Oracle B-tree、位图、全文索引三大索引性能比较及优缺点汇总

stevehai812 · 发表于 2012-9-19 11:41

我顶。为毛我做bitmap实验的时候没走索引？

SQL> select * from t1 where object_type='TABLE';

已选择50656行。

执行计划
----------------------------------------------------------
Plan hash value: 3617692013

--------------------------------------------------------------------------
| Id  | Operation       | Name | Rows  | Bytes | Cost (%CPU)| Time    |
--------------------------------------------------------------------------
| 0 | SELECT STATEMENT  |    | 40953 |  3719K|  5006 (3)| 00:01:01 |
|*  1 |  TABLE ACCESS FULL| T1 | 40953 |  3719K|  5006 (3)| 00:01:01 |
--------------------------------------------------------------------------

Predicate Information (identified by operation id):
---------------------------------------------------

1 - filter("OBJECT_TYPE"='TABLE')

统计信息
----------------------------------------------------------
      1  recursive calls
      0  db block gets
   25469  consistent gets
      0  physical reads
      0  redo size
2654624  bytes sent via SQL*Net to client
   37547  bytes received via SQL*Net from client
   3379  SQL*Net roundtrips to/from client
      0  sorts (memory)
      0  sorts (disk)
   50656  rows processed
请指点一哈。thx