Useful query against v$archived_log in recovery situations

SELECT thread#,
         COUNT(*)                        AS cnt,
         MIN(sequence#)                  AS min_seq,
         MAX(sequence#)                  AS max_seq,
         MIN(first_time)                 AS min_time,
         MAX(next_time)                  AS max_time
  FROM   v$archived_log
  WHERE  deleted = 'NO'
  GROUP  BY thread#
  ORDER  BY thread#;

   THREAD#    CNT    MIN_SEQ    MAX_SEQ               MIN_TIME               MAX_TIME
__________ ______ __________ __________ ______________________ ______________________
         1     80       7936       8015 2026-02-16 15:38:02    2026-02-18 14:15:42

How to recreate the control file and rename the database and the datafiles

To change a database name or file names, it can be practical to recreate the control file, and in some cases your only option.

In this example, I will rename a database and its file structure from "OID11UI" to "OID11U1".

Start by generating a file which holds the current layout of all the database's files:

SQL> alter database backup controlfile to trace as '/u01/oracle/product/11204/dbs/cntr_trace.sql' resetlogs;

Database altered.

The generated file typically look like this:

STARTUP NOMOUNT
CREATE CONTROLFILE REUSE DATABASE "OID11UI" RESETLOGS  NOARCHIVELOG
    MAXLOGFILES 16
    MAXLOGMEMBERS 3
    MAXDATAFILES 100
    MAXINSTANCES 8
    MAXLOGHISTORY 292
LOGFILE
  GROUP 1 '/u02/oradata/OID11UI/redo01.log'  SIZE 50M BLOCKSIZE 512,
  GROUP 2 '/u02/oradata/OID11UI/redo02.log'  SIZE 50M BLOCKSIZE 512,
  GROUP 3 '/u02/oradata/OID11UI/redo03.log'  SIZE 50M BLOCKSIZE 512
-- STANDBY LOGFILE
DATAFILE
  '/u02/oradata/OID11UI/system01.dbf',
  '/u02/oradata/OID11UI/sysaux01.dbf',
  '/u02/oradata/OID11UI/undotbs01.dbf',
  '/u02/oradata/OID11UI/users01.dbf'
CHARACTER SET WE8MSWIN1252
;
-- Database can now be opened zeroing the online logs.
ALTER DATABASE OPEN RESETLOGS;
-- Commands to add tempfiles to temporary tablespaces.
-- Online tempfiles have complete space information.
-- Other tempfiles may require adjustment.
ALTER TABLESPACE TEMP ADD TEMPFILE '/u02/oradata/OID11UI/temp01.dbf'
     SIZE 20971520  REUSE AUTOEXTEND ON NEXT 655360  MAXSIZE 32767M;
-- End of tempfile additions.

Exchange the word "REUSE" against the word "SET":

CREATE CONTROLFILE SET DATABASE "OID11U1"

Optionally, on the first line, add a pointer to a correct parameter file:

STARTUP NOMOUNT PFILE='/u01/oracle/product/11204/dbs/initOID11U1.ora'

Change all references to "OID11UI" (the old name):

STARTUP NOMOUNT PFILE='/u01/oracle/product/11204/dbs/initOID11U1.ora'
CREATE CONTROLFILE SET DATABASE "OID11U1" RESETLOGS  NOARCHIVELOG
    MAXLOGFILES 16
    MAXLOGMEMBERS 3
    MAXDATAFILES 100
    MAXINSTANCES 8
    MAXLOGHISTORY 292
LOGFILE
  GROUP 1 '/u02/oradata/OID11U1/redo01.log'  SIZE 50M BLOCKSIZE 512,
  GROUP 2 '/u02/oradata/OID11U1/redo02.log'  SIZE 50M BLOCKSIZE 512,
  GROUP 3 '/u02/oradata/OID11U1/redo03.log'  SIZE 50M BLOCKSIZE 512
-- STANDBY LOGFILE
DATAFILE
  '/u02/oradata/OID11U1/system01.dbf',
  '/u02/oradata/OID11U1/sysaux01.dbf',
  '/u02/oradata/OID11U1/undotbs01.dbf',
  '/u02/oradata/OID11U1/users01.dbf'
CHARACTER SET WE8MSWIN1252
;
-- Database can now be opened zeroing the online logs.
ALTER DATABASE OPEN RESETLOGS;
-- Commands to add tempfiles to temporary tablespaces.
-- Online tempfiles have complete space information.
-- Other tempfiles may require adjustment.
ALTER TABLESPACE TEMP ADD TEMPFILE '/u02/oradata/OID11U1/temp01.dbf'
     SIZE 20971520  REUSE AUTOEXTEND ON NEXT 655360  MAXSIZE 32767M;
-- End of tempfile additions.

Change the folder name that oracle uses:

usu0oid01:OID11UI>cd /u02/oradata
usu0oid01:OID11UI>mv OID11UI OID11U1

Change the control_files directive in the parameter file:
Before

*.control_files='/u02/oradata/OID11UI/control01.ctl','/u02/oradata/OID11UI/control02.ctl'

After:

*.control_files='/u02/oradata/OID11U1/control01.ctl','/u02/oradata/OID11U1/control02.ctl'

Remove the old controlfiles physically from disk:

cd /u02/oradata/OID11U1
rm *.ctl

Shutdown the database:

SQL> shutdown abort
ORACLE instance shut down.

Change the oracle profile in the operating system:

cd
vi .profile

Before:

export ORACLE_SID=OID11UI

After:

export ORACLE_SID=OID11U1

Source the new profile, and check that the ORACLE_SID environmental variable is correctly set:

. .profile
usu0oid01:OID11U1>echo $ORACLE_SID
OID11U1

Start sqlplus and run script:

usu0oid01:OID11UI>sqlplus / as sysdba @cntr_trace.sql

SQL*Plus: Release 11.2.0.4.0 Production on Wed May 28 14:00:50 2014

Copyright (c) 1982, 2013, Oracle.  All rights reserved.

Connected to an idle instance.

ORACLE instance started.

Total System Global Area 1720328192 bytes
Fixed Size                  2247072 bytes
Variable Size            1107297888 bytes
Database Buffers          603979776 bytes
Redo Buffers                6803456 bytes

Control file created.

Database altered.

Tablespace altered.

SQL> select open_mode from v$database;

OPEN_MODE
--------------------
READ WRITE

Check the location of the data files after the change:

SQL> select file_name from dba_data_files union select member from v$logfile  union  select name from v$controlfile;

FILE_NAME
--------------------------------------------------
/u02/oradata/OID11U1/control01.ctl
/u02/oradata/OID11U1/control02.ctl
/u02/oradata/OID11U1/redo01.log
/u02/oradata/OID11U1/redo02.log
/u02/oradata/OID11U1/redo03.log
/u02/oradata/OID11U1/sysaux01.dbf
/u02/oradata/OID11U1/system01.dbf
/u02/oradata/OID11U1/undotbs01.dbf
/u02/oradata/OID11U1/users01.dbf

Lag en spfile (anbefales):

SQL> create spfile from pfile; 

File created.

SQL> shutdown immediate
Database closed.
Database dismounted.
ORACLE instance shut down.

Startup the database for normal use:

SQL> startup

How to backup your controlfile to trace

SQL> ALTER DATABASE BACKUP CONTROLFILE TO TRACE AS '/fullpath/backup_controlfile.trc' [REUSE] [RESETLOGS | NORESETLOGS];

Note that if you do not specify either RESETLOGS or NORESETLOGS during the create command, oracle will include both versions in the resulting file, and you must pick the appropriate one for your situation.

REUSE will generate a backup controlfile statement which includes the REUSE keyword.
This in turn, indicates that when the "create controlfile" command is executed, you can reuse the existing physical control files on your server. If you don't, and the file exists from a previous database incarnation, Oracle will throw an error, so I prefer to leave it there.

Important files and directories in a Netbackup setup

Important netbackup files and directories on a typcial unix server:

/usr/openv/netbackup/version --> displays the netbackup version
/usr/openv/netbackup/bp.conf --> displays important settings such as SERVER, MEDIA_SERVER, CLIENT_NAME
/usr/openv/netbackup/logs/user_ops/dbext/logs --> log files for rman backups

Example of bp.conf

SERVER = backupserver1.mydomain.com
MEDIA_SERVER = server1-bkp.mydomain.com
CLIENT_NAME = server1-bkp.mydomain.com
REQUIRED_INTERFACE = server1-bkp.mydomain.com

Note that the CLIENT_NAME used above translates into the NB_ORA_CLIENT typically used in when sending backups to tape using Netbackup:

NB_ORA_CLIENT=server1-bkp.mydomain.com

How to restore a sequence of archivelogs back to their original location

connect catalog catowner/*********@RMANCAT
connect target
run {
allocate channel t1 type sbt PARMS="BLKSIZE=1048576"  maxopenfiles 64;
allocate channel t2 type sbt PARMS="BLKSIZE=1048576"  maxopenfiles 64;
send 'NB_ORA_POLICY=ora_dbserver1_00_netwzone1,NB_ORA_CLIENT=dbserver1-bkp.mydomain.com,NB_ORA_SCHED=ora_dbserver1_00_netwzone1_user';
restore archivelog from logseq 412594 until logseq 412656;
release channel t1;
release channel t2;
}

Guaranteed restore points in standby databases

"Before an important release, I decided to create a guaranteed restore point on the primary database.
Unfortunately I forgot to create the same on my standby database. Can I use the as of timestamp to create a guaranteed restore point in the past?"

No, this is not supported.

The syntax below:

SQL> create restore point PRE_RELEASE2_STBY as of timestamp to_date('09.11.2013 09:15:00','DD.MM.YYYY HH24:MI:SS') guarantee flashback database;

Will fail with:

ERROR at line 1:
ORA-38864: cannot create a guaranteed restore point with user specified SCN or
time.

// *Cause:  An SCN or timestamp was specified when creating a guaranteed
//          restore point. This is not supported. You can only create a
//          guaranteed restore point as of the current time.
// *Action: Avoid this combination of options for creating a restore point.

You will have to do with a normal restore point instead:

CREATE RESTORE POINT PRE_RELEASE2_STBY 
AS OF TIMESTAMP TO_DATE('09.11.2013 09:15:00','DD.MM.YYYY HH24:MI:SS');

But you will receive the following error:

ERROR at line 1:
ORA-38867: database not open: cannot create restore point with the specified
timestamp

// *Cause:  An attempt was made to create a restore point with the specified
//          timestamp while the database was not open. The database must be
//          open in order to map the timestamp to an SCN.
// *Action: Open the database first or pick another way to create the restore 
//          point.

So on a standby database, using the AS OF TIMESTAMP is not allowed on a normal restore point, either.
How about using the SCN?

SQL> SELECT timestamp_to_scn(to_date('09.11.2013 09:15:00','DD.MM.YYYY HH24:MI:SS')) SCN 
     FROM   dual;

     SCN
--------
170259165

SQL> create restore point PRE_RELEASE2_STBY AS OF SCN 170259165;
Restore point created.

What are restore points and how are they used?

Definition:

A restore point is an alias to the system change number (SCN) of the database at the time the restore point was created.

Types of restore points:

1. Normal
2. Guaranteed

For both types, the name of the restore point and the SCN are recorded in the database control file.

Normal restore points are very lightweight. The control file can maintain a record of thousands of normal restore points with no significant impact upon database performance. Normal restore points eventually age out of the control file if not manually deleted, so they require no ongoing maintenance.

Guaranteed restore points on the other hand, guarantees that Oracle will retain the flashback logs for a Flashback Database operation.

A guaranteed restore point does not age out of the control file and must be explicitly dropped.
Guaranteed restore points will utilize space in the flash recovery area.
The flash recovery area must be therefore be defined and large enough to hold the flashback logs for the duration of the guaranteed restore point's existence.

Creation example:

CREATE RESTORE POINT PRE_EOD_201208;
CREATE RESTORE POINT PRE_RELEASE2 GUARANTEE FLASHBACK DATABASE;

Usage:

You can use restore points with any commands that recognize a RESTORE POINT clause as a shorthand for specifying an SCN.

Examples:

FLASHBACK DATABASE TO RESTORE POINT < restore point name >;
RESTORE DATABASE TO RESTORE POINT < restore point name >;
FLASHBACK TABLE emp TO RESTORE POINT < restore point name >;

To view the restore points created in your database, use:

select name,scn,time,database_incarnation# "INC NR",
guarantee_flashback_database "guaranteed?"
storage_size/1024/1024 "MB"
from v$restore_point;


         NAME          SCN                               TIME    INC NR    guaranteed?      MB
_____________ ____________ __________________________________ _________ ______________ _______
PREUPGRADE       208072152 22-JAN-25 01.06.35.000000000 PM            2 YES               3072

To create a normal restore point, you need either

the SELECT ANY DICTIONARY system privilege, or

the FLASHBACK ANY TABLE system privilege

To create a guaranteed restore point, you need SYSDBA privileges.

To view or use a restore point, the user need either of the following:

The SELECT ANY DICTIONARY system privilege

The FLASHBACK ANY TABLE system privilege

The SELECT_CATALOG_ROLE role

To drop a restore point:

DROP RESTORE POINT AKSEPT_TEST_START;

How to perform a full restore of Oracle

The following scripts have been tested and proven to work.
Make sure the NB_ORA_POLICY is correctly entered and adheres to the documentation from your MML provider:

#!/bin/ksh
LOGFILE=$SCRIPT_BASE/log/restore_${ORACLE_SID}_`date +%Y%m%d%H%M%S`.log
export RECOVERY_CATALOG=catowner/**********@RMANCAT
nohup rman target / catalog $RECOVERY_CATALOG << EOF > $LOGFILE 2>&1  &
startup force nomount;
 set DBID=1554594349;
 run {
  allocate channel t1 type sbt;
  allocate channel t2 type sbt
  send 'NB_ORA_POLICY=ora_dbserver1_00_netwzone1,NB_ORA_CLIENT=dbserver1-bkp.mydomain.com,NB_ORA_SCHED=ora_dbserver1_00_netwzone1_user';
  set until sequence < logseq > thread 1;
  restore controlfile;
  alter database mount;
  restore database;
  recover database;
 }
 alter database open resetlogs;

EOF
echo "RMAN restore started in background. Check logfile: $LOGFILE"

Script for checking the database flashback settings

I normally use the following script to gather the most important facts about my flashback settings and readyness for a potential flashback database operation:

alter session set nls_date_format='DD.MM.YYYY HH24:MI:SS';
set linesize 300
set trimspool on
col name format a35
col time format a35
col guaranteed format a10
col "oldest flback SCN" format 9999999999999
col SCN format 9999999999999
set pagesize 200
spool chk_flashb.log
prompt =================================================
Prompt give me the
prompt * estimated flashback log size
prompt * retention target
prompt * current accumulated size of all flashback logs
prompt =================================================
select estimated_flashback_size/1024/1024 "Estimated Flbacklog Size mb",
       retention_target/60                "Hours of flback logs",
       flashback_size/1024/1024           "Current Flbacklog Size mb"
from v$flashback_database_log
/

prompt ===============================================
Prompt How far back can the database be flashed back?
prompt ===============================================
select oldest_flashback_scn  "oldest flback SCN",
       oldest_flashback_time "oldest flback time"
from v$flashback_database_log
/

prompt =================================================
prompt show the restore points created the last 2 weeks
prompt =================================================
SELECT NAME,
       SCN,
       TIME,
       DATABASE_INCARNATION#,
       GUARANTEE_FLASHBACK_DATABASE "guaranteed",
       STORAGE_SIZE
FROM V$RESTORE_POINT
where time >= SYSDATE-14;
Prompt ===================================
prompt Show the flash recovery area usage
Prompt ===================================
select * from v$flash_recovery_area_usage;

Prompt ======================================
prompt I/O information for flashback logging
Prompt ======================================
select begin_time "Begin time",
        end_time "End time",
        round(flashback_data/1024/1024) "MB of flbk data written",
        round(redo_data/1024/1024)      "MB of redo data"
from   v$flashback_database_stat
order by begin_time asc;
exit