，自定义词典还是非常有意义的。
下面是一个相关的简单测试
未加关键词之前
SQL> select count(0) from data_query t wherecontains(MDTITILE,'xxxx万地质图')>0;
COUNT(0)
----------
7072
已用时间: 00: 00: 01.54
执行计划
----------------------------------------------------------
Plan hash value: 670767155
--------------------------------------------------------------------------------
---
| Id |Operation | Name | Rows | Bytes | Cost (%CPU)| Time
|
--------------------------------------------------------------------------------
---
| 0 |SELECT STATEMENT | | 1 | 85 | 4 (0)| 00:00:0
1 |
| 1| SORT AGGREGATE | | 1 | 85 | |
|
|* 2| DOMAIN INDEX | DATA_QUERY_IDX | 164 | 13940 | 4 (0)| 00:00:0
1 |
--------------------------------------------------------------------------------
---
Predicate Information (identified by operationid):
--------------------------------------------------
2 - access("CTXSYS"."CONTAINS"("MDTITILE",'xxxx万地质图')>0)
统计信息
----------------------------------------------------------
3528 recursive calls
0 db block gets
10214 consistent gets
1173 physical reads
2824 redo size
535 bytes sent via SQL*Net to client
524 bytes received via SQL*Netfrom client
2 SQL*Net roundtrips to/fromclient
263 sorts (memory)
0 sorts (disk)
1 rows processed
加关键词之后
SQL> select count(0) from data_query t wherecontains(MDTITILE,'xxxx万地质图')>0 ;
COUNT(0)
----------
7072
已用时间: 00: 00: 00.28
执行计划
----------------------------------------------------------
Plan hash value: 670767155
-------------------------------------------------------------------------------
---
| Id |Operation | Name | Rows | Bytes | Cost (%CPU)| Time
|
--------------------------------------------------------------------------------
---
| 0 |SELECT STATEMENT | | 1 | 85 | 4 (0)| 00:00:0
1 |
| 1| SORT AGGREGATE | | 1 | 85 | |
|
|* 2| DOMAIN INDEX | DATA_QUERY_IDX | 164 | 13940 | 4 (0)| 00:00:0
1 |
--------------------------------------------------------------------------------
---
Predicate Information (identified by operationid):
---------------------------------------------------
2 -access("CTXSYS"."CONTAINS"("MDTITILE",'xxxx万地质图')>0)
统计信息
----------------------------------------------------------
643 recursive calls
0 db block gets
2438 consistent gets
34 physical reads
0 redo size
535 bytes sent via SQL*Net toclient
524 bytes received via SQL*Netfrom client
2 SQL*Net roundtrips to/fromclient
34 sorts (memory)
0 sorts (disk)
1 rows processed