Re: AIO vs KAIO

Posted in 1997

Art S. Kagel — Mon, 17 Nov 1997 12:18:06 -0500 — source: Informix-list mailing list archive (1991-1998)

David MacAllister wrote: > > Hi Folks! > > I understand that KAIO has better performance over AOI when doing retrieves > from a database. > Could someone provide figures, ie how much faster KAIO is over AIO It is not the improvement for individual queries for KAIO (and there is improvement) that is the big gain but the vast improvement in overall throughput. KAIO uses the existing VPs more efficently. Having said that this it depends on the platform. On DG/UX for M88K we have found KAIO to be 2x slower that AIO VPs. This is because DG/UX for M88K does not support Kernel Asynchronous I/O and so the DG/Informix port team implemented KAIO as a separate POSIX thread in each CPU VP. The implementation is not as good as on other platforms. I have heard only good things from KAIO on Sun for example. Art S. Kagel