INMEMORY_SIZE

Property	Description
Parameter type	Big integer
Syntax	`INMEMORY_SIZE =` `integer` `[K \| M \| G]`
Default value	`0`
Modifiable	`ALTER SYSTEM`
Range of values	0 to the amount of memory left in the SGA after other allocations
Basic	No
Oracle RAC	All instances should use the same value.

INMEMORY_SIZE sets the size of the In-Memory Column Store (IM column store) on a database instance.

The default value is 0, which means that the IM column store is not used.

The database must be restarted after setting this parameter to enable the IM column store.

The minimum size to which this parameter can be set is 100 MB.

Typically this parameter should be set to at least the size needed to accommodate all the tables that will use the IM column store. It can be set higher to allow for growth of those tables or to accommodate other tables that will use the IM column store in the future.

This parameter can also be set per PDB to limit the maximum size of the IM column store for that PDB. Note that the sum of the PDB values do not have to equal the CDB value, and the sum of the PDB values may even be greater than the CDB value.

Unless this parameter is specifically set on a PDB, each PDB inherits the CDB value, which means they can use all of the available IM column store.

Note:

This initialization parameter is available starting with Oracle Database 12c Release 1 (12.1.0.2).