Add patch for issue9902.

issue9802.diff

@@ -0,0 +1,34 @@
+index 7995ab4..fae4268 100644
+--- a/trytond/trytond/modules/stock/move.py
++++ b/trytond/trytond/modules/stock/move.py
+@@ -841,6 +841,8 @@ class Move(Workflow, ModelSQL, ModelView):
+         child_locations = {}
+         to_write = []
+         to_assign = []
++        to_copy_moves = []
++        to_copy_values = []
+         success = True
+         for move in moves:
+             if move.state != 'draft':
+@@ -900,14 +902,19 @@ class Move(Workflow, ModelSQL, ModelView):
+                     to_assign.append(move)
+                     first = False
+                 else:
+-                    with Transaction().set_context(_stock_move_split=True):
+-                        to_assign.extend(cls.copy([move], default=values))
++                    to_copy_moves.append(move)
++                    to_copy_values.append(values)
+ 
+                 qty_default_uom = Uom.compute_qty(move.uom, qty,
+                         move.product.default_uom, round=False)
+ 
+                 from_key = get_key(move, from_location)
+                 pbl[from_key] = pbl.get(from_key, 0.0) - qty_default_uom
++        if to_copy_moves:
++            with Transaction().set_context(_stock_move_split=True):
++                copied = cls.copy(to_copy_moves)
++            for record, values in zip(copied, to_copy_values):
++                to_write.extend([[record], values])
+         if to_write:
+             cls.write(*to_write)
+         if to_assign:

series

@@ -55,3 +55,5 @@ account_payment_search_payment_amount.diff # [account_payment] Optimize searcher
 purchase_line_rule.diff # [purchase] Add missing rule on purchase_line
 
 issue9797.diff # [account_payment_sepa] Slowness processing sepa
+
+issue9802.diff # [stock] Improve performance when partially assigning moves