diff --git a/addons/point_of_sale/models/pos_payment.py b/addons/point_of_sale/models/pos_payment.py
index 3fe006c0749..fe43e07df08 100644
--- a/addons/point_of_sale/models/pos_payment.py
+++ b/addons/point_of_sale/models/pos_payment.py
@@ -23,8 +23,8 @@ class PosPayment(models.Model):
     currency_id = fields.Many2one('res.currency', string='Currency', related='pos_order_id.currency_id')
     currency_rate = fields.Float(string='Conversion Rate', related='pos_order_id.currency_rate', help='Conversion rate from company currency to order currency.')
     partner_id = fields.Many2one('res.partner', string='Customer', related='pos_order_id.partner_id')
-    session_id = fields.Many2one('pos.session', string='Session', related='pos_order_id.session_id', store=True)
-    company_id = fields.Many2one('res.company', string='Company', related='pos_order_id.company_id')
+    session_id = fields.Many2one('pos.session', string='Session', related='pos_order_id.session_id', store=True, index=True)
+    company_id = fields.Many2one('res.company', string='Company', related='pos_order_id.company_id')  # TODO: add store=True in master
     card_type = fields.Char('Type of card used')
     cardholder_name = fields.Char('Cardholder Name')
     transaction_id = fields.Char('Payment Transaction ID')
diff --git a/addons/point_of_sale/models/pos_session.py b/addons/point_of_sale/models/pos_session.py
index af1b7ba1fa8..12c25c1da79 100644
--- a/addons/point_of_sale/models/pos_session.py
+++ b/addons/point_of_sale/models/pos_session.py
@@ -110,7 +110,10 @@ class PosSession(models.Model):
         for session in self:
             cash_payment_method = session.payment_method_ids.filtered('is_cash_count')[:1]
             if cash_payment_method:
-                total_cash_payment = sum(session.order_ids.mapped('payment_ids').filtered(lambda payment: payment.payment_method_id == cash_payment_method).mapped('amount'))
+                total_cash_payment = 0.0
+                result = self.env['pos.payment'].read_group([('session_id', '=', self.id), ('payment_method_id', '=', cash_payment_method.id)], ['amount'], ['session_id'])
+                if result:
+                    total_cash_payment = result[0]['amount']
                 session.cash_register_total_entry_encoding = session.cash_register_id.total_entry_encoding + (
                     0.0 if session.state == 'closed' else total_cash_payment
                 )
@@ -123,8 +126,10 @@ class PosSession(models.Model):
 
     @api.depends('order_ids.payment_ids.amount')
     def _compute_total_payments_amount(self):
+        result = self.env['pos.payment'].read_group([('session_id', 'in', self.ids)], ['amount'], ['session_id'])
+        session_amount_map = dict((data['session_id'][0], data['amount']) for data in result)
         for session in self:
-            session.total_payments_amount = sum(session.order_ids.mapped('payment_ids.amount'))
+            session.total_payments_amount = session_amount_map.get(session.id) or 0
 
     def _compute_order_count(self):
         orders_data = self.env['pos.order'].read_group([('session_id', 'in', self.ids)], ['session_id'], ['session_id'])
@@ -135,8 +140,8 @@ class PosSession(models.Model):
     @api.depends('picking_ids', 'picking_ids.state')
     def _compute_picking_count(self):
         for session in self:
-            session.picking_count = len(session.picking_ids.ids)
-            session.failed_pickings = bool(session.picking_ids.filtered(lambda p: p.state != 'done'))
+            session.picking_count = self.env['stock.picking'].search_count([('pos_session_id', '=', session.id)])
+            session.failed_pickings = bool(self.env['stock.picking'].search([('pos_session_id', '=', session.id), ('state', '!=', 'done')], limit=1))
 
     def action_stock_picking(self):
         self.ensure_one()