查看oracle执行计划(命令实现)
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看下面小练习,告诉你如何用oracle命令查看执行计划.
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1.想要查看执法计划的SQL语句:
explain plan for select t.*, t.rowid from A5 t where t.l = '101214' and t.k like '%8号' order by i ;
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2.查看此SQL语句的执行计划:
select * from table(dbms_xplan.display);
执行结果如下:
PLAN_TABLE_OUTPUT--------------------------------------------Plan hash value: 1156097717---------------------------------------| Id? | Operation????????? | Name | Rows? | Bytes | Cost (%CPU)| Time???? |---------------------------------------|?? 0 | SELECT STATEMENT?? |????? |??? 12 |? 1524 |??? 71?? (3)| 00:00:01 ||?? 1 |? SORT ORDER BY???? |????? |??? 12 |? 1524 |??? 71?? (3)| 00:00:01 ||*? 2 |?? TABLE ACCESS FULL| A5?? |??? 12 |? 1524 |??? 70?? (2)| 00:00:01 |----------------------------------------Note----- - 'PLAN_TABLE' is old version 12 rows selected
'PLAN_TABLE' is old version : 这句话告诉我们,PLAN_TABLE的版本太旧,需要重新生成.
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3.重新生成PLAN_TABLE表:
-- 删除表drop table PLAN_TABLE;-- 新建表@D:\oracle\product\10.2.0\db_1\RDBMS\ADMIN\utlxplan.sql;
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4.查看执行计划:
select * from table(dbms_xplan.display);
结果如下:
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PLAN_TABLE_OUTPUT--------------------------------------------Plan hash value: 1156097717---------------------------------------| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time |---------------------------------------| 0 | SELECT STATEMENT | | 12 | 1524 | 71 (3)| 00:00:01 || 1 | SORT ORDER BY | | 12 | 1524 | 71 (3)| 00:00:01 ||* 2 | TABLE ACCESS FULL| A5 | 12 | 1524 | 70 (2)| 00:00:01 |---------------------------------------Predicate Information (identified by operation id):--------------------------------------------------- 2 - filter("T"."L"='101214' AND "T"."K" LIKE '%8号') 14 rows selected?
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