diff --git a/trytond/trytond/model/fields/many2one.py b/trytond/trytond/model/fields/many2one.py
index c881d5cc01..ab18133fd8 100644
--- a/trytond/trytond/model/fields/many2one.py
+++ b/trytond/trytond/model/fields/many2one.py
@@ -1,5 +1,7 @@
 # This file is part of Tryton.  The COPYRIGHT file at the top level of
 # this repository contains the full copyright notices and license terms.
+
+import math
 import warnings
 
 from sql import As, Column, Expression, Literal, Null, Query, With
@@ -255,10 +257,15 @@ class Many2One(Field):
                     if operator.startswith('not'):
                         return ~expression
                     return expression
-                elif self.left and self.right:
+                elif (self.left and self.right
+                        and len(ids) <= math.floor(math.log10(
+                                Target.estimated_count() or 1))):
                     return self.convert_domain_mptt(
                         (name, operator, ids), tables)
-                elif self.path:
+                elif (self.path
+                        and (operator.endswith('parent_of')
+                            or len(ids) <= math.floor(math.log10(
+                                    Target.estimated_count() or 1)))):
                     return self.convert_domain_path(
                         (name, operator, ids), tables)
                 else:
diff --git a/trytond/trytond/tests/test_field_many2one.py b/trytond/trytond/tests/test_field_many2one.py
index 8c9c2480d3..ec3da5a5c7 100644
--- a/trytond/trytond/tests/test_field_many2one.py
+++ b/trytond/trytond/tests/test_field_many2one.py
@@ -1,6 +1,8 @@
 # This file is part of Tryton.  The COPYRIGHT file at the top level of
 # this repository contains the full copyright notices and license terms.
 
+from unittest.mock import patch
+
 from sql import Join
 
 from trytond.model.exceptions import DomainValidationError
@@ -348,9 +350,11 @@ class FieldMany2OneTreeTestCase(TestCase):
         Many2One = Pool().get(self.model_name)
         self.create_tree(Many2One)
 
-        result = Many2One.search([
-                ('many2one', 'child_of', [self.root1.id]),
-                ])
+        with patch.object(Many2One, 'estimated_count') as ec:
+            ec.return_value = 100
+            result = Many2One.search([
+                    ('many2one', 'child_of', [self.root1.id]),
+                    ])
 
         self.assertListEqual(
             sorted(result),
@@ -364,9 +368,11 @@ class FieldMany2OneTreeTestCase(TestCase):
         Many2One = Pool().get(self.model_name)
         self.create_tree(Many2One)
 
-        result = Many2One.search([
-                ('many2one', 'not child_of', [self.root1.id]),
-                ])
+        with patch.object(Many2One, 'estimated_count') as ec:
+            ec.return_value = 100
+            result = Many2One.search([
+                    ('many2one', 'not child_of', [self.root1.id]),
+                    ])
 
         self.assertListEqual(
             sorted(result),
@@ -378,9 +384,11 @@ class FieldMany2OneTreeTestCase(TestCase):
         Many2One = Pool().get(self.model_name)
         self.create_tree(Many2One)
 
-        result = Many2One.search([
-                ('many2one', 'child_of', [self.second1.id]),
-                ])
+        with patch.object(Many2One, 'estimated_count') as ec:
+            ec.return_value = 100
+            result = Many2One.search([
+                    ('many2one', 'child_of', [self.second1.id]),
+                    ])
 
         self.assertListEqual(result, [self.second1])
 
@@ -406,10 +414,12 @@ class FieldMany2OneTreeTestCase(TestCase):
         Many2One = Pool().get(self.model_name)
         self.create_tree(Many2One)
 
-        result = Many2One.search([
-                ('many2one', 'child_of',
-                    [self.first1.id, self.second1.id]),
-                ])
+        with patch.object(Many2One, 'estimated_count') as ec:
+            ec.return_value = 100
+            result = Many2One.search([
+                    ('many2one', 'child_of',
+                        [self.first1.id, self.second1.id]),
+                    ])
 
         self.assertListEqual(
             sorted(result),
@@ -421,9 +431,11 @@ class FieldMany2OneTreeTestCase(TestCase):
         Many2One = Pool().get(self.model_name)
         self.create_tree(Many2One)
 
-        result = Many2One.search([
-                ('many2one', 'child_of', []),
-                ])
+        with patch.object(Many2One, 'estimated_count') as ec:
+            ec.return_value = 100
+            result = Many2One.search([
+                    ('many2one', 'child_of', []),
+                    ])
 
         self.assertListEqual(result, [])
 
@@ -433,9 +445,11 @@ class FieldMany2OneTreeTestCase(TestCase):
         Many2One = Pool().get(self.model_name)
         self.create_tree(Many2One)
 
-        result = Many2One.search([
-                ('many2one', 'not child_of', []),
-                ])
+        with patch.object(Many2One, 'estimated_count') as ec:
+            ec.return_value = 100
+            result = Many2One.search([
+                    ('many2one', 'not child_of', []),
+                    ])
 
         self.assertListEqual(
             sorted(result),
@@ -449,9 +463,11 @@ class FieldMany2OneTreeTestCase(TestCase):
         Many2One = Pool().get(self.model_name)
         self.create_tree(Many2One)
 
-        result = Many2One.search([
-                ('many2one', 'child_of', [None]),
-                ])
+        with patch.object(Many2One, 'estimated_count') as ec:
+            ec.return_value = 100
+            result = Many2One.search([
+                    ('many2one', 'child_of', [None]),
+                    ])
 
         self.assertListEqual(result, [])
 
@@ -461,9 +477,11 @@ class FieldMany2OneTreeTestCase(TestCase):
         Many2One = Pool().get(self.model_name)
         self.create_tree(Many2One)
 
-        result = Many2One.search([
-                ('many2one', 'parent_of', [self.root1.id]),
-                ])
+        with patch.object(Many2One, 'estimated_count') as ec:
+            ec.return_value = 100
+            result = Many2One.search([
+                    ('many2one', 'parent_of', [self.root1.id]),
+                    ])
 
         self.assertListEqual(result, [self.root1])
 
@@ -473,9 +491,11 @@ class FieldMany2OneTreeTestCase(TestCase):
         Many2One = Pool().get(self.model_name)
         self.create_tree(Many2One)
 
-        result = Many2One.search([
-                ('many2one', 'not parent_of', [self.root1.id]),
-                ])
+        with patch.object(Many2One, 'estimated_count') as ec:
+            ec.return_value = 100
+            result = Many2One.search([
+                    ('many2one', 'not parent_of', [self.root1.id]),
+                    ])
 
         self.assertListEqual(
             sorted(result),
@@ -489,9 +509,11 @@ class FieldMany2OneTreeTestCase(TestCase):
         Many2One = Pool().get(self.model_name)
         self.create_tree(Many2One)
 
-        result = Many2One.search([
-                ('many2one', 'parent_of', [self.second4.id]),
-                ])
+        with patch.object(Many2One, 'estimated_count') as ec:
+            ec.return_value = 100
+            result = Many2One.search([
+                    ('many2one', 'parent_of', [self.second4.id]),
+                    ])
 
         self.assertListEqual(
             sorted(result),
@@ -503,9 +525,11 @@ class FieldMany2OneTreeTestCase(TestCase):
         Many2One = Pool().get(self.model_name)
         self.create_tree(Many2One)
 
-        result = Many2One.search([
-                ('many2one', 'not parent_of', [self.second4.id]),
-                ])
+        with patch.object(Many2One, 'estimated_count') as ec:
+            ec.return_value = 100
+            result = Many2One.search([
+                    ('many2one', 'not parent_of', [self.second4.id]),
+                    ])
 
         self.assertListEqual(
             sorted(result),
@@ -519,9 +543,11 @@ class FieldMany2OneTreeTestCase(TestCase):
         Many2One = Pool().get(self.model_name)
         self.create_tree(Many2One)
 
-        result = Many2One.search([
-                ('many2one', 'parent_of', []),
-                ])
+        with patch.object(Many2One, 'estimated_count') as ec:
+            ec.return_value = 100
+            result = Many2One.search([
+                    ('many2one', 'parent_of', []),
+                    ])
 
         self.assertListEqual(result, [])
 
@@ -531,9 +557,11 @@ class FieldMany2OneTreeTestCase(TestCase):
         Many2One = Pool().get(self.model_name)
         self.create_tree(Many2One)
 
-        result = Many2One.search([
-                ('many2one', 'not parent_of', []),
-                ])
+        with patch.object(Many2One, 'estimated_count') as ec:
+            ec.return_value = 100
+            result = Many2One.search([
+                    ('many2one', 'not parent_of', []),
+                    ])
 
         self.assertListEqual(
             sorted(result),