Okay,
Again
concate. bitmap local prefix index = 9 secs. and I can't get CBO to use bitmap
merge even with index_combine hint - so explain plan shows just using by default
index with part. key in it (year) and response time is a little over 1
minute. I wish to try bitmap merge - how can I get the CBO to do it.
It might be faster than the concat. bitmap index but I can't try it.
Help.
I have been doing explain plans and it
accesses usually only the bitmapped index that either was created first or has
the same key as what I have part. view on - year. In any case perf. is in
minutes versus seconds and the explain plan does not show an index combine
occurring.
However, I still think the combined bitmapped index query would perform better and can't make CBO try this even with index_combine hint /*+ INDEX_COMBINE */ ..... regardless of optimizer setting.I cannot make it do an index_combine. I have used explain plan set.... then I use the utlxpls.sql from $ORACLE_HOME/rdbms/admin to check my plan. The timing is the same and explain plan show I am just using the index on year.What about the paramater bitmap_merge_... do I need to bump this up?
