after login database slow

[Ranjit Bhise]

hen a user logs into OBIEE, the queries in the Initialization Block in the
RPD file will get fired. If any of these queries results in poor performance,
then the loading of the Init Block result set will be slow. In turn this will
impact the entire OBIEE login time.
.
First we will have to identify the SQL causing the slow performance and fine
tune the database to help the query run faster.
.
1) While trying to login into OBIEE, monitor the DB sessions in parallel.
Identify the session which is running slow and pick the SQL query getting
executed in this session.

[ErmanArslansOracleBlog]

Can you check the following link. Does it satisfy your needs?
http://gerardnico.com/wiki/dat/obiee/manage_session_log