Is there any NoSQL data store that is ACID compliant?

Answer 1

Whilst it's only an embedded engine and not a server, leveldb has WriteBatch and the ability to turn on Synchronous writes to provide ACID behaviour.

Answer 2

Google Cloud Datastore is a NoSQL database that supports ACID transactions

Answer 3

Not only NoSQL is not ACID compliant by design. NoSQL movement embrace the BASE (Basically Available, Soft state, Eventual consistency) claimed to be the opposite of ACID. NoSQL database are often called Eventually-Consisted database. To understand the differences you should drill down into the CAP theorem (aka Brewer's theorem)

Visit http://www.julianbrowne.com/article/viewer/brewers-cap-theorem

Answer 4

Hyperdex Warp http://hyperdex.org/warp/ Warp (ACID feature) is proprietary, but Hyperdex is free.

Answer 5

DynamoDB is a NoSQL database and has ACID transactions.

Answer 6

Please ensure you read the Martin Fowler introduction about NoSQL databases. And the corresponding video.

First of all, we can distinguish two types of NoSQL databases:

1. Aggregate-oriented databases;
2. Graph-oriented databases (e.g. Neo4J).

By design, most Graph-oriented databases are ACID!

Then, what about the other types?

In Aggregate-oriented databases, we can put three sub-types:

• Document-based NoSQL databases (e.g. MongoDB, CouchDB);
• Key/Value NoSQL databases (e.g. Redis);
• Column family NoSQL databases (e.g. Hibase, Cassandra).

What we call an Aggregate here, is what Eric Evans defined in its Domain-Driven Design as a self-sufficient of Entities and Value-Objects in a given Bounded Context.

As a consequence, an aggregate is a collection of data that we interact with as a unit. Aggregates form the boundaries for ACID operations with the database. (Martin Fowler)

So, at Aggregate level, we can say that most NoSQL databases can be as safe as ACID RDBMS, with the proper settings. Of source, if you tune your server for the best speed, you may come into something non ACID. But replication will help.

My main point is that you have to use NoSQL databases as they are, not as a (cheap) alternative to RDBMS. I have seen too much projects abusing of relations between documents. This can't be ACID. If you stay at document level, i.e. at Aggregate boundaries, you do not need any transaction. And your data will be as safe as with an ACID database, even if it not truly ACID, since you do not need those transactions! If you need transactions and update several "documents" at once, you are not in the NoSQL world any more - so use a RDBMS engine instead!

some 2019 update: Starting in version 4.0, for situations that require atomicity for updates to multiple documents or consistency between reads to multiple documents, MongoDB provides multi-document transactions for replica sets.