An in-memory database is a database management system that stores data primarily in the main memory of a computer, in contrast to traditional databases that use disk storage mechanisms. In-memory databases are designed to enable minimal response times by eliminating the need to access disks, which can be slower than accessing data stored in memory. They are ideal for applications that require microsecond response times or have large spikes in traffic, such as gaming leaderboards, session stores, and real-time analytics. In-memory databases are also useful in game programming, where data can be stored in an in-memory database that is much faster than permanent databases.

One potential technical hurdle with in-memory data storage is the volatility of RAM. Specifically, in the event of a power loss, intentional or otherwise, data stored in volatile RAM is lost. However, with the introduction of non-volatile random-access memory technology, in-memory databases will be able to run at full speed and maintain data in the event of power failure.

In-memory databases are great for high-volume data access where a data loss would be acceptable. They are used extensively in industries that depend on rapid response times and real-time data management, such as telecommunications, banking, travel, and gaming. An in-memory database works in a very similar way as any other database, but the data is kept in RAM rather than on a traditional disk. Replacing the disk access with memory operations highly reduces the latency required to access data.

In summary, an in-memory database is a purpose-built database that relies primarily on internal memory for data storage. It is ideal for applications that require microsecond response times or have large spikes in traffic, and it is used extensively in industries that depend on rapid response times and real-time data management.