Patching systems without downtime (Pega 8.3 and earlier)

The Pega patch process is zero-downtime when you use the out-of-place process so you can continue working in your application while you patch your system.

For releases 8.2.x and 8.3.x, patches rely on the following three schemas:

• Data schema – your existing data schema. This will be your data schema after the patch as well.
• Rules schema – your existing rules schema. This schema will be replaced after the patch.
• New rules schema – a schema on the same database you create for staging the patch. This will become the new rules schema.

Clients apply patches by completing the following steps:

1. Prepare the cluster for the patch by configuring the high availability cluster settings.
2. Create a new blank rules schema in your existing database.
   

3. Migrate only the rules from the existing rules schema to the new rules schema.
   

4. Patch the new rules schema.
   

5. For Oracle databases, you must grant access to the new rules schema tables by using migrate.sh again to generate the necessary rules objects (GRANT statements) which will link the data schema to the new rules schema after you patch the new rules schema.
6. Patch the data schema.
   

7. Using a database editing tool, delete the old rules schema from your database and clean up unused temporary data tables in your new rules schemas.

• For High Availability 8.2 and 8.3 systems: Preparing the cluster for patching

  Pega Platform can automatically move rules between the old and new rule schemas after the patch process is complete on a system configured for high availability This allows you to continue making rule changes throughout the patch process. To enable this functionality, you must update the cluster settings to prepare for the patch.

• Migrating rules and objects to the new rules schema

  Use the migrate script to migrate the rules tables and other required database objects from the existing rules schema to the new rules schema. To minimize the time required, run the migration scripts from the same data center as the database server.

• For 8.3 and earlier: Patch methods for the migrated rules schema

  Use either the Installation and Upgrade Assistant or a command-line tool to patch the migrated rules schema.

• For Oracle databases only running Pega Platform earlier than 8.4: Granting access to the new rules schema tables

  Grant access to link the data and new patch schema required for Oracle databases running Pega Platform version prior to 8.4.

• Patching the data schema

  Run the script to patch the data schema.