...
The Database should be open-sourced and able to support APIs for multiple programming languages as it can be extended in future but should definitely support C++ APIs as currently, we are using C++ APIs.
7) Very important comparison:- https://www.influxdata.com/blog/benchmarking-leveldb-vs-rocksdb-vs-hyperleveldb-vs-lmdb-performance-for-influxdb/
8) https://mozilla.github.io/firefox-browser-architecture/text/0017-lmdb-vs-leveldb.html
Popular Key-Value store NoSQL Databases comparison. Also, one of the good comparisons can be found here.
| Databases | Open Source | C++ APIs | Low Latency | Key-Value Storage | Embedded database with on-disk storage mode | In-Memory (Caching) Capabilities | Note | |||
|---|---|---|---|---|---|---|---|---|---|---|
| Aerospike |  | | | |  | | ||||
| Berkeley DB (one of the best) | | | | | | | Developed by Oracle Inc. Support APIs for multiple programming languages. Support many Operating systems as the server. One of the oldest and developed in the year 1994. | |||
| Redis | | | | only In-memory capabilities. Can only use it as cache store so cannot store data larger than RAM size. | | One of the best but cannot store big volumes of data larger than RAM hence cannot be used for our purpose. | ||||
| LevelDB | | | | | | Developed by Google Inc. IoS is not supported as a server operating system. Developed in 2011. | ||||
| RocksDB (also very much recommended) | | | | | | | Developed by Facebook Inc. Developed in 2013. Only supports APIs in language C++ and Java. RocksDB supports Transactions when using a TransactionDB or OptimisticTransactionDB. Transactions have a simple BEGIN/COMMIT/ROLLBACK API and allow applications to modify their data concurrently while letting RocksDB handle the conflict checking. RocksDB supports both pessimistic and optimistic concurrency control. | |||
| LMDB (Very high performant) | | | | | | |||||
| BadgerDB | | | | | | | When Badger is running in in-memory mode, all the data is stored in the memory. Reads and writes are much faster in in-memory mode, but all the data stored in Badger will be lost in case of a crash or close. Badger doesn't support on-disk and in-memory mode together. | Riak KV | | |
| Amazon DynamoDB | | | | | | | |||
| SQLite (Not very good performance) | | | | | | | Does not guarantee domain integrity. SQLite works great as the database engine for most low to medium traffic. |
Considering multiple parameters mentioned above along with support for Transactions etc. We decided to move ahead with RocksDB.