What do you mean by Queued Delta Update Method?

"Queued delta" update method: 

With queued delta update mode, the extraction data (for the relevant application) is written in an extraction queue (instead of in the update data as in V3) and can be transferred to the BW delta queues by an update collective run, as previously executed during the V3 update. 

After activating this method, up to 10000 document delta/changes to one LUW are cumulated per datasource in the BW delta queues.

If you use this method, it will be necessary to schedule a job to regularly transfer the data to the BW delta queues (by means of so-called "update collective run") by using the same delivered reports as before (RMBWV3); instead, report RSM13005 will not be provided any more since it only processes V3 update entries. 

As always, the simplest way to perform scheduling is via the "Job control" function in LBWE. 

SAP recommends to schedule this job hourly during normal operation after successful delta initialization, but there is no fixed rule: it depends from peculiarity of every specific situation (business volume, reporting needs and so on).

BENEFITS, BUT
When you need to perform a delta initialization in the OLTP, thanks to the logic of this method, the document postings (relevant for the involved application) can be opened again as soon as the execution of the recompilation run (or runs, if several and running in parallel) ends, that is when setup tables are filled, and a delta init request is posted in BW, because the system is able to collect new document data during the delta init uploading too (with a deeply felt recommendation: remember to avoid update collective run before all delta init requests have been successfully updated in your BW!).

By writing in the extraction queue within the V1 update process (that is more burdened than by using V3), the serialization is ensured by using the enqueue concept, but collective run clearly performs better than the serialized V3 and especially slowing-down due to documents posted in multiple languages does not apply in this method.
On the contrary of direct delta, this process is especially recommended for customers with a high occurrence of documents (more than 10,000 document changes - creation, change or deletion - performed each day for the application in question.

In contrast to the V3 collective run (see OSS Note 409239 ‘Automatically trigger BW loads upon end of V3 updates’ in which this scenario is described), an event handling is possible here, because a definite end for the collective run is identifiable: in fact, when the collective run for an application ends, an event (&MCEX_nn, where nn is the number of the application) is automatically triggered and, thus, it can be used to start a subsequent job.

Besides, don’t omit that queued delta process extraction is independent of success of the V2 update.

REMEMBER TO EMPTY THE QUEUE
The ‘queued delta’ is a good friend, but some care is required to avoid any trouble.

First of all, if you want to take a look to the data of all extract structures queues in Logistic Cockpit, use transaction LBWQ or "Log queue overview" function in LBWE (but here you can see only the queues currently containing extraction data).

In the posting-free phase before a new init run in OLTP, you should always execute (as with the old V3) the update collective run once to make sure to empty the extraction queue from any old delta records (especially if you are already using the extractor) that, otherwise, can cause serious inconsistencies in your data.

Then, if you want to do some change (through LBWE or RSA6) to the extract structures of an application (for which you selected this update method), you have to be absolutely sure that no data is in the extraction queue before executing these changes in the affected systems (and especially before importing these changes in production environment !). 

To perform a check when the V3 update is already in use, you can run in the target system the RMCSBWCC check report.

The extraction queues should never contain any data immediately before to: 

• perform an R/3 or a plug-in upgrade 
• import an R/3 or a plug-in support packages 

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