Database In-Memory now has a new Base Level feature. This allows the use of Database In-Memory with up to a 16GB column store without triggering any license tracking. This feature allows you to use Database In-Memory without having to license the option. The column store is limited to 16GB when using the Base Level. This helps to show the value of Database In-Memory without having to worry about licensing issues.
Within an individual PDB, you can limit access to the shared In-Memory Area by setting INMEMORY_SIZE to a different value. For example, in a CDB with 100 PDBs, you could set INMEMORY_SIZE to 16G at the CDB level and then set INMEMORY_SIZE to 10G in one PDB, to 6G in a second PDB, and to 0 in the remaining PDBs.
It is the Oracle21c feature backported to Oracle19c 19.8 RU.
For more information see: