Oracle全文索引的性能优势实例

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Oracle全文索引的性能优势实例

2024-07-26 04:04:11 222人阅读

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

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：

1 SQL> create table t_bmap as select * from dba_objects;
2
3 Table created.
4 SQL> create bitmap index ind_bmap on t_bmap(object_name);
5
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

------------------------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time |
------------------------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 1 | 66 | 263 (0)| 00:00:04 |
| 1 | SORT AGGREGATE | | 1 | 66 | | |
| 2 | BITMAP CONVERSION COUNT | | 12 | 792 | 263 (0)| 00:00:04 |
|* 3 | BITMAP INDEX FAST FULL SCAN| IND_BMAP | | | | |
------------------------------------------------------------------------------------------

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

3 - filter("T_BMAP"."OBJECT_NAME" IS NOT NULL AND "T_BMAP"."OBJECT_NAME" LIKE
‘%ObjectStreamClass%‘)

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

Statistics
----------------------------------------------------------
28 recursive calls
0 db block gets
360 consistent gets
591 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_bmap where t_bmap.object_name like ‘%ObjectStreamClass%‘;

COUNT(*)
----------
84

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

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

3 - filter("T_BMAP"."OBJECT_NAME" IS NOT NULL AND "T_BMAP"."OBJECT_NAME" LIKE
‘%ObjectStreamClass%‘)

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

Statistics
----------------------------------------------------------
0 recursive calls
0 db block gets
285 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

2.3、创建表t_all，并创建全文索引：

SQL> create table t_all as select * from dba_objects;

Table created.

SQL> create index ind_all on t_all(object_name) indextype is ctxsys.context;

Index created.

下面改变一下查询语句，但是需要输出的结果是跟之前的一样：

SQL> select count(*) from t_all where contains(t_all.object_name,‘%ObjectStreamClass%‘)>0;

COUNT(*)
----------
84

Execution Plan
----------------------------------------------------------
Plan hash value: 3532980284

----------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time |
----------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 1 | 78 | 4 (0)| 00:00:01 |
| 1 | SORT AGGREGATE | | 1 | 78 | | |
|* 2 | DOMAIN INDEX | IND_ALL | 35 | 2730 | 4 (0)| 00:00:01 |
----------------------------------------------------------------------------

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

2 - access("CTXSYS"."CONTAINS"("T_ALL"."OBJECT_NAME",‘%ObjectStreamCl
ass%‘)>0)

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

Statistics
----------------------------------------------------------
2221 recursive calls
0 db block gets
2228 consistent gets
267 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
254 sorts (memory)
0 sorts (disk)
1 rows processed

SQL> select count(*) from t_all where contains(t_all.object_name,‘%ObjectStreamClass%‘)>0;

COUNT(*)
----------
84

Execution Plan
----------------------------------------------------------
Plan hash value: 3532980284

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

2 - access("CTXSYS"."CONTAINS"("T_ALL"."OBJECT_NAME",‘%ObjectStreamCl
ass%‘)>0)

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

Statistics
----------------------------------------------------------
48 recursive calls
0 db block gets
348 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

Oracle全文索引的性能优势实例

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