diff --git a/addons/decimal_precision/decimal_precision.py b/addons/decimal_precision/decimal_precision.py
index f169b698ebd..728fa9cc99b 100644
--- a/addons/decimal_precision/decimal_precision.py
+++ b/addons/decimal_precision/decimal_precision.py
@@ -48,11 +48,6 @@ class decimal_precision(orm.Model):
     def clear_cache(self, cr):
         """clear cache and update models. Notify other workers to restart their registry."""
         self.precision_get.clear_cache(self)
-        env = openerp.api.Environment(cr, SUPERUSER_ID, {})
-        for model in self.pool.values():
-            for field in model._fields.values():
-                if field.type == 'float':
-                    field._setup_digits(env)
         RegistryManager.signal_registry_change(cr.dbname)
 
     def create(self, cr, uid, data, context=None):
diff --git a/openerp/__init__.py b/openerp/__init__.py
index 24a193bf759..691a7d27c1c 100644
--- a/openerp/__init__.py
+++ b/openerp/__init__.py
@@ -56,11 +56,15 @@ del time
 # The hard-coded super-user id (a.k.a. administrator, or root user).
 SUPERUSER_ID = 1
 
-def registry(database_name):
+def registry(database_name=None):
     """
-    Return the model registry for the given database. If the registry does not
-    exist yet, it is created on the fly.
+    Return the model registry for the given database, or the database mentioned
+    on the current thread. If the registry does not exist yet, it is created on
+    the fly.
     """
+    if database_name is None:
+        import threading
+        database_name = threading.currentThread().dbname
     return modules.registry.RegistryManager.get(database_name)
 
 #----------------------------------------------------------
diff --git a/openerp/fields.py b/openerp/fields.py
index da0ba4dc374..9aadca4b3cb 100644
--- a/openerp/fields.py
+++ b/openerp/fields.py
@@ -991,26 +991,28 @@ class Float(Field):
     """
     type = 'float'
     _digits = None              # digits argument passed to class initializer
-    digits = None               # digits as computed by setup()
     group_operator = None       # operator for aggregating values
 
     def __init__(self, string=None, digits=None, **kwargs):
         super(Float, self).__init__(string=string, _digits=digits, **kwargs)
 
+    @property
+    def digits(self):
+        if callable(self._digits):
+            with registry().cursor() as cr:
+                return self._digits(cr)
+        else:
+            return self._digits
+
     def _setup_digits(self, env):
         """ Setup the digits for `self` and its corresponding column """
-        self.digits = self._digits(env.cr) if callable(self._digits) else self._digits
-        if self.digits:
-            assert isinstance(self.digits, (tuple, list)) and len(self.digits) >= 2, \
-                "Float field %s with digits %r, expecting (total, decimal)" % (self, self.digits)
-        if self.column:
-            self.column.digits_change(env.cr)
+        pass
 
     def _setup_regular(self, env):
         super(Float, self)._setup_regular(env)
         self._setup_digits(env)
 
-    _related_digits = property(attrgetter('digits'))
+    _related__digits = property(attrgetter('_digits'))
     _related_group_operator = property(attrgetter('group_operator'))
 
     _description_digits = property(attrgetter('digits'))
@@ -1021,10 +1023,9 @@ class Float(Field):
 
     def convert_to_cache(self, value, record, validate=True):
         # apply rounding here, otherwise value in cache may be wrong!
-        if self.digits:
-            return float_round(float(value or 0.0), precision_digits=self.digits[1])
-        else:
-            return float(value or 0.0)
+        value = float(value or 0.0)
+        digits = self.digits
+        return float_round(value, precision_digits=digits[1]) if digits else value
 
 
 class _String(Field):
@@ -1790,7 +1791,7 @@ class Id(Field):
         raise TypeError("field 'id' cannot be assigned")
 
 # imported here to avoid dependency cycle issues
-from openerp import SUPERUSER_ID
+from openerp import SUPERUSER_ID, registry
 from .exceptions import Warning, AccessError, MissingError
 from .models import BaseModel, MAGIC_COLUMNS
 from .osv import fields
diff --git a/openerp/models.py b/openerp/models.py
index 76ad1e042bf..0846521888d 100644
--- a/openerp/models.py
+++ b/openerp/models.py
@@ -659,8 +659,6 @@ class BaseModel(object):
 
         # process store of low-level function fields
         for fname, column in cls._columns.iteritems():
-            if hasattr(column, 'digits_change'):
-                column.digits_change(cr)
             # filter out existing store about this field
             pool._store_function[cls._name] = [
                 stored
diff --git a/openerp/osv/fields.py b/openerp/osv/fields.py
index cc11669ef33..239a55e394f 100644
--- a/openerp/osv/fields.py
+++ b/openerp/osv/fields.py
@@ -51,7 +51,7 @@ from openerp.tools.translate import _
 from openerp.tools import float_round, float_repr
 from openerp.tools import html_sanitize
 import simplejson
-from openerp import SUPERUSER_ID
+from openerp import SUPERUSER_ID, registry
 
 _logger = logging.getLogger(__name__)
 
@@ -334,36 +334,42 @@ class html(text):
 
 import __builtin__
 
+def _symbol_set_float(self, x):
+    result = __builtin__.float(x or 0.0)
+    digits = self.digits
+    if digits:
+        precision, scale = digits
+        result = float_repr(float_round(result, precision_digits=scale), precision_digits=scale)
+    return result
+
 class float(_column):
     _type = 'float'
     _symbol_c = '%s'
-    _symbol_f = lambda x: __builtin__.float(x or 0.0)
-    _symbol_set = (_symbol_c, _symbol_f)
     _symbol_get = lambda self,x: x or 0.0
 
+    @property
+    def digits(self):
+        if self._digits_compute:
+            with registry().cursor() as cr:
+                return self._digits_compute(cr)
+        else:
+            return self._digits
+
     def __init__(self, string='unknown', digits=None, digits_compute=None, required=False, **args):
         _column.__init__(self, string=string, required=required, **args)
-        self.digits = digits
         # synopsis: digits_compute(cr) ->  (precision, scale)
-        self.digits_compute = digits_compute
-
-    def new(self, _computed_field=False, **args):
-        # float columns are database-dependent, so always recreate them
-        return type(self)(**args)
+        self._digits = digits
+        self._digits_compute = digits_compute
+        self._symbol_f = lambda x: _symbol_set_float(self, x)
+        self._symbol_set = (self._symbol_c, self._symbol_f)
 
     def to_field_args(self):
         args = super(float, self).to_field_args()
-        args['digits'] = self.digits_compute or self.digits
+        args['digits'] = self._digits_compute or self._digits
         return args
 
     def digits_change(self, cr):
-        if self.digits_compute:
-            self.digits = self.digits_compute(cr)
-        if self.digits:
-            precision, scale = self.digits
-            self._symbol_set = ('%s', lambda x: float_repr(float_round(__builtin__.float(x or 0.0),
-                                                                       precision_digits=scale),
-                                                           precision_digits=scale))
+        pass
 
 class date(_column):
     _type = 'date'
@@ -1240,10 +1246,22 @@ class function(_column):
     # function fields are not copied by default
     copy = False
 
+    @property
+    def digits(self):
+        if self._digits_compute:
+            with registry().cursor() as cr:
+                return self._digits_compute(cr)
+        else:
+            return self._digits
+
 #
 # multi: compute several fields in one call
 #
     def __init__(self, fnct, arg=None, fnct_inv=None, fnct_inv_arg=None, type='float', fnct_search=None, obj=None, store=False, multi=False, **args):
+        # pop attributes that should not be assigned to self
+        self._digits = args.pop('digits', (16,2))
+        self._digits_compute = args.pop('digits_compute', None)
+
         _column.__init__(self, **args)
         self._obj = obj
         self._fnct = fnct
@@ -1253,8 +1271,6 @@ class function(_column):
         if 'relation' in args:
             self._obj = args['relation']
 
-        self.digits = args.get('digits', (16,2))
-        self.digits_compute = args.get('digits_compute', None)
         if callable(args.get('selection')):
             from openerp import api
             self.selection = api.expected(api.cr_uid_context, args['selection'])
@@ -1283,6 +1299,10 @@ class function(_column):
             self._symbol_c = char._symbol_c
             self._symbol_f = lambda x: _symbol_set_char(self, x)
             self._symbol_set = (self._symbol_c, self._symbol_f)
+        elif type == 'float':
+            self._symbol_c = float._symbol_c
+            self._symbol_f = lambda x: _symbol_set_float(self, x)
+            self._symbol_set = (self._symbol_c, self._symbol_f)
         else:
             type_class = globals().get(type)
             if type_class is not None:
@@ -1304,7 +1324,7 @@ class function(_column):
         args = super(function, self).to_field_args()
         args['store'] = bool(self.store)
         if self._type in ('float',):
-            args['digits'] = self.digits_compute or self.digits
+            args['digits'] = self._digits_compute or self._digits
         elif self._type in ('selection', 'reference'):
             args['selection'] = self.selection
         elif self._type in ('many2one', 'one2many', 'many2many'):
@@ -1312,14 +1332,7 @@ class function(_column):
         return args
 
     def digits_change(self, cr):
-        if self._type == 'float':
-            if self.digits_compute:
-                self.digits = self.digits_compute(cr)
-            if self.digits:
-                precision, scale = self.digits
-                self._symbol_set = ('%s', lambda x: float_repr(float_round(__builtin__.float(x or 0.0),
-                                                                           precision_digits=scale),
-                                                               precision_digits=scale))
+        pass
 
     def search(self, cr, uid, obj, name, args, context=None):
         if not self._fnct_search: