In-Memory OLTP Internals - Pro SQL Server Internals - page 634

Interop refers to the ability to reference memory-optimized tables from interpreted
T-SQL code.

Natively-compiled stored procedures refer to stored procedures compiled into machine
code. Those procedures will be covered in the next chapter.

Figure 32-1 shows the architecture of the SQL Server Engine including the in-memory OLTP part. As you can see,
memory-optimized tables do not share memory with on-disk tables. However, you can access both types of tables
from T-SQL and client applications through the interop engine. Natively-compiled stored procedures, on the other
hand, work only with memory-optimized tables and are unable to access on-disk table data.

Figure 32-1. SQL Server Engine architecture

In-memory OLTP stores data in a separate filegroup using a streaming mechanism based on FILESTREAM .
While coverage of FILESTREAM is outside of the scope of this topic, I would like to mention that it is optimized for
sequential I/O performance.

■ Note you can read more about FILESTREAM at: http://technet.microsoft.com/en-us/library/gg471497.aspx .

You need to specify a filegroup that contains memory-optimized tables' data by using the CONTAINS
MEMORY_OPTIMIZED_DATA keyword as shown in Listing 32-1. All in-memory OLTP files used by the database will reside
in the S:\HKData\Hekaton_InMemory folder after you run the script.