Month: May 2010

This is a simple article on how to convert physical standby to logical standby.

A metalink note ID is provided in the reference section. I used the same metalink note and did the conversion. I will brief the steps that I have done and the outputs of those steps.

Pre-reqs before starting the setup – You have a physical standby functioning correctly and that all the redo logs sequences on primary has been applied on standby

I will list the steps which needs to be done on primary as well as on standby

On standby database

1. Make sure that all the sequences generated on primary side has been applied on standby.

SQL to check that is given below

SQL> SELECT ARCH.THREAD# "Thread", ARCH.SEQUENCE# "Last Sequence Received", APPL.SEQUENCE# "Last Sequence Applied"

  2  FROM

  3  (SELECT THREAD# ,SEQUENCE# FROM V$ARCHIVED_LOG WHERE (THREAD#,FIRST_TIME ) IN (SELECT THREAD#,MAX(FIRST_TIME) FROM V$ARCHIVED_LOG GROUP BY THREAD#)) ARCH,

  4  (SELECT THREAD# ,SEQUENCE# FROM V$LOG_HISTORY WHERE (THREAD#,FIRST_TIME ) IN (SELECT THREAD#,MAX(FIRST_TIME) FROM V$LOG_HISTORY GROUP BY THREAD#)) APPL

  5  WHERE

  6  ARCH.THREAD# = APPL.THREAD#

  7  ORDER BY 1;

    Thread Last Sequence Received Last Sequence Applied

---------- ---------------------- ---------------------

         1                    177                   177

SQL> ALTER DATABASE RECOVER MANAGED STANDBY DATABASE CANCEL;
Database altered.

SQL> show parameters archive

NAME                                 TYPE        VALUE

------------------------------------ ----------- ------------------------------

archive_lag_target                   integer     0

log_archive_config                   string

log_archive_dest                     string

log_archive_dest_1                   string      location=/slot/ems3079/oracle/

                                                 db_1/arch/sitst01/

log_archive_dest_10                  string

log_archive_dest_2                   string      service=sitst02

log_archive_dest_3                   string

On primary set the VALID_FOR parameter to make destination 1 as valid for online redo logs and role as all roles. This mean even if we change the role of primary server to standby server, online redo logs will get archived to archive destination 1.

SQL> alter system set log_archive_dest_1='location=/slot/ems3079/oracle/db_1/arch/sitst01/ valid_for=(ONLINE_LOGFILES,ALL_ROLES)';

System altered.

-bash-3.00$ mkdir -p /slot/ems3079/oracle/db_1/arch/standby/

-bash-3.00$ sqlplus "/as sysdba"

SQL> alter system set LOG_ARCHIVE_DEST_3='LOCATION=/slot/ems3079/oracle/db_1/arch/standby/ VALID_FOR=(STANDBY_LOGFILES,STANDBY_ROLE)';

System altered.

SQL> EXECUTE DBMS_LOGSTDBY.BUILD;

PL/SQL procedure successfully completed.

SQL> ALTER DATABASE RECOVER TO LOGICAL STANDBY testdb;
ALTER DATABASE RECOVER TO LOGICAL STANDBY standby
*
ERROR at line 1:
ORA-16254: change db_name to TESTDB in the client-side parameter file (pfile)
ORA-27037: unable to obtain file status
Linux Error: 2: No such file or directory
Additional information: 3

SQL> shut immediate
ORA-01507: database not mounted




ORACLE instance shut down.
SQL>

change following parameters in init.ora

*.db_name='testdb'
db_unique_name='testdb'

SQL> STARTUP MOUNT pfile=initsitst02.ora
ORACLE instance started.


Total System Global Area  419430400 bytes
Fixed Size                  1267812 bytes
Variable Size             130025372 bytes
Database Buffers          281018368 bytes
Redo Buffers                7118848 bytes
Database mounted.
SQL>

SQL> alter system set log_archive_dest_1='LOCATION=/slot/ems6826/oracle/db_1/dbs/arch/sitst02 VALID_FOR=(ONLINE_LOGFILES,ALL_ROLES)';


System altered.


SQL> alter system set LOG_ARCHIVE_DEST_2='service=sitst01 LGWR ASYNC VALID_FOR=(ONLINE_LOGFILES,PRIMARY_ROLE)';


System altered.


SQL> alter system set LOG_ARCHIVE_DEST_3='LOCATION=/slot/ems6826/oracle/db_1/dbs/arch/standby VALID_FOR=(STANDBY_LOGFILES,STANDBY_ROLE)';


System altered.

SQL> ALTER DATABASE OPEN RESETLOGS;
Database altered.

SQL> ALTER DATABASE START LOGICAL STANDBY APPLY IMMEDIATE;
ALTER DATABASE START LOGICAL STANDBY APPLY IMMEDIATE
*
ERROR at line 1:
ORA-16239: IMMEDIATE option not available without standby redo logs


We got the above error, because we didn't create standby redo log files
Create standby redo logs as shown below.

SQL> alter database add standby logfile group 4 ('/slot/ems6826/oracle/oradata/sitst02/redo4.dbf') size 100M;
Database altered.
SQL> alter database add standby logfile group 5 ('/slot/ems6826/oracle/oradata/sitst02/redo5.dbf') size 100M;
Database altered.
SQL> alter database add standby logfile group 6 ('/slot/ems6826/oracle/oradata/sitst02/redo6.dbf') size 100M;
Database altered.
SQL> ALTER DATABASE START LOGICAL STANDBY APPLY IMMEDIATE;
Database altered.

SQL> select name, database_role from v$database;


NAME      DATABASE_ROLE
--------- ----------------
STANDBY   LOGICAL STANDBY

SQL> select DEST_ID, THREAD#, SEQUENCE#, ARCHIVED, APPLIED from v$archived_log where DEST_ID = 2 ;




   DEST_ID    THREAD#  SEQUENCE# ARC APP
---------- ---------- ---------- --- ---
         2          1        179 YES YES
         2          1        181 YES YES
         2          1        182 YES YES
         2          1        183 YES YES
         2          1        184 YES YES
         2          1        185 YES YES
         2          1        186 YES YES
         2          1        187 YES YES
         2          1        188 YES YES
         2          1        189 YES YES
         2          1        190 YES NO

On standby

SQL> SELECT SEQUENCE#, FIRST_TIME, NEXT_TIME, DICT_BEGIN, DICT_END FROM DBA_LOGSTDBY_LOG ORDER BY SEQUENCE#;






 SEQUENCE# FIRST_TIME         NEXT_TIME          DIC DIC
---------- ------------------ ------------------ --- ---
 189 02-MAY-10 02:17:59 02-MAY-10 02:20:32 NO  NO
 190 02-MAY-10 02:20:32 02-MAY-10 02:20:33 NO  NO






SQL> SELECT TYPE, HIGH_SCN, STATUS FROM V$LOGSTDBY;






TYPE                             HIGH_SCN STATUS
------------------------------ ---------- ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
COORDINATOR                       5846054 ORA-16116: no work available
READER                            5846054 ORA-16240: Waiting for logfile (thread# 1, sequence# 191)
BUILDER                           5846050 ORA-16116: no work available
PREPARER                          5846049 ORA-16116: no work available
ANALYZER                          5845790 ORA-16117: processing
APPLIER                           5845733 ORA-16116: no work available
APPLIER                           5845739 ORA-16116: no work available
APPLIER                           5845784 ORA-16116: no work available
APPLIER                           5845790 ORA-16116: no work available
APPLIER                           5845429 ORA-16116: no work available



SQL> SELECT EVENT_TIME, STATUS, EVENT FROM DBA_LOGSTDBY_EVENTS ORDER BY EVENT_TIME, COMMIT_SCN;






EVENT_TIM
---------
STATUS
--------------------------------------------------------------------------------
EVENT
--------------------------------------------------------------------------------
02-MAY-10
ORA-16111: log mining and apply setting up



SQL> SELECT FILE_NAME, SEQUENCE#, FIRST_CHANGE#, NEXT_CHANGE#, TIMESTAMP, DICT_BEGIN, DICT_END, THREAD# FROM DBA_LOGSTDBY_LOG ORDER BY SEQUENCE#;






FILE_NAME
--------------------------------------------------------------------------------
 SEQUENCE# FIRST_CHANGE# NEXT_CHANGE# TIMESTAMP DIC DIC    THREAD#
---------- ------------- ------------ --------- --- --- ----------
/slot/ems6826/oracle/db_1/dbs/arch/standby/1_189_713333254.dbf
 189       5845702      5845832 02-MAY-10 NO  NO           1



/slot/ems6826/oracle/db_1/dbs/arch/standby/1_190_713333254.dbf
 190       5845832      5846054 02-MAY-10 NO  NO           1






SQL> SQL> ALTER SESSION SET NLS_DATE_FORMAT = 'DD-MON-YY HH24:MI:SS';






Session altered.



SQL> SQL> SELECT L.SEQUENCE#, L.FIRST_TIME, (CASE WHEN L.NEXT_CHANGE# < P.READ_SCN THEN 'YES'WHEN L.FIRST_CHANGE# < P.APPLIED_SCN THEN 'CURRENT' ELSE 'NO' END) APPLIED FROM DBA_LOGSTDBY_LOG L, DBA_LOGSTDBY_PROGRESS P ORDER BY SEQUENCE#;






 SEQUENCE# FIRST_TIME         APPLIED
---------- ------------------ -------
 189 02-MAY-10 02:17:59 CURRENT
 190 02-MAY-10 02:20:32 CURRENT






SQL> SQL> SELECT NAME, VALUE FROM V$LOGSTDBY_STATS WHERE NAME LIKE 'coordinator%' or NAME LIKE 'transactions%';






NAME
----------------------------------------------------------------
VALUE
----------------------------------------------------------------
coordinator state
IDLE



transactions ready
26



transactions applied
26






NAME
----------------------------------------------------------------
VALUE
----------------------------------------------------------------
coordinator uptime
564

References:

Metalink note ID : 738643.1