As you maintain your application architecture for continuous operation, you can use ABL features to make changes to schemas, triggers, fields, and more while your application and database are online to push updates without the need to bring them down.

PAS for OpenEdge application deployment was designed for supporting modern day web applications in a scalable and continuously operating environment. PAS for OpenEdge supports multiple strategies to meet various product deployment requirements. The deployment strategy that fits scalability and continuous operations best is the instance. PAS for OpenEdge instances are self-contained, easy to deploy, and scalable HTTP/S web servers that may appear in on-premise virtual machine (VM), cloud images, or Linux container deployments.

Much of PAS for OpenEdge application development's ability to support continuous operations depends on eliminating its instances of single points of failure, and enabling dynamic removal and addition of instances without client outage. In most cases HTTP load balancer products can be used to manage client traffic when PAS for OpenEdge instances go out of service, or are returned to service.

Configure schema changes online

To minimize downtime and to avoid any negative impacts on your applications, you can perform schema maintenance tasks while your database is running by using the SCHEMA-CHANGE attribute during an ABL session. The SCHEMA-CHANGE attribute relaxes the requirement for exclusive access to a database so that you can:
  • Add new sequences.
  • Add new tables, and any associated fields, indexes, and database triggers.
  • Add new fields to an existing table.
  • Add new inactive indexes to an existing table.
For more information, see Change schemas while the database is running.

Change non-structural fields while online

The non-structural fields of the _File and _Field tables have been designed to be changed while the database remains running. These field changes do not require an exclusive schema lock, enabling you to avoid disruptions in user experience. For more information, see Change non-structural fields of _File and _Field online.

Modify ABL triggers while online

In OpenEdge, you can modify the schema for your ABL trigger definitions while online and without it being necessary to acquire an exclusive lock on the entire schema. You can perform online operations to create new trigger definitions, to update, and to delete existing trigger definitions all while your users enjoy continuous access to your application. For more information, see Change ABL triggers online.

Rename fields using ABL while online

To support continuous operation, you can rename user table fields while the database is running. Renaming a database field no longer requires that you have an exclusive schema lock or that you must disconnect users from the database. This enables you to keep your users engaged with your services longer. For more information, see Rename fields using ABL.

Change Int to Int64 while online

Similar to being able to rename fields while online, you can change the datatype of a field in an application table from Int to Int64 while the database is running. This change does not require exclusive access to the database.

The change takes effect without:

  • Dumping and loading the affected table.
  • Rebuilding indexes, if the affected field is an index key component.
  • Recompiling r-code, if the data stored in the affected fields contains values in the Int range.

For more information, see Change Int to Int64 online.