Real-Time Data Acquisition 

Description

Real-time data acquisition (RDA) supports operative reporting. The data is transferred into BI at regular intervals and is then updated in the DataStore objects, which are directly available for reporting. Background processes (daemons) in the BI system initiate the InfoPackages and data transfer processes assigned to them (to update the PSA data in DataStore objects).

To simplify the processing of and reporting on the data, the requests are kept open in the DataStore object and in the PSA. Based on settings in the InfoPackage, the daemons decide when a request is to be closed and when a new request is to be opened.

The data can be transferred from the source to the entry layer in BI (PSA) in two ways:

●     Using a Web Service Push

A Web service push can write the data directly from the source to the PSA. The data transfer is not controlled by BI. An InfoPackage (for full upload) is required only to specify request-related settings for RDA.

●     Using a Service API

If the data is transferred via a delta queue of an SAP source system, the data is also written to the PSA. This requires a special InfoPackage to be created; this InfoPackage ensures data is transferred from the source system and is used for specifying request-related settings. To generate an entry for the DataSource in the delta queue, an InfoPackage with delta initialization must be created and executed.

Requirement
The DataSource has to support real-time data acquisition. The option to support real-time data acquisition is a property of the DataSource. DataSources used for RDA can no longer be used for standard extraction (scheduling using InfoPackages). The reason for this is that the DataSource can have one extraction mechanism only ('RDA' or  'scheduled data transfer'). It is not possible to have multiple extractions mechanisms simultaneously, since the delta queue can only contain one entry for each DataSource and target system at any given time.

For more information, see Real-Time Data Acquisition.

General Practices with Migration

If you want to integrate the extraction of data with real-time data acquisition into an existing data flow, there are two alternatives:

●     Using two different DataSources

The existing data flow remains unchanged; the data is made available periodically using scheduled extraction – InfoPackages specify the selection parameters and control the data request. Imagine, for example, a DataSource that makes information available at item level. A second RDA-enabled DataSource could be connected in parallel to write the data to a separate DataObject in shorter intervals using the daemon. This DataSource could provide header information only, for example. For reporting, this data flow could be incorporated by means of InfoProviders.

●     Using a single DataSource

If just one DataSource is to be used, the existing data flow must be changed over to RDA. This is a result of the fact mentioned above – a DataSource can have one extraction mechanism only.