Factors affecting upgrade duration Various factors affect how long the system takes to perform an upgrade. The Upgrade Monitor can help you understand those factors and estimate how long the upgrade to your production instance takes. Many factors can affect the duration of the upgrade process: The number of records in the database The number of customizations in the database The number of nodes in the instance The size of tables in the instance that require a schema-change in the instance. The number of fix scripts required and the size of the tables those fix scripts manipulate. Upgrading a sub-production instance can help you estimate how long the upgrade takes on production, but differences between the instances can significantly affect the duration: When you cloned the production instance to the sub-production instance, you may have clone-excluded some tables. This reduces the size of the database and makes the sub-production instance upgrade faster than the production instance. The production instance may have more memory and processing power. The production instance may have more nodes than the sub-production instance. After upgrading the first sub-production instance, examine the Upgrade Summary Report for data to help estimate the impact of these factors.