Business Intelligence Server Enterprise Edition – Version: 188.8.131.52.0  and later [Release: 11g and later ]
Information in this document applies to any platform.
1) Customer upgraded 10.1.3.4.1 RPD and web catalog to 184.108.40.206.
2) Its noticed that in 220.127.116.11 the same reports take a lot longer to execute:
Eg: 1 min 30 sec in 11G vs. only 30 sec in 10G.
3) RPD doesn’t have any metadata inconsistencies, connection pool settings are good.
4) The memory usage spikes up when reports are run, and BI Server is taking too long compiling these reports.
5) Customer notices that the XML copied from 10g to 11g creates a more complicated logical query in 11g compared to 10g.
6) When customer copies the logical query from 10g and runs in 11g it gives the same performance as 10g.
Basically this is caused by many column with the empty string formula: ”, causing it to have 2nd UNION leaf to calculate the subtotal in 18.104.22.168.
These columns with a column formula ” where used as separators in the report.
Replaced all column separators with “duplicate measure” columns with a column length of 0.
This ensures the subtotals are NOT trying to use the separators as dimensions and create extra queries with UNION ALL.