Storage capacity of in-memory database?

Question

Is storage capacity of in-memory database limited to size of RAM? If yes, is there any ways to increase its capacity except for increasing RAM size. If no, please give some explanations.

Answer 1

As previously mentioned, in-memory storage capacity is limited by the addressable memory, not by the amount of physical memory in the system. Simon was also correct that the OS will swap memory to the page file, but you really want to avoid that. In the context of the DBMS, the OS will do a worse job of it than if you simply used a persistent database with as large of a cache as you have physical memory to support. IOW, the DBMS will manage its cache more intelligently than the OS would manage paged memory containing in-memory database content.