I am not able to identify which features are missing in the previous SP. I think that no problem should arise with the compression of the DB of an SAP system lower than SP21, what could be possible drawbacks in this scenario?
This simply means that SAP does not recommend using compression with a lower level. Things that might not work are for example:
- DBACOCKPIT does not show if a segment is compressed or not
- BRtools don't allow the use of compression
- SE11/SE14 does not show the table properties correctly
It might even be that some programs won't work properly with compression. The best thing in your case certainly is to consider applying a current support package stack. This never hurts and you don't have to wonder about problems you might run into (especially when SAP has fixed them already).
I have compressed several SAP systems and didn't care for SAP DDIC support for Oracle Advanced Compression. Since the feature is transparent, it simply works.
SAP could be a little bit more specific in SAP note 1436352, I agree. I believe they mean things like in table DDSTORAGE, the compressed tables have a feature PARNAME='COMPR_CLAUSE' so the SAP DDIC is also aware that a table is compressed.
@Michael: Applying a complete SP stack is a separate activity on its own, just think about SPDD and SPAU adjustments (and subsequest testing) in highly customized environments, so I would like to avoid the effort required.
@Mark: I completely agree with you, SAP could be more specific.
Thanks for your help,