diff --git a/erpnext/patches/v10_0/update_territory_and_customer_group.py b/erpnext/patches/v10_0/update_territory_and_customer_group.py
index 56152f9..3889c73 100644
--- a/erpnext/patches/v10_0/update_territory_and_customer_group.py
+++ b/erpnext/patches/v10_0/update_territory_and_customer_group.py
@@ -1,13 +1,36 @@
 import frappe
-from frappe.model.rename_doc import update_linked_doctypes, get_fetch_fields
+from frappe.model.rename_doc import get_fetch_fields
 
 def execute():
+	ignore_doctypes = ["Lead", "Opportunity", "POS Profile", "Tax Rule", "Pricing Rule"]
 	customers = frappe.get_all('Customer', fields=["name", "territory", "customer_group"])
-	territory_fetch = get_fetch_fields('Customer', 'Territory')
-	customer_group_fetch = get_fetch_fields('Customer', 'Customer Group')
 
-	for customer in customers:
-		# Update Territory across all transaction
-		update_linked_doctypes(territory_fetch, customer.name, customer.territory_value)
-		# Update Territory across all transaction
-		update_linked_doctypes(customer_group_fetch, customer.name, customer.customer_group_value)
+	territory_fetch = get_fetch_fields('Customer', 'Territory', ignore_doctypes)
+	customer_group_fetch = get_fetch_fields('Customer', 'Customer Group', ignore_doctypes)
+
+	batch_size = 1000
+	for i in range(0, len(customers), batch_size):
+		batch_customers = customers[i:i + batch_size]
+		for source_fieldname, linked_doctypes_info in [["customer_group", customer_group_fetch], ["territory", territory_fetch]]:
+			for d in linked_doctypes_info:
+				when_then = []
+				for customer in batch_customers:
+					when_then.append('''
+						WHEN `{master_fieldname}` = "{docname}" and {linked_to_fieldname} != "{value}"
+						THEN "{value}"
+					'''.format(
+						master_fieldname=d["master_fieldname"],
+						linked_to_fieldname=d["linked_to_fieldname"],
+						docname=frappe.db.escape(customer.name).encode("utf-8"),
+						value=frappe.db.escape(customer.get(source_fieldname)).encode("utf-8")))
+				
+				frappe.db.sql("""
+					update
+						`tab{doctype}`
+					set
+						{linked_to_fieldname} = CASE {when_then_cond}  ELSE `{linked_to_fieldname}` END
+				""".format(
+					doctype = d['doctype'],
+					when_then_cond=" ".join(when_then),
+					linked_to_fieldname=d.linked_to_fieldname
+				))
diff --git a/erpnext/selling/doctype/customer/customer.py b/erpnext/selling/doctype/customer/customer.py
index 761c017..b84a952 100644
--- a/erpnext/selling/doctype/customer/customer.py
+++ b/erpnext/selling/doctype/customer/customer.py
@@ -11,7 +11,7 @@
 from erpnext.utilities.transaction_base import TransactionBase
 from erpnext.accounts.party import validate_party_accounts, get_dashboard_info, get_timeline_data # keep this
 from frappe.contacts.address_and_contact import load_address_and_contact, delete_contact_and_address
-from frappe.model.rename_doc import update_linked_doctypes, get_fetch_fields
+from frappe.model.rename_doc import update_linked_doctypes
 
 class Customer(TransactionBase):
 	def get_feed(self):
@@ -76,12 +76,15 @@
 		if self.flags.is_new_doc:
 			self.create_lead_address_contact()
 
+		self.update_territory_and_customer_groups()
+
+	def update_territory_and_customer_groups(self):
+		ignore_doctypes = ["Lead", "Opportunity", "POS Profile", "Tax Rule", "Pricing Rule"]
 		if frappe.flags.territory_changed:
-			territory_fetch = get_fetch_fields('Customer', 'Territory')
-			update_linked_doctypes(territory_fetch, self.name, self.territory)
+			update_linked_doctypes('Customer', self.name, 'Territory', self.territory, ignore_doctypes)
 		if frappe.flags.customer_group_changed:
-			customer_group_fetch = get_fetch_fields('Customer', 'Customer Group')
-			update_linked_doctypes(customer_group_fetch, self.name, self.customer_group)
+			update_linked_doctypes('Customer', self.name, 'Customer Group',
+				self.customer_group, ignore_doctypes)
 
 	def create_primary_contact(self):
 		if not self.customer_primary_contact and not self.lead_name: