Archiving, Stragglers and Updates: Straggler Management with PBS CBW NLS

For many years, PBS has been providing the well-approved and efficient nearline storage solution CBW NLS. With the high data compression and outstanding performance of the used nearline databases SAP IQ and IBM DB2 BLU, it has supported many customers to improve their overall SAP BW system performance and significantly reduce operating costs.

The Challenge: Dealing with Stragglers

Archiving of DataStore objects is based on time slices. SAP BW locks archived time slices and protects them against any changes. If a document that belongs to such time slice – a so-called straggler – should be transferred to the BW after archiving, it is rejected due to the time slice lock. The updated data is therefore not available for reporting. The lock can only be removed by reloading the archived data. After updating the straggler information, the data has to be archived again, which involves considerable effort.

This aspect puts off many BW users from performing data archiving. Data remains in the database longer than necessary and the advantages of nearline storage cannot be leveraged.

The Solution: PBS Straggler Management – Optimal Results with Minimal Effort

Straggler Management in CBW NLS provides a way out of this dilemma as it enables the archiving and updating of stragglers for DataStore objects. Straggler Management is activated with just a few administrative steps: First, the data transfer process is activated for the feature "Write error stack, update valid record" regarding the DataStore object. Subsequently, a PBS administration transaction is used to generate additional objects for each DataStore object, which is involved. After activation, all stragglers can be transferred and posted into the nearline storage database.

Once the stragglers have been updated using the PBS transaction they are considered for all future reporting. They can also be included in the update of successor objects such as InfoCubes.

With this new functionality in PBS CBW NLS, it is no longer necessary to prevent DSO archiving in BW – instead – more aggressive archiving can be achieved.