Direct comparison
MySQL vs PostgreSQL for Research Data
MySQL vs PostgreSQL: both are ACID with MVCC, but default isolation, licensing and native data types differ. Sourced table for research databases.
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How do MySQL, PostgreSQL compare side by side?
The table below compares MySQL, PostgreSQL across 9 procurement-relevant dimensions, from licence through source.
Side-by-side comparison
| Dimension | MySQL | PostgreSQL |
|---|---|---|
| Licence | Dual licensed: open source under the GNU GPL, or a standard commercial licence from Oracle. MySQL is a trademark of Oracle Corporation. | Free and open source, described as highly extensible: you can define your own data types, custom functions and code in other languages. |
| ACID transactions by default | Yes. InnoDB is the default storage engine in MySQL 8.4, and its DML operations follow the ACID model with commit, rollback and crash recovery. | Yes. PostgreSQL states it has been ACID-compliant since 2001. |
| Concurrency control | InnoDB uses row-level locking; its feature table lists MVCC (multi-version concurrency control) as supported. | Multi-Version Concurrency Control (MVCC) is listed among its core features. |
| Default isolation level | REPEATABLE READ (InnoDB). | READ COMMITTED. |
| Isolation levels offered | All four SQL:1992 levels. | Four can be requested, but only three are distinct internally: READ UNCOMMITTED behaves like READ COMMITTED. |
| Strictest level (SERIALIZABLE) | Offered as one of the four SQL:1992 isolation levels. | Implemented as Serializable Snapshot Isolation. |
| Release documented here | MySQL 8.4 reference manual. | PostgreSQL 18 (released September 2025) conforms to at least 170 of the 177 mandatory SQL:2023 Core features; the project states no relational database meets full conformance. |
| When to pick it | Your institution already runs MySQL, or Oracle's dual-licence terms are acceptable. The repeatable-read default means you should state the isolation level explicitly in analysis scripts so results do not depend on it. | You want array, range, UUID or JSONB columns, a single open-source licence, or the closest documented SQL:2023 conformance. Because READ COMMITTED is the default, request REPEATABLE READ or SERIALIZABLE explicitly when an analysis needs a consistent snapshot. |
| Source | MySQL 8.4 Reference Manual: dev.mysql.com/doc/refman/8.4/en/introduction.html, innodb-introduction.html and innodb-transaction-isolation-levels.html (read 2026-10-29). | postgresql.org/about and postgresql.org/docs/current/transaction-iso.html (read 2026-10-29). |
Common questions
Common questions about MySQL vs PostgreSQL
Is MySQL ACID compliant?
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Yes, with its default storage engine. The MySQL 8.4 manual states that InnoDB is the default storage engine and that its DML operations follow the ACID model, with commit, rollback and crash-recovery capabilities.
Does MySQL support MVCC?
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InnoDB does. The MySQL 8.4 manual's InnoDB feature table lists MVCC as supported, with row-level locking granularity.
Which has the stricter default isolation level?
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MySQL's InnoDB defaults to REPEATABLE READ; PostgreSQL defaults to READ COMMITTED. Both can be set to other levels, so analysis code that depends on a particular level should set it explicitly.
Is PostgreSQL free for institutional use?
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PostgreSQL describes itself as free and open source. MySQL is dual licensed: open source under the GNU GPL, or under a standard commercial licence from Oracle.
Does PostgreSQL support JSON and array columns?
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Yes. The PostgreSQL about page lists Array, Range and Multirange, UUID, JSON/JSONB, XML and key-value (hstore) types, and says users can define their own data types.
How standard is PostgreSQL's SQL?
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As of the version 18 release in September 2025, PostgreSQL states it conforms to at least 170 of the 177 mandatory features for SQL:2023 Core, and notes that no relational database meets full conformance.
