On Mon, 13 Mar 2006 [EMAIL PROTECTED] wrote:
> [snip aio API stuff]
>After finding out about this api, I found out that at least mysql and
>postgresql use it, so I am guessing that changing the sql engine to
>generate batches of read/writes is possible.
>
>My guess is that using this api will increase performance a lot as the
>hard drive heads won't have to go back and forth, seeking at random
>places on the disk (thus reducing the impact of having small caches).
It would only be available for reads. Writes are written to the hard disk
using fsync, which will allow the OS to order outstanding writes in
whatever order it sees optimal.
Reads must be done in order in general, as you must know what you want to
read before trying to read it (think of trying to navigate a btree in
parallel. You can't as you don't know which node to read in until you
processed the current node) so you'll get little benefit in performance.
The only other option to use AIO would be to traverse multiple btrees in
parallel, such as when you have multiple cursors open in your query. But
then you have potentially complicated the virtual machine.
>
>Nicolas
>
Christian
--
/"\
\ / ASCII RIBBON CAMPAIGN - AGAINST HTML MAIL
X - AGAINST MS ATTACHMENTS
/ \
