Ameer Khan

Env Details:-

Primary DB Version: 19.15

Env : RAC 2 node Exadata

GI: 19.15.0.0

OS: OEL 7

Standby DB Version : 19.15

Env : Standalone DB on ODA

GI: 19.15.0.0

OS: OEL 7

Scenario: – For one of my customers, there was a requirement to change compatible parameter in both primary and standby database. The customer went through a database upgrade (12c to 19c) activity and had GRP (Guaranteed Restore Point) in the database. The GRP was kept for a week post DB upgrade to make sure there is in case of any requirement Database can fall back to its old version. Now after a week, once GRP was dropped, we had to set compatible parameter to 19.0.0 in both primary and standby database. Following are the steps that I performed to achieve this.

Steps:-

First make sure there is no log gap between primary & Standby Database

SQL> SELECT ARCH.THREAD# “Thread”, ARCH.SEQUENCE# “Last Sequence Received”,   2  APPL.SEQUENCE# “Last Sequence Applied”, (ARCH.SEQUENCE# – APPL.SEQUENCE#) “Difference”   3  FROM   4  (SELECT THREAD# ,SEQUENCE# FROM V$ARCHIVED_LOG WHERE (THREAD#,FIRST_TIME ) IN   5  (SELECT THREAD#,MAX(FIRST_TIME) FROM V$ARCHIVED_LOG GROUP BY THREAD#)) ARCH,   6  (SELECT THREAD# ,SEQUENCE# FROM V$LOG_HISTORY WHERE (THREAD#,FIRST_TIME ) IN   7  (SELECT THREAD#,MAX(FIRST_TIME) FROM V$LOG_HISTORY GROUP BY THREAD#)) APPL   8  WHERE   9  ARCH.THREAD# = APPL.THREAD#  10  ORDER BY 1;         Thread Last Sequence Received Last Sequence Applied Difference ———- ———————- ——————— ———-          1                  97989                 97989          0          2                  90142                 90142          0

Current compatible set in database

SQL> show parameter compatible   NAME                                 TYPE        VALUE ———————————— ———– —————————— compatible                           string      12.1.0.2.0

Now change the compatible parameter in standby database then do it on primary database.

On Standby DB:-

STANDBYDB_SQL> alter system set compatible=’19.0.0′ scope=spfile ;

After changing we need to bounce the database to get it in effect, so cancel the MRP apply.

STANDBYDB_SQL> alter database recover managed standby database cancel;

Now stop and start the standby database.

[oracle@standbydb]$ srvctl stop database -d $ORACLE_UNQNAME

[oracle@standbydb]$ srvctl start database -d $ORACLE_UNQNAME -o mount

Now start the MRP process to apply the redologs in standby db.

STANDBYDB_SQL> alter database recover managed standby database disconnect from session;

On Primary DB:-

Login to, primary database and change the compatible parameter.

PRIMARYDB_SQL> alter system set compatible=’19.0.0′ scope=spfile sid=’*’; 

[oracle@primarydb]$ srvctl stop database -d $ORACLE_UNQNAME

[oracle@primarydb]$ srvctl start database -d $ORACLE_UNQNAME