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
首页 → 数据库技术
背景：
阅读新闻
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
———–本文来源gaodai#ma#com搞@@代~&码网^———————————————–
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
转载请注明原文链接：Oracle全文索引的性能优势实例
