1 files changed, 7 insertions, 4 deletions

diff --git a/src/mailman/model/user.py b/src/mailman/model/user.py
index 576015dbe..ab581fdc8 100644
--- a/src/mailman/model/user.py
+++ b/src/mailman/model/user.py
@@ -56,8 +56,8 @@ class User(Model):
 
     id = Column(Integer, primary_key=True)
     display_name = Column(Unicode)
-    _password = Column('password', LargeBinary) # TODO : was RawStr()
-    _user_id = Column(UUID)
+    _password = Column('password', LargeBinary)
+    _user_id = Column(UUID, index=True)
     _created_on = Column(DateTime)
 
     addresses = relationship(
@@ -66,12 +66,15 @@ class User(Model):
 
     _preferred_address_id = Column(
         Integer,
-        ForeignKey('address.id', use_alter=True, name='_preferred_address'))
+        ForeignKey('address.id', use_alter=True,
+                   name='_preferred_address',
+                   ondelete='SET NULL'))
+
     _preferred_address = relationship(
         'Address', primaryjoin=(_preferred_address_id==Address.id),
         post_update=True)
 
-    preferences_id = Column(Integer, ForeignKey('preferences.id'))
+    preferences_id = Column(Integer, ForeignKey('preferences.id'), index=True)
     preferences = relationship(
         'Preferences', backref=backref('user', uselist=False))