In-Memory Column Store in Oracle Database 12c

 

https://oracle-base.com/articles/12c/in-memory-column-store-12cr1

The In-Memory Column Store (IM column store) was the headline feature of the 12.1.0.2 patchset. This features allows you to store columns, tables, partitions and materialized views in memory in a columnar format, rather than the typical row format. The advantage of having data in memory is obvious, but the columnar storage lends itself extremely well to analytic queries found in business intelligence products.

ALTER SYSTEM SET INMEMORY_SIZE=2G SCOPE=SPFILE;

ALTER SYSTEM SET INMEMORY_QUERY=ENABLE;

CREATE TABLE im_tab (
  id  NUMBER
) INMEMORY;

CREATE TABLE noim_tab (
  id  NUMBER
) NO INMEMORY;
SELECT table_name,
       inmemory,
       inmemory_priority,
       inmemory_distribute,
       inmemory_compression,
       inmemory_duplicate  
FROM   user_tables
ORDER BY table_name;