bbolt vs H2 Database Engine

bbolt is a maintained fork of Bolt, providing Go applications with an embedded key-value store instead of a full database server. It keeps the database in one file, representing a consistent snapshot of its data. Key/value pairs are arranged in buckets, which can be nested, and bucket keys are stored in byte-sorted order. The library supports serializable ACID transactions: one read-write transaction at a time, alongside multiple concurrent read-only transactions.

A read-only transaction can create a consistent hot backup without blocking other database reads and writes. bbolt exposes operation statistics that can be logged or sent to a service such as statsd. The project describes it as a fit for read-intensive workloads and range scans, while warning that random writes can be slow. The database file has an exclusive write lock, so multiple processes cannot share it for writing; read-only mode permits multiple readers. The project documents gomobile bindings for iOS and Android, as well as Windows, macOS and Linux support. It is free under the MIT license, with no paid support plan listed.

H2 Database Engine is a free SQL database written in Java. It runs in embedded, server or mixed modes, with databases held on disk or in memory. H2 supports standard SQL and JDBC; server mode also accepts JDBC or ODBC over TCP/IP. A browser-based Console provides autocomplete. Listed database capabilities include transactions, multi-version concurrency and row-level locking, with JSON data support and high availability listed. Compatibility modes cover IBM DB2, Apache Derby, HSQLDB, MS SQL Server, MySQL, Oracle and PostgreSQL. Database files can use AES-128 encryption, while remote JDBC connections can use TLS. H2 is available for Linux, macOS and Windows, as an API, and for self-hosted or web deployment. It is dual licensed under MPL 2.0 or EPL 1.0, allowing integration into and distribution with commercial applications. The JAR is described as around 2.5 MB. The plan costs nothing.