Oracle性能优化有时就这么简单_index(二)

2014-11-24 17:17:54 · 作者: · 浏览: 1
'XXXDBA') from dual;



DBMS_METADATA.GET_DDL('INDEX','P_ORACLETABLEAVAILABLE','XXXDBA')


--------------------------------------------------------------------------------------------------------------------



CREATE UNIQUE INDEX "XXXDBA"."P_ORACLETABLEAVAILABLE" ON "XXXDBA"."ORACLETABLEAVAILABLE" ("RESOURCEID", "TIME")


PCTFREE 10 INITRANS 2 MAXTRANS 255 COMPUTE STATISTICS


STORAGE(INITIAL 131072 NEXT 1048576 MINEXTENTS 1 MAXEXTENTS 2147483645


PCTINCREASE 0 FREELISTS 1 FREELIST GROUPS 1 BUFFER_POOL DEFAULT)


TABLESPACE "PERFORMANCE"





再次查看执行计划,这速度,杠杠的



SQL> explain plan for SELECT V0900,H,L,A,to_char(HTIME,'yyyy-mm-dd hh24:mi:ss'),to_char(LTIME,'yyyy-mm-dd hh24:mi:ss')


2 FROM XXXDBA.ORACLETABLEAVAILABLE


3 WHERE RESOURCEID = :1 AND TIME = to_date(:2,'yyyy-mm-dd')


4 ;



Explained.



SQL> select * from table(dbms_xplan.display);



PLAN_TABLE_OUTPUT


------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------


Plan hash value: 1279632247



-----------------------------------------------------------------------------------------------------------


| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time |


-----------------------------------------------------------------------------------------------------------


| 0 | SELECT STATEMENT | | 1 | 65 | 3 (0)| 00:00:01 |


| 1 | TABLE ACCESS BY INDEX ROWID| ORACLETABLEAVAILABLE | 1 | 65 | 3 (0)| 00:00:01 |


|* 2 | INDEX UNIQUE SCAN | P_ORACLETABLEAVAILABLE | 1 | | 2 (0)| 00:00:01 |


-----------------------------------------------------------------------------------------------------------



Predicate Information (identified by operation id):


---------------------------------------------------



2 - access("RESOURCEID"=:1 AND "TIME"=TO_DATE(:2,'yyyy-mm-dd'))



14 rows selected.