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SAP Gateway Foundation caches the metadata information of a service for a significant performance increase. Three types of caching are offered:

  • Caching on the hub.

    On the hub the metadata model, the annotation model and also the annotation texts of a service are cached.

  • Caching on the backend.

    In the backend only the metadata model and the annotation model is cached. The annotation texts are not needed in the backend for service instantiation and hence not cached here.

  • Co-deployment scenario.

    Co-deployment scenario means that hub and backend are one system. Therefore, caching has to be done only once and not once for the hub and for each backend system.

For performance reasons, the same development artifacts are used for the hub and for the backend.

The SAP Gateway Foundation settings made in transaction SPRO (see the SAP Implementation Guide: Start of the navigation path SAP NetWeaver Next navigation step SAP Gateway Next navigation step OData Channel Next navigation step Administration Next navigation step Cache Settings Next navigation step Metadata Next navigation step Activate of Deactivate Cache End of the navigation path) in regards to the metadata caching are only applicable for OData V2 services. There is no possibility for the SAP Gateway Foundation V4 implementation to disable the metadata caching.

Note

In the OData Channel programming paradigm the model provider class including the last modified time stamp is only called once when initially loading the metadata and storing it in the SAP Gateway Foundation metadata cache. If the model provider class is changed afterwards (for example, on account of coding changes or due to an import of a changed model provider class) the metadata cache performs a handshake for every service document or service metadata document request and checks whether the cache contains most up-to-date metadata. If the metadata is outdated a cache refresh is triggered automatically.

The activity which is available for OData V4 services is also available in the SAP Implementation Guide: Start of the navigation path SAP NetWeaver Next navigation step SAP Gateway Next navigation step OData Channel Next navigation step Administration Next navigation step Cache Settings Next navigation step Metadata Next navigation step Clear Cache End of the navigation path.

This activity allows you to fully clear the cache or to clear the cache for a range of models. It also depends on the installation scenario you have chosen. To clear the cache you can use either of the following:

  • Transaction /IWBEP/CACHE_CLEANUP which is also availabel in the SAP Implementation Guide in your specific system under Start of the navigation path SAP NetWeaver Next navigation step SAP Gateway Service Enablement Next navigation step Backend OData Channel Next navigation step Support Utilities Next navigation step Clear Cache End of the navigation path.

  • SAP Gateway Foundation Client.