create table a3 as select * from dba_objects create index a3_idx1 on a3(owner); select owner from a3 where owner='SCOTT'; SQL> set linesize 200 SQL> set pagesize 200 SQL> set autot trace SQL> select owner from a3 where owner='SCOTT'; 1870 rows selected. Execution Plan ---------------------------------------------------------- Plan hash value: 3836947260 ---------------------------------------------------------------------------- | Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time | ---------------------------------------------------------------------------- | 0 | SELECT STATEMENT | | 1870 | 31790 | 5 (0)| 00:00:01 | |* 1 | INDEX RANGE SCAN| A3_IDX1 | 1870 | 31790 | 5 (0)| 00:00:01 | ---------------------------------------------------------------------------- Predicate Information (identified by operation id): --------------------------------------------------- 1 - access("OWNER"='SCOTT') Note ----- - dynamic sampling used for this statement (level=2) Statistics ---------------------------------------------------------- 7 recursive calls 0 db block gets 212 consistent gets 0 physical reads 0 redo size 25551 bytes sent via SQL*Net to client 1783 bytes received via SQL*Net from client 126 SQL*Net roundtrips to/from client 0 sorts (memory) 0 sorts (disk) 1870 rows processed
INDEX RANG SCAN无需回表的情况
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