Why should we not upgrade to Oracle 12c……YET

Why should we not upgrade to Oracle 12c……YET

Oracle Database 12c is one of the most amazing release so far. Personally, it’s also the first “release” that I experienced since I started out as an Oracle DBA on 11gR2. Everyone has been raving about it’s features and performance. There are several new features that got every DBAs out there excited.

  1. Multi-Tenant – Database Consolidation
  2. In-Memory – Storing data in memory using columnar store
  3. Automatic Data Optimisation – Information lifecycle management feature

In this post, I shall discuss about the Multi-Tenant feature.

Multi-Tenant requires additional licensing feature on top of Enterprise Edition. According to Oracle Global Price List, it costs about 17,500 USD per core.  This does not come at a cheap cost. But consider this, if we can consolidate multiple under-utilised databases into a single machine, we could potentially save money from the EE licences instead. So please do the necessary planning before embarking on your upgrade/migration journey. According to the Oracle documentation, there are several features still unsupported on Please do take note, else you will be in for a surprise!

The following is a list of components that are not available or are restricted in this release of Oracle Database 12c Release 1 (

  • Oracle Fail Safe release 4.1.0, shipping with Oracle Database 12c Release 1 (, does not support the new multitenant container database (CDB) feature introduced in Release 12c. This restriction is documented in the ReadMe for Oracle Fail Safe 4.1.0 patch set 1 ( Support for CDB will be introduced in Oracle Fail Safe release (not a patch set) currently targeted to release in H1CY2015.
  • Only rolling upgrades to Oracle Grid Infrastructure release are supported when upgrading Oracle Grid Infrastructure clusters that are operating in Oracle Flex Cluster mode. The Oracle Clusterware stack on all nodes in the cluster (Hub Node and Leaf Node) needs to be up and running prior to the upgrade. For environments operating in Standard cluster mode, rolling and non-rolling upgrades are supported.
  • Database Resident Connection Pooling (DRCP) is not supported with Transaction Guard.
  • XStream does not support LONG columns in databases with varying width multibyte character sets.
  • Java Database Connectivity (JDBC) thin driver Database Change Notification (DCN) is not supported by PDB.
  • Oracle Automatic Storage Management Cluster File System (Oracle ACFS) does not currently support Hybrid Columnar Compression (HCC).

The following is a list of features that are not available or are restricted for a multitenant container database (CDB) in this release of Oracle Database 12c Release 1 (

  • Data Recovery Advisor
  • Flashback Pluggable Database
  • Flashback Transaction Backout
  • Database Change Notification
  • Continuous Query Notification (CQN)
  • Client Side Cache
  • Heat Map
  • Automatic Data Optimization
  • Oracle Streams

If you are currently using any of the features above, you might want to stick it out until the features are ready. I am not saying that you should never upgrade to Oracle Database 12c. That would be a silly thing to say. My point is that do not jump into a new technology just because it seems promising. Please do your due diligence and homework. In fact, according to the Oracle documentation, non-CDB database, meaning pre-12c databases will be deprecated. By June 2018, when 11gR2 is out of premier support, we should see plenty of consolidated database environments 🙂

Till then, please start planning for your journey to 12c!

Wei Shan


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