Originally posted by grjohnson
Check you DB_FILE_MULTIBLOCK_READ_COUNT parameter.. now that you've analyzed your tablesa, the CBO probably thinks that a FTS is cheaper than and index lookup. Sometimes the DB__FILE_MULTIBLOCK_READ_COUNT can be set to high making the CBO choose FTS's. Try a setting of 8.
Thanks.

SQL> show parameter db_file

NAME TYPE VALUE
------------------------------------ ------- ------------------------------
db_file_direct_io_count integer 64
db_file_multiblock_read_count integer 8
db_file_name_convert string
db_files integer 200
SQL>

Do I need to specify explicitly db_file_multiblock_read_count = 8 in parameter file.

Regards