Summary
| database | key length | data length | Transactions | License |
|---|---|---|---|---|
| FineDB | 64 KB | 4 GB | partial | Apache |
| Redis | 2 GB | 512 MB | yes | BSD |
| Couchbase | 250 bytes | 20 MB | no | Apache |
| FoundationDB | 10 KB | 100 KB | yes | Proprietary |
| Riak | 255 bytes | 64 MB | no | Apache |
| Cassandra | 64 KB | 2 GB | no | Apache |
| MongoDB | 128 bytes | 16 MB | no | GNU AGPL |
| HyperDex | ? | 128 MB | yes | BSD + proprietary |
| DynamoDB | 64 KB | 64 KB | no | Proprietary |
Data length
FineDB
- keys: up to 64 KB
- values: up to 4 GB
Redis
Couchbase
FoundationDB
- keys: up to 10 KB
- values: up to 100 KB
Riak
- keys: up to 255 bytes
- values: “practical limit around 64 MB”
Cassandra (Apache)
- keys: less than 64 KB
- column values: less than 2 GB; «"single digits of MB" in practice»
MongoDB
- index names: up to 128 bytes
- documents: up to 16 MB once BSON-serialized
Hyperdex
- documents: up to 128 MB
DynamoDB (Amazon)
- keys: up to 64 KB
- values: up to 64 KB
The 64 KB limit applies on a whole element, its attribute names and values. See http://docs.aws.amazon.com/amazondynamod...
Transactions
Redis
Couchbase
Multi-operation transactions are not supported.
FoundationDB
Riak
Transactions are not supported.
Cassandra
Transactions are not supported.
MongoDB
Multi-operation transactions are not supported.
HyperDex
Transactions are supported by the Warp superset.
DynamoDB
Multi-operation transactions are not supported.
Licenses
FineDB
Redis
Three clause BSD license
Couchbase
- Community Edition: Apache License v2.0
- Enterprise Edition: Proprietary
FoundationDB
Commercial licenses.
Riak
Apache License v2.0
Cassandra
Apache License v2.0
MongoDB
- Server and tools: GNU AGPL v3.0
- Drivers: Apache License v2.0
- Documentation: Creative Commons BY-NC-SA
Hyperdex
BSD license for the core + proprietary license for transactions.
DynamoDB
Proprietary. SaaS service, not installable.