Using memtables in sql. When is it reasonable and safe?

Question

I just read the update from the friend project, mentioning the use of memtables to store data temporarily, and then flush to a table on disk. So far, I have never encountered a situation where I would use memtable, or a situation where I think that using the mem table would be useful; so I wonder when someone will use mem tables? what makes memtable (appart on access speed) a smart choice? and how safe is it, even for temporary data? There is always a limitation on the available physical memory.

Answer 1

Is your friend a project using Cassandra (or a similar NoSQL project)? Because this product uses Memtables structures exactly as you describe.

While all DBMS products included in tags already implement their own memory management / data writing procedures. I cannot imagine why we would like to impose a function that RDBMS already provides to us. If we have too much free time and we need to burn the budget.