b6a15dbbe9
DEFAULT(col) was evaluated against the worker's row. Item_default_value is an Item_field whose field is a private copy made by make_default_field(), reading the share's default_values but carrying the column's own table. Its deep_copy() shares that field, and Pwt_field_rebinder, seeing the manager's table, repointed it at the worker's real column. DEFAULT(col) then read the current row's value, and for an expression default calculate() called set_default() and wrote the default into the row -- wrong results in a release build, a marked_for_write assertion in a debug one. It shows only when the expression also names the column some other way; alone, DEFAULT(col) is table-independent and evaluated at optimize time. The gate now refuses any expression holding a DEFAULT(), found with check_func_default_processor, which only Item_default_value answers. Found by running the main suite with --parallel-worker-threads=4, where type_temporal_innodb lost a "Truncated incorrect BOOLEAN value" warning because the worker's WHERE evaluated to NULL. parallel_query_clone covers a lost row, a gained row and the expression default that crashed, and checks that none of them ran in the workers. This commit was prepared with Claude Code (Opus 5.5), which traced the wrong result from a main-suite sweep with workers enabled to the rebinder, wrote the gate refusal and the test, confirmed the test fails without the refusal, and ran the parallel_query tests in normal and --ps-protocol modes.
MariaDB Server
MariaDB Server is one of the most widely deployed open source relational databases. It is built by a global community of contributors together with the MariaDB Foundation and MariaDB plc, and it powers workloads from small applications to large-scale production systems.
MariaDB began as a fork of MySQL, led by the original MySQL developers, and it maintains a high degree of MySQL compatibility. It has since grown into a database with its own capabilities, including native vector search, multiple pluggable storage engines, synchronous clustering, and analytical features, while remaining a straightforward migration target for existing MySQL deployments.
Key features
- Native vector search. A built-in VECTOR data type with approximate nearest-neighbour indexing (HNSW), available since MariaDB 11.8 with no extension required.
- Pluggable storage engines. InnoDB (default for transactional workloads), Aria, MyRocks, ColumnStore for analytics, Spider for sharding, and S3 for archival, among others.
- Replication and clustering. Asynchronous, semi-synchronous, and parallel replication with global transaction IDs, plus Galera synchronous multi-primary clustering.
- Advanced SQL. Common table expressions and recursive CTEs, window functions, system-versioned (temporal) tables, sequences, and a broad set of JSON functions.
- MySQL and Oracle compatibility. Wire-protocol and syntax compatibility with MySQL, plus an Oracle SQL mode supporting PL/SQL-style stored routines.
- Spatial and full-text search. GIS data types and functions, and built-in full-text indexing.
- Security. Role-based access control, pluggable authentication (ed25519, PAM, GSSAPI, and more), data-at-rest encryption, and TLS for connections.
Documentation
- Project home, community, and getting involved
- Reference manual and release notes
- MariaDB compared to MySQL
Releases
MariaDB Server follows a yearly long-term support (LTS) model alongside quarterly rolling releases. Binary LTS releases are maintained for three years and are recommended for production; rolling releases deliver new features sooner with a shorter support window.
For the current version and full history, see Releases and the MariaDB release calendar.
Installing
Packages and installation instructions for all supported platforms are available at https://mariadb.org/download/.
Building from source
To build MariaDB from source and run the test suite, follow the developer guide
It covers building the code correctly, running the MariaDB testing framework, and choosing the right branch to target for contributions.
Contributing
Contributions are welcome, from code and documentation to bug reports and reviews. See CONTRIBUTING.md to get started, and CODING_STANDARDS.md for code style. Contributors and community members are recognised in CREDITS.
Getting help
- Zulip chat
- Maria Discuss mailing list
- Bug reports
- Security vulnerabilities: see SECURITY.md
Licensing
MariaDB Server is licensed under version 2 of the GNU General Public License (GPLv2), without the "any later version" clause. This is inherited from MySQL. License information is in the COPYING file, and third-party license information is in the THIRDPARTY file.
About MariaDB Foundation
MariaDB is brought to you by the MariaDB Foundation and MariaDB plc. The MariaDB Foundation is the custodian of the MariaDB Server codebase, ensuring it stays open and that anyone can contribute. See CREDITS for details on the Foundation and the people developing MariaDB.
MySQL, the base of MariaDB, is a product and trademark of Oracle Corporation, Inc.