diff --git a/addons/test_mail/data/subtype_demo.xml b/addons/test_mail/data/subtype_demo.xml
index 20a486aace8..2645f3d1186 100644
--- a/addons/test_mail/data/subtype_demo.xml
+++ b/addons/test_mail/data/subtype_demo.xml
@@ -1,6 +1,14 @@
 <?xml version="1.0" encoding="utf-8"?>
 <odoo>
 
+    <record id="st_mail_test_simple_external" model="mail.message.subtype">
+        <field name="name">External subtype</field>
+        <field name="description">External subtype</field>
+        <field name="res_model">mail.test.simple</field>
+        <field name="default" eval="False"/>
+        <field name="internal" eval="False"/>
+    </record>
+
     <record id="st_mail_test_full_umbrella_upd" model="mail.message.subtype">
         <field name="name">Umbrella Changed Subtype</field>
         <field name="description">Umbrella Changed</field>
diff --git a/addons/test_mail/tests/test_performance.py b/addons/test_mail/tests/test_performance.py
index a544b447422..983686be809 100644
--- a/addons/test_mail/tests/test_performance.py
+++ b/addons/test_mail/tests/test_performance.py
@@ -131,6 +131,17 @@ class TestAdvMailPerformance(TransactionCase):
             'notification_type': 'inbox',
             'groups_id': [(6, 0, [self.env.ref('base.group_user').id])],
         })
+        self.customer = self.env['res.partner'].with_context(self._quick_create_ctx).create({
+            'name': 'Test Customer',
+            'email': 'test@example.com',
+        })
+        self.user_test = self.env['res.users'].with_context(self._quick_create_ctx).create({
+            'name': 'Paulette Testouille',
+            'login': 'paul',
+            'email': 'p.p@example.com',
+            'notification_type': 'inbox',
+            'groups_id': [(6, 0, [self.env.ref('base.group_user').id])],
+        })
 
     @users('admin', 'emp')
     @warmup
@@ -145,17 +156,125 @@ class TestAdvMailPerformance(TransactionCase):
     @mute_logger('odoo.models.unlink')
     def test_adv_activity_full(self):
         record = self.env['mail.test.activity'].create({'name': 'Test'})
-        model = self.env['mail.activity'].with_context({
+        MailActivity = self.env['mail.activity'].with_context({
             'default_res_model': 'mail.test.activity',
         })
 
         with self.assertQueryCount(admin=47, emp=54):  # com runbot 46 - 52 // test_mail only: 35 - 41
-            model.create({
+            activity = MailActivity.create({
                 'summary': 'Test Activity',
                 'res_id': record.id,
                 'activity_type_id': self.env.ref('mail.mail_activity_data_todo').id,
             })
 
+        with self.assertQueryCount(admin=84, emp=116):  # com runbot 84 - 116 // test_mail only: 68 - 96
+            activity.action_feedback(feedback='Zizisse Done !')
+
+    @mute_logger('odoo.addons.mail.models.mail_mail', 'odoo.models.unlink')
+    @users('admin', 'emp')
+    @warmup
+    def test_message_assignation_email(self):
+        self.user_test.write({'notification_type': 'email'})
+        record = self.env['mail.test.track'].create({'name': 'Test'})
+
+        with self.assertQueryCount(admin=80, emp=109):  # test_mail only: 69 - 96
+            record.write({
+                'user_id': self.user_test.id,
+            })
+
+    @users('admin', 'emp')
+    @warmup
+    def test_message_assignation_inbox(self):
+        record = self.env['mail.test.track'].create({'name': 'Test'})
+
+        with self.assertQueryCount(admin=22, emp=28):  # test_mail only: 20 - 26
+            record.write({
+                'user_id': self.user_test.id,
+            })
+
+    @users('admin', 'emp')
+    @warmup
+    def test_message_log(self):
+        record = self.env['mail.test.simple'].create({'name': 'Test'})
+
+        with self.assertQueryCount(admin=5, emp=5):  # test_mail only: 3 - 3
+            record._message_log(
+                body='<p>Test _message_log</p>',
+                message_type='comment')
+
+    @users('admin', 'emp')
+    @warmup
+    def test_message_log_with_post(self):
+        record = self.env['mail.test.simple'].create({'name': 'Test'})
+
+        with self.assertQueryCount(admin=31, emp=43):  # test_mail only: 29 - 40
+            record.message_post(
+                body='<p>Test message_post as log</p>',
+                subtype='mail.mt_note',
+                message_type='comment')
+
+    @users('admin', 'emp')
+    @warmup
+    def test_message_post_no_notification(self):
+        record = self.env['mail.test.simple'].create({'name': 'Test'})
+
+        with self.assertQueryCount(admin=31, emp=43):  # test_mail only: 29 - 40
+            record.message_post(
+                body='<p>Test Post Performances basic</p>',
+                partner_ids=[],
+                message_type='comment',
+                subtype='mail.mt_comment')
+
+    @mute_logger('odoo.addons.mail.models.mail_mail', 'odoo.models.unlink')
+    @users('admin', 'emp')
+    @warmup
+    def test_message_post_one_email_notification(self):
+        record = self.env['mail.test.simple'].create({'name': 'Test'})
+
+        with self.assertQueryCount(admin=85, emp=115):  # com runbot 83 - 112 // test_mail only: 81 - 110
+            record.message_post(
+                body='<p>Test Post Performances with an email ping</p>',
+                partner_ids=self.customer.ids,
+                message_type='comment',
+                subtype='mail.mt_comment')
+
+    @users('admin', 'emp')
+    @warmup
+    def test_message_post_one_inbox_notification(self):
+        record = self.env['mail.test.simple'].create({'name': 'Test'})
+
+        with self.assertQueryCount(admin=44, emp=58):  # com runbot 42 - 55 // test_mail only: 42 - 55
+            record.message_post(
+                body='<p>Test Post Performances with an inbox ping</p>',
+                partner_ids=self.user_test.partner_id.ids,
+                message_type='comment',
+                subtype='mail.mt_comment')
+
+    @mute_logger('odoo.models.unlink')
+    @users('admin', 'emp')
+    @warmup
+    def test_message_subscribe_default(self):
+        record = self.env['mail.test.simple'].create({'name': 'Test'})
+
+        with self.assertQueryCount(admin=7, emp=8):  # test_mail only: 7 - 8
+            record.message_subscribe(partner_ids=self.user_test.partner_id.ids)
+
+        with self.assertQueryCount(admin=19, emp=19):  # test_mail only: 19 - 19
+            record.message_subscribe(partner_ids=self.user_test.partner_id.ids)
+
+    @mute_logger('odoo.models.unlink')
+    @users('admin', 'emp')
+    @warmup
+    def test_message_subscribe_subtypes(self):
+        record = self.env['mail.test.simple'].create({'name': 'Test'})
+        subtype_ids = (self.env.ref('test_mail.st_mail_test_simple_external') | self.env.ref('mail.mt_comment')).ids
+
+        with self.assertQueryCount(admin=7, emp=8):  # test_mail only: 7 - 8
+            record.message_subscribe(partner_ids=self.user_test.partner_id.ids, subtype_ids=subtype_ids)
+
+        with self.assertQueryCount(admin=19, emp=19):  # test_mail only: 18 - 18
+            record.message_subscribe(partner_ids=self.user_test.partner_id.ids, subtype_ids=subtype_ids)
+
 
 class TestHeavyMailPerformance(TransactionCase):
 
@@ -326,9 +445,35 @@ class TestHeavyMailPerformance(TransactionCase):
     @mute_logger('odoo.tests', 'odoo.addons.mail.models.mail_mail', 'odoo.models.unlink')
     @users('admin', 'emp')
     @warmup
-    def test_complex_create_tracking_subscription(self):
-        """ Create record using most features: auto subscription, tracking
-        and templates. """
+    def test_complex_tracking_assignation(self):
+        """ Assignation performance test on already-created record """
+        rec = self.env['mail.test.full'].create({
+            'name': 'Test',
+            'umbrella_id': self.umbrella.id,
+            'customer_id': self.customer.id,
+            'user_id': self.env.uid,
+        })
+        self.assertEqual(rec.message_partner_ids, self.partners | self.env.user.partner_id)
+
+        with self.assertQueryCount(admin=87, emp=117):  # test_mail only: 76 - 104
+            rec.write({'user_id': self.user_portal.id})
+
+        self.assertEqual(rec.message_partner_ids, self.partners | self.env.user.partner_id | self.user_portal.partner_id)
+        # write tracking message
+        self.assertEqual(rec.message_ids[0].subtype_id, self.env.ref('mail.mt_note'))
+        self.assertEqual(rec.message_ids[0].needaction_partner_ids, self.env['res.partner'])
+        # create tracking message
+        self.assertEqual(rec.message_ids[1].subtype_id, self.env.ref('test_mail.st_mail_test_full_umbrella_upd'))
+        self.assertEqual(rec.message_ids[1].needaction_partner_ids, self.partners)
+        # creation message
+        self.assertEqual(rec.message_ids[2].subtype_id, self.env.ref('mail.mt_note'))
+        self.assertEqual(rec.message_ids[2].needaction_partner_ids, self.env['res.partner'])
+
+    @mute_logger('odoo.tests', 'odoo.addons.mail.models.mail_mail', 'odoo.models.unlink')
+    @users('admin', 'emp')
+    @warmup
+    def test_complex_tracking_subscription_create(self):
+        """ Creation performance test involving auto subscription, assignation, tracking with subtype and template send. """
         umbrella_id = self.umbrella.id
         customer_id = self.customer.id
         user_id = self.user_portal.id
@@ -342,7 +487,7 @@ class TestHeavyMailPerformance(TransactionCase):
             })
 
         self.assertEqual(rec.message_partner_ids, self.partners | self.env.user.partner_id | self.user_portal.partner_id)
-        # tracking message
+        # create tracking message
         self.assertEqual(rec.message_ids[0].subtype_id, self.env.ref('test_mail.st_mail_test_full_umbrella_upd'))
         self.assertEqual(rec.message_ids[0].needaction_partner_ids, self.partners | self.user_portal.partner_id)
         # creation message
@@ -352,12 +497,40 @@ class TestHeavyMailPerformance(TransactionCase):
     @mute_logger('odoo.tests', 'odoo.addons.mail.models.mail_mail', 'odoo.models.unlink')
     @users('admin', 'emp')
     @warmup
-    def test_complex_write_tracking_subscription(self):
-        """ Create record using most features: auto subscription, tracking
-        and templates. """
+    def test_complex_tracking_subscription_subtype(self):
+        """ Write performance test involving auto subscription, tracking with subtype """
+        rec = self.env['mail.test.full'].create({
+            'name': 'Test',
+            'umbrella_id': False,
+            'customer_id': False,
+            'user_id': self.user_portal.id,
+        })
+        self.assertEqual(rec.message_partner_ids, self.user_portal.partner_id | self.env.user.partner_id)
+
+        with self.assertQueryCount(admin=236, emp=275):  # test_mail only: 230 - 268
+            rec.write({
+                'name': 'Test2',
+                'umbrella_id': self.umbrella.id,
+                })
+
+        self.assertEqual(rec.message_partner_ids, self.partners | self.env.user.partner_id | self.user_portal.partner_id)
+        # write tracking message
+        self.assertEqual(rec.message_ids[0].subtype_id, self.env.ref('test_mail.st_mail_test_full_umbrella_upd'))
+        self.assertEqual(rec.message_ids[0].needaction_partner_ids, self.partners | self.user_portal.partner_id)
+        # create tracking message
+        self.assertEqual(rec.message_ids[1].subtype_id, self.env.ref('mail.mt_note'))
+        self.assertEqual(rec.message_ids[1].needaction_partner_ids, self.env['res.partner'])
+        # creation message
+        self.assertEqual(rec.message_ids[2].subtype_id, self.env.ref('mail.mt_note'))
+        self.assertEqual(rec.message_ids[2].needaction_partner_ids, self.env['res.partner'])
+
+    @mute_logger('odoo.tests', 'odoo.addons.mail.models.mail_mail', 'odoo.models.unlink')
+    @users('admin', 'emp')
+    @warmup
+    def test_complex_tracking_subscription_write(self):
+        """ Write performance test involving auto subscription, tracking with subtype and template send """
         umbrella_id = self.umbrella.id
         customer_id = self.customer.id
-        user_id = self.user_portal.id
         umbrella2 = self.env['mail.test'].with_context(mail_create_nosubscribe=True).create({
             'name': 'Test Umbrella 2',
             'customer_id': False,
@@ -368,7 +541,7 @@ class TestHeavyMailPerformance(TransactionCase):
             'name': 'Test',
             'umbrella_id': umbrella2.id,
             'customer_id': False,
-            'user_id': user_id,
+            'user_id': self.user_portal.id,
         })
         self.assertEqual(rec.message_partner_ids, self.user_portal.partner_id | self.env.user.partner_id)
 
@@ -389,3 +562,39 @@ class TestHeavyMailPerformance(TransactionCase):
         # creation message
         self.assertEqual(rec.message_ids[2].subtype_id, self.env.ref('mail.mt_note'))
         self.assertEqual(rec.message_ids[2].needaction_partner_ids, self.env['res.partner'])
+
+    @mute_logger('odoo.tests', 'odoo.addons.mail.models.mail_mail', 'odoo.models.unlink')
+    @users('admin', 'emp')
+    @warmup
+    def test_complex_tracking_template(self):
+        """ Write performance test involving assignation, tracking with template """
+        customer_id = self.customer.id
+
+        rec = self.env['mail.test.full'].create({
+            'name': 'Test',
+            'umbrella_id': self.umbrella.id,
+            'customer_id': False,
+            'user_id': self.user_portal.id,
+            'mail_template': self.env.ref('test_mail.mail_test_full_tracking_tpl').id,
+        })
+        self.assertEqual(rec.message_partner_ids, self.partners | self.env.user.partner_id | self.user_portal.partner_id)
+
+        with self.assertQueryCount(admin=72, emp=101):  # test_mail only: 64 - 91
+            rec.write({
+                'name': 'Test2',
+                'customer_id': customer_id,
+                'user_id': self.env.uid,
+            })
+
+        # write template message (sent to customer, mass mailing kept for history)
+        self.assertEqual(rec.message_ids[0].subtype_id, self.env['mail.message.subtype'])
+        self.assertEqual(rec.message_ids[0].subject, 'Test Template')
+        # write tracking message
+        self.assertEqual(rec.message_ids[1].subtype_id, self.env.ref('mail.mt_note'))
+        self.assertEqual(rec.message_ids[1].needaction_partner_ids, self.env['res.partner'])
+        # create tracking message
+        self.assertEqual(rec.message_ids[2].subtype_id, self.env.ref('test_mail.st_mail_test_full_umbrella_upd'))
+        self.assertEqual(rec.message_ids[2].needaction_partner_ids, self.partners | self.user_portal.partner_id)
+        # creation message
+        self.assertEqual(rec.message_ids[3].subtype_id, self.env.ref('mail.mt_note'))
+        self.assertEqual(rec.message_ids[3].needaction_partner_ids, self.env['res.partner'])