Re: directio and async io on redhat linux 3 and oracle 9i

From: chao_ping <zhuchao_at_gmail.com>
Date: 9 May 2005 03:11:50 -0700
Message-ID: <1115633510.393998.293760@z14g2000cwz.googlegroups.com>

To Noons:
I guess the create index on directio filesystem can be slower, is it true?

To yong:
file handle 26200/26201 are datafiles on ufs. Others are on vxfs with Qio. _filesystemio_options=directio.

truss dbwr result:

ioctl(26204, 0x0403, 0xFFFFFFFF7FFFCCDC)        = 0
ioctl(13, 0x0403, 0xFFFFFFFF7FFFCB4C)           = 0
ioctl(13, 0x0405, 0xFFFFFFFF7FFFCAC8)           = 0
ioctl(26203, 0x0403, 0xFFFFFFFF7FFFCCDC)        = 0
ioctl(13, 0x0403, 0xFFFFFFFF7FFFCB4C)           = 0
ioctl(13, 0x0405, 0xFFFFFFFF7FFFCAC8)           = 0
ioctl(26202, 0x0403, 0xFFFFFFFF7FFFCCDC)        = 0
ioctl(26201, 0x0403, 0xFFFFFFFF7FFFCCDC)        Err#25 ENOTTY
ioctl(26201, _ION('f', 76, 0), 0x00000001)      = 0    ----does this
_ION means call with directio?
ioctl(26200, 0x0403, 0xFFFFFFFF7FFFCCDC)        Err#25 ENOTTY
ioctl(26200, _ION('f', 76, 0), 0x00000001)      = 0

[oracle_at_ebaysha2**8i]$pfiles 28606
28606: ora_dbw0_8i
26200: S_IFREG mode:0640 dev:272,21007 ino:7 uid:500 gid:500 size:10493952

      O_RDWR|O_DSYNC|O_LARGEFILE FD_CLOEXEC
      /ufs/2.dbf

26201: S_IFREG mode:0640 dev:272,21007 ino:6 uid:500 gid:500 size:10493952

      O_RDWR|O_DSYNC|O_LARGEFILE FD_CLOEXEC
      /ufs/1.dbf

And with your second test plan:
[oracle_at_ebaysha2**8i]$grep direct dio3.log
/1_at_1: -> libc:directio(0x6655, 0x1, 0xfffffffe7e355e40,
0x746571fefefefeff)
/1_at_1: <- libc:directio() = 0
/1_at_1: -> libc:directio(0x6654, 0x1, 0xfffffffe7e355e40,
0x746571fefefefeff)
/1_at_1: <- libc:directio() = 0
/1_at_1: -> libc:directio(0x6653, 0x1, 0xfffffffe7e3559e0,
0x746571fefefefeff)
/1_at_1: <- libc:directio() = 0
/1_at_1: -> libc:directio(0x6652, 0x1, 0xfffffffe7e3559e0,
0x746571fefefefeff)
/1_at_1: <- libc:directio() = 0

But for datafiles on vxfs, it is not supported in this way, that means _filesystemio_options=directio does not work for vxfs based datafiles.

Seems what you said is correct. Platform is solaris 10 for sparc.

Actually I am not quite familiar with the libc:directio :(. Do not have unix c programming experience.

THanks Received on Mon May 09 2005 - 05:11:50 CDT