Re: Async I/O is NOT supppressed for filesystem datafiles in 8.1.5?

I found an 8.1.6.0.0 database at my disposal. Interestingly, the result is different from 8.1.7.2.0. Regardless of the setting of disk_asynch_io, only pwrite64 call is seen in truss dbw0, not preceded by kaio or lwp-whatever. The file system is as usual for me, UFS. OS: Solaris 2.6, Patch Generic_105181-16, archetecture sun4u. I wonder if this version of Oracle confirms what their official article says.

Yong Huang
yong321_at_yahoo.com

yong321_at_yahoo.com (Yong Huang) wrote in message news:<b3cb12d6.0112311103.28d27b9b_at_posting.google.com>...
>
> Again, my own test on 8.1.7.2 on Solaris 2.6 shows that if
> disk_asynch_io is true, kaio() is attempted by DBWR with ENOTSUP
> returned, followed by lwp_cond_signal(), lwp_cond_wait() and
> pwrite64(). If disk_asynch_io is false, pwrite64() is not preceded by
> kaio() and the lwp_cond_XX calls. I didn't see a fstat(2) call in
> truss. Maybe you used a slightly older version of Oracle or Solaris?
> As Bob Sneed's message says, the logic is do kaio, if that fails, do
> lwp-based aio. Solaris does not use ioctl (you said fstat) to test
> whether it's raw prior to kaio, because that's too expensive. But the
> failed kaio call (if failed), is very lightweight, and so I infer that
> turning off aio (lwp-based) with disk_asynch_io in Oracle only sligtly
> helps.
Received on Fri Jan 04 2002 - 12:10:30 CST