Controlling Real-Time Data Acquisition with Process Chains

With the two process types Start Real-Time Data Acquisition (RDA) Load Process and Stop Real-Time Data Acquisition (RDA) Load Process you can start or stop the RDA data transfer for one or more DataSources using a process chain. In this way you can, for example, combine the data transfer using real-time data acquisition with the standard data transfer and control it using a process chain.

The following graphic shows a possible scenario:

As a travel agency you offer two ways to book a trip: An Internet application with which customers can book their trips online, and travel agencies that book trips using an SAP application. The Internet application sends the booking data to BW using a Web service. During the day, you want to analyze this data at short notice; you therefore load this data to a DataStore object using real-time data acquisition. The travel agencies send their booking data every evening. You need to temporarily stop the RDA data transfer in order to be able to load the data into the same DataStore object. You now transfer the booking data from the travel agencies to BW using the standard procedure (scheduled) and continue to process the data in the BW system. You then restart the transfer of the online booking data by real-time acquisition. In the morning you can analyze all the bookings from the previous day as well as the current online booking data. In the course of the day you also get the current data from the Internet application in a timely fashion.

After initialization of the data transfer, a process chain that supports this scenario might be as follows:

The start of the process chain is scheduled so that the chain begins every day at a defined time after the travel agency has closed. First the RDA data transfer is stopped; then the delta transfer of the data from the travel agencies is started. This is followed by the postprocessing, such as activation of the data in the DataStore object.

You are in the plan view of a process chain into which you want to link one or both processes.

The process types are available in the Loading Process and Postprocessing process category.

1. Insert the requiredprocess type into the process chain by using drag and drop or by double-clicking.
2. In the next dialog box, select a process variant and confirm your entry.
   1. To create a new process variant, enter a name for the variant and choose Create.
   2. In the resulting dialog box, enter the description of the process variant and choose Next.

      The maintenance screen for the process variant appears.

   3. In the variant maintenance, select the DataSources for which real-time data acquisition should be started or stopped for one or more InfoPackages for real-time data acquisition.
   4. Save the variant and go back to the previous screen.
   5. In the resulting dialog box, confirm the insertion of the process variant into your process chain.

You inserted real-time data acquisition in a process chain. After including any additional process variants in your chain, check the chain and activate it.

If the process chain is running, the system proceeds as follows:

• Start Real-Time Data Acquisition (RDA) Load Process

  If the InfoPackages selected in the process variant are not yet assigned to a daemon, the system selects one or more suitable daemons and assigns the corresponding DataSources to them. When searching for a suitable daemon, the system proceeds as follows:

  1. Assignment based on the InfoProvider (data target)

     Different DataSources (and therefore InfoPackages) that define values for the same InfoProvider must be assigned to the same daemon.

  2. Assignment to the daemon that was last assigned to the DataSource (and therefore to the InfoPackage)
     Note

     The system stores the information about the assignment of a DataSource to a daemon when the daemon assignment is deleted. This information can therefore be used later for another assignment to a daemon.

  3. Assignment to the daemon to which the fewest DataSources are assigned

     If multiple daemons are possible here, the assignment is made to the daemon with the lowest number

  If there is not yet a daemon available, the system creates one and assigns the DataSources to the daemon. If the DataSources are already assigned to a daemon, this daemon is used.

  The data transfer processes assigned to the DataSources are also assigned to the daemon.

  If all the assignments have been made and the daemon or daemons are not running at the time of process execution, the process chain schedules the daemons for immediate use and the process variant ends.

  If an InfoPackage selected in the process variant is assigned to a daemon that is already running, the steps described here are not applicable and not performed.

• Stop Real-Time Data Acquisition (RDA) Load Process

  Running data transfers for the InfoPackages and corresponding data transfer processes selected in the process variant are terminated.

  The open PSA, DTP and possibly change log requests are closed (if the daemon is running, after ending the data transfer; directly if the daemon is not running).

  The system then deletes the assignments of the corresponding DataSources to the daemon.

  Note

  As mentioned above, the system stores the information about the assignment of the DataSource to the daemon, and this information can be used again later when the daemon is again assigned.

  If an InfoPackage selected in the process variant is not assigned to a daemon, the steps described here are not applicable and not performed.