Oracle全文索引的性能优势实例

一、实验说明： 操作系统：rhel 5.4 x86 数据库：Oracle 11g R2 二、操作步骤： 2.1、首先创建一个表t_btree，并创建

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Oracle全文索引的性能优势实例

[日期：2014-10-08] 来源：Linux公社  作者：Linux [字体：]

一、实验说明：

     操作系统：rhel 5.4 x86

    数据库：Oracle 11g R2

二、操作步骤：

  2.1、首先创建一个表t_btree，并创建B-Tree索引，索引键是object_name:

SQL> create table t_btree as select * from dba_objects;

Table created.

SQL> create index ind_btree on t_btree(object_name);

Index created.

接着是执行下面的查询语句两次：

SQL> set linesize 150;
SQL> set autotrace on;
SQL> select count(*) from t_btree where t_btree.object_name like '%ObjectStreamClass%';

  COUNT(*)
----------
    84

Execution Plan
----------------------------------------------------------
Plan hash value: 3266099700

-----------------------------------------------------------------------------------
| Id  | Operation          | Name      | Rows  | Bytes | Cost (%CPU)| Time      |
-----------------------------------------------------------------------------------
|  0 | SELECT STATEMENT      |      |    1 |    66 |  103  (0)| 00:00:02 |
|  1 |  SORT AGGREGATE      |      |    1 |    66 |          |      |
|*  2 |  INDEX FAST FULL SCAN| IND_BTREE |    12 |  792 |  103  (0)| 00:00:02 |
-----------------------------------------------------------------------------------

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

  2 - filter("T_BTREE"."OBJECT_NAME" IS NOT NULL AND
          "T_BTREE"."OBJECT_NAME" LIKE '%ObjectStreamClass%')

Note
-----
  - dynamic sampling used for this statement (level=2)

Statistics
----------------------------------------------------------
    28  recursive calls
      0  db block gets
    454  consistent gets
    726  physical reads
      0  redo size
    422  bytes sent via SQL*Net to client
    419  bytes received via SQL*Net from client
      2  SQL*Net roundtrips to/from client
      0  sorts (memory)
      0  sorts (disk)
      1  rows processed

SQL> select count(*) from t_btree where t_btree.object_name like '%ObjectStreamClass%';

  COUNT(*)
----------
    84

Execution Plan
----------------------------------------------------------
Plan hash value: 3266099700

-----------------------------------------------------------------------------------
| Id  | Operation          | Name      | Rows  | Bytes | Cost (%CPU)| Time      |
-----------------------------------------------------------------------------------
|  0 | SELECT STATEMENT      |      |    1 |    66 |  103  (0)| 00:00:02 |
|  1 |  SORT AGGREGATE      |      |    1 |    66 |          |      |
|*  2 |  INDEX FAST FULL SCAN| IND_BTREE |    12 |  792 |  103  (0)| 00:00:02 |
-----------------------------------------------------------------------------------

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

  2 - filter("T_BTREE"."OBJECT_NAME" IS NOT NULL AND
          "T_BTREE"."OBJECT_NAME" LIKE '%ObjectStreamClass%')

Note
-----
  - dynamic sampling used for this statement (level=2)

Statistics
----------------------------------------------------------
      0  recursive calls
      0  db block gets
    369  consistent gets
      0  physical reads
      0  redo size
    422  bytes sent via SQL*Net to client
    419  bytes received via SQL*Net from client
      2  SQL*Net roundtrips to/from client
      0  sorts (memory)
      0  sorts (disk)
      1  rows processed

2.2、创建表t_bmap，并创建BitMap索引：

t_bmap
SQL
6 Index created。

执行之前的同样的语句查询：

SQL> select count(*) from t_bmap where t_bmap.object_name like '%ObjectStreamClass%';

  COUNT(*)
----------
    84

Execution Plan
----------------------------------------------------------
Plan hash value: 891302759