Category Archives: Multitenant

Automatic Startup all PDB in a CDB

November 6, 2015 Larry Catt Leave a comment

In Oracle 12c multitenant databases consist of a container database CDB which contain one or more pluggable databases PDB. Startup of the PDB must be done after the CDB it is contained in has been started. This procedures covers the implementation of a trigger to startup all PDBs in a CDB.

Logon to your server as the oracle software owner.

[larry@linux2 ~]$ su – oracle

Password:

Last login: Mon Oct 24 14:55:04 EDT 2016 on pts/1

[oracle@linux2 ~]$

Logon to your CDB where the PDB you wish to start is stored.

[oracle@linux2 ~]$ sqlplus / as sysdba

SQL*Plus: Release 12.1.0.2.0 Production on Tue Oct 25 09:41:06 2016

Connected to an idle instance.

SQL> startup open

ORACLE instance started.

Total System Global Area 734003200 bytes

Fixed Size 2928728 bytes

Variable Size 524292008 bytes

Database Buffers 201326592 bytes

Redo Buffers 5455872 bytes

Database mounted.

Database opened.

SQL>

View the available PDBs within the CDB with SQL statement: select name, open_mode from v$pdbs.

SQL> select name, open_mode from v$pdbs;

NAME OPEN_MODE

—————————— ———-

PDB$SEED READ ONLY

PDB1 MOUNTED

PDB2 MOUNTED

SQL>

NOTE: MOUNTED is the closed state for a PDB while it CDB is open.

Create a trigger which executes after the CDB starts with the following create trigger statement.

create trigger PDB_OPEN

after startup on database

begin

execute immediate ‘alter pluggable database all open’;

end;

/SQL> 2 3 4 5 6

Trigger created.

SQL>

Now shutdown the CDB with the command: shutdown immediate.

SQL> shutdown immediate

Database closed.

Database dismounted.

ORACLE instance shut down.

SQL>

Restart the CDB with command: startup open.

SQL> startup open

ORACLE instance started.

Total System Global Area 734003200 bytes

Fixed Size 2928728 bytes

Variable Size 524292008 bytes

Database Buffers 201326592 bytes

Redo Buffers 5455872 bytes

Database mounted.

Database opened.

SQL>

Check the status of PDBs with SQL statement: select name, open_mode from v$pdbs.

SQL> select name, open_mode from v$pdbs;

PDB$SEED READ ONLY

PDB1 READ WRITE

PDB2 READ WRITE

SQL>

Note: All PDBs are now open after restart of CDB without the need to manually issue a command from SQL prompt.
This completes startup of all PDB within its CDB automatically.

Larry Catt

OCP

12c, dbca, Multitenant, PDB

Oracle 12c Create PDB

November 2, 2015 Larry Catt Leave a comment

In Oracle 12c, Container Databases (CDB) were introduced which allowed for multiple Pluggable Database (PDB) to be placed in a single oracle instance to reduce the amount of resource consumed. This procedure covers the creation of a PDB in an already existing CDB using Oracle Database Configuration Assistant in a Windows environment.

Logon your windows server as the administrator.

Open Oracle Database Configuration Assistant.

At the Database Operation Page select “Create Database”

At the Manage Pluggable Database Page select “Create a Pluggable Database”

At the Database List Page, select the Container Database CDB you would like your PDB to be created in.

At the Create Pluggable Database page, select “Create a new Pluggable Database” and press Next.

At the Pluggable Database Options page, Enter the name of the Pluggable Database, Storage options, and Password Credentials. NOTE: This is an administrator account inside of the new PDB, not administrator account of OS or CDB. Press Next button.

At the Summary Page, Press the Finish button.

The PDB will now be created in Windows.

A confirmation screen will appear once the install is completed and press the OK button.

Back at the Progress Page, press the Close button to terminate Database Configuration Assistant.

This completes creation of Oracle 12c PDB in an existing CDB with Database Configuration Assistant.

Larry Catt

OCP

12c, CDB, Multitenant, PDB, privileges, Users

Privileges of Local Users in Oracle Multitenant Database

October 2, 2015 Larry Catt Leave a comment

In Oracle Multitenant Databases, local users only have access and privileges to a single PDB and not the CDB. You can have the same user name across multiple PDBs housed in the same CDB, but the users share no privileges and only shares a common name. This procedure give a brief overview of local user privileges in Oracle 12c Multitenant Databases. Listed below are the stated restriction on local user privileges.

A privilege granted locally can only be used in that container, even if granted by common user.
Both common and local users can grant privileges locally.
Both common and local users can grant privileges to other common or local users.
Grantor must connect to container and specify CONTAINER=CURRENT clause.
Common and Local user can grant privileges locally if they have appropriate privileges.

A privilege granted locally can only be used in that container, even if granted by common user.

As the common user c##dba logon to pdb1 and pdb2 creating users user_local.

SQL> connect c##dba/password@pdb1

Connected.

SQL> create user user_local identified by password;

User created.

SQL> connect c##dba/password@pdb2

Connected.

SQL> create user user_local identified by password;

User created.

SQL>

Now connect to pdb1 as c##dba and grant the user user_local the DBA role. Connect as user_local and create an additional local user user_test. NOTE: The user user_local can successfully connect to pdb1 and create an additional local user in this PDB.

SQL> connect c##dba/password@pdb1

Connected.

SQL> grant dba to user_local;

Grant succeeded.

SQL> connect user_local/password@pdb1

Connected.

SQL> create user user_test identified by password;

User created.

SQL>

Now attempt to connect to pdb2 with local user user_local. NOTE: The user user_local does not even have permission to connect to pdb2, even though the user exists in pdb2.

SQL> connect user_local/password@pdb2

ERROR:

ORA-01045: user USER_LOCAL lacks CREATE SESSION privilege; logon denied

Warning: You are no longer connected to ORACLE.

SQL>

Both common and local users can grant privileges locally.

Using local_user created above from pdb1, you can grant privileges to the newly created user user_test logon as local_user.

SQL> connect user_local/password@pdb1

Connected.

SQL> grant resource to user_test;

Grant succeeded.

SQL>

Both common and local users can grant privileges to other common or local users.

Using local_user created above from pdb1, you can grant privileges to the newly created user user_test logon as local_user.

SQL> connect user_local/password@pdb1

Connected.

SQL> grant resource to user_test;

Grant succeeded.

SQL>

Grantor must connect to container and specify CONTAINER=CURRENT clause or specify no CONTAINER clause. CONTAINER=ALL is not available in PDB.

As the user_local grant resource to user_test without a container clause and CONTAINER=ALL clause.

SQL> connect user_local/password@pdb1

Connected.

SQL> grant resource to user_test;

Grant succeeded.

SQL> grant resource to user_test container=all;

grant resource to user_test container=all

ERROR at line 1:

ORA-65029: a Local User may not grant or revoke a Common Privilege or Role

SQL>

Common and Local user can grant privileges locally if they have appropriate privileges.

Local user_local can create additional users in PDB pdb1 once the user has been granted the DBA role.

SQL> connect c##dba/password@pdb1

Connected.

SQL> grant dba to user_local;

Grant succeeded.

SQL> connect user_local/password@pdb1

Connected.

SQL> create user user_test identified by password;

User created.

SQL>

This completes the overview of privileges for local users in Oracle 12c Multitenant Database.

Larry Catt

OCP

12c, CDB, Multitenant, privileges, Users

Privileges of Common Users in Oracle Multitenant Database

September 21, 2015 Larry Catt Leave a comment

Privileges for Common Users in Oracle 12c multitenant database architecture have unique constraints allowing for privileges at the CDB level and the PDB levels. Common users may or may not have privileges at all containers in the multitenant database or they may be restricted to only a few. Additionally, privileges maybe restricted to objects in individual containers. The following are general rules governing privileges of common users and we will examine each rule in the below procedures:

A privilege granted commonly can be used in every container and future container.
Only common users can grant common privileges.
Granter of common privileges must connect to root and specify CONTAINER=ALL clause.
Can include system and object privilege.
Privileges should never be given to public.

A privilege granted commonly can be used in every container and future container.

Using the common user C##DBA we will create the user at the CDB level and grant DBA privileges with the CONTAINER clause equal to all.

SQL> show con_name

CON_NAME

——————————

CDB$ROOT

SQL> create user c##dba identified by password;

User created.

SQL> grant dba to c##dba container=all;

Grant succeeded.

SQL> connect c##dba/password@cdb1;

Connected.

SQL> create user c##user identified by password container=all;

User created.

SQL>

Now alter the session to container PDB1 as the same user and create a user there. NOTE: Permissions are good both in CDB1 and PDB1 for Common users. This is true because container clause was set to ALL.

SQL> show user

USER is “C##DBA”

SQL> alter session set container=PDB1;

Session altered.

SQL> show user

USER is “C##DBA”

SQL> create user pdb1_user identified by password;

User created.

SQL>

Only common users can grant common privileges.

As the common user c##dba grant resource to common user c##user.

SQL> connect c##dba/password@cdb1;

Connected.

SQL> grant resource to c##user;

Grant succeeded.

SQL>

Granter of common privileges must connect to root and specify CONTAINER=ALL clause for privileges to be granted in all containers.

This one is a little tricky because it appears that you can do it, however the key is common privilege, you can have privileges in the CDB and a few PDB and it not be common. This procedure shows an example of this scenario.
Connect to PDB1 as the common user c##dba and grant dba to the user c##user.

SQL> connect c##dba/password@pdb1

Connected.

SQL> grant dba to c##user;

Grant succeeded.

SQL>

Now a user with common privilege of DBA should be able to connect to any PDB in the CDB, however when we try to connect to pdb2, it fails. Further more when we look at the view dba_role_privs, we note that user C##USER does have DBA role, but not commonly.

SQL> connect c##user/password@pdb2

ERROR:

ORA-01045: user C##USER lacks CREATE SESSION privilege; logon denied

Warning: You are no longer connected to ORACLE.

SQL> connect c##dba/password@pdb1

Connected.

SQL> column grantee format a30

select grantee, common from dba_role_privs where grantee=’C##USER’;

SQL>

GRANTEE COM

—————————— —

C##USER NO

SQL>

Now logon to the root container as the C##DBA user and grant the DBA role to C##USER. Then view the dba_role_privs table and attempt to connect to PDB2.

SQL> connect c##dba/password@cdb1

Connected.

SQL> grant dba to c##user container=all;

Grant succeeded.

SQL> column grantee format a30

select grantee, common from dba_role_privs where grantee=’C##USER’;

SQL>

GRANTEE COM

—————————— —

C##USER NO

C##USER YES

SQL> connect c##user/password@pdb2

Connected.

SQL>

Can include system and object privilege.

Revoke all rights from user C##USER. If you are following from the above example, the user C##USER has been granted the DBA role twice locally and once commonly. So revoke Common grant at ROOT container and local root grant. Then connect to PDB1 to remove local grant at PDB1.

SQL> connect c##dba/password@cdb1

Connected.

SQL> column grantee format a30

select grantee, common from dba_role_privs where grantee=’C##USER’;

SQL>

GRANTEE COM

—————————— —

C##USER NO

C##USER YES

SQL> revoke dba from c##user container=ALL;

Revoke succeeded.

SQL> column grantee format a30

select grantee, common from dba_role_privs where grantee=’C##USER’;

SQL>

GRANTEE COM

—————————— —

C##USER NO

SQL> revoke dba from c##user container=current;

Revoke succeeded.

SQL> column grantee format a30

select grantee, common from dba_role_privs where grantee=’C##USER’;

SQL>

GRANTEE COM

—————————— —

C##USER NO

SQL> connect c##dba/password@pdb1

Connected.

SQL> revoke dba from c##user;

Revoke succeeded.

SQL>

SQL> column grantee format a30

select grantee, common from dba_role_privs where grantee=’C##USER’;

SQL>

no rows selected

SQL>

Now reconnect to C##DBA at the root level and grant connect and select on V$SESSIONS commonly the user C##USER. To test common privilege to objects.

SQL> connect c##dba/password@cdb1

Connected.

SQL> grant create session to c##user container=all;

Grant succeeded.

SQL> grant select on sys.v_$session to c##user container=all;

Grant succeeded.

SQL>

Connect the C##USER and execute a select statement on v$session and v$sql objects to validate access from root container. NOTE: We are able to access object v$session but not v$sql.

SQL> connect c##user/password@cdb1

Connected.

SQL> select count(*) from v$session;

COUNT(*)

———-

SQL> select count(*) from v$sql;

select count(*) from v$sql

ERROR at line 1:

ORA-00942: table or view does not exist

SQL>

Connect to PDB1 and repeat the above queries to validate common access privileges to objects.

SQL> connect c##user/password@pdb1

Connected.

SQL> select count(*) from v$session;

COUNT(*)

———-

SQL> select count(*) from v$sql;

select count(*) from v$sql

ERROR at line 1:

ORA-00942: table or view does not exist

SQL>

Privileges should never be given to public from common account.

Once a privilege is granted to public, all users have access to that privilege, which is a huge security risk. However, there is no restrictions built into Oracle to prevent this from occurring. We will demonstrate this by the creation of new user c##dba2, grant the new user no privileges, grant dba role to public, connect to both the CDB and PDB, and finally create a user. This is extremely dangerous, because granting privileges to public grants access to system and object privileges to every user. Finally we will revoke DBA role from public and note that the new user c##dba2 can no longer connect.

SQL> connect / as sysdba

Connected.

SQL> alter session set container=cdb$root;

Session altered.

SQL> create user c##dba2 identified by password;

User created.

SQL> grant dba to public container=all;

Grant succeeded.

SQL> connect c##dba2/password@cdb1

Connected.

SQL> connect c##dba2/password@pdb1

Connected.

SQL> create user testing identified by password;

User created.

SQL> connect / as sysdba

Connected.

SQL> revoke dba from public container=all;

Revoke succeeded.

SQL> connect c##dba2/password@cdb1

ERROR:

ORA-01045: user C##DBA2 lacks CREATE SESSION privilege; logon denied

Warning: You are no longer connected to ORACLE.

SQL>

This completes overview of Privileges for Common Users in Oracle Multitenant Databases.

Larry Catt

OCP

12c, backup/recovery, CDB, flashback, Multitenant

Perform Flashback for a CDB in Oracle 12c

August 13, 2015 Larry Catt Leave a comment

Oracle 12c provides the ability to flashback the database to a previous state. This procedures demonstrates the use of this process to flashback the database 15 minutes. NOTE: Four states must exist for flashback to work:

Must be in archivelog mode.
Database must have flashback on.
Control files must contain flashback logs, thus not recreated.
No tablespaces exist with flashback off set.

Logon to your Oracle database server as the Oracle software owner and logon to SQLPLUS.

[root@linux2 etc]# su – oracle

Last login: Thu Jul 1 09:25:23 EST 2015 on pts/1

[oracle@linux2 ~]$

[oracle@linux2 ~]$ sqlplus / as sysdba

SQL*Plus: Release 12.1.0.2.0 Production on Thu Jul 1 13:47:01 2015

Connected to:

Oracle Database 12c Enterprise Edition Release 12.1.0.2.0 – 64bit Production

With the Partitioning, OLAP, Advanced Analytics and Real Application Testing options

SQL>

Determine SCN of database 15 min ago by using the timestamp_to_scn().

SQL> select timestamp_to_scn(sysdate-1/96) from dual;

TIMESTAMP_TO_SCN(SYSDATE-1/96)

——————————

5067892

SQL>

Now using SCN extracted by the previous step, shutdown the database, startup in mount mode and execute the flashback command.

SQL> shutdown immediate

Database closed.

Database dismounted.

ORACLE instance shut down.

SQL> startup mount

ORACLE instance started.

Total System Global Area 734003200 bytes

Fixed Size 2928728 bytes

Variable Size 524292008 bytes

Database Buffers 201326592 bytes

Redo Buffers 5455872 bytes

Database mounted.

SQL> FLASHBACK DATABASE TO SCN 5067892;

Flashback complete.

SQL>

Startup the database for normal use with resetlogs option and see that all transactions of the last 15 minutes are gone.

SQL> alter database open resetlogs;

Database altered.

SQL>

NOTE: You should take a full backup of the database as soon after flashback as possible to ensure future recovery.

This completes the use of Flashback in Oracle 12c.

Larry Catt

OCP

Catt Solutions

Category Archives: Multitenant

Automatic Startup all PDB in a CDB

Oracle 12c Create PDB

Privileges of Local Users in Oracle Multitenant Database

Privileges of Common Users in Oracle Multitenant Database

Perform Flashback for a CDB in Oracle 12c

Oracle tips and tricks.