PDB Cloning In Oracle

 

Remote PDB cloning method is basically use to clone the PDB from source to target database and for that we use Database link to clone the PDB.

  Pre-Checks For Remote PDB Cloning

➢ From 12cR2 we don’t need to put the Source PDB in read-only mode now we can clone the  source PDB while it’s working in read-write mode, However for 12cR1 we’ve to put the PDB      in read-only mode prior to start the cloning.

➢ Database link must be able to connect with source CDB , if it’s not there then create a database link.
➢ User that we use to perform the PDB cloning can either be a common user OR a local user at PDB level 
➢ The user that is suppose to perform cloning must have CREATE PLUGGABLE DATABASE privileges
➢ When cloning from a NON-CDB then source & target database must be using 12cR1 or higher
➢ The endian format , character set of both source & target CDB should be same


       SOURCE CDB 
➢ Create a common user in source CDB with CREATE PLUGGABLE DATABASE privilege , So that the same user can be use  for remote cloning

Create user remote_user identified by welcome#1;
Grant create session to remote_user container=all;
Grant create pluggable database to remote_user container=all;

Note : If DB Version is 12cR1 then put the Source PDB in read-only mode 

Alter pluggable database S_PDB close immediate instaces=all;
Alter pluggable database S_PDB open read only instances=all;

     Start PDB Service Othewise It Won't Be Able To Clone The PDB
Srvctl start service -d <DB_UNIQUE_NAME> -s <PDB_SERVICE_NAME>
Srvctl status service -d <DB_UNIQUE_NAME > -s <PDB_SERVICE_NAME>

      Create Database Link Between Source & Target Database For Remote Cloning

Create pluggable database link “test_link” connect to “remote_user” identified by Welcome#123 using <”PDB_SERVICE_NAME”>

        Verify That DB Link Is Working Fine

SQL> Select sysdate from dual@test_link;
SYSDATE
-------------
23-APR-22


            Shell Script To Run PDB Cloning In Background

#!/bin/ksh
Sqlplus -S “/ as sysdba” <<EOF
Set echo on
Set timing on
Create pluggable database T_PDB from test_link@<PDB_SERVICE_LINK> parallel 32;
Exit;
EOF

Note : The duration of the cloning totally depends upon the size of the source PDB and also the network bandwidth for data transfer between source & target server

                SQL Query To Monitor The Progress Of Cloning Operation
Select a.inst_id,a.service_name,a.sid,a.serial#,a.sql_id,a.sql_text,a.logon_time,a.username,a.target ,sofar,totalwork,opname,time_remaining still,elapsed_seconds tillnow,round(c.SOFAR*100/c.TOTALWORK,0)||’%’ as “%DONE%” from gv$session a,gv$ql b,gv$session_longops c Where a.sid=c.sid AND a.sql_address=b.address AND a.sql_address=c.sql_address AND status=’ACTIVE’ AND time_reamining>0 order by target;

                    Open Newly Created Target PDB In Read-Write Mode
Once the cloning will be done then by default the PDB started in mount mode so post remote cloning we’ve to start the target PDB in read-write mode.

Alter pluggable database T_PDB open instances=all;