B-Tree索引性能优于BitMap索引

建立两张表：

CREATETABLE t_btree ASSELECT * FROM dba_objects

在t_btree上建立bitmap索引

createbitmapINDEX object_id_bmx ont_btree(object_id);

执行两次查询

SELECT * FROM t_btree WHERE object_id=9999;

发现了执行了71次cr，扫描路径是bitmap索引

Dropindex object_id_bmx

创建btree索引：

CREATE INDEX object_id_btx on t_btree(object_id);

执行两次查询

SELECT * FROM t_btree WHERE object_id=9999;

发现了执行了4次cr，扫描路径是index range，证明是btree索引