diff --git a/modules/customer/commerce_customer.install b/modules/customer/commerce_customer.install
index 7789259..2ae2889 100644
--- a/modules/customer/commerce_customer.install
+++ b/modules/customer/commerce_customer.install
@@ -19,8 +19,7 @@ function commerce_customer_schema() {
         'description' => 'The current {commerce_customer_profile_revision}.revision_id version identifier.',
         'type' => 'int',
         'unsigned' => TRUE,
-        'not null' => TRUE,
-        'default' => 0,
+        'not null' => FALSE,
       ),
       'type' => array(
         'description' => 'The {commerce_customer_profile_type}.type of this profile.',
@@ -252,3 +251,17 @@ function commerce_customer_update_7101() {
 
   return t('Database indexes added to the uid and type columns of the commerce_customer_profile table.');
 }
+
+/**
+ * Allow NULL values for revision_id on {commerce_customer} to avoid locking issues.
+ */
+function commerce_customer_update_7102() {
+  db_change_field('commerce_customer_profile', 'revision_id', array(
+    'description' => 'The current {commerce_customer_profile_revision}.revision_id version identifier.',
+    'type' => 'int',
+    'unsigned' => TRUE,
+    'not null' => FALSE,
+  ));
+
+  return t('Schema for the commerce_customer_profile has been updated.');
+}
diff --git a/modules/order/commerce_order.install b/modules/order/commerce_order.install
index d29bb23..907a7f8 100644
--- a/modules/order/commerce_order.install
+++ b/modules/order/commerce_order.install
@@ -26,7 +26,6 @@ function commerce_order_schema() {
         'type' => 'int',
         'unsigned' => TRUE,
         'not null' => FALSE,
-        'default' => 0,
       ),
       'type' => array(
         'description' => 'The type of this order.',
@@ -458,3 +457,17 @@ function commerce_order_update_7108() {
 
   return t('Schema for the commerce_order and commerce_order_revision tables has been updated.');
 }
+
+/**
+ * Remove default value for revision_id on {commerce_order}.
+ */
+function commerce_order_update_7109() {
+  db_change_field('commerce_order', 'revision_id', array(
+    'description' => 'The current {commerce_order_revision}.revision_id version identifier.',
+    'type' => 'int',
+    'unsigned' => TRUE,
+    'not null' => FALSE,
+  ));
+
+  return t('Schema for the commerce_order has been updated.');
+}
diff --git a/modules/payment/commerce_payment.install b/modules/payment/commerce_payment.install
index dd36c11..f136bf6 100644
--- a/modules/payment/commerce_payment.install
+++ b/modules/payment/commerce_payment.install
@@ -25,8 +25,7 @@ function commerce_payment_schema() {
         'description' => 'The current {commerce_payment_transaction_revision}.revision_id version identifier.',
         'type' => 'int',
         'unsigned' => TRUE,
-        'not null' => TRUE,
-        'default' => 0,
+        'not null' => FALSE,
       ),
       'uid' => array(
         'description' => 'The {users}.uid that created this transaction.',
@@ -280,3 +279,17 @@ function commerce_payment_update_7101() {
 
   return t('Database indexes added to the uid and order_id columns of the commerce_payment_transaction table.');
 }
+
+/**
+ * Allow NULL values for revision_id on {commerce_payment_transaction} to avoid locking issues.
+ */
+function commerce_payment_update_7102() {
+  db_change_field('commerce_payment_transaction', 'revision_id', array(
+    'description' => 'The current {commerce_payment_transaction_revision}.revision_id version identifier.',
+    'type' => 'int',
+    'unsigned' => TRUE,
+    'not null' => FALSE,
+  ));
+
+  return t('Schema for the commerce_payment_transaction has been updated.');
+}
diff --git a/modules/product/commerce_product.install b/modules/product/commerce_product.install
index de1559f..63e9efb 100644
--- a/modules/product/commerce_product.install
+++ b/modules/product/commerce_product.install
@@ -21,7 +21,6 @@ function commerce_product_schema() {
         'type' => 'int',
         'unsigned' => TRUE,
         'not null' => FALSE,
-        'default' => NULL,
       ),
       'sku' => array(
         'description' => 'The unique, human-readable identifier for a product.',