diff --git a/addons/website/models/ir_actions.py b/addons/website/models/ir_actions.py
index 176187ea4e0..478972d9a86 100644
--- a/addons/website/models/ir_actions.py
+++ b/addons/website/models/ir_actions.py
@@ -39,7 +39,7 @@ class ServerAction(models.Model):
     def _get_website_url(self):
         for action in self:
             if action.state == 'code' and action.website_published:
-                action.website_url = self._compute_website_url(action.website_path, action.xml_id)
+                action.website_url = action._compute_website_url(action.website_path, action.xml_id)
 
     @api.model
     def _get_eval_context(self, action):
diff --git a/odoo/addons/base/module/module.py b/odoo/addons/base/module/module.py
index 22ae3ca2c58..2b5fe2db583 100644
--- a/odoo/addons/base/module/module.py
+++ b/odoo/addons/base/module/module.py
@@ -16,6 +16,7 @@ from docutils.core import publish_string
 from docutils.transforms import Transform, writer_aux
 from docutils.writers.html4css1 import Writer
 import lxml.html
+import psycopg2
 
 try:
     from cStringIO import StringIO
@@ -479,6 +480,14 @@ class Module(models.Model):
 
     @api.multi
     def _button_immediate_function(self, function):
+        try:
+            # This is done because the installation/uninstallation/upgrade can modify a currently
+            # running cron job and prevent it from finishing, and since the ir_cron table is locked
+            # during execution, the lock won't be released until timeout.
+            self._cr.execute("SELECT * FROM ir_cron FOR UPDATE NOWAIT")
+        except psycopg2.OperationalError:
+            raise UserError(_("The server is busy right now, module operations are not possible at"
+                              " this time, please try again later."))
         function(self)
 
         self._cr.commit()
diff --git a/odoo/models.py b/odoo/models.py
index dbabd1c14f2..ba1d51b2df0 100644
--- a/odoo/models.py
+++ b/odoo/models.py
@@ -2500,7 +2500,11 @@ class BaseModel(object):
                             cr.execute("SELECT indexname FROM pg_indexes WHERE indexname = %s and tablename = %s", (indexname, self._table))
                             res2 = cr.dictfetchall()
                             if not res2 and field.index:
-                                cr.execute('CREATE INDEX "%s_%s_index" ON "%s" ("%s")' % (self._table, name, self._table, name))
+                                try:  # DO NOT FORWARD-PORT TO SAAS-15 AND UP (stop at saas-14)
+                                    with cr.savepoint():
+                                        cr.execute('CREATE INDEX "%s_%s_index" ON "%s" ("%s")' % (self._table, name, self._table, name))
+                                except psycopg2.OperationalError as e:
+                                    _schema.error('Unable to add index for %s (%s):\n %s', self._table, name, e.message)
                                 cr.commit()
                                 if field.type == 'text':
                                     # FIXME: for fields.text columns we should try creating GIN indexes instead (seems most suitable for an ERP context)