What is PI Cache Refresh?

As we all know, the PI objects are created or edited using the Integration Builder tools. The development area is isolated from runtime area in PI. Changing or creating objects does not change or create them directly in runtime.

Runtimes have their own database for storing the PI objects. Only the latest, active versions of the objects are available in runtime.

What is PI Cache Refresh?


When the PI objects are changed in IB, the changes are written as an xml message and sent to the runtime components  (ABAP Integration Server, Java Adapter Engine CPA cache, Java Message Mapping Cache and Java Value Mapping Cache). The runtime components read this message and make the adjustment to their versions of XI objects to keep the objects in sync with the recent changes.

If for some reason the cache updates triggered by changes in IB fail, one can trigger a delta cache or a full cache refresh to keep the objects consistent using the URL http://<pi-host>:<pi-j2ee-port>/CPACache/refresh?mode=delta

A delta cache affects only the objects that are not up to date in the same order that they were changed (EOIO), whereas the Full cache refresh replaces all the objects.

The full cache refresh creates a large xml message and has all the objects serialized. The serialization causes Full cache refresh take time in the order of 10's of minutes and the huge size of xml objects can cause OOM errors. Full cache refresh should not be done on productive system as it is considered equivalent to an outage for the duration of the cache refresh.

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Did you know? When an object is deleted from Integration Builder, it is not actually deleted from the system in many cases! This fact can help you recover PI objects if they are deleted accidentally.

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