For a customer we are installing the myHR suite from Cordis Solutions to deliver ESS/MSS functionality within SharePoint application. The myHR suite is a SAP-certified Duet Enterprise product. As part of the project we first deploy the prerequisite supporting platform elements SAP NetWeaver Gateway 2.0 and Duet Enterprise for SharePoint and SAP. And next install the myHR suite. We do this across the customer landscapes of development/test, acceptance and production environments. Each environment installation ends with technical validation of the environment: Gateway, Duet Enterprise, Cordis myHR.
Per technical validation of the environments, I encounter the issue that the first 2 to 3 invocations for each of the myHR Duet Enterprise services returns the error CX_SY_REF_IS_INITIAL. After 3 service invocation calls, each myHR service successfully returns the requested SAP data. The explanation of this behavior is a kind of ‘warm-up’ effect: the Duet Enterprise services installed in the SAP Gateway system are not yet compiled / generated until first invocation, resulting in the CX_SY_REF_IS_INITIAL error on the Gateway system, and NullPointer exception in the invoking SharePoint UI-context. After a few invocation attempts, the service components are generated and available at runtime in the SAP system, and the invocation from there on gets successful the SAP data result.
Last week upon technical validation of the acceptance environment this symptom again manifested it as I expected. However, to my surprise the warm-up effect was not effectuated. All service invocations remained in erroneous state. Via ABAP debugging, I traced the error location. The problem originated at internal SAP Gateway method ‘GET_META_MODELS’ to instantiate the metadata model of the invoked service. I compared the runtime behavior on the faulty system versus an environment that has successfully be ‘warmed-up’. The difference was that on the latter system, the method to create the metadata model was not even reached. Well, not anymore… It was not needed to create the metadata model, because it could be retrieved from the Gateway Metadata cache.
This appeared the problem cause why the warm-up effect was not applied: at SAP Gateway deployment, one had forgot to activate the Gateway Metadata cache in this environment. After correcting that, the myHR services do start returning data. Well, that is… from each 3rd invocation on…