oracle11g 怎么没有Index Skip Scan
oracle11g 怎么没有Index Skip Scan 是不是默认没了，有参数？？？ oracle11g 跳跃索引扫描
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SQL> select * from v$version;

BANNER
--------------------------------------------
Oracle Database 11g Enterprise Edition Release 11.1.0.6.0 - Production
PL/SQL Release 11.1.0.6.0 - Production
CORE    11.1.0.6.0      Production
TNS for Linux: Version 11.1.0.6.0 - Production
NLSRTL Version 11.1.0.6.0 - Production

SQL> desc t
 Name                                      Null?    Type
 ----------------------------------------- -------- ----------------------------
 ID                                                 NUMBER
 NAME                                               VARCHAR2(10)
 SEX                                                CHAR(2)

SQL> create index idx_t on t (sex,id);

Index created.

SQL> analyze index idx_t compute statistics;

Index analyzed.

SQL> set autot trace exp
SQL> select /*+ index_ss(t) */ id from t where id=8;
 
 
Execution Plan
----------------------
Plan hash value: 1727616455

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 Id  
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 Operation        
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 Name  
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 Rows  
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 Bytes 
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 Cost (%CPU)
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 Time     
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   0 
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 SELECT STATEMENT 
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     1 
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    13 
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     4   (0)
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 00:00:01 
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*  1 
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  INDEX SKIP SCAN 
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 IDX_T 
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     1 
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    13  
 
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     4   (0)
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 00:00:01 
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Predicate Information (identified by operation id):
---------------------------------------------------

   1 - access("ID"=8)
       filter("ID"=8)

Note
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   - dynamic sampling used for this statement