diff --git a/rhodecode/model/db.py b/rhodecode/model/db.py
--- a/rhodecode/model/db.py
+++ b/rhodecode/model/db.py
@@ -39,7 +39,8 @@ from rhodecode.lib.vcs.utils.helpers imp
 from rhodecode.lib.vcs.exceptions import VCSError
 from rhodecode.lib.vcs.utils.lazy import LazyProperty
 
-from rhodecode.lib import str2bool, safe_str, get_changeset_safe, safe_unicode
+from rhodecode.lib.utils2 import str2bool, safe_str, get_changeset_safe, \
+    safe_unicode
 from rhodecode.lib.compat import json
 from rhodecode.lib.caching_query import FromCache
 
@@ -145,12 +146,18 @@ class BaseModel(object):
         obj = cls.query().get(id_)
         Session.delete(obj)
 
+    def __repr__(self):
+        if hasattr(self, '__unicode__'):
+            # python repr needs to return str
+            return safe_str(self.__unicode__())
+        return '<DB:%s>' % (self.__class__.__name__)
 
 class RhodeCodeSetting(Base, BaseModel):
     __tablename__ = 'rhodecode_settings'
     __table_args__ = (
         UniqueConstraint('app_settings_name'),
-        {'extend_existing': True}
+        {'extend_existing': True, 'mysql_engine':'InnoDB',
+         'mysql_charset': 'utf8'}
     )
     app_settings_id = Column("app_settings_id", Integer(), nullable=False, unique=True, default=None, primary_key=True)
     app_settings_name = Column("app_settings_name", String(length=255, convert_unicode=False, assert_unicode=None), nullable=True, unique=None, default=None)
@@ -181,8 +188,8 @@ class RhodeCodeSetting(Base, BaseModel):
         """
         self._app_settings_value = safe_unicode(val)
 
-    def __repr__(self):
-        return "<%s('%s:%s')>" % (
+    def __unicode__(self):
+        return u"<%s('%s:%s')>" % (
             self.__class__.__name__,
             self.app_settings_name, self.app_settings_value
         )
@@ -224,7 +231,8 @@ class RhodeCodeUi(Base, BaseModel):
     __tablename__ = 'rhodecode_ui'
     __table_args__ = (
         UniqueConstraint('ui_key'),
-        {'extend_existing': True}
+        {'extend_existing': True, 'mysql_engine':'InnoDB',
+         'mysql_charset': 'utf8'}
     )
 
     HOOK_UPDATE = 'changegroup.update'
@@ -274,7 +282,8 @@ class User(Base, BaseModel):
     __tablename__ = 'users'
     __table_args__ = (
         UniqueConstraint('username'), UniqueConstraint('email'),
-        {'extend_existing': True}
+        {'extend_existing': True, 'mysql_engine':'InnoDB',
+         'mysql_charset': 'utf8'}
     )
     user_id = Column("user_id", Integer(), nullable=False, unique=True, default=None, primary_key=True)
     username = Column("username", String(length=255, convert_unicode=False, assert_unicode=None), nullable=True, unique=None, default=None)
@@ -294,10 +303,15 @@ class User(Base, BaseModel):
     repositories = relationship('Repository')
     user_followers = relationship('UserFollowing', primaryjoin='UserFollowing.follows_user_id==User.user_id', cascade='all')
     repo_to_perm = relationship('UserRepoToPerm', primaryjoin='UserRepoToPerm.user_id==User.user_id', cascade='all')
+    repo_group_to_perm = relationship('UserRepoGroupToPerm', primaryjoin='UserRepoGroupToPerm.user_id==User.user_id', cascade='all')
 
     group_member = relationship('UsersGroupMember', cascade='all')
 
-    notifications = relationship('UserNotification',)
+    notifications = relationship('UserNotification', cascade='all')
+    # notifications assigned to this user
+    user_created_notifications = relationship('Notification', cascade='all')
+    # comments created by this user
+    user_comments = relationship('ChangesetComment', cascade='all')
 
     @hybrid_property
     def email(self):
@@ -328,8 +342,8 @@ class User(Base, BaseModel):
     def is_admin(self):
         return self.admin
 
-    def __repr__(self):
-        return "<%s('id:%s:%s')>" % (self.__class__.__name__,
+    def __unicode__(self):
+        return u"<%s('id:%s:%s')>" % (self.__class__.__name__,
                                      self.user_id, self.username)
 
     @classmethod
@@ -376,6 +390,9 @@ class User(Base, BaseModel):
 
     def __json__(self):
         return dict(
+            user_id=self.user_id,
+            first_name=self.name,
+            last_name=self.lastname,
             email=self.email,
             full_name=self.full_name,
             full_name_or_username=self.full_name_or_username,
@@ -386,7 +403,10 @@ class User(Base, BaseModel):
 
 class UserLog(Base, BaseModel):
     __tablename__ = 'user_logs'
-    __table_args__ = {'extend_existing': True}
+    __table_args__ = (
+        {'extend_existing': True, 'mysql_engine':'InnoDB',
+         'mysql_charset': 'utf8'},
+    )
     user_log_id = Column("user_log_id", Integer(), nullable=False, unique=True, default=None, primary_key=True)
     user_id = Column("user_id", Integer(), ForeignKey('users.user_id'), nullable=False, unique=None, default=None)
     repository_id = Column("repository_id", Integer(), ForeignKey('repositories.repo_id'), nullable=True)
@@ -405,7 +425,10 @@ class UserLog(Base, BaseModel):
 
 class UsersGroup(Base, BaseModel):
     __tablename__ = 'users_groups'
-    __table_args__ = {'extend_existing': True}
+    __table_args__ = (
+        {'extend_existing': True, 'mysql_engine':'InnoDB',
+         'mysql_charset': 'utf8'},
+    )
 
     users_group_id = Column("users_group_id", Integer(), nullable=False, unique=True, default=None, primary_key=True)
     users_group_name = Column("users_group_name", String(length=255, convert_unicode=False, assert_unicode=None), nullable=False, unique=True, default=None)
@@ -413,9 +436,10 @@ class UsersGroup(Base, BaseModel):
 
     members = relationship('UsersGroupMember', cascade="all, delete, delete-orphan", lazy="joined")
     users_group_to_perm = relationship('UsersGroupToPerm', cascade='all')
+    users_group_repo_to_perm = relationship('UsersGroupRepoToPerm', cascade='all')
 
-    def __repr__(self):
-        return '<userGroup(%s)>' % (self.users_group_name)
+    def __unicode__(self):
+        return u'<userGroup(%s)>' % (self.users_group_name)
 
     @classmethod
     def get_by_group_name(cls, group_name, cache=False,
@@ -443,7 +467,10 @@ class UsersGroup(Base, BaseModel):
 
 class UsersGroupMember(Base, BaseModel):
     __tablename__ = 'users_groups_members'
-    __table_args__ = {'extend_existing': True}
+    __table_args__ = (
+        {'extend_existing': True, 'mysql_engine':'InnoDB',
+         'mysql_charset': 'utf8'},
+    )
 
     users_group_member_id = Column("users_group_member_id", Integer(), nullable=False, unique=True, default=None, primary_key=True)
     users_group_id = Column("users_group_id", Integer(), ForeignKey('users_groups.users_group_id'), nullable=False, unique=None, default=None)
@@ -461,7 +488,8 @@ class Repository(Base, BaseModel):
     __tablename__ = 'repositories'
     __table_args__ = (
         UniqueConstraint('repo_name'),
-        {'extend_existing': True},
+        {'extend_existing': True, 'mysql_engine':'InnoDB',
+         'mysql_charset': 'utf8'},
     )
 
     repo_id = Column("repo_id", Integer(), nullable=False, unique=True, default=None, primary_key=True)
@@ -489,9 +517,9 @@ class Repository(Base, BaseModel):
 
     logs = relationship('UserLog')
 
-    def __repr__(self):
-        return "<%s('%s:%s')>" % (self.__class__.__name__,
-                                  self.repo_id, self.repo_name)
+    def __unicode__(self):
+        return u"<%s('%s:%s')>" % (self.__class__.__name__,self.repo_id,
+                                   self.repo_name)
 
     @classmethod
     def url_sep(cls):
@@ -710,7 +738,8 @@ class RepoGroup(Base, BaseModel):
     __table_args__ = (
         UniqueConstraint('group_name', 'group_parent_id'),
         CheckConstraint('group_id != group_parent_id'),
-        {'extend_existing': True},
+        {'extend_existing': True, 'mysql_engine':'InnoDB',
+         'mysql_charset': 'utf8'},
     )
     __mapper_args__ = {'order_by': 'group_name'}
 
@@ -728,8 +757,8 @@ class RepoGroup(Base, BaseModel):
         self.group_name = group_name
         self.parent_group = parent_group
 
-    def __repr__(self):
-        return "<%s('%s:%s')>" % (self.__class__.__name__, self.group_id,
+    def __unicode__(self):
+        return u"<%s('%s:%s')>" % (self.__class__.__name__, self.group_id,
                                   self.group_name)
 
     @classmethod
@@ -837,13 +866,16 @@ class RepoGroup(Base, BaseModel):
 
 class Permission(Base, BaseModel):
     __tablename__ = 'permissions'
-    __table_args__ = {'extend_existing': True}
+    __table_args__ = (
+        {'extend_existing': True, 'mysql_engine':'InnoDB',
+         'mysql_charset': 'utf8'},
+    )
     permission_id = Column("permission_id", Integer(), nullable=False, unique=True, default=None, primary_key=True)
     permission_name = Column("permission_name", String(length=255, convert_unicode=False, assert_unicode=None), nullable=True, unique=None, default=None)
     permission_longname = Column("permission_longname", String(length=255, convert_unicode=False, assert_unicode=None), nullable=True, unique=None, default=None)
 
-    def __repr__(self):
-        return "<%s('%s:%s')>" % (
+    def __unicode__(self):
+        return u"<%s('%s:%s')>" % (
             self.__class__.__name__, self.permission_id, self.permission_name
         )
 
@@ -874,7 +906,8 @@ class UserRepoToPerm(Base, BaseModel):
     __tablename__ = 'repo_to_perm'
     __table_args__ = (
         UniqueConstraint('user_id', 'repository_id', 'permission_id'),
-        {'extend_existing': True}
+        {'extend_existing': True, 'mysql_engine':'InnoDB',
+         'mysql_charset': 'utf8'}
     )
     repo_to_perm_id = Column("repo_to_perm_id", Integer(), nullable=False, unique=True, default=None, primary_key=True)
     user_id = Column("user_id", Integer(), ForeignKey('users.user_id'), nullable=False, unique=None, default=None)
@@ -894,15 +927,16 @@ class UserRepoToPerm(Base, BaseModel):
         Session.add(n)
         return n
 
-    def __repr__(self):
-        return '<user:%s => %s >' % (self.user, self.repository)
+    def __unicode__(self):
+        return u'<user:%s => %s >' % (self.user, self.repository)
 
 
 class UserToPerm(Base, BaseModel):
     __tablename__ = 'user_to_perm'
     __table_args__ = (
         UniqueConstraint('user_id', 'permission_id'),
-        {'extend_existing': True}
+        {'extend_existing': True, 'mysql_engine':'InnoDB',
+         'mysql_charset': 'utf8'}
     )
     user_to_perm_id = Column("user_to_perm_id", Integer(), nullable=False, unique=True, default=None, primary_key=True)
     user_id = Column("user_id", Integer(), ForeignKey('users.user_id'), nullable=False, unique=None, default=None)
@@ -916,7 +950,8 @@ class UsersGroupRepoToPerm(Base, BaseMod
     __tablename__ = 'users_group_repo_to_perm'
     __table_args__ = (
         UniqueConstraint('repository_id', 'users_group_id', 'permission_id'),
-        {'extend_existing': True}
+        {'extend_existing': True, 'mysql_engine':'InnoDB',
+         'mysql_charset': 'utf8'}
     )
     users_group_to_perm_id = Column("users_group_to_perm_id", Integer(), nullable=False, unique=True, default=None, primary_key=True)
     users_group_id = Column("users_group_id", Integer(), ForeignKey('users_groups.users_group_id'), nullable=False, unique=None, default=None)
@@ -936,15 +971,16 @@ class UsersGroupRepoToPerm(Base, BaseMod
         Session.add(n)
         return n
 
-    def __repr__(self):
-        return '<userGroup:%s => %s >' % (self.users_group, self.repository)
+    def __unicode__(self):
+        return u'<userGroup:%s => %s >' % (self.users_group, self.repository)
 
 
 class UsersGroupToPerm(Base, BaseModel):
     __tablename__ = 'users_group_to_perm'
     __table_args__ = (
         UniqueConstraint('users_group_id', 'permission_id',),
-        {'extend_existing': True}
+        {'extend_existing': True, 'mysql_engine':'InnoDB',
+         'mysql_charset': 'utf8'}
     )
     users_group_to_perm_id = Column("users_group_to_perm_id", Integer(), nullable=False, unique=True, default=None, primary_key=True)
     users_group_id = Column("users_group_id", Integer(), ForeignKey('users_groups.users_group_id'), nullable=False, unique=None, default=None)
@@ -958,7 +994,8 @@ class UserRepoGroupToPerm(Base, BaseMode
     __tablename__ = 'user_repo_group_to_perm'
     __table_args__ = (
         UniqueConstraint('user_id', 'group_id', 'permission_id'),
-        {'extend_existing': True}
+        {'extend_existing': True, 'mysql_engine':'InnoDB',
+         'mysql_charset': 'utf8'}
     )
 
     group_to_perm_id = Column("group_to_perm_id", Integer(), nullable=False, unique=True, default=None, primary_key=True)
@@ -975,7 +1012,8 @@ class UsersGroupRepoGroupToPerm(Base, Ba
     __tablename__ = 'users_group_repo_group_to_perm'
     __table_args__ = (
         UniqueConstraint('users_group_id', 'group_id'),
-        {'extend_existing': True}
+        {'extend_existing': True, 'mysql_engine':'InnoDB',
+         'mysql_charset': 'utf8'}
     )
 
     users_group_repo_group_to_perm_id = Column("users_group_repo_group_to_perm_id", Integer(), nullable=False, unique=True, default=None, primary_key=True)
@@ -990,7 +1028,11 @@ class UsersGroupRepoGroupToPerm(Base, Ba
 
 class Statistics(Base, BaseModel):
     __tablename__ = 'statistics'
-    __table_args__ = (UniqueConstraint('repository_id'), {'extend_existing': True})
+    __table_args__ = (
+         UniqueConstraint('repository_id'),
+         {'extend_existing': True, 'mysql_engine':'InnoDB',
+          'mysql_charset': 'utf8'}
+    )
     stat_id = Column("stat_id", Integer(), nullable=False, unique=True, default=None, primary_key=True)
     repository_id = Column("repository_id", Integer(), ForeignKey('repositories.repo_id'), nullable=False, unique=True, default=None)
     stat_on_revision = Column("stat_on_revision", Integer(), nullable=False)
@@ -1006,7 +1048,8 @@ class UserFollowing(Base, BaseModel):
     __table_args__ = (
         UniqueConstraint('user_id', 'follows_repository_id'),
         UniqueConstraint('user_id', 'follows_user_id'),
-        {'extend_existing': True}
+        {'extend_existing': True, 'mysql_engine':'InnoDB',
+         'mysql_charset': 'utf8'}
     )
 
     user_following_id = Column("user_following_id", Integer(), nullable=False, unique=True, default=None, primary_key=True)
@@ -1027,7 +1070,11 @@ class UserFollowing(Base, BaseModel):
 
 class CacheInvalidation(Base, BaseModel):
     __tablename__ = 'cache_invalidation'
-    __table_args__ = (UniqueConstraint('cache_key'), {'extend_existing': True})
+    __table_args__ = (
+        UniqueConstraint('cache_key'),
+        {'extend_existing': True, 'mysql_engine':'InnoDB',
+         'mysql_charset': 'utf8'},
+    )
     cache_id = Column("cache_id", Integer(), nullable=False, unique=True, default=None, primary_key=True)
     cache_key = Column("cache_key", String(length=255, convert_unicode=False, assert_unicode=None), nullable=True, unique=None, default=None)
     cache_args = Column("cache_args", String(length=255, convert_unicode=False, assert_unicode=None), nullable=True, unique=None, default=None)
@@ -1038,14 +1085,17 @@ class CacheInvalidation(Base, BaseModel)
         self.cache_args = cache_args
         self.cache_active = False
 
-    def __repr__(self):
-        return "<%s('%s:%s')>" % (self.__class__.__name__,
+    def __unicode__(self):
+        return u"<%s('%s:%s')>" % (self.__class__.__name__,
                                   self.cache_id, self.cache_key)
+    @classmethod
+    def clear_cache(cls):
+        cls.query().delete()
 
     @classmethod
     def _get_key(cls, key):
         """
-        Wrapper for generating a key
+        Wrapper for generating a key, together with a prefix
 
         :param key:
         """
@@ -1054,13 +1104,26 @@ class CacheInvalidation(Base, BaseModel)
         iid = rhodecode.CONFIG.get('instance_id')
         if iid:
             prefix = iid
-        return "%s%s" % (prefix, key)
+        return "%s%s" % (prefix, key), prefix, key.rstrip('_README')
 
     @classmethod
     def get_by_key(cls, key):
         return cls.query().filter(cls.cache_key == key).scalar()
 
     @classmethod
+    def _get_or_create_key(cls, key, prefix, org_key):
+        inv_obj = Session.query(cls).filter(cls.cache_key == key).scalar()
+        if not inv_obj:
+            try:
+                inv_obj = CacheInvalidation(key, org_key)
+                Session.add(inv_obj)
+                Session.commit()
+            except Exception:
+                log.error(traceback.format_exc())
+                Session.rollback()
+        return inv_obj
+
+    @classmethod
     def invalidate(cls, key):
         """
         Returns Invalidation object if this given key should be invalidated
@@ -1069,10 +1132,12 @@ class CacheInvalidation(Base, BaseModel)
 
         :param key:
         """
-        return cls.query()\
-                .filter(CacheInvalidation.cache_key == key)\
-                .filter(CacheInvalidation.cache_active == False)\
-                .scalar()
+
+        key, _prefix, _org_key = cls._get_key(key)
+        inv = cls._get_or_create_key(key, _prefix, _org_key)
+
+        if inv and inv.cache_active is False:
+            return inv
 
     @classmethod
     def set_invalidate(cls, key):
@@ -1082,17 +1147,16 @@ class CacheInvalidation(Base, BaseModel)
         :param key:
         """
 
-        log.debug('marking %s for invalidation' % key)
-        inv_obj = Session.query(cls)\
-            .filter(cls.cache_key == key).scalar()
-        if inv_obj:
-            inv_obj.cache_active = False
-        else:
-            log.debug('cache key not found in invalidation db -> creating one')
-            inv_obj = CacheInvalidation(key)
+        key, _prefix, _org_key = cls._get_key(key)
+        inv_objs = Session.query(cls).filter(cls.cache_args == _org_key).all()
+        log.debug('marking %s key[s] %s for invalidation' % (len(inv_objs),
+                                                             _org_key))
+        try:
+            for inv_obj in inv_objs:
+                if inv_obj:
+                    inv_obj.cache_active = False
 
-        try:
-            Session.add(inv_obj)
+                Session.add(inv_obj)
             Session.commit()
         except Exception:
             log.error(traceback.format_exc())
@@ -1113,7 +1177,10 @@ class CacheInvalidation(Base, BaseModel)
 
 class ChangesetComment(Base, BaseModel):
     __tablename__ = 'changeset_comments'
-    __table_args__ = ({'extend_existing': True},)
+    __table_args__ = (
+        {'extend_existing': True, 'mysql_engine':'InnoDB',
+         'mysql_charset': 'utf8'},
+    )
     comment_id = Column('comment_id', Integer(), nullable=False, primary_key=True)
     repo_id = Column('repo_id', Integer(), ForeignKey('repositories.repo_id'), nullable=False)
     revision = Column('revision', String(40), nullable=False)
@@ -1142,7 +1209,10 @@ class ChangesetComment(Base, BaseModel):
 
 class Notification(Base, BaseModel):
     __tablename__ = 'notifications'
-    __table_args__ = ({'extend_existing': True},)
+    __table_args__ = (
+        {'extend_existing': True, 'mysql_engine':'InnoDB',
+         'mysql_charset': 'utf8'},
+    )
 
     TYPE_CHANGESET_COMMENT = u'cs_comment'
     TYPE_MESSAGE = u'message'
@@ -1194,7 +1264,8 @@ class UserNotification(Base, BaseModel):
     __tablename__ = 'user_to_notification'
     __table_args__ = (
         UniqueConstraint('user_id', 'notification_id'),
-        {'extend_existing': True}
+        {'extend_existing': True, 'mysql_engine':'InnoDB',
+         'mysql_charset': 'utf8'}
     )
     user_id = Column('user_id', Integer(), ForeignKey('users.user_id'), primary_key=True)
     notification_id = Column("notification_id", Integer(), ForeignKey('notifications.notification_id'), primary_key=True)
@@ -1212,7 +1283,10 @@ class UserNotification(Base, BaseModel):
 
 class DbMigrateVersion(Base, BaseModel):
     __tablename__ = 'db_migrate_version'
-    __table_args__ = {'extend_existing': True}
+    __table_args__ = (
+        {'extend_existing': True, 'mysql_engine':'InnoDB',
+         'mysql_charset': 'utf8'},
+    )
     repository_id = Column('repository_id', String(250), primary_key=True)
     repository_path = Column('repository_path', Text)
     version = Column('version', Integer)