diff --git a/addons/mail/mail_followers.py b/addons/mail/mail_followers.py
index 2a20c4f58dc..dea10bbd7a1 100644
--- a/addons/mail/mail_followers.py
+++ b/addons/mail/mail_followers.py
@@ -22,7 +22,7 @@
 import threading
 
 from openerp.osv import osv, fields
-from openerp import tools, SUPERUSER_ID
+from openerp import api, tools, SUPERUSER_ID
 from openerp.tools.translate import _
 from openerp.tools.mail import plaintext2html
 
@@ -55,20 +55,31 @@ class mail_followers(osv.Model):
     # Modifying followers change access rights to individual documents. As the
     # cache may contain accessible/inaccessible data, one has to refresh it.
     #
-    def create(self, cr, uid, vals, context=None):
-        res = super(mail_followers, self).create(cr, uid, vals, context=context)
-        self.invalidate_cache(cr, uid, context=context)
+    @api.multi
+    def _invalidate_documents(self):
+        """ Invalidate the cache of the documents followed by ``self``. """
+        for record in self:
+            if record.res_id:
+                self.env[record.res_model].invalidate_cache(ids=[record.res_id])
+
+    @api.model
+    def create(self, vals):
+        record = super(mail_followers, self).create(vals)
+        record._invalidate_documents()
+        return record
+
+    @api.multi
+    def write(self, vals):
+        if 'res_model' in vals or 'res_id' in vals:
+            self._invalidate_documents()
+        res = super(mail_followers, self).write(vals)
+        self._invalidate_documents()
         return res
 
-    def write(self, cr, uid, ids, vals, context=None):
-        res = super(mail_followers, self).write(cr, uid, ids, vals, context=context)
-        self.invalidate_cache(cr, uid, context=context)
-        return res
-
-    def unlink(self, cr, uid, ids, context=None):
-        res = super(mail_followers, self).unlink(cr, uid, ids, context=context)
-        self.invalidate_cache(cr, uid, context=context)
-        return res
+    @api.multi
+    def unlink(self):
+        self._invalidate_documents()
+        return super(mail_followers, self).unlink()
 
     _sql_constraints = [('mail_followers_res_partner_res_model_id_uniq','unique(res_model,res_id,partner_id)','Error, a partner cannot follow twice the same object.')]
 
diff --git a/addons/mail/tests/test_mail_features.py b/addons/mail/tests/test_mail_features.py
index a457dd0db73..50ee8db7eaf 100644
--- a/addons/mail/tests/test_mail_features.py
+++ b/addons/mail/tests/test_mail_features.py
@@ -209,6 +209,16 @@ class test_mail(TestMail):
         self.assertTrue(subtype_data['mt_mg_nodef']['followed'], 'Admin should follow mt_mg_nodef in pigs')
         self.assertTrue(subtype_data['mt_all_nodef']['followed'], 'Admin should follow mt_all_nodef in pigs')
 
+    def test_10_cache_invalidation(self):
+        """ Test that creating a mail-thread record does not invalidate the whole cache. """
+        # make a new record in cache
+        record = self.env['res.partner'].new({'name': 'Brave New Partner'})
+        self.assertTrue(record.name)
+
+        # creating a mail-thread record should not invalidate the whole cache
+        self.env['res.partner'].create({'name': 'Actual Partner'})
+        self.assertTrue(record.name)
+
     def test_11_notification_url(self):
         """ Tests designed to test the URL added in notification emails. """
         cr, uid, group_pigs = self.cr, self.uid, self.group_pigs
diff --git a/addons/portal/mail_message.py b/addons/portal/mail_message.py
index 36b06484e9e..1030deeb941 100644
--- a/addons/portal/mail_message.py
+++ b/addons/portal/mail_message.py
@@ -51,6 +51,8 @@ class mail_message(osv.Model):
         """
         if uid == SUPERUSER_ID:
             return super(mail_message, self).check_access_rule(cr, uid, ids=ids, operation=operation, context=context)
+        if isinstance(ids, (int, long)):
+            ids = [ids]
         group_ids = self.pool.get('res.users').browse(cr, uid, uid, context=context).groups_id
         group_user_id = self.pool.get("ir.model.data").get_object_reference(cr, uid, 'base', 'group_user')[1]
         if group_user_id not in [group.id for group in group_ids]:
diff --git a/addons/purchase/purchase.py b/addons/purchase/purchase.py
index d28a14bdfa5..494fb3abfe7 100644
--- a/addons/purchase/purchase.py
+++ b/addons/purchase/purchase.py
@@ -72,7 +72,6 @@ class purchase_order(osv.osv):
                     ('order_id', '=', po.id), '|', ('date_planned', '=', po.minimum_planned_date), ('date_planned', '<', value)
                 ], context=context)
                 pol_obj.write(cr, uid, pol_ids, {'date_planned': value}, context=context)
-        self.invalidate_cache(cr, uid, context=context)
         return True
 
     def _minimum_planned_date(self, cr, uid, ids, field_name, arg, context=None):