Oracle Database - DISK_ASYNCH_IO parameter

For optimum performance make sure you use asynchronous I/Os.

TRUE is the default parameter value for the majority of platforms.

[email protected]>SHOW PARAMETER disk_asynch_io

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------
disk_asynch_io                       boolean     TRUE

select * from v$parameter where lower(name) = 'disk_asynch_io' ;

These parameters enable or disable the operating system's asynchronous I/O facility. They allow query server processes to overlap I/O requests with processing when performing table scans.

Asynchronous operations are currently supported for parallel table scans, hash joins, sorts, and serial table scans. However, this feature can require operating system specific configuration and may not be supported on all platforms.

• Oracle SQL Parallel Execution - An Oracle White Paper - June 2008
• DISK_ASYNCH_IO and TAPE_ASYNCH_IO