Oracle enables asynchronous IO (db file async I/O submit)

The city board has a large number of DB file async I/O submit wait events in the dual random AWR report

Refer to two articles:

Case Oracle Wait Event db file async I/O submit cause and workaround

DB file Async I/O Submit wait Event optimization

See if the data file is open for asynchronous IO

Select Name, Asynch_Io
  From V$datafile f, V$iostat_File i
 Where f.File# = i.File_No
   And (Filetype_Name = ‘Data File‘ Or Filetype_Name = ‘Temp File‘);

See two parameters

SQL> show parameter disk_asynch_io

NAME                     TYPE     VALUE
------------------------------------ ----------- ------------------------------
disk_asynch_io                 boolean     TRUE
SQL> show parameter filesystemio

NAME                     TYPE     VALUE
------------------------------------ ----------- ------------------------------
filesystemio_options             string     none

Modify parameter filesystemio_options

 
alter system set filesystemio_options =asynch sid =‘*‘ scope=spfile;

Restart database

Oracle enables asynchronous IO (db file async I/O submit)