Cassandra vs FoundationDB: What are the differences?

Key Differences between Cassandra and FoundationDB

Cassandra and FoundationDB are both highly scalable distributed databases that offer different features and functionalities. Here are the key differences between them:

1. Data Model: Cassandra is a wide-column store database that follows a key-value data model. It is based on the key-value store concept, where each row has a primary key and multiple columns with values. On the other hand, FoundationDB is a key-value store database that follows a document data model. It supports advanced data structures like JSON or nested documents, allowing for more complex data representation and querying.

2. Consistency Model: Cassandra follows a tunable consistency model known as eventual consistency. It prioritizes high availability and partition tolerance over strong consistency, allowing for fast and scalable operations. FoundationDB, on the other hand, follows a strongly consistent model by default. It ensures that all clients see the same data at the same time, providing strong guarantees for correctness and integrity.

3. Scalability: Both Cassandra and FoundationDB are designed to scale horizontally. However, Cassandra provides a more seamless and auto-sharding approach to handle large datasets and high traffic loads. It employs a shared-nothing architecture with peer-to-peer replication, allowing for easy addition and removal of nodes. FoundationDB also supports horizontal scalability, but it requires explicit partitioning of data to distribute it across multiple nodes.

4. Conflict Resolution: In the case of concurrent updates or conflicts, Cassandra uses a last-write-wins conflict resolution strategy. The most recent write will overwrite the previous values. On the other hand, FoundationDB uses multi-version concurrency control (MVCC) to handle conflicts. It keeps track of different versions of a value and enables clients to resolve conflicts based on their specific requirements.

5. Transactions: Cassandra has limited support for transactions that only span a single partition. It does not provide support for distributed ACID transactions. In contrast, FoundationDB provides full support for distributed ACID transactions, allowing multiple operations across different keys or key ranges to be executed atomically.

6. Query Language: Cassandra uses Cassandra Query Language (CQL), which is a SQL-like language with some extensions specific to Cassandra's data model. It allows for basic CRUD operations, as well as filtering and aggregation. FoundationDB does not have a specific query language but provides client libraries and APIs that allow developers to build their own query interface using their preferred programming language.

In summary, Cassandra is a wide-column store with eventual consistency, while FoundationDB is a key-value store with strong consistency. Cassandra prioritizes scalability and high availability, while FoundationDB focuses on strong consistency and ACID transactions. The choice between the two depends on the specific requirements of the application, data model complexity, and the need for transactional guarantees.