oracle执行计划调优

DISPLAY_PLAN

DISPLAY_SQL_PLAN_BASELINE

DISPLAY_SQLSET

alter session set sql_trace true;

在init.ora中设置SQL_TRACE=true

 

alter session set statistics = all--设置可以获取rows信息

select sql_id,sql_text from v$SQL where sql_text like

EXPLAIN PLAN set STATEMENT_ID= 'ds' FOR SELECT * FROM CRM_EXPAND_AUDIT;

explain plan for select * from test;

select * from table(dbms_xplan.display);

select * from table(dbms_xplan.display(format=>'ALL'));

select * from table(dbms_xplan.display_cursor(null,null,'ALLSTATS LAST'));

select * from table(dbms_xplan.display_cursor('1707443579',0,'ALLSTATS LAST'));

父游标

select * from v$sqlarea where sql_id = '';

select * from v$sql_plan where sql_id = '';

select * from v$sql_optimizer_env where sql_id = ''

推荐format格式

select * from table(dbms_xplan.display_cursor(null,null,'ADVANCED ALLSTATS LAST PEEKED_BINDS'));

 

select count(decode(a,'01',x,null)),sum(decode(a,sal,null)) from sale

select * from table where (a,b)=(select a,b from table where v = '1')

where > group>having

not exists>not in

索引列

< or > > <> > not

 

外连接代替not in  =(+)

count(索引列>*>1)