SQL & PL/SQL

Hey guys just got a question about my data warehouse and wanted some input.

I have this fact table in my data warehouse which comprises of several foreign keys to dimension tables and columns which hold metric values in a time series layout (t1, t2, t3... t~n~). As new data comes in, I make use of a global temporary table that is a replica of the fact table in the data warehouse. Therefore the new data coming in is re-arranged to fit into the data model in the temporary table. Once that is done, I perform a merge (on temp.object_key = fact.object_key etc).

Currently the explain plan shows that it performs a full table scan on both the fact table and the temp table to perform the merge; this is because there is no bitmap index on the temp table to correspond with its respective fact table. My question is, has anyone had long-term success with placing bitmap indexes on the temporary table so that when the merge is executed it will use the bitmap indexes rather than performing a full table scan; provided the CBO thinks it best?

No I haven't tried it myself, I was just curious to hear what others think. I am also getting this weird error when trying to place a regular bitmap index on a GTT; the dreaded ORA-03113: End of file on communication channel. http://www.dba-oracle.com/m_ora_03113_end_of_file_on_communications_channel.htm

I know that I can't make a bitmap join index on a GTT but I haven't seen anything that says I can't just make a regular bitmap index on a GTT. Any help on that error would be appreciated too, I know it's a generic catch-all error, but if anyone's had problems with this particular case of creating a bitmap index on a GTT and had solved it let me know.

Regards,
TimS