The Library is currently in the process of being upgraded from Oracle Database Version 188.8.131.52 to 184.108.40.206.
Demos are being upgraded to reflect the new Container paradigm as well as EBR (Edition Based Redefinition) and may contain references to CDBs, PDBs,
and other objects you may not be familiar with such as CDB_OBJECTS_AE: Welcome to 12c.
Have you viewed the Library's main Table of Contents? If not ... [Click Here]
... scroll down the page and you will find links to the largest collection of Oracle Database demos on the net.
WHERE table_name = 'T2';
-- repeat the query without a hint
WHERE person_id = 221;
-- note that Oracle uses the index and the cost is much lower
Another Index Quality Query
SELECT dt.table_name, di.index_name, blocks, clustering_factor, (blocks/clustering_factor) CF_RATIO
FROM dba_tables dt, dba_indexes di
WHERE dt.owner NOT LIKE '%SYS%'
AND dt.owner = di.owner
AND dt.table_name = di.table_name
AND dt.blocks > 0
AND di.clustering_factor > (blocks*5)
ORDER BY 5;