常用SQL（六）

31、创建目录
create directory mydir as 'C:\Users\DELL\Desktop\yw_busline_gd_20150819';

32、从DBA_HIST_SQlSTAT视图中发现最糟糕的查询

select
snap_id,
disk_reads_delta read_delta,
executions_delta exec_delta,
disk_reads_delta/decode(executions_delta,0,1,executions_delta) rds_exec_radio,
sql_id
from dba_hist_sqlstat t where t.disk_reads_delta > 100000
order by t.disk_reads_delta desc;

--select * from v$sqltext where sql_id = '4kzmf960t0u4m';
--再查询执行的语句
select * from table(dbms_xplan.display_awr('5prkjmm672vph'));

33、DDL语句并行执行

create index idx_name on table_name(column_name) local parallel 4;

34、恢复索引默认的并行度

alter index index_name noparallel;

35、查看DDL创建对象的并行度

select index_name,degree,from dba_indexes where index_name = 'index_name';