Managing the DDIC Cache

Data DICtionary Cache (DDIC Cache)

The Data DICtionary Cache (DDIC) is a cache that holds information about SAP function modules, structure definitions, Business Objects, ALE mappings, and IDocs. Adapter for SAP retrieves this information from an SAP system when it performs RFC, BAPI, or IDoc lookups. To improve performance, Adapter for SAP caches information it receives about function modules and structure definitions.

Adapter for SAP receives information about function modules and structure functions when:

  • An RFC, BAPI, or IDoc lookup is requested from the Lookup screen.
  • Adapter for SAP executes a service that invokes an RFC or BAPI on an SAP system.
  • An SAP system executes an RFC that invokes a service.
  • An IDoc gets processed by Adapter for SAP.

Adapter for SAP keeps separate cached function modules, structure definitions, Business Objects, ALE mappings, and IDocs for each SAP system. When Adapter for SAP requires specific data, it checks its DDIC cache for the specific SAP system to determine if the information it requires is in cache. If the required information is in the DDIC cache, Adapter for SAP uses the cached information rather than retrieving it from the SAP system.

The DDIC cache is always active. There are no configuration tasks required to activate it. When you are developing services, there may be times when the information in the DDIC cache becomes outdated; for example, if you change an RFC signature on an SAP system. In these situations, you can use the DDIC cache screens to view the information in the cache and remove specific function modules or structure definitions from the cache as necessary without having to restart Integration Server.

Note: The DDIC cache does not persist through shutdown and restart of Integration Server.

Viewing Information in the DDIC Cache

About this task

Perform one of the following procedures to view information about the function modules, structure definitions, Business Objects, ALE mappings, and IDocs that are in the DDIC cache.

To view information in the DDIC cache

Procedure

  1. In the Adapters menu in the Integration Server Administrator navigation area, click IBM webMethods Adapter for SAP.
  2. Click DDIC-Cache.

    The SAP Repository Cache table appears, showing all of the element types stored in the cache.

    Note: The System ID field uniquely identifies an SAP system within one SAP domain. If one or more RFC connections use the same system ID, they will share the same cache. For more information about defining RFC connections, refer to Configuring Adapter Connections.
    Note: If you have configured and enabled an RFC listener, you will also see a 'Local' entry in the System ID. list. The cached elements of this System ID cannot be deleted or modified.
  3. To view the names of cached function modules for an SAP system, click the number in the Functionscolumn for the appropriate System ID.

    The Cached Functions table appears. To view more details about a function module:

    1. Click the name of the function module for which you want to see the function interface.

      Adapter for SAP displays a screen that lists the function interface for the selected function module.

    2. View the structure definition of the displayed parameters by following the hyperlink in the Table column.
  4. To view the names of the cached structure definitions for an SAP system, click the number in the Structurescolumn for the appropriate System ID.

    The Cached Structures table appears. To see the structure definition, click the structure name of the structure you want to view.

    Adapter for SAP displays a screen that lists the structure definition for the selected function module.

  5. To view the names of the cached business objects for an SAP system, click the number in the Business Objects column for the appropriate System ID.

    The Cached Business Objects table appears.

  6. To view the names of the cached BAPIs for an SAP system (for which ALE information of an SAP system has been checked and extracted), click the number in the ALE Mappings column for the appropriate System ID.

    The Cached ALE Mappings table appears.

  7. To view the names of the cached IDocs for an SAP system, click the number in the IDocs column for the appropriate System ID.

    The Cached IDocs table appears.

    Note: The list also contains BAPIs for which no ALE interface has been generated in the SAP system, but for which the availability has already been checked. This is because Adapter for SAP tries only once to retrieve ALE information. If this retrieval fails, Adapter for SAP retains this fact.
  8. After enabling one (or more) RFC listeners, a new entry named LOCAL is listed in theDDIC Cache screen of Adapter for SAP. The LOCAL entry contains four function definitions: WM_PUSH_START_EVENT, WM_PUSH_STOP_EVENT, WM_PUSH_ERROR_EVENT, and WM_PUSH_BUSINESS_DATA and two structure definitions: WMKEYVALUE and WMBUSINESSDATA.

Removing Information from the DDIC Cache

You can clear the entire cache for an SAP system, or you can clear individual elements from the cache. This section describes how to do both.

Clearing the DDIC Cache for an SAP System

About this task

To clear the entire DDIC cache for an SAP system

Procedure

  1. In the Adapters menu in the Integration Server Administrator navigation area, click IBM webMethods Adapter for SAP.
  2. Click DDIC-Cache.

    The SAP Repository Cache table appears, showing all of the element types stored in the cache.

  3. Identify the System ID of the SAP system for which you want to clear the cache, and click in Clear Cache column for that System ID.

Clearing Elements from the DDIC Cache

About this task

If a function module, structure definition, Business Object, ALE mapping, or IDoc in the DDIC cache becomes outdated or corrupt, you can use the following procedures to remove it from the DDIC cache.

To remove elements from the DDIC cache

Procedure

  1. In the Adapters menu in the Integration Server Administrator navigation area, click IBM webMethods Adapter for SAP.
  2. Click DDIC-Cache.

    The SAP Repository Cache table appears, showing all of the element types stored in the cache.

    To clear an element from the DDIC cache:

    1. Identify the System ID of the SAP system for which you want to clear elements of the cache.
    2. For that System ID, click the number in the column of the element type you want to clear. For example, if you want to clear a function module, click the number in the Functions column for the appropriate System ID.

      The appropriate table for that element type appears.

    3. Identify the specific element you want to clear, and click the icon in the Remove column for that element.
      Note: The default entries of the LOCAL entry cannot be deleted.
  3. Click Return to DDIC-Cache to return to the SAP Repository Cache table.