Cluster Tables are Strongly Compressed Tables. They are Factor 10 - 20 Smaller than Transpararent Tables. Because of a bug, these Tables Sometimes get Converted Witout any Need.
We saw cases where the cluster table of 13GB got converted to an intermediate table QCMBSEG (as BSEG is part of RFBLG) of 110 GB. This took more than 12 hours - and "just" happened during a "normal" Support Packs Installation.
So, this Support Packagage Installation took more than 24 h in total ...
Mainly the following tables are in danger:
This problem is fixed with Basis Support Pack 19 for 7.00. If you want to prevent this issue, you either need this support pack in the system BEFORE you apply the application support packs or you need to apply the note individually.
It is not sufficient, to just create one big queue based of that, as the ABAP Contents becomes active AFTER the DDIC Activation.
More information on this issue is available in note 1283197.