In-Memory Database Guide : Overview of features : Types of in-memory tables
  
Types of in-memory tables
There are two basic types of in-memory tables: persistent tables and non-persistent tables. Persistent tables provide recoverability of data; non-persistent tables provide fast access.
Disk-based tables are always persistent tables.
See also
Persistent in-memory tables
Non-persistent in-memory tables
Table types and referential integrity
Overview of features