CovenantSQL

CovenantSQL is a decentralized SQL database management system derived from SQLite and built on top of a blockchain. It supports most of the SQL-92 features. Each party interacting with CovenantSQL is either a client, a block producer, or a miner. ## Client A client supplies queries and wait for responses, which contain result sets of the queries. ## Block Producer A block producer matches clients with miners and maintains metadata about the clients (e.g. query history, digital signature, etc.) and the miners (e.g. availability, computing power, etc.). ## Miner A miner is a single database engine that serves both as a storage system and an execution engine. Miners register themselves with the block producers to indicate their desire to server clients. When a client sends a connection request, the request is directed to one node among a group of block producers. The block producers maintain a public blockchain (main chain). When a block producer receives a request, it allocates a number of miners. The miners self-organize and produce a separate block chain, called a shard chain. Each miner is an independent database engine running SQLite. CovenantSQL uses Go's driver for SQLite to interact with individual miners. The main chain implements Delegated Proof-of-Stake, which provides eventual consistency among block producers. The block producers pack all SQL queries from clients along with the shard chain's signature into the main block chain. The shard chains themselves consist of database contents and query results. The miners pertaining a shard chain use Byzantine Fault-Toleranted Raft, which provides strong consistency among miners that serve the same client. The leader in each miner group uses two phase commit to support transactions.

History

CovenantSQL was developed and made open source in 2018. It is currently under active development.

Checkpoints

Non-Blocking Blocking

Individual miners run [SQLite](https://dbdb.io/db/sqlite).

Data Model

Relational

Individual miners run [SQLite](https://dbdb.io/db/sqlite).

Foreign Keys

Supported

Individual miners run [SQLite](https://dbdb.io/db/sqlite).

Indexes

B+Tree

Individual miners run [SQLite](https://dbdb.io/db/sqlite).

Logging

Physical Logging

Individual miners run [SQLite](https://dbdb.io/db/sqlite).

Query Compilation

Code Generation

Individual miners run [SQLite](https://dbdb.io/db/sqlite).

Query Execution

Tuple-at-a-Time Model

Individual miners run [SQLite](https://dbdb.io/db/sqlite).

Query Interface

SQL

CovenantSQL supports the same set of standard [SQLite](https://dbdb.io/db/sqlite) commands.

Storage Architecture

Disk-oriented In-Memory

Clients can specify the storage architecture through a parameter in the connection request to the database. Same as [SQLite](https://dbdb.io/db/sqlite).

Storage Model

N-ary Storage Model (Row/Record)

Individual miners run [SQLite](https://dbdb.io/db/sqlite).

Stored Procedures

Not Supported

Same as [SQLite](https://dbdb.io/db/sqlite).

System Architecture

Shared-Nothing

CovenantSQL uses a three-level architecture, consisting of a main block chain, many shard chains, and individual miners. The main block chain is produced by a group of nodes called block producers, responsible for matching clients to shard chains. Each shard chain, which is produced by a designated group of computing nodes called miners, is a single database. Each miner is a standalone database engine that is responsible for storage and query processing. The miners reach consensus using a variant of Byzantine Fault-Tolerated Raft, which the developers call Kayak. When a leading miner goes offline, the miners in the same shard chain resort to a block producer to decide whether to wait for the leader to come back online or to elect a new leader. This is different from the original Raft, which handles changes in leader internally.

CovenantSQL Logo
Website

https://covenantsql.io/

Source Code

https://github.com/CovenantSQL/CovenantSQL

Tech Docs

https://godoc.org/github.com/CovenantSQL/CovenantSQL,http://developers.covenantsql.io/docs/en/intro

Developer

Covenant Labs

Country of Origin

CN

Start Year

2018

Project Type

Commercial, Open Source

Written in

Go

Supported languages

Go, Java, JavaScript, Python, SQL

Derived From

SQLite

Operating Systems

Linux, OS X

Licenses

Apache v2