diff --git a/python/ycm/diagnostic_interface.py b/python/ycm/diagnostic_interface.py
index f58baf9d..29092647 100644
--- a/python/ycm/diagnostic_interface.py
+++ b/python/ycm/diagnostic_interface.py
@@ -17,7 +17,7 @@
 # You should have received a copy of the GNU General Public License
 # along with YouCompleteMe.  If not, see <http://www.gnu.org/licenses/>.
 
-from collections import defaultdict
+from collections import defaultdict, namedtuple
 from ycm import vimsupport
 import vim
 
@@ -31,6 +31,7 @@ class DiagnosticInterface( object ):
     self._next_sign_id = 1
     self._previous_line_number = -1
     self._diag_message_needs_clearing = False
+    self._placed_signs = []
 
 
   def OnCursorMoved( self ):
@@ -47,8 +48,10 @@ class DiagnosticInterface( object ):
     self._buffer_number_to_line_to_diags = _ConvertDiagListToDict( diags )
 
     if self._user_options[ 'enable_diagnostic_signs' ]:
-      self._next_sign_id = _UpdateSigns( self._buffer_number_to_line_to_diags,
-                                         self._next_sign_id )
+      self._placed_signs, self._next_sign_id = _UpdateSigns(
+        self._placed_signs,
+        self._buffer_number_to_line_to_diags,
+        self._next_sign_id )
 
     if self._user_options[ 'enable_diagnostic_highlighting' ]:
       _UpdateSquiggles( self._buffer_number_to_line_to_diags )
@@ -102,21 +105,81 @@ def _UpdateSquiggles( buffer_number_to_line_to_diags ):
           is_error = is_error )
 
 
-def _UpdateSigns( buffer_number_to_line_to_diags, next_sign_id ):
-  vimsupport.UnplaceAllSignsInBuffer( vim.current.buffer.number )
+def _UpdateSigns( placed_signs, buffer_number_to_line_to_diags, next_sign_id ):
+  new_signs, kept_signs, next_sign_id = _GetKeptAndNewSigns(
+    placed_signs, buffer_number_to_line_to_diags, next_sign_id
+  )
+  # Dummy sign used to prevent "flickering" in Vim when last mark gets
+  # deleted from buffer. Dummy sign prevents Vim to collapsing the sign column
+  # in that case.
+  # There's also a vim bug which causes the whole window to redraw in some
+  # conditions (vim redraw logic is very complex). But, somehow, if we place a
+  # dummy sign before placing other "real" signs, it will not redraw the
+  # buffer (patch to vim pending).
+  dummy_sign_needed = not kept_signs and new_signs
+
+  if dummy_sign_needed:
+    vimsupport.PlaceDummySign( next_sign_id + 1,
+                               vim.current.buffer.number,
+                               new_signs[ 0 ].line )
+
+  # We place only those signs that haven't been placed yet.
+  new_placed_signs = _PlaceNewSigns( kept_signs, new_signs )
+
+  # We use incremental placement, so signs that already placed on the correct
+  # lines will not be deleted and placed again, which should improve performance
+  # in case of many diags. Signs which don't exist in the current diag should be
+  # deleted.
+  _UnplaceObsoleteSigns( kept_signs, placed_signs )
+
+  if dummy_sign_needed:
+    vimsupport.UnPlaceDummySign( next_sign_id + 1, vim.current.buffer.number )
+
+  return new_placed_signs, next_sign_id
+
+
+def _GetKeptAndNewSigns( placed_signs, buffer_number_to_line_to_diags,
+                         next_sign_id ):
+  new_signs = []
+  kept_signs = []
   for buffer_number, line_to_diags in buffer_number_to_line_to_diags.iteritems():
     if not vimsupport.BufferIsVisible( buffer_number ):
       continue
 
-    vimsupport.UnplaceAllSignsInBuffer( buffer_number )
     for line, diags in line_to_diags.iteritems():
       for diag in diags:
-        vimsupport.PlaceSign( next_sign_id,
-                              line,
-                              buffer_number,
-                              _DiagnosticIsError( diag ) )
-        next_sign_id += 1
-  return next_sign_id
+        sign = _DiagSignPlacement( next_sign_id,
+                                   line,
+                                   buffer_number,
+                                   _DiagnosticIsError( diag ) )
+        if sign not in placed_signs:
+          new_signs += [ sign ]
+          next_sign_id += 1
+        else:
+          # We use .index here because `sign` contains a new id, but
+          # we need the sign with the old id to unplace it later on.
+          # We won't be placing the new sign.
+          kept_signs += [ placed_signs[ placed_signs.index( sign ) ] ]
+  return new_signs, kept_signs, next_sign_id
+
+
+
+def _PlaceNewSigns( kept_signs, new_signs ):
+  placed_signs = kept_signs
+  for sign in new_signs:
+    # Do not set two signs on the same line, it will screw up storing sign
+    # locations.
+    if sign in placed_signs:
+      continue
+    vimsupport.PlaceSign( sign.id, sign.line, sign.buffer, sign.is_error )
+    placed_signs += [ sign ]
+  return placed_signs
+
+
+def _UnplaceObsoleteSigns( kept_signs, placed_signs ):
+  for sign in placed_signs:
+    if sign not in kept_signs:
+      vimsupport.UnplaceSignInBuffer( sign.buffer, sign.id )
 
 
 def _ConvertDiagListToDict( diag_list ):
@@ -140,3 +203,12 @@ def _ConvertDiagListToDict( diag_list ):
 def _DiagnosticIsError( diag ):
   return diag[ 'kind' ] == 'ERROR'
 
+
+class _DiagSignPlacement( namedtuple( "_DiagSignPlacement",
+                                      [ 'id', 'line', 'buffer', 'is_error' ] ) ):
+  # We want two signs that have different ids but the same location to compare
+  # equal. ID doesn't matter.
+  def __eq__( self, other ):
+    return ( self.line == other.line and
+             self.buffer == other.buffer and
+             self.is_error == other.is_error )
diff --git a/python/ycm/vimsupport.py b/python/ycm/vimsupport.py
index dc150309..fff54f4f 100644
--- a/python/ycm/vimsupport.py
+++ b/python/ycm/vimsupport.py
@@ -137,16 +137,12 @@ def GetBufferFilepath( buffer_object ):
   return os.path.join( folder_path, str( buffer_object.number ) )
 
 
-# NOTE: This unplaces *all* signs in a buffer, not just the ones we placed. We
-# used to track which signs we ended up placing and would then only unplace
-# ours, but that causes flickering Vim since we have to call
-#    sign unplace <id> buffer=<buffer-num>
-# in a loop. So we're forced to unplace all signs, which might conflict with
-# other Vim plugins.
-def UnplaceAllSignsInBuffer( buffer_number ):
+def UnplaceSignInBuffer( buffer_number, sign_id ):
   if buffer_number < 0:
     return
-  vim.command( 'sign unplace * buffer={0}'.format( buffer_number ) )
+  vim.command(
+    'try | exec "sign unplace {0} buffer={1}" | catch /E158/ | endtry'.format(
+        sign_id, buffer_number ) )
 
 
 def PlaceSign( sign_id, line_num, buffer_num, is_error = True ):
@@ -160,6 +156,26 @@ def PlaceSign( sign_id, line_num, buffer_num, is_error = True ):
     sign_id, line_num, sign_name, buffer_num ) )
 
 
+def PlaceDummySign( sign_id, buffer_num, line_num ):
+    if buffer_num < 0 or line_num < 0:
+      return
+    vim.command( 'sign define ycm_dummy_sign' )
+    vim.command(
+      'sign place {0} name=ycm_dummy_sign line={1} buffer={2}'.format(
+        sign_id,
+        line_num,
+        buffer_num,
+      )
+    )
+
+
+def UnPlaceDummySign( sign_id, buffer_num ):
+    if buffer_num < 0:
+      return
+    vim.command( 'sign undefine ycm_dummy_sign' )
+    vim.command( 'sign unplace {0} buffer={1}'.format( sign_id, buffer_num ) )
+
+
 def ClearYcmSyntaxMatches():
   matches = VimExpressionToPythonType( 'getmatches()' )
   for match in matches: