topic Understanding in memory table in Viya in SAS Viya

Understanding in memory table in Viya

esbabu — Tue, 28 Oct 2025 19:02:22 GMT

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.

Re: Understanding in memory table in Viya

SASKiwi — Tue, 28 Oct 2025 20:10:13 GMT

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.

Re: Understanding in memory table in Viya

Sajid01 — Sun, 16 Nov 2025 05:31:03 GMT

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