select /*+ dynamic_sampling(b 10) dynamic_sampling_est_cdn(b) gather_plan_statistics*/ count(*) from tvb b;
SELECT * FROM TABLE(dbms_xplan.display_cursor(NULL,NULL,'ALLSTATS LAST'));

注意dynamic sampling used for this statement (level=2) 显示的level 2不是真的！ level 10在这里真的是LEVEL 10!

EXPLAIN PLAN SET STATEMENT_ID = 'abc' FOR
select count(*) from tvb ;

SELECT * FROM TABLE(dbms_xplan.display('PLAN_TABLE','abc','ALL'));

set linesize 200 pagesize 1400;

select /* FINDSQLID */ SQL_ID,SQL_FULLTEXT from V$SQL