SAP BW : PSA and Changelog Deletion

 

Best practice to have a strategy on PSA and changelog deletion. For PSA data below are the best practices in my view.


PSA Deletion in SAP BW/BI(Business Intelligence)


1.    Transaction Data – Keep upto 45 days, delete the requests older than 45 days. The rationale behind 45 days is that month end reporting is done within the first two weeks of the month. So by keeping 45 days we will have the opportunity to reload/recover data from PSA if there are in issues with data.
2.    Master Data : For master data it depends on attribute or texts, delta or full.

Attribute Delta Loads : 2 weeks.
Attribute  full Loads : 1 week
Texts: One week or no PSA at all

Change Log Data : I think there is lot of confusion in forums on deleting changelog data. Some say we can delete the changelog data no problem, some say we will get incorrect data if there are any updates for deleted old data.

For the record, change log data can be deleted, there are no issues with it even when we get changes for the records we deleted. Here is how change log /delta from ODS to the cube works.

1.    Data is first loaded into new table (This is before ODS activation)


2.    ODS Activation : During activation SAP compares records in new table with records in active table and generates changelog records and puts them under a unique id which corresponds to request id in the active table. Records in new table are deleted at the end of activation.


3.    Now when you do a delta from the ODS to the cube it loads the records from changelog table based on request id, after the delta load is complete the records in change log table are never used for anything again unless you want to reconstruct/reload data requests by requests.


4.    Even if you need to reload you do it by either full or delta init loads or data will be loaded from active table.

 

How to delete changelog or PSA data in SAP BW?

    OK. Now you have decided to delete change log and PSA data which has been sitting out there. How to know how many requests are there, what are big change log/PSA to get rid of first to save some much needed spaces.


      You can go to table RSTSODSREQUEST and export the list to excel or access file. It will give the no of requests by PSA and ODS.


     Actual deletion of change log can be done either in process chains or from the ODS ->Manange -> Environment -> Delete change log data.


  Any questions? Leave a comment, I will answer them.


Comments (2)

Diane
Said this on 10-1-2010 At 04:31 am

In BW3.5 we deleted PSA and Change Log data via the "Delete PSA Request" process in our process chains.   After doing a TECHNICAL only upgrade to BI7.01 (servicepack 6) we are only able to delete the PSA requests via the process chains.   The "Deletion of Requests from the Change Log" does not select any change logs to delete.   We ARE able to manually delete the change logs through the Manage --> Environment --> Delete Change Log Data of the DSO object.    Has anyone been able to delete change logs via a process chain after a TECHNICAL only upgrade to BI7.01?????

Thanks in advance for any help!

Hans
Said this on 11-9-2011 At 08:18 pm

hello, we also upgrade our BW to BI7.01 and now have the problem that PSA delete in process chains for ODS-Object does not select any change logs to delete.   We are only able to manually delete the change logs.

Has anyone been able to delete change logs via a process chain ?

Thanks in advance for any help! 

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