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Embedded MongoDB when running integration tests
I want to use In-Memory mode for unit test, is there an in In-Memory mode like RavenDB?
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MongoDB is not an in-memory database. Although it can be configured to run that way. But it makes liberal use of cache, meaning data records kept memory for fast retrieval, as opposed to on disk.
The short answer is MongoDB relies on both its internal memory caches as well as the operating system's cache. The OS cache generally is seen as “Unallocated” by sysadmins, dba's, and devs. This means they steal memory from the OS and allocate it internally to MongoDB.
MongoDB does store all its data on disk so that it can persist it during server restarts. However, it is primarily liking memory. It relies on the Operating System to schedule which bits of its database stay in memory, and which stays on disk.
Memory Mapped Files MongoDB uses memory-mapped files to store it's data (A memory-mapped file is a segment of virtual memory which has been assigned a direct byte-for-byte correlation with some portion of a file or file).
There is no in-memory mode for MongoDB. As per this link, this feature won't be included until at least MongoDB 2.8. Though since it's using Memory-mapped IO, it should be as speedy as in-memory during the actual processing. Not the startup though. Also, there's a hack to use RAM disk drive and put your mongo db there.
Use the right-hand menu to navigate.) MongoDB is not an in-memory database. Although it can be configured to run that way. But it makes liberal use of cache, meaning data records kept memory for fast retrieval, as opposed to on disk.
This can be super useful for applications like: That would be really neat indeed if it was possible: one could leverage the advanced querying / indexing capabilities of MongoDB without hitting the disk.
On MongoDB Atlas instances using the M40 tier or higher, 50% of the available memory is used for caching. The other 50% is used for in-memory operations and the other services running on the server. WiredTiger will try to fetch data from the cache, and then rely on disk storage.
There is no in-memory mode for MongoDB. As per this link, this feature won't be included until at least MongoDB 2.8.
Though since it's using Memory-mapped IO, it should be as speedy as in-memory during the actual processing. Not the startup though.
Also, there's a hack to use RAM disk drive and put your mongo db there. That way it would be entirely in memory.
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