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HSQLDB

hsqldb.org

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Spec score 9.2 #1 of 23 in Sql Databases

What it is

HSQLDB is a Java-based relational database engine for embedded or server use, with both in-memory and disk-based tables. It supports SQL:2023 core features and many optional features, plus lock-based and MVCC transaction models; the engine is fully multithreaded. Listed capabilities include JSON constructor functions, CSV loading and unloading, temporal system-versioned tables, row-level access control, and log-based replica synchronization. It includes a command-line SQL tool and simple GUI query tools. The latest official release listed is version 2.7.4, compatible with JDK 8 and above, and packages include Java 11 module jars as well as Java 8 jars for HSQLDB and SQL Tool. HSQLDB is self-hosted, with high availability, read replicas, and JSON data support listed. Its default combined limit for CACHED tables is 8TB, extendable to 256TB with a connection property; each TEXT table is limited to 256GB, and memory tables depend on available memory. The software is free to use in commercial products when license terms are met; its licenses are based on the new BSD License. The HSQLDB plan is free. A Developer subscription is $100 a year; Premier Corporate is $2,500 a year at the base level. Support options include community channels and paid commercial support.

Spec sheet

What it does
HSQLDB (HyperSQL) is a Java relational database engine supporting transactional in-memory and disk tables in embedded or server deployments.Read 15 Oct 2026 · hsqldb.org
Product
HSQLDB is a Java-based relational database engine with in-memory and disk-based tables, supporting embedded and server modes.Read 7 Oct 2026 · hsqldb.org
Free plan
YesRead 22 Sep 2026 · hsqldb.org
Integrations
The project documents JDBC and ODBC connectivity and integration with OpenOffice.org and LibreOffice.Read 15 Oct 2026 · hsqldb.org
Support
Support options include a help forum, a user mailing list, bug and feature request trackers, paid SupportWare, and professional commercial support.Read 7 Oct 2026 · hsqldb.org
License
HSQLDB source and binaries use permissive BSD-based licenses, with separate terms for legacy Hypersonic SQL code.Read 15 Oct 2026 · hsqldb.org
Founded
2001Read 28 Sep 2026 · hsqldb.org
Maker
HSQLDB is developed and published by The HSQL Development Group, formed in 2001.Read 7 Oct 2026 · hsqldb.org
Backup
The engine supports fast startup and shutdown with incremental backup plus online and offline backups and SQL-script dumps.Read 15 Oct 2026 · hsqldb.org
Capacity
Official limits include disk tables up to 8 TB, text tables up to 256 GB and individual CLOB/BLOB storage up to 64 TB.Read 15 Oct 2026 · hsqldb.org
Concurrency
The engine is multithreaded and offers lock-based, MVCC and hybrid transaction-control models.Read 15 Oct 2026 · hsqldb.org
Data storage limit
The FAQ states the default combined size limit for CACHED tables is 8TB, extendable to 256TB with a connection property; TEXT tables are limited to 256GB each.Read 7 Oct 2026 · hsqldb.org
Deployment protocols
Embedded and client-server operation are supported through HSQL, HTTP and HSQL-BER protocols, each with an SSL option.Read 15 Oct 2026 · hsqldb.org
Developer tooling
The distribution includes SQLTool command-line administration, two GUI database managers, a transfer utility and a test/script utility.Read 15 Oct 2026 · hsqldb.org
Developer tools
The product includes a command-line SQL tool and simple GUI query tools.Read 7 Oct 2026 · hsqldb.org
Distribution
The release package includes Java 11 module jars and Java 8 jars for HSQLDB and SQL Tool.Read 7 Oct 2026 · hsqldb.org
Documentation depth
The project publishes HTML, PDF and text guides, JavaDoc for public classes, utilities documentation, examples, tests and SQL scripts.Read 15 Oct 2026 · hsqldb.org
Extensibility
Applications can define Java stored procedures, Java or SQL triggers, aggregate functions and routines with INOUT parameters and multiple result sets.Read 15 Oct 2026 · hsqldb.org
Installation requirement
Installation consists of downloading and unpacking hsqldb.zip and requires a Java Runtime Environment or JDK.Read 15 Oct 2026 · hsqldb.org
Java compatibility
The latest official release listed is version 2.7.4, which works with JDK 8 and above.Read 7 Oct 2026 · hsqldb.org
Java support
HSQLDB is written entirely in Java; the standard jar targets Java 11+ while an alternative jar supports Java 8+.Read 15 Oct 2026 · hsqldb.org
JDBC API
It provides extensive JDBC support including batch statements, scrollable and updatable ResultSets, metadata, CallableStatement and PreparedStatement.Read 15 Oct 2026 · hsqldb.org
Latest release
The official latest release is version 2.7.4, dated 25 October 2024.Read 15 Oct 2026 · hsqldb.org
Limit: Capterra scale
One Capterra reviewer says the embedded database is not suitable for a large project, and another notes it is unsupported in newer SAP Commerce Cloud versions.Read 15 Oct 2026 · capterra.com
Limit: SourceForge debugging
A critical SourceForge review complained that older error messages did not identify the failing table or column, making debugging laborious.Read 15 Oct 2026 · sourceforge.net
Limit: SourceForge DSV handling
A reviewer reported that an older SqlTool DSV export failed to escape quotes and line breaks, preventing reliable re-import of multiline data.Read 15 Oct 2026 · sourceforge.net
Maker and founding
The HSQL Development Group is the publisher and says it was formed in 2001.Read 15 Oct 2026 · hsqldb.org
Memory requirements
Memory tables are limited by available memory, while CACHED table data and indexes are saved to disk.Read 7 Oct 2026 · hsqldb.org
Notable news
SourceForge listed HSQLDB 2.7.5 release-candidate jars dated May, August and September 2026 while identifying 2.7.4 as the latest stable release.Read 15 Oct 2026 · sourceforge.net
Praise: Capterra integration
Capterra reviewers praise lightweight Java integration through JDBC, portability and multiple storage modes.Read 15 Oct 2026 · capterra.com
Praise: G2 usability
G2 reviewers repeatedly describe HyperSQL as easy to install, simple to use and suitable for small databases.Read 15 Oct 2026 · g2.com
Praise: SourceForge footprint
SourceForge reviewers praise HSQLDB as small, easy to use, lightweight and effective for embedding in Java applications.Read 15 Oct 2026 · sourceforge.net
Project funding
The project says development is funded by SupportWare, HyperXtremeSQL license sales and professional support services.Read 15 Oct 2026 · hsqldb.org
Rating on Capterra
4.3 out of 5 from 3 reviews.Read 15 Oct 2026 · capterra.com
Rating on G2
4.0 out of 5 from 22 reviews.Read 15 Oct 2026 · g2.com
Rating on SourceForge
4.8 out of 5 stars from 68 reviews.Read 15 Oct 2026 · sourceforge.net
Recent features
The site lists JSON constructor functions, CSV load and unload, temporal system-versioned tables, row-level access control, and log-based replica synchronization.Read 7 Oct 2026 · hsqldb.org
Security controls
Security features include passwords, users, roles, GRANT/REVOKE privileges and fine-grained row-level access control.Read 15 Oct 2026 · hsqldb.org
SQL standard
Version 2.7.4 implements SQL:2023 core syntax and many optional features, including ANY_VALUE, LISTAGG and CAST templates.Read 15 Oct 2026 · hsqldb.org
SQL support
The site says HSQLDB supports SQL:2023 core features and an extensive list of optional features.Read 7 Oct 2026 · hsqldb.org
Storage options
Users can choose memory tables, disk CACHED tables or text tables backed by external files such as CSV.Read 15 Oct 2026 · hsqldb.org
Support model
Community support is provided through documentation and a SourceForge forum, while SupportWare subscribers receive priority support and feature consideration.Read 15 Oct 2026 · hsqldb.org
Transactions
The engine supports lock-based and MVCC transaction models and is fully multithreaded.Read 7 Oct 2026 · hsqldb.org
Upgrade warning
Upgrading databases from versions before 2.0 is required before opening them with 2.7, and the upgrade is one-way so the project advises keeping a backup.Read 15 Oct 2026 · hsqldb.org

Plans and prices

Developer subscription $100 a year Annual subscription Priority support · Input into future development Read 22 Sep 2026 · hsqldb.org
Basic Corporate subscription Price not published Less than 50 distributed units Read 22 Sep 2026 · hsqldb.org
Premier Corporate subscription $2,500 a year Base level; annual subscription For large corporations and large-scale use or distribution · Full deployment support · Enhancement requests Read 22 Sep 2026 · hsqldb.org
HSQLDB Free Database software is free to use and distribute under its licenses Read 7 Oct 2026 · hsqldb.org
HSQLDB software Free Free to use and distribute under BSD-based licenses Open-source database engine · embedded or server modes Read 15 Oct 2026 · hsqldb.org
Developer SupportWare $100 a year Annual subscription Individual developer · priority support · input into future development Read 15 Oct 2026 · hsqldb.org
SupportWare Developer subscription $100 a year $100 annually Individual developers; priority questions and a say in future development Read 7 Oct 2026 · hsqldb.org
Basic Corporate SupportWare $500 a year Annual subscription; $500-$1,000 Corporations with limited internal use or fewer than 50 distributed units · priority support and feature input Read 15 Oct 2026 · hsqldb.org
SupportWare Basic Corporate subscription $500 a year $500-$1000 annually Corporations with limited internal use or fewer than 50 distributed units; priority support and input on future development Read 7 Oct 2026 · hsqldb.org
Premier Corporate SupportWare $2,500 a year Annual subscription; base level Large-scale use or distribution · enhancement requests · full deployment support Read 15 Oct 2026 · hsqldb.org
SupportWare Premier Corporate subscription $2,500 a year Base level $2500 annually Large corporations or large-scale use or distribution; deployment support and enhancement requests Read 7 Oct 2026 · hsqldb.org

Every HSQLDB plan and price →

Strong points and limits

Strong points

  • Supports embedded and server operation
  • Includes lock-based and MVCC transaction models
  • Offers JSON, CSV, and temporal table features
  • Free to use under applicable license terms
  • High availability and read replicas are listed

Limits

  • Self-hosted deployment requires an environment to run it
  • CACHED tables default to an 8TB combined limit
  • TEXT tables are limited to 256GB each
  • Premier Corporate starts at $2,500 a year

Who it suits

HSQLDB suits developers and organizations that can run a Java database themselves and need embedded or server modes. Commercial users should review the license terms, and teams needing support can consider the listed subscriptions.

Verdict

HSQLDB provides a broad relational feature set in a self-hosted Java engine, with free use available under its license terms. Buyers should weigh table limits and the cost of paid support or corporate subscriptions against their deployment needs.

Where Specifiction places it

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