Project: NomsDB (App Definition and Development / Database)
File: faq.md

&nbsp; | &nbsp;&nbsp; | &nbsp;&nbsp; | &nbsp; | &nbsp;&nbsp; | &nbsp;FAQ&nbsp; <br><br> No, decentralized like Git. Specifically, Noms isn't itself a peer-to-peer network. If you can get two instances to share data, somehow, then they can synchronize. Noms doesn't define how this should happen though. Currently, instances mainly share data via either HTTP/DNS or a filesystem. But it should be easy to add other mechanisms. For example, it seems like Noms could run well on top of BitTorrent, or IPFS. You should . Noms deduplicates chunks of data that are identical within one database. So if multiple versions of one dataset share a lot of data, or if the same data is present in multiple datasets, Noms only stores one copy. That said, it is definitely possible to have write patterns that defeat this. Deduplication is done at the chunk level, and chunks are currently set to an average size of 4KB. So if you change about 1 byte in every 4096 in a single commit, and those changed bytes are well-distributed throughout the dataset, then we will end up making a complete copy of the dataset. Theoretically, definitely. In Git, for example, the concept of "shallow clones" exists, and we could do something similar in Noms. This has not been implemented yet. Noms provides several built-in policies that can automatically merge common cases of conflicts. For example concurrent edits to sets are always mergeable and concurrent edits to different keys in a map or struct are also mergeable. The conflict resolution system is pluggable so new policies that are application-specific can be added. However, it's possible to build surprisingly complex applications with just the built-in policies. are a class of distributed data structures that provably converge to some agreed-upon state with no synchronization. Stated differently: CRDTs define a merge policy that is commutative over all their

CRDTs are nice because they require no custom conflict/merge code from the developer. Noms defines a set of intutive built-in merge policies for its core datatypes. For example, the default policy makes all operations on Noms Sets commute (add wins in the case of concurrent remove/add). This means that with the default policy, Noms Sets are a CRDT. If your application uses only operations on Noms datatypes that can be merged with whatever merge policy you are using, then your schema is a CRDT. It's possible to build surprisingly complex applications this way with just the default policy. Noms also allows you to provide your own custom policy. If your policy commutes, then the resulting datatype will be a CRDT. However, it would be nice if application developers could more easily opt-in to using only mergeable operations, thereby enforcing that their schema is a CRDT, and providing confidence that custom merge logic doesn't need to be implemented. More generally, perhaps there could be a way to test that all possible conflict cases have been handled by the developer. This would allow developers to implement their own custom CRDTs. This is something we'd like to research in the future. We are a tiny team and we all personally use Macs as our development machines, and we use Linux in production. These two platforms are very close to identical, and so we can generally test on Mac and assume it will work on Linux. Adding Windows would add significant complexity to our code and build processes which we're not willing to take on. No, because then we'll have to maintain those patches. You can use it in a virtual machine. We have also heard Noms works OK with gitbash or cygwin, but that's coincidence. It's insert-only. OMNOMNOM. It's content addressed. Every value has its own hash, or . Pretty sure. But if you like, you can pretend it stands for Non-Mutable Store.