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在查看SQL执行计划的时候有很多方式
我常用的方式有三种
SQL> explain plan for
2 select * from scott.emp where ename=‘KING‘;
已解释。
第一种 最常用的
SQL> select * from table(dbms_xplan.display);
Plan hash value: 3956160932 -------------------------------------------------------------------------- | Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time | -------------------------------------------------------------------------- | 0 | SELECT STATEMENT | | 1 | 38 | 3 (0)| 00:00:01 | |* 1 | TABLE ACCESS FULL| EMP | 1 | 38 | 3 (0)| 00:00:01 | -------------------------------------------------------------------------- Predicate Information (identified by operation id): --------------------------------------------------- 1 - filter("ENAME"=‘KING‘) 已选择13行。
第二种
SQL> select * from table(dbms_xplan.display_cursor(null,null,‘ALLSTATS LAST‘));
Plan hash value: 2637181423 --------------------------------------------------- | Id | Operation | Name | E-Rows | --------------------------------------------------- | 0 | DELETE STATEMENT | | | | 1 | DELETE | PLAN_TABLE$ | | |* 2 | TABLE ACCESS FULL| PLAN_TABLE$ | 1 | --------------------------------------------------- Predicate Information (identified by operation id): --------------------------------------------------- 2 - filter("STATEMENT_ID"=:1) Note ----- - dynamic sampling used for this statement (level=2) - Warning: basic plan statistics not available. These are only collected when: * hint ‘gather_plan_statistics‘ is used for the statement or * parameter ‘statistics_level‘ is set to ‘ALL‘, at session or system level 已选择26行。
第三种
SQL> select * from table(dbms_xplan.display(null,null,‘ADVANCED -PROJECTION‘));
Plan hash value: 3956160932 -------------------------------------------------------------------------- | Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time | -------------------------------------------------------------------------- | 0 | SELECT STATEMENT | | 1 | 38 | 3 (0)| 00:00:01 | |* 1 | TABLE ACCESS FULL| EMP | 1 | 38 | 3 (0)| 00:00:01 | -------------------------------------------------------------------------- Query Block Name / Object Alias (identified by operation id): ------------------------------------------------------------- 1 - SEL$1 / EMP@SEL$1 Outline Data ------------- /*+ BEGIN_OUTLINE_DATA FULL(@"SEL$1" "EMP"@"SEL$1") OUTLINE_LEAF(@"SEL$1") ALL_ROWS DB_VERSION(‘11.2.0.1‘) OPTIMIZER_FEATURES_ENABLE(‘11.2.0.1‘) IGNORE_OPTIM_EMBEDDED_HINTS END_OUTLINE_DATA */ Predicate Information (identified by operation id): --------------------------------------------------- 1 - filter("ENAME"=‘KING‘) 已选择32行。
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原文地址：http://www.cnblogs.com/SUN-PH/p/4837490.html
