Fwd: "low open file" at solaris

From: zhu chao <zhuchao_at_gmail.com>
Date: Fri, 17 Dec 2004 14:10:24 +0800
Message-ID: <962cf44b041216221056f6a402@mail.gmail.com>

Hi, yong
  We do have database with more than 1024 datafiles. This seems wired. DBWR should open all datafiles, but from os point view, they can open open 1024 files, now actually the dbwr reaches this limit. but database still runs OK.

hostname$> pfiles 13704|more
13704: ora_dbw0_SOLD
  Current rlimit: 1024 file descriptors

   0: S_IFCHR mode:0666 dev:244,0 ino:405605 uid:0 gid:3 rdev:13,2
      O_RDONLY|O_LARGEFILE
   1: S_IFCHR mode:0666 dev:244,0 ino:405605 uid:0 gid:3 rdev:13,2
      O_RDONLY|O_LARGEFILE

 ....

1022: S_IFCHR mode:0640 dev:244,7005 ino:32 uid:32000 gid:101 rdev:247,202
      O_RDWR|O_DSYNC|O_LARGEFILE FD_CLOEXEC
1023: S_IFCHR mode:0644 dev:244,7018 ino:40 uid:32000 gid:101 rdev:247,849
      O_RDWR|O_DSYNC|O_LARGEFILE FD_CLOEXEC

SQL> show parameter db_files

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
db_files                             integer     2000

SQL> select count(*) from v$datafile;

  COUNT(*)

---

      1128

On Thu, 16 Dec 2004 05:46:59 -0800 (PST), Yong Huang <yong321_at_yahoo.com> wrote:
> There should not be performance degradation. If one process wants to open
> rlim_fd_max files at the same time, the process open() call fails. It
> won't slow down anything. Default 1024 is more than enough in most cases.
>
> Background processes hold all datafiles open. Imagine a database that has
> close to 1000 datafiles? Oracle Apps DB may be an example but still far
> lower than that (older version has more than 300 datafiles but I don't
> remember newer versions).
>
> Server processes only open datafiles as needed. In addition, in dedicated
> configuration, each server process connects to one client (sqlplus e.g.).
> I don't remember the files (including sockets etc) opened by a server (or
> dispatcher?) process in shared server configuration. Does one process
> serve one client or many?
>
> Yong
>
> --- zhu chao <zhuchao_at_gmail.com> wrote:
>
> > Hi, all,
> > I believe many people are running oracle 9i on solaris platform.
> > Does anyone noticed this message while starting oracle instance at
> > solaris:
> > "Wed Dec 15 21:00:06 2004
> > Oracle instance running on a system with low open file
> > descriptor limit. Tune your system to increase this
> > limit to avoid severe performance degradation.
> > "
> > According to metalink, os parameter "open files" (rlim_fd_max at
> > solaris?) need to be tuned as formular: 2*db_files +
> > controlfile+logfile ..., if my db_files=1000, then I have to set
> > rlim_fd_max to near 2400. Without changing this parameter, will there
> > really be some performance degradation?
> >
> > If I reduce the db_files to 100 or so, then no warning any more.
> >
> > Thanks.
> > --
> > Regards
> > Zhu Chao
> > www.cnoug.org
>

-- 
Regards
Zhu Chao
www.cnoug.org
--
http://www.freelists.org/webpage/oracle-l

Received on Fri Dec 17 2004 - 00:08:31 CST