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  • 【测试】使用hr用户下的employees表写一条SQL语句,执行计划走索引全扫描

    SQL> select count(*) from employees;
    
      COUNT(*)
    ----------
           107
    
    
    Execution Plan
    ----------------------------------------------------------
    Plan hash value: 3580537945
    
    -------------------------------------------------------------------------
    | Id  | Operation        | Name         | Rows  | Cost (%CPU)| Time     |
    -------------------------------------------------------------------------
    |   0 | SELECT STATEMENT |              |     1 |     1   (0)| 00:00:01 |
    |   1 |  SORT AGGREGATE  |              |     1 |            |          |
    |   2 |   INDEX FULL SCAN| EMP_EMAIL_UK |   107 |     1   (0)| 00:00:01 |
    -------------------------------------------------------------------------
    
    
    Statistics
    ----------------------------------------------------------
            224  recursive calls
              0  db block gets
            180  consistent gets
              1  physical reads
              0  redo size
            527  bytes sent via SQL*Net to client
            523  bytes received via SQL*Net from client
              2  SQL*Net roundtrips to/from client
              6  sorts (memory)
              0  sorts (disk)
              1  rows processed

     

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  • 原文地址:https://www.cnblogs.com/tomatoes-/p/5970980.html
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