BigchainDB is an open-source blockchain database. It is a NoSQL database that has blockchain properties such as immutability, decentralization and owner-controlled asset. Immutability is the property that once the data is stored in BigchainDB, it can’t be modified or erased. Decentralization means there is no single point of failure in the control and storage process of the data. The owner-controlled asset is the property that only the owner of the asset can transfer the asset. The database provides the user with Byzantine Fault Tolerance (BFT) with no more than one-third arbitrary node failures. There are two main layers in BigchainDB, the consensus layer based on Tendermint the and storage layer based on MongoDB.
The first version of BigchainDB was published in February 2016. However, there were many issues with the initial version. For example, the system was not Byzantine Fault tolerant, and there was a single point of failure in the underlying storage database and the system supported only one logical database, which means once got the control of the database the adversary could delete the whole database. BigchainDB 2.0 was published in 2018 and solved all the issues above.
Two-Phase Locking (Deadlock Prevention) Optimistic Concurrency Control (OCC)
The consensus layer is based on Tendermint. Tendermint uses LevelDB as blockchain storage. LevelDB uses Two-Phase Locking with Deadlock Prevention, see LevelDB for more details. The storage layer on each node is based on MongoDB. MongoDB uses Two-Phase Locking with Deadlock Prevention and Optimistic Concurrency Control, see MongoDB for more details.
https://github.com/bigchaindb/bigchaindb
https://docs.bigchaindb.com/en/latest/
BigchainDB GmbH
2015