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Oracle Database 12c: Network Recovery in RMAN

Over the past 8 months, I have had the pleasure of working on a soon-to-be-released update for our popular Beginner's Guide for Oracle Database 12c. The publisher was looking for a "new brand" for this book, which has been published for Oracle 7, Oracle 8, Oracle 8 i, Oracle 9, Database 10 g, and Database 11 g. The works have been translated into 15 languages; I have always wanted to get a translation done back into English and see what it says :). The new work is entitled Oracle Database 12c: Install, Configure, and Maintain Like a Professional. I have had the pleasure of sharing the author responsibilities with colleagues in and outside of Pythian. Ian Abramson, Michelle Malcher, and Mike Corey are the primary authors alongside yours truly. Michael McKee, Fahd Mirza, and Marc Fielding of Pythian are contributing authors to this latest work. Many of the new features have fascinated me and my peers; rman has been a friend and good companion since a business case in 2000 provided the opportunity to get "dirty" with this product. (Thanks Steve Jacobs, wherever you are.) I have thirsted in particular for the following handful of rman enhancements that are bundled with Database 12 c:
  • Multisection incremental backups where the data files can be broken up into smaller chunks that can be backed up in parallel across multiple channels.
  • Network-enabled restore - copying of one or more database files from a primary to a physical standby or vice-versa over the network. The work can be done using compression and the new multi-section feature.
Not long before intensive work began on the new book, Pythian invested a huge amount of money and time in setting up a Private Cloud environment called Delphic Lab. With its emergence under the auspices of the Office of the CTO and dedicated volunteers, it was bye-bye to local Linux VMs on my two MacBooks for me. I do not miss them in the least.

Prep of VM

The setup to house the databases used to thrash the new features covered in this post is as follows:
O/S
 
 Oracle Linux Server release 6.4 Linux dlabvm46.dlab.pythian.com
 
 Disk space 
 
 Filesystem 1K-blocks Used Available Use% Mounted on 
 /dev/xvda2 9823392 1206832 8118056 13% / 
 tmpfs 1005964 0 1005964 0% /dev/shm 
 /dev/xvda1 497829 63408 408719 14% /boot 
 /dev/xvdb 1113160 7553396 40963364 `6% /u01 
 Database creation (dbca.cmd)
 /u01/app/oracle/product/12.1.0/db_1/bin/dbca -silent \
 -createDatabase \
 -templateName General_Purpose.dbc \
 -gdbName pythian \
 -sid pythian \
 -createAsContainerDatabase false \
 -SysPassword manager \
 -SystemPassword manager \
 -emConfiguration NONE \
 -datafileDestination /u01/oradata \
 -storageType FS \
 -characterSet AL32UTF8 \
 -memoryPercentage 40 \
When dbca.cmd was run, the output displayed was:
oracle@dlabvm46.dlab.pythian.com --> (pythian)
 /home/oracle> ./pythian.cmd
 Copying database files
 1% complete
 2% complete
 8% complete
 13% complete
 19% complete
 24% complete
 27% complete
 Creating and starting Oracle instance
 29% complete
 32% complete
 33% complete
 34% complete
 38% complete
 42% complete
 43% complete
 45% complete
 Completing Database Creation
 48% complete
 51% complete
 53% complete
 62% complete
 70% complete
 72% complete
 78% complete
 83% complete
 100% complete
 Look at the log file "/u01/app/oracle/cfgtoollogs/dbca/pythian/pythian.log" for further details.
To perform the testing, I put the database in archivelog mode as follows: [code language="sql"]oracle@dlabvm46.dlab.pythian.com --> (pythian) /home/oracle> sqlplus / as sysdba SQL*Plus: Release 12.1.0.1.0 Production on Sat Aug 3 11:44:08 2013 Copyright (c) 1982, 2013, Oracle. All rights reserved. Connected to: Oracle Database 12c Enterprise Edition Release 12.1.0.1.0 - 64bit Production With the Partitioning, OLAP, Advanced Analytics and Real Application Testing options SQL> archive log list Database log mode No Archive Mode Automatic archival Disabled Archive destination USE_DB_RECOVERY_FILE_DEST Oldest online log sequence 13 Current log sequence 15 SQL> shutdown immediate Database closed. Database dismounted. ORACLE instance shut down. SQL> startup mount ORACLE instance started. Total System Global Area 822579200 bytes Fixed Size 2293736 bytes Variable Size 595591192 bytes Database Buffers 218103808 bytes Redo Buffers 6590464 bytes Database mounted. SQL> alter database archivelog; Database altered. SQL> alter database open; Database altered SQL> archive log list Database log mode Archive Mode Automatic archival Enabled Archive destination USE_DB_RECOVERY_FILE_DEST Oldest online log sequence 13 Next log sequence to archive 15 Current log sequence 15 SQL>[/code] The following Oracle*Net files were created:
********************************
 * Oracle*Net configuration files
 ********************************
 
 ** on the primary
 
 # listener.ora
 
 LISTENER=
 (DESCRIPTION=
 (ADDRESS_LIST=
 (ADDRESS=(PROTOCOL=tcp)(HOST=dlabvm46)(PORT=1521))
 (ADDRESS=(PROTOCOL=ipc)(KEY=extproc))))
 
 SID_LIST_LISTENER=
 (SID_LIST=
 (SID_DESC=
 (GLOBAL_DBNAME=pythian)
 (ORACLE_HOME=/u01/app/oracle/product/12.1.0/db_1)
 (SID_NAME=pythian)
 )
 )
 
 # tnsnames.ora
 
 PYTHIAN =
 (DESCRIPTION =
 (ADDRESS_LIST =
 (ADDRESS = 
 (PROTOCOL = TCP)
 (HOST = dlabvm46.dlab.pythian.com) 
 (PORT = 1521)
 )
 )
 (CONNECT_DATA =
 (SERVICE_NAME = pythian) 
 )
 )
 
 PYTHIANSB =
 (DESCRIPTION =
 (ADDRESS_LIST =
 (ADDRESS = 
 (PROTOCOL = TCP)
 (HOST = dlabvm48.dlab.pythian.com) 
 (PORT = 1521)
 )
 )
 (CONNECT_DATA =
 (SERVICE_NAME = pythian) 
 )
 )
 
 ** on the standby
 
 # listener.ora
 
 LISTENER=
 (DESCRIPTION=
 (ADDRESS_LIST=
 (ADDRESS=(PROTOCOL=tcp)(HOST=dlabvm48)(PORT=1521))
 (ADDRESS=(PROTOCOL=ipc)(KEY=extproc))))
 
 SID_LIST_LISTENER=
 (SID_LIST=
 (SID_DESC=
 (GLOBAL_DBNAME=pythian)
 (ORACLE_HOME=/u01/app/oracle/product/12.1.0/db_1)
 (SID_NAME=pythian)
 )
 )
 
 # tnsnames.ora
 
 PYTHIAN =
 (DESCRIPTION =
 (ADDRESS_LIST =
 (ADDRESS = 
 (PROTOCOL = TCP)
 (HOST = dlabvm48.dlab.pythian.com) 
 (PORT = 1521)
 )
 )
 (CONNECT_DATA =
 (SERVICE_NAME = pythian) 
 (UR = A)
 )
 )
 
 PYTHIANPR =
 (DESCRIPTION =
 (ADDRESS_LIST =
 (ADDRESS = 
 (PROTOCOL = TCP)
 (HOST = dlabvm46.dlab.pythian.com) 
 (PORT = 1521)
 )
 )
 (CONNECT_DATA =
 (SERVICE_NAME = pythian) 
 )
 )

Build the physical standby

Next, the standby was prepared to house the duplicated primary.
** Prepare standby for duplication
 oracle@dlabvm48.dlab.pythian.com--> (pythian) ** Standby **
 /u01/app/oracle/product/12.1.0/db_1/network/admin> sqlplus / as sysdba
 
 SQL*Plus: Release 12.1.0.1.0 Production on Wed Aug 7 18:42:31 2013
 
 Copyright (c) 1982, 2013, Oracle. All rights reserved.
 
 Connected to:
 Oracle Database 12c Enterprise Edition Release 12.1.0.1.0 - 64bit Production
 With the Partitioning, OLAP, Advanced Analytics and Real Application Testing options
 
 SQL> startup nomount
 ORACLE instance started.
 
 Total System Global Area 409194496 bytes
 Fixed Size 2288968 bytes
 Variable Size 331350712 bytes
 Database Buffers 71303168 bytes
 Redo Buffers 4251648 bytes
 SQL>
Time to create the standby: first, a status reality check.
Status of primary database: OPEN
 Status of standby database: NOMOUNT
The duplicate performed from the primary site:
oracle@dlabvm46.dlab.pythian.com--> (pythian) ** Master **
 /home/oracle> rman
 
 Recovery Manager: Release 12.1.0.1.0 - Production on Wed Aug 7 18:47:38 2013
 
 Copyright (c) 1982, 2013, Oracle and/or its affiliates. All rights reserved.
 
 RMAN> connect target sys/******
 
 connected to target database: PYTHIAN (DBID=2086712234)
 
 RMAN> connect auxiliary sys/******@pythiansb
 
 connected to auxiliary database: PYTHIAN (not mounted)
 
 RMAN> duplicate target database for standby from active database nofilenamecheck;
 
 Starting Duplicate Db at 07-AUG-13
 using target database control file instead of recovery catalog
 allocated channel: ORA_AUX_DISK_1
 channel ORA_AUX_DISK_1: SID=20 device type=DISK
 
 contents of Memory Script:
 {
  backup as copy reuse
  targetfile '/u01/app/oracle/product/12.1.0/db_1/dbs/orapwpythian' auxiliary format 
  '/u01/app/oracle/product/12.1.0/db_1/dbs/orapwpythian' ;
 }
 executing Memory Script
 
 Starting backup at 07-AUG-13
 allocated channel: ORA_DISK_1
 channel ORA_DISK_1: SID=51 device type=DISK
 Finished backup at 07-AUG-13
 
 contents of Memory Script:
 {
  backup as copy current controlfile for standby auxiliary format '/u01/oradata/pythian/control01.ctl';
  restore clone controlfile to '/u01/app/oracle/fast_recovery_area/pythian/control02.ctl' from 
  '/u01/oradata/pythian/control01.ctl';
 }
 executing Memory Script
 
 Starting backup at 07-AUG-13
 using channel ORA_DISK_1
 channel ORA_DISK_1: starting datafile copy
 copying standby control file
 output file name=/u01/app/oracle/product/12.1.0/db_1/dbs/snapcf_pythian.f tag=TAG20130807T184803
 channel ORA_DISK_1: datafile copy complete, elapsed time: 00:00:03
 Finished backup at 07-AUG-13
 
 Starting restore at 07-AUG-13
 using channel ORA_AUX_DISK_1
 
 channel ORA_AUX_DISK_1: copied control file copy
 Finished restore at 07-AUG-13
 
 contents of Memory Script:
 {
  sql clone 'alter database mount standby database';
 }
 executing Memory Script
 
 sql statement: alter database mount standby database
 
 contents of Memory Script:
 {
  set newname for tempfile 1 to 
  "/u01/oradata/pythian/temp01.dbf";
  switch clone tempfile all;
  set newname for datafile 1 to 
  "/u01/oradata/pythian/system01.dbf";
  set newname for datafile 3 to 
  "/u01/oradata/pythian/sysaux01.dbf";
  set newname for datafile 4 to 
  "/u01/oradata/pythian/undotbs01.dbf";
  set newname for datafile 6 to 
  "/u01/oradata/pythian/users01.dbf";
  backup as copy reuse
  datafile 1 auxiliary format 
  "/u01/oradata/pythian/system01.dbf" datafile
  3 auxiliary format 
  "/u01/oradata/pythian/sysaux01.dbf" datafile 
  4 auxiliary format 
  "/u01/oradata/pythian/undotbs01.dbf" datafile 
  6 auxiliary format 
  "/u01/oradata/pythian/users01.dbf" ;
  sql 'alter system archive log current';
 }
 executing Memory Script
 
 executing command: SET NEWNAME
 
 renamed tempfile 1 to /u01/oradata/pythian/temp01.dbf in control file
 
 executing command: SET NEWNAME
 
 executing command: SET NEWNAME
 
 executing command: SET NEWNAME
 
 executing command: SET NEWNAME
 
 Starting backup at 07-AUG-13
 using channel ORA_DISK_1
 channel ORA_DISK_1: starting datafile copy
 input datafile file number=00001 name=/u01/oradata/pythian/system01.dbf
 output file name=/u01/oradata/pythian/system01.dbf tag=TAG20130807T184815
 channel ORA_DISK_1: datafile copy complete, elapsed time: 00:01:05
 channel ORA_DISK_1: starting datafile copy
 input datafile file number=00003 name=/u01/oradata/pythian/sysaux01.dbf
 output file name=/u01/oradata/pythian/sysaux01.dbf tag=TAG20130807T184815
 channel ORA_DISK_1: datafile copy complete, elapsed time: 00:01:05
 channel ORA_DISK_1: starting datafile copy
 input datafile file number=00004 name=/u01/oradata/pythian/undotbs01.dbf
 output file name=/u01/oradata/pythian/undotbs01.dbf tag=TAG20130807T184815
 channel ORA_DISK_1: datafile copy complete, elapsed time: 00:00:15
 channel ORA_DISK_1: starting datafile copy
 input datafile file number=00006 name=/u01/oradata/pythian/users01.dbf
 output file name=/u01/oradata/pythian/users01.dbf tag=TAG20130807T184815
 channel ORA_DISK_1: datafile copy complete, elapsed time: 00:00:01
 Finished backup at 07-AUG-13
 
 sql statement: alter system archive log current
 
 contents of Memory Script:
 {
  switch clone datafile all;
 }
 executing Memory Script
 
 datafile 1 switched to datafile copy
 input datafile copy RECID=3 STAMP=822855043 file name=/u01/oradata/pythian/system01.dbf
 datafile 3 switched to datafile copy
 input datafile copy RECID=4 STAMP=822855043 file name=/u01/oradata/pythian/sysaux01.dbf
 datafile 4 switched to datafile copy
 input datafile copy RECID=5 STAMP=822855043 file name=/u01/oradata/pythian/undotbs01.dbf
 datafile 6 switched to datafile copy
 input datafile copy RECID=6 STAMP=822855043 file name=/u01/oradata/pythian/users01.dbf
 Finished Duplicate Db at 07-AUG-13
 
 RMAN>
In most cases, the next step would be to start managed recovery on the standby site. However, we will do some manual recovery to ensure log transport services are working as expected. We will test the arrival and manual application of archived redo on the standby site as follows:
  1. Switch logfile a few times on the primary.
  2. Run command to discover the status of redo to ascertain:
    • oldest online log sequence
    • next log sequence to archive
    • current log sequence
  3. Recover the standby database to confirm arrival of archived redo.
  4. Allow recovery to abend when it runs out of archived redo.
Manual recovery test for proof-of-concept:
** Switch logfiles on primary
 
 oracle@dlabvm46.dlab.pythian.com--> (pythian) ** Master **
 /u01/app/oracle/fast_recovery_area/PYTHIAN/archivelog/2013_08_07> !sqlp
 sqlplus / as sysdba
 
 SQL*Plus: Release 12.1.0.1.0 Production on Wed Aug 7 18:58:16 2013
 
 Copyright (c) 1982, 2013, Oracle. All rights reserved.
 
 Connected to:
 Oracle Database 12c Enterprise Edition Release 12.1.0.1.0 - 64bit Production
 With the Partitioning, OLAP, Advanced Analytics and Real Application Testing options
 
 SQL> archive log list 
 Database log mode Archive Mode
 Automatic archival Enabled
 Archive destination USE_DB_RECOVERY_FILE_DEST
 Oldest online log sequence 19
 Next log sequence to archive 21
 Current log sequence 22
 
 SQL> alter system switch logfile;
 
 System altered.
 
 SQL> archive log list
 Database log mode Archive Mode
 Automatic archival Enabled
 Archive destination USE_DB_RECOVERY_FILE_DEST
 Oldest online log sequence 20
 Next log sequence to archive 22
 Current log sequence 22
 
 SQL>
If all goes well, we should be able to toddle off to the standby and perform manual recovery expecting successful application of archived log sequences 19 and 20. The envelope, please... Recovery test on the standby:
** Recover standby manually
 
 oracle@dlabvm48.dlab.pythian.com--> (pythian) ** Standby **
 /u01/app/oracle> sqlplus / as sysdba
 
 SQL*Plus: Release 12.1.0.1.0 Production on Wed Aug 7 18:58:03 2013
 
 Copyright (c) 1982, 2013, Oracle. All rights reserved.
 
 Connected to:
 Oracle Database 12c Enterprise Edition Release 12.1.0.1.0 - 64bit Production
 With the Partitioning, OLAP, Advanced Analytics and Real Application Testing options
 
 SQL> recover standby database
 ORA-00279: change 1882090 generated at 08/07/2013 18:57:22 needed for thread 1
 ORA-00289: suggestion :
 /u01/app/oracle/fast_recovery_area/PYTHIAN/archivelog/2013_08_07/o1_mf_1_20_%u_.
 arc
 ORA-00280: change 1882090 for thread 1 is in sequence #20
 
 Specify log: {=suggested | filename | AUTO | CANCEL}
 
 ORA-00279: change 1882266 generated at 08/07/2013 18:58:54 needed for thread 1
 ORA-00289: suggestion :
 /u01/app/oracle/fast_recovery_area/PYTHIAN/archivelog/2013_08_07/o1_mf_1_21_%u_.
 arc
 ORA-00280: change 1882266 for thread 1 is in sequence #21
 ORA-00278: log file
 '/u01/app/oracle/fast_recovery_area/PYTHIAN/archivelog/2013_08_07/o1_mf_1_20_905
 n6lw5_.arc' no longer needed for this recovery
 
 Specify log: {=suggested | filename | AUTO | CANCEL}
 
 ORA-00279: change 1884132 generated at 08/07/2013 19:09:24 needed for thread 1
 ORA-00289: suggestion :
 /u01/app/oracle/fast_recovery_area/PYTHIAN/archivelog/2013_08_07/o1_mf_1_22_%u_.
 arc
 ORA-00280: change 1884132 for thread 1 is in sequence #22
 ORA-00278: log file
 '/u01/app/oracle/fast_recovery_area/PYTHIAN/archivelog/2013_08_07/o1_mf_1_21_905
 n9gfc_.arc' no longer needed for this recovery
 
 Specify log: {=suggested | filename | AUTO | CANCEL}
 
 ORA-00279: change 1884132 generated at 08/07/2013 19:09:24 needed for thread 1
 ORA-00289: suggestion :
 /u01/app/oracle/fast_recovery_area/PYTHIAN/archivelog/2013_08_07/o1_mf_1_22_%u_.
 arc
 ORA-00280: change 1884132 for thread 1 is in sequence #22
 ORA-00278: log file
 '/u01/app/oracle/fast_recovery_area/PYTHIAN/archivelog/2013_08_07/o1_mf_1_21_905
 n9gfc_.arc' no longer needed for this recovery
 
 Specify log: {=suggested | filename | AUTO | CANCEL}
 
 ORA-16145: archival for thread# 1 sequence# 22 in progress

Network-based recovery

Looks like the stage is set to try recovering the standby from the primary. A few tasks are to be performed beforehand, then away we go. Each task is outlined in the following code:
Task #1: get the service name for the standby database
 From standby site
 
 sqlplus / as sysdba
 show parameters service
 
 Task #2: verify the open mode and that this is a physical standby
 From standby site
 
 SQL> select open_mode from v$database;
 
 OPEN_MODE
 --------------------
 MOUNTED
 
 SQL> select database_role from v$database;
 
 DATABASE_ROLE
 ----------------
 PHYSICAL STANDBY
 
 Task #3: verify managed recovery is not running
 From standby site
 
 SQL> alter database recover managed standby database cancel;
 alter database recover managed standby database cancel
 *
 ERROR at line 1:
 ORA-16136: Managed Standby Recovery not active
 SQL>
 
 Task #4: create a new table on the primary site
 From primary site
 
 SQL> create table tester1 as select * from obj_1
 
 Table created.
 
 Task #5: switch a few logfiles
 From primary site
 
 SQL> alter system switch logfile;
 
 System altered.
 SQL> alter system switch logfile;
 
 System altered.
 SQL>
 
 Task #6: verify TESTER1 table not there
 From standby site
 
 SQL> alter database open read only;
 
 Database altered.
 
 SQL> desc pythian.tester1
 ERROR:
 ORA-04043: object pythian.tester1 does not exist
 
 Task #7: put standby back in MOUNT mode
 From standby site
 
 SQL> shutdown immediate
 Database closed.
 Database dismounted.
 ORACLE instance shut down.
 SQL> startup nomount
 ORACLE instance started.
 
 Total System Global Area 409194496 bytes
 Fixed Size 2288968 bytes
 Variable Size 331350712 bytes
 Database Buffers 71303168 bytes
 Redo Buffers 4251648 bytes
 SQL> alter database mount standby database;
 
 Database altered.
 
 SQL> select open_mode,database_role from v$database;
 
 OPEN_MODE DATABASE_ROLE
 -------------------- ----------------
 MOUNT PHYSICAL STANDBY
 
 Task #8: perform network-based recovery
 From primary site
 
 oracle@dlabvm46.dlab.pythian.com--> (pythian) ** Master **
 /home/oracle> rman
 
 Recovery Manager: Release 12.1.0.1.0 - Production on Tue Aug 13 16:22:51 2013
 
 Copyright (c) 1982, 2013, Oracle and/or its affiliates. All rights reserved.
 
 RMAN> connect target "sys/m3n3g3r@pythiansb as sysdba"
 
 connected to target database: PYTHIAN (DBID=2086712234, not open)
 
 RMAN> recover database
 2> from service pythian
 3> section size 120m
 4> using compressed backupset;
 
 Starting recover at 13-AUG-13
 using target database control file instead of recovery catalog
 allocated channel: ORA_DISK_1
 channel ORA_DISK_1: SID=27 device type=DISK
 skipping datafile 1; already restored to SCN 1997353
 skipping datafile 3; already restored to SCN 1997353
 skipping datafile 4; already restored to SCN 1997353
 skipping datafile 6; already restored to SCN 1997353
 
 starting media recovery
 
 archived log for thread 1 with sequence 30 is already on disk as file /u01/app/oracle/fast_recovery_area/PYTHIAN/archivelog/2013_08_13/o1_mf_1_30_90o56dp6_.arc
 archived log for thread 1 with sequence 31 is already on disk as file /u01/app/oracle/fast_recovery_area/PYTHIAN/archivelog/2013_08_13/o1_mf_1_31_90o56dyj_.arc
 archived log for thread 1 with sequence 32 is already on disk as file /u01/app/oracle/fast_recovery_area/PYTHIAN/archivelog/2013_08_13/o1_mf_1_32_90o56k6p_.arc
 archived log file name=/u01/app/oracle/fast_recovery_area/PYTHIAN/archivelog/2013_08_13/o1_mf_1_30_90o56dp6_.arc thread=1 sequence=30
 archived log file name=/u01/app/oracle/fast_recovery_area/PYTHIAN/archivelog/2013_08_13/o1_mf_1_31_90o56dyj_.arc thread=1 sequence=31
 archived log file name=/u01/app/oracle/fast_recovery_area/PYTHIAN/archivelog/2013_08_13/o1_mf_1_32_90o56k6p_.arc thread=1 sequence=32
 media recovery complete, elapsed time: 00:00:01
 Finished recover at 13-AUG-13
 
 Task #9: open standby read only and verify TESTER1 is there
 From standby site
 
 SQL> alter database open read only;
 
 Database altered.
 
 SQL> desc pythian.tester1
 Name Null? Type
 ----------------------------------------- -------- ----------------------------
 OBJ# NOT NULL NUMBER
 DATAOBJ# NUMBER
 OWNER# NOT NULL NUMBER
 NAME NOT NULL VARCHAR2(128)
 NAMESPACE NOT NULL NUMBER
 SUBNAME VARCHAR2(128)
 TYPE# NOT NULL NUMBER
 CTIME NOT NULL DATE
 MTIME NOT NULL DATE
 STIME NOT NULL DATE
 STATUS NOT NULL NUMBER
 REMOTEOWNER VARCHAR2(128)
 LINKNAME VARCHAR2(128)
 FLAGS NUMBER
 OID$ RAW(16)
 SPARE1 NUMBER
 SPARE2 NUMBER
 SPARE3 NUMBER
 SPARE4 VARCHAR2(1000)
 SPARE5 VARCHAR2(1000)
 SPARE6 DATE
 SIGNATURE RAW(16)
 SPARE7 NUMBER
 SPARE8 NUMBER
 SPARE9 NUMBER
 
 SQL> select count(*) from pythian.tester1;
 
 COUNT(*)
 ----------
 90775
 
 SQL>

Closing remarks

Only testing and time will confirm the usability and time saving of this new-fangled feature. This blog post has shown an example of an alternative way to recover a physical standby database. Up until 12 c, archived redo was the only way to do it other than shutting down the standby and refreshing its database files. Gone are the days of the forever-flashing cursor as a recovery exercise plows through days of archived redo. This example showed how a standby is caught up with its primary. Network-based recovery can be used as well to replace missing datafiles, control files, or tablespaces on the primary using the corresponding entity from the physical standby.

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