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Date: Sun, 12 Apr 1998 13:37:00 -0400
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From: Jordan Henderson <jordanh@ccia.com>
To: maillist@candle.pha.pa.us
CC: pgsql-hackers@postgreSQL.org
In-reply-to: <199804121422.KAA22778@candle.pha.pa.us> (message from Bruce
	Momjian on Sun, 12 Apr 1998 10:22:42 -0400 (EDT))
Subject: Re: [HACKERS] Safe/Fast I/O ...

>> When doing a sequential scan on a table, the OS is doing a one-page
>> prefetch, which is probably enough.  The problem is index scans of the
>> table.  Those are not sequential in the main heap table (unless it is
>> clustered on the index), so a prefetch would help here a lot.
>> 
>> That is where we need async i/o.  I am looking in BSDI, and I don't see
>> any way to do async i/o.  The only way I can think of doing it is via
>> threads.
>
>
>     O_ASYNC      Enable the SIGIO signal to be sent to the process group when
>                  I/O is possible, e.g., upon availability of data to be read.
>
>Now I am questioning this.  I am not sure this acually for file i/o, or
>only tty i/o.
>

async file calls:
	aio_cancel
	aio_error
	aio_read
	aio_return -- gets status of pending io call
	aio_suspend
	aio_write

And yes the Gray book is great!

Jordan Henderson