Open-source alternatives to Toydb

This project serves as a comprehensive technical reference for the architecture and design of data-intensive applications. It provides a structured analysis of the fundamental principles required to build reliable, scalable, and maintainable software systems, covering the core trade-offs inherent in modern data infrastructure. The repository explores the mechanics of distributed data management, including strategies for replication, partitioning, and achieving consensus across multiple nodes. It details the design of storage engines, indexing techniques, and transaction management models, whi

LanceDB is a vector database and columnar data store designed to function as a versioned dataset manager and vector search engine. It serves as a high-performance backend for indexing and retrieving high-dimensional embeddings, providing the foundation for machine learning data pipelines. The system distinguishes itself through a combination of cloud-native object storage and immutable version tracking, allowing for data time-travel and reproducible AI experiments. It integrates hybrid search capabilities, merging dense vector similarity with BM25 full-text search and SQL-like scalar filters

GreptimeDB is a distributed, open-source time-series database built for unified observability. It stores and queries metrics, logs, and traces together in a single columnar engine, supporting both SQL and PromQL for analysis. The database is designed as a Kubernetes-native operator with a decoupled compute and storage architecture, enabling horizontal scaling and multi-region deployment. What distinguishes GreptimeDB is its role as a multi-protocol ingestion gateway, accepting data through OpenTelemetry, Prometheus Remote Write, InfluxDB, Loki, Elasticsearch, Kafka, and MQTT protocols without

H2 is a JDBC-compliant relational database management system written in Java. It functions as an embeddable SQL database that can run directly within an application process to remove network latency, or as an in-memory database for high-performance volatile storage. It also includes a web-based console for executing SQL commands and administering schemas. The system is characterized by its flexible deployment modes, including a standalone server mode for remote TCP/IP access and a mixed mode for simultaneous local and remote connectivity. It features a dialect emulation layer and compatibilit

This is a Raft consensus library and distributed consensus engine implemented in Go. It provides the primitives necessary to build fault-tolerant distributed services by implementing a replicated state machine that ensures a group of servers agree on a shared system state through leader election and log replication. The project distinguishes itself through a pluggable architecture for storage backends and snapshot storage, decoupling the consensus logic from physical persistence. It includes specialized mechanisms for leadership transfer, protocol version management to support rolling upgrade

Delta is a lakehouse table format that brings ACID transactions and data warehouse consistency to large scale data lakes on cloud object storage. It serves as an ACID transaction manager, coordinating atomic commits and serializable isolation for concurrent reads and writes across distributed compute engines. The project provides a multi-engine interoperability layer that uses format translation to allow diverse SQL engines and processing frameworks to read and write the same tables. It functions as a data versioning system, utilizing a transaction log to enable time travel, historical snapsh

Hazelcast is a distributed data platform that combines an in-memory data grid with a stream processing engine to support real-time analytics and event-driven applications. It functions as a partitioned, distributed key-value store that replicates data across cluster nodes to provide low-latency access and high availability. The platform also serves as a distributed SQL query engine, allowing users to execute standard SQL statements against both in-memory datasets and external data sources. What distinguishes Hazelcast is its use of a distributed consensus subsystem to maintain strongly consis

This project is a reactive, offline-first NoSQL database engine designed for JavaScript applications. It provides a robust framework for managing application state by synchronizing data across browsers, mobile devices, and server-side runtimes. By treating local storage as the primary source of truth, it enables applications to remain functional without network connectivity, automatically reconciling changes with remote backends once a connection is restored. The database distinguishes itself through a modular architecture that supports cross-environment synchronization and high-performance d

Drift is a type-safe SQL persistence library and relational mapper that provides a structured way to map database tables to classes and execute SQL queries with build-time validation. It functions as a type-safe query builder and a wrapper for SQLite and PostgreSQL, eliminating manual result set parsing by binding query outputs to native objects. The project distinguishes itself through a build-time code generation system that produces type-safe APIs and validates raw SQL statements against database versions before execution. It features reactive query streaming, which transforms SQL queries

The AWS Cloud Development Kit is an infrastructure-as-code framework that enables developers to define and provision cloud resources using familiar programming languages. By utilizing construct-based synthesis, it translates high-level, object-oriented code into declarative templates, allowing for the automated management of complex cloud environments through a centralized, code-driven control plane. The framework distinguishes itself through its ability to model infrastructure as a dependency-aware resource graph, ensuring that components are provisioned and updated in the correct order. It

dqlite is a distributed SQL database that embeds a relational database engine to provide replicated storage across a cluster of nodes. It functions as a replicated SQL engine designed to ensure data remains available and consistent during node failures. The system utilizes a consensus algorithm to manage leader election and synchronize a replicated log across the cluster. This approach enables automatic cluster failover and leader promotion to maintain continuous service without manual intervention. The project covers state machine replication, network-based cluster membership, and transacti

Dolt is a relational database engine that integrates version control directly into the database management layer. It functions as a version-controlled SQL database that tracks every row and schema change using a commit-based history, allowing users to branch, merge, and audit data modifications. By implementing a wire-protocol-compatible server, the system enables standard SQL clients and tools to interact with versioned data as if they were connecting to a traditional relational database. The platform distinguishes itself by applying repository-style workflows to data management, including s

rqlite is a distributed relational database that replicates SQLite data across a cluster using the Raft consensus algorithm. It functions as a fault-tolerant storage system that provides high availability and a web API for executing SQL queries and managing relational data without requiring native database drivers. The system distinguishes itself by using an HTTP SQL interface to expose database operations and cluster management. It features a real-time change data capture stream that pushes database mutations to external HTTP endpoints via webhooks and supports the scaling of read throughput

Raft-java is a lightweight Java consensus library and replicated state machine engine designed to synchronize transaction logs and maintain fault-tolerant state across distributed server nodes. The framework relies on a leader-based replication model that routes write operations through a designated coordinator node, executing RPC-driven consensus protocols and automatic leader elections to maintain cluster agreement. The library supports dynamic cluster membership changes, allowing nodes to be added or removed during runtime without downtime through joint consensus configuration entries app

Raft-rs is a Raft consensus library and distributed consensus engine implemented in Rust. It functions as a systems-level protocol implementation that provides foundational message formats and data structures for state serialization across nodes. The library executes the underlying consensus protocol to ensure multiple distributed state machines agree on a shared sequence of log entries. It coordinates state changes across a cluster of nodes to keep replicated logs synchronized and consistent. Additional capabilities include defining protocol buffer messages for consensus communication, enco

LibSQL is a high-performance, distributed SQL database engine that extends SQLite to support remote network access, edge computing, and real-time synchronization. It functions as an embedded database library that integrates directly into application processes while providing the infrastructure to maintain consistency across multiple geographic regions. The platform distinguishes itself by enabling database interaction over standard HTTP protocols, allowing applications to query remote data sources in serverless and edge environments without requiring local filesystem access. It includes nativ

Bolt is a single-file embedded key-value store for Go applications. It is an ACID transactional database that organizes data in B+trees on disk to provide efficient sorted key retrieval and range scans. The system uses a memory-mapped model to map the database file directly into the process address space for fast random-access reads. The project distinguishes itself through a multi-version concurrency control architecture that allows multiple simultaneous readers to access a consistent snapshot of data without blocking a writer. It employs a single-writer multi-reader locking model and uses a

SQLiteStudio is an open-source graphical tool for browsing, editing, and managing SQLite database files. It combines a full-featured SQL editor with syntax highlighting, a visual database schema designer for creating entity-relationship diagrams, and a plugin-based extensibility platform that allows adding custom functionality through C/C++, JavaScript, Tcl, or Python. The application distinguishes itself through its multi-language scripting engine, which embeds JavaScript, Tcl, and Python interpreters to enable user-defined functions and scripts within SQL queries. It supports encrypted data

FoundationDB is an ACID-compliant distributed transactional key-value store. It functions as a scalable database engine that ensures strict serializability and data consistency across a cluster of servers using a shared-nothing architecture. The system is distinguished by its multi-region replication capabilities, allowing data to be synchronized across different datacenters for high availability and disaster recovery. It utilizes optimistic concurrency control to manage distributed transactions and employs a majority-based coordination system to maintain cluster state. The platform provides

Sled is an embedded key-value store and ACID-compliant database designed for high-performance data persistence. It functions as a log-structured storage engine that organizes data using B+ trees to support efficient range queries and prefix scans. The engine implements a zero-copy data store model, utilizing epoch-based reclamation to provide direct references to cached values without memory allocations. It distinguishes itself through a combination of write-ahead logging, page cache optimizations to reduce write amplification on flash storage, and serializable transactions for atomic multi-k

TablePro is a cross-platform database management client designed for browsing, querying, and administering both SQL and NoSQL databases. It functions as a unified workspace that integrates a code-centric SQL editor with schema visualization tools, allowing developers to manage complex data models and execute queries across diverse database engines. The application distinguishes itself through an agentic AI integration layer that connects language models directly to database tools, enabling automated query generation, optimization, and error fixing with configurable approval gates. It features

This project is a curated collection of academic papers, books, and technical resources designed for studying the architecture and implementation of database management systems. It serves as a comprehensive educational guide for engineers and researchers looking to understand the fundamental principles behind modern data storage and retrieval. The repository distinguishes itself by providing structured learning paths across critical database domains, including the design of persistent storage engines, the mechanics of query optimization, and the complexities of distributed transaction managem

Raft is a Go library implementing the Raft consensus protocol for coordinating reliable state machine replication across a cluster. It functions as a distributed systems library for building applications that require strongly consistent replicated state, keeping distributed nodes synchronized and fault-tolerant through automated node elections and log distribution. The library conducts periodic node elections using majority votes to designate a single data authority and prevent split-brain conflicts, while distributing deterministic command logs from leaders to follower nodes using a multi-ph

Dragonboat is a Go implementation of the Raft consensus protocol designed to maintain consistent state across a distributed cluster of nodes. It provides a library for building distributed state machines that ensure data integrity and fault tolerance during system failures. The project distinguishes itself through a multi-group Raft implementation, which partitions data across independent consensus groups to distribute workloads and increase overall system processing capacity. It also incorporates mutual TLS to encrypt inter-node communication and verify the identity of cluster members. The

OceanBase is a distributed SQL database designed for high availability and strong consistency across multiple nodes and regions. It functions as a hybrid transactional and analytical processing engine, allowing real-time analytics and transactions to execute on a single data copy. The system also serves as a vector database engine for indexing and querying vector data to power semantic search and recommendation systems. The platform features native compatibility layers for MySQL and Oracle, enabling the migration of legacy workloads without rewriting SQL code. It utilizes a Paxos-based distri

Raft is a portable C programming library that implements the Raft distributed consensus protocol. It serves as a state machine replication engine and coordination primitive for building fault-tolerant distributed applications and clustered systems. The library manages leader election timeouts, heartbeat monitoring, and log replication across peer nodes to maintain consistent state across servers. It handles client write operations, redirects requests from non-leader nodes, processes voting and replication messages, and supports dynamic cluster membership changes through specialized log entri

sofa-jraft is a Java implementation of the Raft consensus algorithm. It serves as a distributed consensus engine and linearizable state machine designed to ensure high availability and data consistency across a cluster of nodes. The project provides a replicated key-value store and a coordination engine for managing distributed state. It distinguishes itself through support for multi-group consensus sharding to distribute traffic and a service provider interface that allows for custom log storage and entry encoding implementations. The system covers a wide range of distributed capabilities,