OIC - How many different scheduled integrations can run in parallel in Oracle Integration | Decoupled scheduler and Business Logic pattern.

Though OIC now provides dynamic threading model for scheduled orchestration integrations but it still has thread limitation. Thread count is internal to Oracle and may vary based on instance / subscription type.

Scheduled integration interfaces are widely used in batch integrations. Oracle Integration cloud provides feature to build scheduled integration flows, that can execute at defined frequency. However sometimes users complain about inconsistent behavior of scheduled flows like schedules are getting delayed by few minutes to few hours.

In this blog, We will discuss a common design issue that causes such incidents and solution for it.

What problem we faced and observed:

If we have a large of number of scheduled integrations running in parallel, then we will observe that few are running and others kept in queued and the backlog getting increased which delayed the processing of the backlog scheduled integrations.

For instance:

 I have created 6 scheduled integrations and run them in parallel and observed:

• 4 scheduled integrations are running in parallel. 
• whereas 2 integrations are in queued. 
• Once running ones completed, then the queued one started running. 

So what I understand for my OIC instance it has 4 scheduler threads limitation.

• o it can be made as re-usable component.

Solution:

We can decouple scheduler and integration logic into 2 different flows and let scheduled integration just invoke the child integration using Fire & Forget pattern.

1. For decoupled design, instead of creating many scheduled inegrations, we can create 1 or few  parent (Scheduled integrations) and others are Child (non-scheduled) application integration flows, simply exposed as REST endpoint.
2. Child flow exposes REST endpoint with "POST" verb and not returning any response hence making it a "One Way" flow. So it can be invoked as Fire & Forget .
3. Each Parent flow invokes its respective child flow. However since child is "one way" flow its not returning anything. So parent flow won't wait for the response after invoking child flow. It will either terminate and release the thread or move to next activity (if any).
4. Child integrations will use worker thread for processing. So this time, when one or few scheduled integration triggered at the same time, they were terminated within few seconds and there were 6 or more child integrations in "running" state, Running in parallel.

Reference:

https://www.ateam-oracle.com/post/oic-scheduler-decoupled-scheduler-and-business-logic-pattern