oracle的執行計劃

--刪除上一個執行計劃

delete from plan_table where statement_id='testplan';

--執行計劃

explain plan set statement_id='testplan' for

select count(1) from tb_site_month

--查看執行計劃

  select lpad('',5*(level-1))||operation operation,options,

  object_name,cost,position

  from plan_table

  start with id=0 and statement_id='testplan'

  connect by prior id=parent_id;

--查看執行計劃2

select  

STATEMENT_ID  "語句ID",

PLAN_ID "計劃ID",

TIMESTAMP "時間戳",

OPERATION "操作",

OPTIMIZER "優化器",

OBJECT_NAME "對象名稱",

OBJECT_TYPE "對象的類型(表、索引等)",       

SEARCH_COLUMNS "搜索欄",

PARTITION_START "分區啓動",   

PARTITION_STOP  "分區停止",

PARTITION_ID "分區ID" ,

CPU_COST "CPU成本",

IO_COST "IO成本"

from plan_table

start with id=0 and statement_id='testplan'

connect by prior id=parent_id;