I have few unbalanced heirarchies in the rpd. I have created level beased heirarchy for those ragged and skipped hierarchy but while generating the report using those hierarchy generates a huge SQL involving 20-30 UNION ALLs . Instead it should have generated comparatively smaller query using Group by Grouping Sets but it is not.
I have also tried enabling this parameter in DB properties in OBIEE11g ( changed the default DB from 9i to 11g in obiapps 188.8.131.52 rpd) but still no use .
As a result of huge query geenration the performance is badly impacted.