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Configuration data maintained in Integration Directory is replicated to the involved runtime engines by a cache refresh mechanism.

Note Note

As configuration data also uses design data from the Enterprise Services Repository (ES Repository), cache refresh can also include data from the ES Repository. This applies to mapping programs used in configuration objects in particular.

End of the note.

This mechanism improves performance when operating integration scenarios because it minimizes the communication between the runtime engines, ES Repository, and Integration Directory involved. In addition to this, the caching mechanism makes sure that the runtime engines can continue their operation also if the connection to the ES Repository and the Integration Directory is interrupted temporarily.

Cache refresh is triggered automatically when an object in the ES Repository or in the Integration Directory is activated. In addition to this, the cache refresh can be initiated manually.

The following figure shows the runtime caches in an SAP NetWeaver PI dual-stack installation.

Note Note

In an Advanced Adapter Engine Extended (AEX) installation, the Integration Engine cache is missing. Besides that, the figure also applies for the AEX.

End of the note.

This graphic is explained in the accompanying text.

Runtime Caches (SAP NetWeaver PI Dual-Stack Installation)

The following runtime caches (also referred to as cache consumer) are used:

  • CPA cache

    Is used by the Advanced Adapter Engine (AAE) in order to process messages at runtime in accordance to the configuration settings.

    This cache contains, for example, all configuration data related to configuration of adapters of the AAE.

  • Mapping cache

    Is used by the mapping runtime in order to execute mappings at runtime in accordance to the configuration in Integration Directory and the mapping program defined in the ES Repository.

  • Integration Engine cache

    Is used by the Integration Engine in order to process messages at runtime in accordance to the configuration settings.

    This cache contains, for example, all configuration data for the adapters that run on the Integration Engine.

  • Business system cache (AS ABAP)

    Is used in connected SAP systems based on Application Server ABAP.

    This cache contains in particular configuration settings related to communication components.

    It also contains configuration data maintained in communication channels with adapter type WS.

One configuration object can have multiple cache consumer.

Example Example

Depending on the scenario, the configuration settings of a communication channel are replicated to the CPA cache and to a business system cache.

End of the example.
Automatic Cache Refresh

Automatic cache refresh is initiated when a cache-relevant object in the ES Repository (for example, a mapping) is changed and activated. Then the ES Repository notification service (see figure above) sends cache notifications to the Integration Directory. Depending on the information sent with the notification, the notification service of the Integration Directory evaluates the relevant cache consumer and sends an HTTP request to the cache targets. The cache consumer are then provided with the relevant update.