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Newbie queries on Multi Tenant

Jimbo Member Posts: 354
edited Aug 13, 2014 11:23AM in Multitenant

Hi, I have a list of newbie questions on Multi Tenant Architecture at 12c -

Q1.The Oracle WP on MTA suggests you should not consider a database for being a PDB if it already holds schema consolidation. Is this true - what happens if a database already has schema consolidation ? Can it not be converted to a PDB ?

Q2. My PDB will have a SYSTEM user, however does it also have the internal SYS connection ?

Q3. Can you have a CDB and a non CDB/PDB database running from the same 12c ORACLE_HOME on a Database Server or should they have their own separate ORACLE_HOMEs

Q4. If you unplug a PDB from a CDB at 12.1.1 and plug it into a CDB at 12.1.2, is the PDB automatically upgraded to that patchset or do you still have to run some of the patchset scripts against the PDB ?

Q5. Similarly to Q2, What is the situation if you are re-plugging a PDB into a CDB with a completely different release eg from 12.1 to 12.2

Q6. I believe RMAN is used only at the CDB level but can still do PITR at the PDB level? Is this correct ?

Q7. How does RAC fit into the model ? I presume it is only at the CDB level since only that provides the instance ? So if you had some databases that were to be RAC and some that were not, you would need more than 1 CDB i.e. a RAC deployed one and a non RAC deployed one ?

Q8. If my CDB is a 3 node RAC does that effectively make every PDB of that CDB, also a 3 node RAC database ?

Q9. If I have a 5 node database and want to convert it to a PDB but my CDB is a 3 node RAC does that mean my database ( PDB ) will have to be a 3 node RAC ( unless I increase the nodes of the CDB from 3 to 5 ) ?

Q10. How does Data Guard fit into the model ? Does Data Guard only get implemented at the CDB level and not the PDB level ? I am presuming so, since the Redo Logs are only at the CDB Level ?

Q11. If your Primary is the CDB, do the Standby have to be a CDB on your DR server or can the DR server simply hold a number of Standby Databases that are non CDB/PDB based or does the architecture on the DR side also have to be CDB / PDB ?

Q12. What type of Standby can you have in Multi Tenant i.e. Physical, Logical, Snapshot ? Also what protection modes are allowed ?

Q13. What happens if you want to convert a database into a PDB but that database is already using Data Guard ?

Any help greatly appreciated

thanks - Jim



  • carajandb
    carajandb Member Posts: 260 Bronze Badge

    Hi Jim

    here are some answers:

    Q1: any database can be converted to a PDB

    Q2: yes SYS is still available but you cannot directly connect to a PDB (e.g. sqlplus / as sysdba) but you can use ALTER SESSION SET CONTAINER=<pdbname>

    Q3: yes

    Q4:No, a PDB must be upgraded as well

    Q5: all pdbs are "version aware" so have to migrate or upgrade whenever the version of the CDB is different

    Q6: yes

    Q7: PDBs are instance agnostic but the CDB has to be RAC aware. So you can simple plug out a PDB from a single instance CDB and plug it into a RAC CDB (my absolute favorite!)

    Q8: --> Q7

    Q9: --> Q7

    Q10: Data Guard is working on the CDB level so per default every PDB in that CDB will use data guard as well. But with you can exclude PDBs from being replicated using data guard

    Q11: Primary and standby have to be the same architecture

    Q12: --> Q10

    Q13: --> Q10

This discussion has been closed.