Lealone
activeby Lealone Database Group (zhh) · since 2013 · also known as Lealone Database, Lealone Agent
Chinese Java OLTP database derived from H2, now repositioned as an AI agent platform built on its SQL engine.
Overview
Lealone is an open-source Java database started in 2012-2013 by a Chinese developer (zhh), originally forked from H2 and rebuilt around an asynchronous, thread-scheduled architecture for high-concurrency OLTP. It offers SQL with MVCC transactions, embedded and client-server modes, replication and sharding, an ORM, and 'services' declared in SQL that are exposed over HTTP; first-party plugins speak the MySQL, PostgreSQL and MongoDB wire protocols. Since 2025-26 the project describes itself as a 'self-evolving general AI agent': the 8.0 line adds an agent console that calls LLMs (Doubao, DeepSeek) to generate applications, while commits still mostly touch the storage and transaction engine. The last stable release is 6.0.1 (2024) and 8.0.0-beta1 was tagged in February 2026.
Strengths & trade-offs
Strengths
- +Asynchronous, scheduler-based engine aimed at very high OLTP concurrency
- +Runs embedded in a JVM or as a server, with replication and sharding
- +First-party plugins for MySQL, PostgreSQL and MongoDB protocols
- +Business services can be declared in SQL and served over HTTP
Trade-offs
- −SSPL licensing restricts offering it as a service
- −Documentation and community are almost entirely Chinese-language
- −Shifting focus toward LLM agents makes the roadmap hard to predict
- −Few public production references
Great for
- +Embedded or standalone OLTP in Java applications
- +Experimenting with SQL-defined services and LLM-generated apps
- +Learning a modern rework of the H2 codebase
Think twice for
- −Teams needing English documentation and commercial support
- −Vendors planning to resell it as a managed service (SSPL)
Capabilities
Native or official first-party support · 7 of 25 tracked
Scale & consistency
- Comfortable data size
- Medium · ≤ 10 TB
- Horizontal scaling
- Native
- Multi-region
- No
- Transactions
- Full ACID
- Consistency
- Strong
- Schema
- Strict
- Architecture
- Embedded, Client server, Distributed
- Query languages
- SQL
Supports replication and sharding; production references outside China are scarce.
Deployment
Ecosystem
Alternatives to Lealone
Fast pure-Java SQL engine for embedded, in-memory and test databases, with compatibility modes.
lealone vs h2 →Long-running pure-Java SQL database with strong SQL:2023 coverage, used embedded and in LibreOffice.
lealone vs hsqldb →Pure-Java embedded SQL database from the Cloudscape lineage, retired by Apache in 2025.
lealone vs apache-derby →MySQL-compatible distributed SQL with a row store for OLTP and a columnar replica for real-time analytics.
lealone vs tidb →Postgres-wire distributed SQL built to survive node, zone and region failures with serializable transactions.
lealone vs cockroachdb →Desktop database and forms builder bundled with Microsoft 365; still everywhere in back offices.
lealone vs microsoft-access →Lealone FAQ
What is Lealone?
Lealone is a relational database by Lealone Database Group (zhh), first released in 2013. Lealone is an open-source Java database started in 2012-2013 by a Chinese developer (zhh), originally forked from H2 and rebuilt around an asynchronous, thread-scheduled architecture for high-concurrency OLTP. It offers SQL with MVCC transactions, embedded and client-server modes, replication and sharding, an ORM, and 'services' declared in SQL that are exposed over HTTP; first-party plugins speak the MySQL, PostgreSQL and MongoDB wire protocols. Since 2025-26 the project describes itself as a 'self-evolving general AI agent': the 8.0 line adds an agent console that calls LLMs (Doubao, DeepSeek) to generate applications, while commits still mostly touch the storage and transaction engine. The last stable release is 6.0.1 (2024) and 8.0.0-beta1 was tagged in February 2026.
Is Lealone open source?
Not in the OSI sense. Lealone is source-available: you can read the code, but the license restricts some uses, typically offering it as a competing managed service. License: Server Side Public License v1 (H2-derived files under the H2 license).
Does Lealone support ACID transactions?
Yes. Lealone supports full ACID transactions, with strong consistency.
Does Lealone scale horizontally?
Lealone scales horizontally out of the box, with built-in sharding or partitioning. It is comfortable at medium scale (≤ 10 TB).
How can I run Lealone?
You can self-host it and embed it in your application.
What is Lealone best for?
Lealone is a strong fit for embedded or standalone OLTP in Java applications; experimenting with SQL-defined services and LLM-generated apps; and learning a modern rework of the H2 codebase. Think twice for teams needing English documentation and commercial support.
What are the best alternatives to Lealone?
Common alternatives to Lealone include H2 Database, HyperSQL (HSQLDB), Apache Derby, TiDB and CockroachDB. The right choice depends on your workload, scale and hosting; WhichDB's smart match ranks them against your requirements.
How popular is Lealone?
Lealone ranks #458 of 844 databases on the WhichDB Score (2.8/100), and #142 among relational databases. The score combines public adoption signals such as package downloads, GitHub activity, job posts and developer discussion.