BW housekeeping can be a hot topic, because it falls into that grey area between the BW consulting team & the basis team. The basis team are usually familiar with standard ERP housekeeping tasks, but maybe not the BW tasks, so this is an area where the BW team & the basis team need to work together in order to keep the system in good shape.
The database is the heart & soul of SAP BW, and it needs to be looked after & cared for. Look after your database, and your database will look after you. Undertaking the regular housekeeping tasks which are required to keep the BW database in good working order can be a bit of a chore, but it will pay off in the long term with better system performance & increased stability.
SAP Note 706478 covers the basics of housekeeping in both ERP & BW systems, and you should read it if you are planning on undertaking any housekeeping tasks on your SAP system.
The Grey Area between BW Housekeeping & BW Performance Tuning
Some of the housekeeping tasks mentioned in these blog postings will help to improve system performance for both dataloads & reporting, which yet another good reason to get them done. Proper BW performance tuning is a separate topic which I will cover in a future series.
When not to do housekeeping
Don’t delete PSA data for transactional datasources, (especially the horrible logistics 2LIS_xx ones), where re-initialising the data from source is very impactful on the ERP system & requires downtime or posting-free time. Ideally you want to be able to re-initialise all this sort of data from the PSA rather than going to source, so leave the PSA tables alone for these datasources unless your data volumes are small and/or you know you can take the ERP system offline for a weekend without bringing the business to a standstill.
Don’t delete archive files created using the BWREQARCH object in SARA. If you do this, you will cause your BW system to stop working under certain circumstances, and while there is a workaround, it’s still a situation worth avoiding.
When deleting large amounts of data from a database, your DBMS redo logs will take a hammering and can fill up and crash the DBMS. To avoid this, delete data in fairly small chunks, and also make the basis team aware of what you’re up to so they can keep an eye on the DBMS. And of course, make sure you run your deletions when the system is not busy.
Some DBMS (such as Oracle) require a tablespace organisation to be run in order to fully release the space freed up by large-scale deletions performed as part of housekeeping. Talk to your basis team about this.
Has this piqued your interest? If so, tune in to this blog again next week when I will start to cover off some of the specific BW housekeeping tasks in detail.
Find out more. Register for our Knowledge Transfer Session: BW Housekeeping on 28th July.
Guest author: Mark Wheaton