Databases Reference
In-Depth Information
to all control files specified by the
CONTROL_FILES
initialization parameter. If Oracle can't write to one of the control
files, an error is thrown:
ORA-00210: cannot open the specified control file
If one of your control files becomes unavailable, shut down your database, and resolve the issue before restarting
(see Chapter 19 for using RMAN to restore a control file). Fixing the problem may mean resolving a storage-device
failure or modifying the
CONTROL_FILES
initialization parameter to remove the control file entry for the control file that
isn't available.
DISpLaYING the CONteNtS OF a CONtrOL FILe
You can use the
ALTER SESSION
statement to display the physical contents of the control file; for example,
SQL> oradebug setmypid
SQL> oradebug unlimit
SQL> alter session set events 'immediate trace name controlf level 9';
SQL> oradebug tracefile_name
the prior line of code displays the following name of the trace file:
/ora01/app/oracle/diag/rdbms/o12c/o12c/trace/o12c_ora_4153.trc
in oracle database 11g and above, the trace file is written to the
$ADR_HOME/trace
directory. You can also view
the trace directory name via this query:
SQL> select value from v$diag_info where name='Diag Trace';
in oracle 10g and below, the trace directory is defined by the
USER_DUMP_DEST
initialization parameter.
here is a partial listing of the contents of the trace file:
***************************************************************************
DATABASE ENTRY
***************************************************************************
(size = 316, compat size = 316, section max = 1, section in-use = 1,
last-recid= 0, old-recno = 0, last-recno = 0)
(extent = 1, blkno = 1, numrecs = 1)
09/28/2012 16:04:54
DB Name "O12C"
Database flags = 0x00404001 0x00001200
Controlfile Creation Timestamp 09/28/2012 16:04:57
Incmplt recovery scn: 0x0000.00000000
You can inspect the contents of the control file when troubleshooting or when you're trying to gain a better
understanding of oracle internals.
