Tuning OBIEE query with DB index, but it's getting slower

Question

Hello guys
I just have a quick question about tuning the performance of sql query using bitmap indexes..
Currently, there are 2 tables, date and fact. Fact table has about 1 billion row and date dim has about 1 million. These 2 tables are joined by 2 columns:
Date.Dateid = Fact.snapshot.dates and Date.companyid = fact.companynumber
I have query that needs to be run as the following:
Select dates.dayofweek, dates,dates, fact.opened_amount from dates, facts
where Date.Dateid = Fact.snapshot.dates and Date.companyid = fact.companynumber and dates.dayofweek = 'monday'.
Currently this query is running forever. I think it is joining that takes a lot of time. I have created bitmap index on dayofweek column because it's low on distinctive rows. But it didn't seem to speed up with the performance, but rather made it worse. The explain plan before and after creating that index was the same as:
Select statement optimizer
nested loops
partition list all
index full scan RD_T.PK_FACTS_SNPSH
TABLE ACCESS BY INDEX ROWID DATES_DIM
INDEX UNIQUE SCAN DATES_DIM_DATE
It seems the bitmap index I created for DATES_DIM wasn't used... Also, I am thinking what other indexes I should create for fact table..
I'd like to know what other indexes will be helpful for me and on which table & columns?.. I am thinking of creating another one for companynumber since it also have low distinctive records.
Currently I can't purge data or create smaller table, I have to what with what I have..
So please let me know your thoughts in terms of performance tunings for such situation..
Thanks

Answer 1

Jack,
Thank you for your response. It helped me to clean up the query. All the changes did not give a much better explain plan - at least not to my inexperienced eyes - but the total execution time for the query is now reduced to under two minutes. The query as it is now:
select /*+ ordered all_rows */ x.rowid1
from table(sdo_join('CYCLORAMA','GEOMETRIE','CYCLORAMA','GEOMETRIE','distance=3 mask=ANYINTERACT')) x
, cyclorama s, cyclorama t
where not x.rowid1 = x.rowid2
and s.rowid = x.rowid1 and x.rowid2 = t.rowid
and s.datasetid != t.datasetid
and s.opnamedatum < t.opnamedatum;Because the docs state that mask=FILTER is the default, I added an explicit mask=ANYINTERACT to the sdo_join parameters when I removed the sdo_distance from the query. Still, the query returns 205035 records with the sdo_distance, and 205125 without. But this may be the result of the extra 0.001 from sdo_dim. I did not investigate as the 3 meter is not crucial.
I believe I already had a mechanism in place to reduce the number of self-joins with "not x.rowid1 = x.rowid2" and "s.opnamedatum < t.opnamedatum". I can not guarantee that for all records s.opnamedatum < t.opnamedatum equals x.rowid1 < x.rowid2.
Based on the [url http://download.oracle.com/docs/cd/B19306_01/appdev.102/b14255/sdo_operat.htm#BGEDJIBF]docs, I finally added an 'ordered' hint and reshuffled the tables in the from clause.
I'm happy with performance now, and creating a new table with the records to keep should not be a problem. Still I'm curious about the following:
<li>Is it worth optimizing the SDO_DIM_ARRAY for the original table, e.g. narrowing the range of coordinate values?
<li>How can sdo_join best be used for an anti-join, to select the records to keep?
Thank you,
J-----.