diff --git a/oml/queryparser.py b/oml/queryparser.py
index 2810729..939611b 100644
--- a/oml/queryparser.py
+++ b/oml/queryparser.py
@@ -129,7 +129,7 @@ class Parser(object):
             nickname, name = v.split(':', 1)
             if nickname:
                 try:
-                    u = self._user.query.filter_by(nickname=nickname).one()
+                    u = self._user.query.filter_by(nickname=nickname, peered=True).one()
                 except sqlalchemy.orm.exc.NoResultFound:
                     ids = []
                     return self.in_ids(ids, exclude)
diff --git a/oml/settings.py b/oml/settings.py
index 4ef0843..bdc6c31 100644
--- a/oml/settings.py
+++ b/oml/settings.py
@@ -95,4 +95,4 @@ FULLTEXT_SUPPORT = fulltext.platform_supported()
 if not FULLTEXT_SUPPORT:
     config['itemKeys'] = [k for k in config['itemKeys'] if k['id'] != 'fulltext']
 
-DB_VERSION = 15
+DB_VERSION = 16
diff --git a/oml/setup.py b/oml/setup.py
index b243a00..69024d0 100644
--- a/oml/setup.py
+++ b/oml/setup.py
@@ -43,11 +43,11 @@ CREATE TABLE user (
     peered BOOLEAN, 
     online BOOLEAN, 
     PRIMARY KEY (id), 
-    UNIQUE (nickname), 
     CHECK (queued IN (0, 1)), 
     CHECK (peered IN (0, 1)), 
     CHECK (online IN (0, 1))
 );
+CREATE INDEX ix_user_nichname ON user (nichname);
 CREATE TABLE metadata (
     created DATETIME, 
     modified DATETIME, 
diff --git a/oml/update.py b/oml/update.py
index 07cddb4..4177800 100644
--- a/oml/update.py
+++ b/oml/update.py
@@ -373,6 +373,8 @@ class Update(Thread):
                 db_version = migrate_13()
             if db_version < 15:
                 db_version = migrate_15()
+            if db_version < 16:
+                db_version = migrate_16()
             settings.server['db_version'] = db_version
 
     def run(self):
@@ -437,7 +439,7 @@ def migrate_5():
         'DROP INDEX IF EXISTS user_metadata_index',
         'CREATE UNIQUE INDEX user_metadata_index ON user_metadata(item_id, user_id)',
         'UPDATE sort SET sharemetadata = 0',
-    ]),
+    ])
     with db.session() as session:
         import user.models
         for m in user.models.Metadata.query:
@@ -631,3 +633,28 @@ def migrate_15():
                 del u.info['local']
                 u.save()
     return 15
+
+def migrate_16():
+    db.run_sql([
+        '''CREATE TABLE user2 (
+    created DATETIME,
+    modified DATETIME,
+    id VARCHAR(43) NOT NULL,
+    info BLOB,
+    nickname VARCHAR(256),
+    pending VARCHAR(64),
+    queued BOOLEAN,
+    peered BOOLEAN,
+    online BOOLEAN,
+    PRIMARY KEY (id),
+    CHECK (queued IN (0, 1)),
+    CHECK (peered IN (0, 1)),
+    CHECK (online IN (0, 1))
+    )''',
+    '''INSERT INTO user2 (created, modified, id, info, nickname, pending, queued, peered, online)
+              SELECT created, modified, id, info, nickname, pending, queued, peered, online FROM user''',
+    'DROP TABLE user',
+    'ALTER TABLE user2 RENAME TO user',
+    'CREATE INDEX IF NOT EXISTS ix_user_nickname ON user (nickname)'
+    ])
+    return 16
diff --git a/oml/user/models.py b/oml/user/models.py
index 3d7284a..8e7164d 100644
--- a/oml/user/models.py
+++ b/oml/user/models.py
@@ -30,7 +30,7 @@ class User(db.Model):
     id = sa.Column(sa.String(43), primary_key=True)
     info = sa.Column(MutableDict.as_mutable(sa.PickleType(pickler=json_pickler)))
 
-    nickname = sa.Column(sa.String(256), unique=True)
+    nickname = sa.Column(sa.String(256), index=True)
 
     pending = sa.Column(sa.String(64))  # sent|received
     queued = sa.Column(sa.Boolean())
diff --git a/oml/websocket.py b/oml/websocket.py
index 12795ce..9178bb8 100644
--- a/oml/websocket.py
+++ b/oml/websocket.py
@@ -1,8 +1,8 @@
 # -*- coding: utf-8 -*-
 
-
-from tornado.websocket import WebSocketHandler
+from tornado.websocket import WebSocketHandler, WebSocketClosedError
 from tornado.ioloop import IOLoop
+from tornado.iostream import StreamClosedError
 import json
 
 from oxtornado import json_dumps
@@ -72,9 +72,9 @@ class Handler(WebSocketHandler):
         try:
             task = self.write_message(message)
             await task
-        except tornado.iostream.StreamClosedError as e:
+        except StreamClosedError as e:
             self.on_close()
-        except tornado.websocket.WebSocketClosedError as e:
+        except WebSocketClosedError as e:
             self.on_close()