrp.routing.workcenter', 'Operation To Consume', check_company=True,
         domain="[('id', 'in', allowed_operation_ids)]")
     workorder_id = fields.Many2one(
-        'mrp.workorder', 'Work Order To Consume', copy=False, check_company=True)
+        'mrp.workorder', 'Work Order To Consume', copy=False, check_company=True, index='btree_not_null')
     # Quantities to process, in normalized UoMs
     bom_line_id = fields.Many2one('mrp.bom.line', 'BoM Line', check_company=True)
     byproduct_id = fields.Many2one(