The total size of in-memory database tables (M-tables) cannot exceed the amount of virtual memory available.

Since virtual memory is swapped to disk frequently, using virtual memory negates part of the advantage of M-tables. You should limit your M-tables to less than the size of the available physical memory, not the size of the available virtual memory.

The amount of space that is required to store a table includes the space not only for the data that is in the table, but also for any indexes on that table, including any indexes that are created in support of primary key and foreign key constraints. Also, tables occupy significantly more space in memory than on disk.

If the server runs out of virtual memory when it tries to allocate memory (for example, to expand a table during an INSERT or ALTER TABLE operation), you will get an error message.