MariaDB vs MySQL: differences

If you have ever installed a MySQL server on Linux, you have probably run into MariaDB: many distributions and tutorials install one in place of the other, and the mysql and mysqldump commands work on both. That makes them look like the same thing.

They aren't. MariaDB started as a fork of MySQL and, with each release, gained features that MySQL doesn't have (and the other way around). In a simple app you won't notice; once you rely on JSON, replication or authentication, the differences show.

What are MySQL and MariaDB?#

MySQL is a relational database maintained by Oracle. Its default storage engine is InnoDB, with ACID transactions and row-level locking. It has two release tracks: LTS, which only receives fixes, and Innovation, which brings new features. The support dates for each series are in Oracle's end-of-life policy. See what MySQL is.

MariaDB is a fork of MySQL maintained by the MariaDB Foundation and the MariaDB company. It ships LTS releases regularly, each with a few years of community support, and releases that are not LTS get short support. The MariaDB maintenance policy shows which series are supported.

Watch the version numbers: a higher number on MariaDB does not make it "newer" than MySQL, nor does it make the two versions equivalent. The two stopped following the same numbering years ago, and that is part of the divergence.

Why do they look so much alike?#

Because they share an origin. The client protocol, most of the SQL syntax, the utilities (mysql, mysqldump) and the most common drivers work on both. An app that only uses SELECT, INSERT, indexes and simple transactions usually runs on either one without changing a line.

The MariaDB documentation itself says versions 10.0 and 10.1 were only limited drop-in replacements for MySQL 5.6 and notes implementation differences. The more advanced features you use, the lower the compatibility.

What has changed between them?#

Three of these points need more detail.

How does each one handle JSON?#

In MySQL, a JSON column stores the document in an internal binary format, validates the input and lets you look up keys without rereading the whole document. Invalid input fails with an error:

INSERT INTO events (data) VALUES ('[1, 2,');
-- ERROR 3140 (22032): Invalid JSON text: ...

In MariaDB, JSON is just an alias for LONGTEXT COLLATE utf8mb4_bin, created for compatibility. The value is stored as text, unchanged, and validation comes from a CHECK constraint added automatically. The JSON_EXTRACT, JSON_VALUE and similar functions exist in both, but storage and comparison are not identical, and the MariaDB documentation itself warns that it doesn't support MySQL 5.7's packed JSON objects. If you move JSON columns between the two, test your queries and indexes.

What does MariaDB have that MySQL doesn't?#

Two things anyone coming from PostgreSQL or Oracle will recognize. The first is INSERT ... RETURNING, which returns the written rows in the same query:

INSERT INTO users (name) VALUES ('Ana') RETURNING id, name;

In MySQL, you run the INSERT and then read LAST_INSERT_ID() or run a SELECT. The second is the sequence, a number generator independent of any table:

CREATE SEQUENCE orders_seq START WITH 100 INCREMENT BY 10;
SELECT NEXTVAL(orders_seq);

CREATE TABLE orders (
  id INT PRIMARY KEY DEFAULT NEXTVAL(orders_seq),
  total DECIMAL(10,2)
);

MariaDB also has a VECTOR(N) type for similarity search, available since 11.7. MySQL has its own VECTOR type, but check your edition's documentation for which distance functions and indexes it includes before porting embedding code.

What about replication?#

Here the incompatibility is explicit. According to MariaDB's compatibility page, its GTID is not compatible with MySQL's (a MySQL 5.6 server can't act as a replica of a MariaDB 10.0 server) and the system variables are different. The same page says MySQL's Group Replication is incompatible with MariaDB's Galera Cluster. If you plan a multi-node cluster or read replicas, pick the engine first and build replication with its own tools.

Can you swap one for the other?#

Yes, carefully. Migration is usually simpler when the app only uses standard SQL. The things that break most often are JSON columns, user accounts with sha256_password authentication, performance_schema and sys, replication and views created by old versions. After starting MariaDB on top of a MySQL data directory, you still need to run mysql_upgrade (called mariadb-upgrade in recent versions) to update the system tables.

A safe plan: export with mysqldump, restore on a test server running the other engine, run your test suite and compare query plans with EXPLAIN. See also how to back up a database.

Which one should you choose?#

Choose MySQL if your stack already requires it, if your software's documentation (CMS, ERP, framework) lists MySQL first or if you want Oracle's LTS track.

Choose MariaDB if you want RETURNING, sequences, Galera or MariaDB's VECTOR, or if your Linux distribution already installs it by default.

Popular software accepts both. WordPress, for example, recommends supported LTS versions of both. In that case, pick whichever your provider offers and stay on a supported version.

Either way, choose a supported LTS series: a version past its end of support no longer gets security fixes. If your question is broader (relational or NoSQL, PostgreSQL or MySQL), see which database to choose and PostgreSQL vs MySQL.

How to do this on Square Cloud#

Square Cloud offers MongoDB, PostgreSQL, MySQL and Redis hosting starting on the Standard plan; the Hobby plan doesn't include database hosting. Of the two engines compared here, MySQL is the one available, always on a recent version.

You create the database in the dashboard, and it is provisioned in seconds in the same datacenter as your applications (about 1 ms average latency). TLS is mandatory, with the certificate downloaded from the dashboard. You take manual snapshots whenever you want, and every plan that includes databases also has a daily automatic snapshot.

You connect your application with the connection URL the dashboard gives you. If your app only uses plain SQL, it runs on the hosted MySQL without changes. If it depends on RETURNING or sequences, adjust the code first, because MySQL doesn't have them. Galera is out too: the database is a single node. See the MySQL hosting page.