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Asif Momen

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Views expressed here are solely that of my own. Please make sure that you test the code/queries that appear on my blog before applying them to the production environment.
Updated: 1 week 2 days ago

Oracle Database 12c: In-Memory Option

Sun, 2014-08-03 06:16
Starting with Oracle Database 12cR1 (12.1.0.2), a new static pool in the SGA is designed to store data in the columnar format and is called In-Memory Column Store (IMCS). Each table column is stored as a separate structure in IMCS. The In-Memory column store does not replace the buffer cache, rather supplements by storing data in columnar format.
Following the levels at which IMCS can be enabled at:
  • Column
  • Partition / sub-partition
  • Table
  • Materialized view
  • Tablespace
The IMCS is populated by a set of background processes. Objects are populated into the IMCS either in a prioritized list soon after database start-up or after they are queried for the first time.

Like other Oracle Database Options, you make NO changes in your application to start benefiting from the In-Memory Option. It is completely transparent to the applications. Also, Oracle Optimizer is fully aware of the column format and automatically utilizing IMCS when required.

I plan to test and blog more on the In-Memory option. Following are few of the topics that I plan to post a blog entry on:
  • Enable and disable In-Memory Option
  • In-Memory Option at various levels
  • In-Memory Space pressure
  • In-Memory background processes
  • In-Memory with compression levels
  • In-Memory statistics
  • In-Memory and Data Pump Export
  • In-Memory with Multi-tenant Option