Understanding how UWL gets work items from backend systems

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If you are reading this blog, you are probably familiar with UWL and how it renders work items from SAP Business Workflow. In SAP NetWeaver 2004s a new delta pull mechanism has been introduced. First we will review how UWL pulls work items from backend systems in SAP NetWeaver 2004, then we will discuss the changes in SAP NetWeaver 2004s. UWL pull from backend systems in SAP NetWeaver 2004

• When UWL pulls backend systems, the work items are stored in UWL cache. This cache is refreshed every 5 minutes.
• Assume a user logs in at 10:00 AM. Work items are pulled by user ID. The user logs out at 10:02 AM and back in at 10:04 AM. The second time the user logs a call to the backend will not be made since it is within the cache timeframe. However, if the user logs in at 10:06 AM, the backend call will occur.
• Users can also force a manual refresh of their work items.
• This behaviour works the same for all versions of SAP backend application systems.

UWL pull from backend systems in SAP NetWeaver 2004s

• The pulling no longer occurs for each user ID, users are bundled for backend pulls.
• The behavior for the pull is configured in the UWL system configuration. The following screen shot shows the new fields in the UWL configuration.

The two new fields are Pull Channel Delta Refresh Period and Snaphsot Refresh Period. Pull Channel Delta Refresh Period determines how often we should check to see if new items have entered the users inbox. It defaults to 60 seconds. If it is set to 0 or a negative number, no delta pull takes place. Snapshort Refresh Period refers to how often we should retrieve all items from the backend system. If left blank or negative, all work items are retrieved each time the user logs in. We recommend that the snapshot refresh occurs once a day.

• In order to use the new delta pull:
  • Your backend must also be on SAP NetWeaver 2004s. (I know this means it could be awhile before you can try this out, but the application backend must be running on SAP NetWeaver 2004s.)
  • Specific background jobs in your backend must be scheduled (see details below).
• Major benefits for the delta pull include:
  • It no longer pulls data for each user ID, users are grouped. Fifty users are used for one pull, which results in fewer logins to the backend system.
  • Response time for the user is greatly improved since there is not backend pull that occurs each time the user logs in.
  • The user still has the option to do a manual refresh.

The new delta pull and the required background jobs are explained very well in the online help. The most important points are:

• UWL_SERVICE is a user ID created on the portal for you. UWL_SERVICE must also exist on your backend sysetm.
• UWL_SERVICE must the be user ID on the backend system that runs background job RSWNUWLSEL. The online help discusses the required variants.

Recently when I registered a SAP NetWeaver 2004s backend on my UWL I received the message: "System TE3CLNT800 is not configured for optimized delta pull. Check the uwl_service user configuration." This message will appear if either the background jobs are not scheduled, or UWL cannot tell that the background jobs are scheduled. The message no longer appears once I ensure the background jobs are scheduled to run via the user id UWL_SERVICE and that user is mapped to my portal user ID UWL_SERVICE. This feature brings us a significant improvement with UWL performance. SAP NetWeaver 2004s is still in ramp-up; ramp-up will end later this year.