diff --git a/IPython/Extensions/ipy_completers.py b/IPython/Extensions/ipy_completers.py
index 1347005..18b02a8 100644
--- a/IPython/Extensions/ipy_completers.py
+++ b/IPython/Extensions/ipy_completers.py
@@ -8,34 +8,60 @@ but the basic idea is to do:
 ip.set_hook('complete_command', svn_completer, str_key = 'svn')
 
 """
-
 import IPython.ipapi
 import glob,os,shlex,sys
 import inspect
+from time import time
 ip = IPython.ipapi.get()
 
+TIMEOUT_STORAGE = 3 #Time in seconds after which the rootmodules will be stored
+TIMEOUT_GIVEUP = 20 #Time in seconds after which we give up
+
 def getRootModules():
     """
     Returns a list containing the names of all the modules available in the
     folders of the pythonpath.
     """
     modules = []
+    if ip.db.has_key('rootmodules'):
+        return ip.db['rootmodules']
+    t = time()
+    store = False
     for path in sys.path:
-        modules += moduleList(path)
+        modules += moduleList(path)        
+        if time() - t >= TIMEOUT_STORAGE and not store:
+            store = True
+            print "\nCaching the list of root modules, please wait!" 
+            print "(This will only be done once - type '%rehashx' to " + \
+            "reset cache!)"
+            print
+        if time() - t > TIMEOUT_GIVEUP:
+            print "This is taking too long, we give up."
+            print
+            ip.db['rootmodules'] = []
+            return []
+
     modules += sys.builtin_module_names
     modules = list(set(modules))
     if '__init__' in modules:
         modules.remove('__init__')
-    return list(set(modules))
+    modules = list(set(modules))
+    if store:
+        ip.db['rootmodules'] = modules
+    return modules
 
 def moduleList(path):
     """
     Return the list containing the names of the modules available in the given
     folder.
     """
-    folder_list = glob.glob(os.path.join(path,'*'))
+    if os.path.isdir(path):
+        folder_list = os.listdir(path)
+    else:
+        folder_list = []
+    #folder_list = glob.glob(os.path.join(path,'*'))
     folder_list = [path for path in folder_list  \
-       if (os.path.isdir(path) and os.path.exists(os.path.join(path,'__init__.py')))\
+       if os.path.exists(os.path.join(path,'__init__.py'))\
            or path[-3:] in ('.py','.so')\
            or path[-4:] in ('.pyc','.pyo')]
     folder_list += folder_list
diff --git a/IPython/Magic.py b/IPython/Magic.py
index be1d546..b8cd54a 100644
--- a/IPython/Magic.py
+++ b/IPython/Magic.py
@@ -1,7 +1,7 @@
 # -*- coding: utf-8 -*-
 """Magic functions for InteractiveShell.
 
-$Id: Magic.py 2225 2007-04-08 02:48:16Z jdh2358 $"""
+$Id: Magic.py 2276 2007-04-26 16:35:02Z vivainio $"""
 
 #*****************************************************************************
 #       Copyright (C) 2001 Janko Hauser <jhauser@zscout.de> and
@@ -2533,7 +2533,17 @@ Defaulting color scheme to 'NoColor'"""
 
         Under Windows, it checks executability as a match agains a
         '|'-separated string of extensions, stored in the IPython config
-        variable win_exec_ext.  This defaults to 'exe|com|bat'. """
+        variable win_exec_ext.  This defaults to 'exe|com|bat'.
+        
+        This function also resets the root module cache of module completer,
+        used on slow filesystems.
+        """
+        
+        
+        ip = self.api
+
+        # for the benefit of module completer in ipy_completers.py
+        del ip.db['rootmodules']
         
         path = [os.path.abspath(os.path.expanduser(p)) for p in 
             os.environ['PATH'].split(os.pathsep)]
@@ -2583,7 +2593,7 @@ Defaulting color scheme to 'NoColor'"""
             # Call again init_auto_alias() so we get 'rm -i' and other
             # modified aliases since %rehashx will probably clobber them
             self.shell.init_auto_alias()
-            db = self.getapi().db
+            db = ip.db
             db['syscmdlist'] = syscmdlist
         finally:
             os.chdir(savedir)
diff --git a/doc/ChangeLog b/doc/ChangeLog
index 4b220e7..c97ea0b 100644
--- a/doc/ChangeLog
+++ b/doc/ChangeLog
@@ -1,3 +1,11 @@
+2007-04-26  Ville Vainio  <vivainio@gmail.com>
+
+	* Extensions/ipy_completers.py: Olivier's module completer now
+	saves the list of root modules if it takes > 4 secs on the first run.
+	
+	* Magic.py (%rehashx): %rehashx now clears the completer cache
+	
+
 2007-04-26  Fernando Perez  <Fernando.Perez@colorado.edu>
 
 	* ipython.el: fix incorrect color scheme, reported by Stefan.
@@ -21,8 +29,8 @@
 
 2007-04-22  Jörgen Stenarson  <jorgen.stenarson@bostream.nu>
 
-	* Fix bug in iplib.py/safe_execfile when launching ipython with a script like ipython.py foo.py
-	  which raised a IndexError.
+	* Fix bug in iplib.py/safe_execfile when launching ipython with a script
+	like ipython.py foo.py which raised a IndexError.
 
 2007-04-21  Ville Vainio  <vivainio@gmail.com>