By Margaret Hamburger-Oracle on Mar 23, 2015
Just in case you missed it- Watch the Forum On-Demand!
The Oracle Database Innovation Forum that was broadcast on March 18th and is now available on-demand. Once you registered, stay as long as you like or return at your convenience to watch another session or replay one that's really made an impact. The forum, featuring Oracle Database guru Tom Kyte, was followed by Oracle Database Innovation experts and customers sharing best practices and the reasons why they chose Oracle Database 12c. The Forum keynote and following sessions provide a little something for everyone - from DBaaS and Multitenant and private clouds - to Big Data, Database In-Memory and Data Warehousing best practices. Sessions on Database Management and Advanced Security, High Availability, Storage Optimization and even best practices for upgrading to Oracle Database 12c are offered.
During the forum, we received so many great questions that I'll share only a few with you here. The questions we get most often concern licensing database options and comparing Enterprise Edition and Standard Edition features and option availability. A great resource to help you understand the Oracle Database options can be found in this 'family' white paper
Here are three questions we received about Oracle Multitenant:
Q: How does a Multitenant architecture differ from a traditional SQLSERVER instance based architecture?
A: In that Microsoft SQL Server supports multiple "databases" within a single server, while Oracle Multitenant supports multiple Pluggable Databases (PDBs) within a single Container Database (CDB), there is a superficial similarity between the two. There are some important differences, however, Microsoft SQL Server users are defined at server level, so there's imperfect namespace isolation, which makes it less suitable for Database as a Service (DBaaS). SQL Server Databases are difficult to move between servers. By contrast the pluggable portability of Pluggable Databases (PDBs) allows for a great range of flexibility.
Q: We are already using OVM for consolidation - what does Multitenant give us over that?
A: OVM is good for infrastructure consolidation. Multitentant is specifically designed for databsase consolidation - much higher consolidation density, simpler management as you can now manage many databases as one. You could still use MT for further consolidation benefits on top of OVM.
Q: Do you have any guidance regarding capacity/resource sizing of multitenant database?
A: This is highly dependent on the loads being consolidated. The savings are proportional to the numbers of databases consolidated. Rough rules of thumb for minimal savings are about 1.5GB per database and maybe 1/3 core for databases under load. On top of that, you might expect greater savings because of the ability to share "peaks and troughs" in load. In terms of storage, snapshot clones facilitate huge savings in storage and IOPS. Don't forget the operational savings because of the ability to manage many databases as one.
Three questions we received about Oracle Database In-Memory:
Q: How is In-Memory enabled?
A: Database In-Memory is enabled by setting the initialization parameter inmemory_size > 0.
Q: Does Oracle Database 12c using in-memory capabilities by default, or does the DBA need to configure?
A: Oracle Database 12c does not enable Database In-Memory by default. To enable Oracle Database In-Memory the inmemory_size initialization parameter must be set to a value greater than zero. You then need to alter one or more tables, partitions, sub-partitions or materialized veiws to be populated into the IM column store. The Oracle optimizer can then transparently make use of the IM column store.
Q: Does Database In-memory have a hardware dependency like some specific quality of RAM?
A: No, Database In-Memory can run on any hardware platform supported for Oracle Database 12c. You do have to have enough memory to support the In-Memory column store in addition to the other components in the SGA though.
Three questions about Automatic Data Optimization:
Q: Are indexes automatically maintained during the ILM compression (alter table move partition update indexes)?
A: Yes, indexes are automatically maintained when applying a compression policy.
Q: Why not always compress to the highest level that saves I/O?
A: You make the decision based on the type of data. Archive data, that is accessed less frequently, should be compressed at the highest rate. Read more about Oracle Automatic Data Optimization
Q: Is Automatic Data Optimization available on all servers or only on Oracle Exadata?
A: ADO is what can be achieved with a combination of database storage optimization technologies used on any hardware. Of course we optimize engineered systems for the Oracle Database so we think there are some great advantages over commodity hardware infrastructures that you build yourself.
Here's the complete FAQ.