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Home -> Community -> Mailing Lists -> Oracle-L -> RE: Undocumented Instance/Media Recover Feature?
> Was an old or backup control file used to start the db=20
Nope. And I never witnessed any datadictionary views that weren't in
sync with the control files.
-----Original Message-----
From: oracle-l-bounce_at_freelists.org
[mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Powell, Mark D
Sent: Wednesday, May 26, 2004 10:17 AM
To: 'oracle-l_at_freelists.org'
Subject: RE: Undocumented Instance/Media Recover Feature?
Pardon me if I am butting in but I think because the information in the control file does not match up to sys.file$ which ties file numbers to tablespaces. There apparently is a file# in file$ that is not in the control file.
Was an old or backup control file used to start the db by the other DBA/Developer?
-----Original Message-----
From: oracle-l-bounce_at_freelists.org
[mailto:oracle-l-bounce_at_freelists.org]On Behalf Of Orr, Steve
Sent: Wednesday, May 26, 2004 11:58 AM
To: oracle-l_at_freelists.org
Subject: RE: Undocumented Instance/Media Recover Feature?
The curiousity is that the file didn't exist in the O/S, Oracle created it without telling me, and it created and placed a database object into that file, again, without telling me. I just stumbled across this but I'd like to KNOW when this happens.
V$DATAFILE and V$TABLESPACE get information from the control file so how could they be out of sync?=3D20
-----Original Message-----
From: oracle-l-bounce_at_freelists.org
[mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Tim Johnston
Sent: Wednesday, May 26, 2004 9:46 AM
To: oracle-l_at_freelists.org
Subject: Re: Undocumented Instance/Media Recover Feature?
Hi Steve...
I believe you are seeing a mismatch between the controlfile and =
the=3D20
data dictionary... Basically, you started up your database and the data
dictionary says you have tablespace "blah" associated with file id "x"=3D20 but the controlfile doesn't have a file for that tablespace... So, it=3D20 places a dummy placeholder file in it's place... You can simulate this=3D20 but doing the following:
$ sqlplus "/ as sysdba"
SQL*Plus: Release 9.2.0.3.0 - Production on Wed May 26 11:37:32 2004
Copyright (c) 1982, 2002, Oracle Corporation. All rights reserved.
Connected to an idle instance.
SQL> Create Tablespace Tim Datafile '/export/home/oradata/PV429/tim.dbf' size 10M;
Tablespace created.
SQL> alter database backup controlfile to trace;
Database altered.
SQL> shutdown immediate
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL>
Then edit the create control file command and removed the line for
the=3D20 newly created datafile...
$ sqlplus "/ as sysdba"
SQL*Plus: Release 9.2.0.3.0 - Production on Wed May 26 11:40:21 2004
Copyright (c) 1982, 2002, Oracle Corporation. All rights reserved.
Connected to an idle instance.
SQL> startup nomount
ORACLE instance started.
Total System Global Area 252793548 bytes
Fixed Size 455372 bytes Variable Size 167772160 bytes Database Buffers 83886080 bytes Redo Buffers 679936 bytesSQL> @cre_control
Control file created.
SQL> alter database open;
Database altered.
SQL> set pagesize 1000 =3D20SQL> select * from dba_data_files where tablespace_name =3D3D 'TIM';
FILE_NAME
FILE_ID TABLESPACE_NAME BYTES BLOCKS STATUS ---------- ------------------------------ ---------- ----------
35 TIM
AVAILABLE
35
SQL> Tim
Orr, Steve wrote:
>We have this QA database which I can mostly ignore but Mr. QA dude
found
>a bug caused by the compatible init.ora parameter not being properly=20
>set. Since they kind of admin their own database and know the timing of
>their database availability needs for QA testing, I gave QA dude=20 >instructions on recycling the database... "SQL> shutdown abort" and=20 >"SQL> startup"=3D3D20 > >But the database didn't come back up due to a shared memory error so I=20 >figured I'd have to fix things with ipcs/ipcrm. But before getting into >that I just tried "SQL> startup" myself and behold, everything started=20 >up just fine with no warning messages or anything. Hmmm... That's=20 >curious... I guess the oracle just likes me better. I was in=20>$ORACLE_HOME/dbs verifying the existence of the "lk$ORACLE_SID" file=20 >when I saw something curious... A 100MB file named "MISSING00042" which
>had the same database startup timestamp as the lk$ORACLE_SID file and=20
>wondered what it was and where it came from. So I queried
dba_data_files
>and the data file with file_id 42 has the path of=20
>$ORACLE_HOME/dbs/MISSING00042. Whoa!!! That directory path and 100MB
are
>the default values when using Oracle-managed files and 42 is the answer
>to all things! But we don't use Oracle-managed files. Curious but how=20 >could the oracle create this datafile automagically for me and not even
>tell me? Where's it going to get the data? Then I look at dba_segments=20 >and see that there's only one object in that tablespace/datafile, an=20 >index which could be rebuilt from the data in another tablespace the=20 >table is in. Does this mean that the oracle couldn't find the datafile=20 >but created it for me automagically just because it could and because=20 >the only object was an index?=3D3D20 > >Has anybody seen this behavior before? Is there any documentation onit?
>Running Oracle 9.2.0.4 on Linux. > > >Steve Orr >Curious in Bozeman, Montana >---------------------------------------------------------------- >Please see the official ORACLE-L FAQ: http://www.orafaq.com >---------------------------------------------------------------- >To unsubscribe send email to: oracle-l-request_at_freelists.org put=20 >'unsubscribe' in the subject line. >-- >Archives are at http://www.freelists.org/archives/oracle-l/ >FAQ is at http://www.freelists.org/help/fom-serve/cache/1.html >-----------------------------------------------------------------
--=3D20
Regards,
Tim Johnston
Tel: 978-322-4226
Fax: 978-322-4100
-- Archives are at http://www.freelists.org/archives/oracle-l/ FAQ is at http://www.freelists.org/help/fom-serve/cache/1.html ----------------------------------------------------------------- ---------------------------------------------------------------- Please see the official ORACLE-L FAQ: http://www.orafaq.com ---------------------------------------------------------------- To unsubscribe send email to: oracle-l-request_at_freelists.org put 'unsubscribe' in the subject line. -- Archives are at http://www.freelists.org/archives/oracle-l/ FAQ is at http://www.freelists.org/help/fom-serve/cache/1.html ----------------------------------------------------------------- ---------------------------------------------------------------- Please see the official ORACLE-L FAQ: http://www.orafaq.com ---------------------------------------------------------------- To unsubscribe send email to: oracle-l-request_at_freelists.org put 'unsubscribe' in the subject line. -- Archives are at http://www.freelists.org/archives/oracle-l/ FAQ is at http://www.freelists.org/help/fom-serve/cache/1.html ----------------------------------------------------------------- ---------------------------------------------------------------- Please see the official ORACLE-L FAQ: http://www.orafaq.com ---------------------------------------------------------------- To unsubscribe send email to: oracle-l-request_at_freelists.org put 'unsubscribe' in the subject line. -- Archives are at http://www.freelists.org/archives/oracle-l/ FAQ is at http://www.freelists.org/help/fom-serve/cache/1.html -----------------------------------------------------------------Received on Wed May 26 2004 - 11:26:10 CDT
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