Re: ASYNCH I/O

Hi Doug,
I will use the AIX implementation as example. On AIX you both need to enable the asynch I/O feature of the OS and set USE_ASYNCH_IO to true.
Otherwise it won't work. The two options are complementing each other. The basic idea about asynch i/o is the requesting process doesn't wait for the I/O to complete. This does indeed mean having multiple database writers is useless, when async i/o has been enabled. On AIX the operating system itself will create extra writers, the number of writers is variable and can be changed through SMIT.

Hth,

Sybrand Bakker, Oracle DBA

Doug Cowles <dcowles_at_bigfoot.com> wrote in message news:377FA9F6.5844956E_at_bigfoot.com...
> Ran across a statment that multiple database writters are useless if you
> are using
> Asynch I/O. Does this statement apply to OS Asynch I/O, or the Oracle
> simulated
> Asynch I/O created with USE_ASYNCH_IO = true, or is it true at all?
>
> Incidentally, can someone shed some light on what this does
> specifically. In other words,
> if you are not using Asynch I/O, then database blocks have to be written
> out in order?
> As opposed to whatever the OS finds convenient by disk drive? Or what?
>
> - Dc.
>
Received on Sun Jul 04 1999 - 15:42:38 CDT