[FIX] mail performance: avoid useless queries

Avoid making queries that are known to return empty recordsets, and do not
format messages to be notified on no channel.

addons/mail/models/mail_channel.py

@@ -302,6 +302,8 @@ class Channel(models.Model):
             of the received message indicates on wich mail channel the message should be displayed.
             :param : mail.message to broadcast
         """
+        if not self:
+            return
         message.ensure_one()
         notifications = self._channel_message_notifications(message)
         self.env['bus.bus'].sendmany(notifications)

addons/mail/models/mail_message.py

@@ -794,13 +794,13 @@ class Message(models.Model):
         self_sudo = self.sudo()
 
         self.ensure_one()
-        partners_sudo = self.env['res.partner'].sudo() | self_sudo.partner_ids
-        channels_sudo = self.env['mail.channel'].sudo() | self_sudo.channel_ids
+        partners_sudo = self_sudo.partner_ids
+        channels_sudo = self_sudo.channel_ids
 
         # all followers of the mail.message document have to be added as partners and notified
         # and filter to employees only if the subtype is internal
         if self_sudo.subtype_id and self.model and self.res_id:
-            followers = self.env['mail.followers'].sudo().search([
+            followers = self_sudo.env['mail.followers'].search([
                 ('res_model', '=', self.model),
                 ('res_id', '=', self.res_id),
                 ('subtype_ids', 'in', self_sudo.subtype_id.id),
@@ -815,29 +815,28 @@ class Message(models.Model):
             partners_sudo = partners_sudo - self_sudo.author_id
 
         # update message, with maybe custom values
-        message_values = {
-            'channel_ids': [(6, 0, channels_sudo.ids)],
-            'needaction_partner_ids': [(6, 0, partners_sudo.ids)]
-        }
+        message_values = {}
+        if channels_sudo:
+            message_values['channel_ids'] = [(6, 0, channels_sudo.ids)]
+        if partners_sudo:
+            message_values['needaction_partner_ids'] = [(6, 0, partners_sudo.ids)]
         if self.model and self.res_id and hasattr(self.env[self.model], 'message_get_message_notify_values'):
             message_values.update(self.env[self.model].browse(self.res_id).message_get_message_notify_values(self, message_values))
-        self.write(message_values)
+        if message_values:
+            self.write(message_values)
 
         # notify partners and channels
         # those methods are called as SUPERUSER because portal users posting messages
         # have no access to partner model. Maybe propagating a real uid could be necessary.
         email_channels = channels_sudo.filtered(lambda channel: channel.email_send)
-        # make a dedicated search on res.users to avoid user_ids.notification_type that will be user_ids.id in [ARRAY]
-        notif_users = self.env['res.users'].sudo().search([
-            ('partner_id', 'in', partners_sudo.ids),
-            ('notification_type', '=', 'inbox')
-        ])
-        partners_sudo.search([
-            '|',
-            ('id', 'in', (partners_sudo - notif_users.mapped('partner_id')).ids),
-            ('channel_ids', 'in', email_channels.ids),
-            ('email', '!=', self_sudo.author_id and self_sudo.author_id.email or self_sudo.email_from),
-        ])._notify(self, force_send=force_send, send_after_commit=send_after_commit, user_signature=user_signature)
+        notif_partners = partners_sudo.filtered(lambda partner: 'inbox' in partner.mapped('user_ids.notification_type'))
+        if email_channels or partners_sudo - notif_partners:
+            partners_sudo.search([
+                '|',
+                ('id', 'in', (partners_sudo - notif_partners).ids),
+                ('channel_ids', 'in', email_channels.ids),
+                ('email', '!=', self_sudo.author_id.email or self_sudo.email_from),
+            ])._notify(self, force_send=force_send, send_after_commit=send_after_commit, user_signature=user_signature)
         channels_sudo._notify(self)
 
         # Discard cache, because child / parent allow reading and therefore

odoo/addons/test_performance/tests/test_performance.py

@@ -141,7 +141,7 @@ class TestPerformance(TransactionCase):
 
         records.write({'value': self.int(20)})
 
-    @queryCount(admin=42, demo=59)
+    @queryCount(admin=22, demo=35)
     def test_write_mail_with_tracking(self):
         """ Write records inheriting from 'mail.thread' (with field tracking). """
         record = self.env['test_performance.mail'].search([], limit=1)
@@ -180,7 +180,7 @@ class TestPerformance(TransactionCase):
         model = self.env['test_performance.mail']
         model.with_context(tracking_disable=True).create({'name': self.str('X')})
 
-    @queryCount(admin=81, demo=107)
+    @queryCount(admin=43, demo=61)
     def test_create_mail_with_tracking(self):
         """ Create records inheriting from 'mail.thread' (with field tracking). """
         model = self.env['test_performance.mail']