To commemorate Oracle’s second major release of their flagship 12c database, I thought I’d take a moment to go over some of the new features and where they might be useful in the real world!
The new release, 12cR2 is not yet certified for use with Oracle e-Business Suite, but I would expect it is only a matter of time before this changes, and I’ve attached a full description of the new features here.
I’d also like to mention that as of 12cR1, the idea of a “standard”, non-multitenant database is deprecated – that is not to say unsupported, but it is likely that any further new features Oracle release will only be relevant/available for multitenant deployments of the database. It is not clear yet when the “standard” deployment of Oracle Databases will become de-supported.
There are some general improvements to Oracle Dataguard as part of 12cR2, small tweaks to allow features that were available in some architectures but not others are now included. Immediate examples of this include fast-start failover now being possible when running in maximum protection mode, and support for LOBS and other datatypes when using database links across PDBs (Pluggable databases) – essentially plugging some holes left behind when these features were introduced as part of 12cR1. More specific, detailed examples include:
The “Database Compare” feature allows the DBA to compare the Dataguard instance at a block level to the primary instance. This can be especially useful when identifying issues within the standby database where the data may have become corrupt, but logically remains “correct” and as such would not be picked up by more traditional tools such as DBVERIFY.
This also presents the opportunity for customers to reduce the need to run quite so many intensive DR tests. If the DR environment can be verified accurately and regularly, then a degree of comfort over its “usability” can be obtained without requiring as many time-consuming tests. The tests will still be required to prove the PROCESS of failing over to DR, but the integrity of the DR environment is now all but ensured.
Subset Standby takes the idea of multitenant databases a step further, and allows the DBA to replicate individual pluggable databases for standby rather than having to replicate the entire container database. This leads to, in qualifying environments, for smaller overhead in maintaining DR and reduced cost of ownership of the solution – a very cost-effective enhancement!
A new feature for 12cR2 that we haven’t seen before is Database Sharding. Building on the idea of pluggable databases, Sharding allows you to effectively run single applications supported by multiple back-end databases.
This is a similar concept to running an instance with RAC (Real Application Clusters) in that you allow for high performance in splitting the application load across multiple instances of the database. However, the concept of Sharding is subtly different – it’s specifically intended for use in custom OLTP systems that have been designed to benefit from this technology. It can be used to separate partitions of data across geographies for legislative reasons and to bolster performance of OLTP transactions.
Deployment of Oracle Sharding comes with automatic configuration of Oracle Dataguard or Goldengate to manage replication between the shards which collectively make up the database presented to the application.
I find this feature interesting as I can’t think of many current scenarios that would benefit from this architecture, but it does present some very interesting possibilities going forward as to how databases can be managed an arranged in the future, adding to the wealth of options currently available with RAC and pluggable databases.
As you’d imagine, any new release of a database is always accompanied by various database improvements and bug fixes. In addition:
RMAN has been improved to allow more features in terms of cross platform migrations, and some syntax enhancements.
The upgrade process has been refreshed, allowing seamless rolling upgrades in certain architectures.
Some DBA maintenance tasks have now been updated to allow on-line manipulation, such as table moves and various partitioning tasks.
There is also now the ability to split redo application between nodes of a RAC instance for extra manageability in those complex architectures.
In summary, another new release of Oracle’s flagship database product and pretty much what we would expect – some nice new features, some nice to have features and a whole raft of new bug fixes and minor improvements.
Overall, it’s a solid release from Oracle but nothing ground breaking. However, there are a few nods to the future with features such as Oracle Sharding, which may become a much larger topic for discussion in later releases of the database.
Mike is responsible for Claremont’s DBA delivery function across both Consultancy and Managed Services practices.In addition, he is responsible for the maintenance and enhancement of Claremont’s internal IT infrastructure.