Understanding in memory table in Viya

[esbabu]

Hello
I am trying to grasp a conceptual understanding of the concept of "in memory" table in SAS Viya.
Is all the data loaded into memory and resides there? If not were does data resides?
I would appreciate if any body can explain this.

[SASKiwi]

In-memory tables are used extensively in Viya and are managed by CAS servers. As soon as a CAS server is shut down, the tables disappear. To read the tables back into memory the CAS server needs to be started and the tables read back in from permanent storage.

However Viya also has Compute servers which function just like the SAS 9.4 ones where data is read from and written to permanent storage.

[Sajid01]

In memory tables are actually are tables stored in SASHDAT format in the CAS_DISK_CACHE.
The address of this data table is mapped to the process space in memory (RAM). Look here for more details https://www.ibm.com/docs/es/aix/7.2?topic=memory-understanding-mapping