Most websites that store data use either MySQL or PostgreSQL. Between them, these two open-source relational databases power a staggering proportion of the web — from billion-user social platforms to simple WordPress blogs. They’re both mature, both free, both excellent. And yet they make meaningfully different choices about how a relational database should work.

For many hosting decisions, the database question barely registers — you’re on shared hosting, cPanel gives you MySQL, and that’s that. But as sites grow, as developers take more control over their stack, and as applications become more complex, the MySQL vs. PostgreSQL choice becomes increasingly consequential. Picking the wrong one for your use case creates friction; picking the right one makes hard problems easier.

This guide explains both databases honestly — where each genuinely excels, where each falls short, how hosting availability differs between them, and which choice fits which situation. No tribal allegiances, no database-wars posturing. Just the practical information you need to make a good decision.

1. What Each Database Is

MySQL

MySQL was created in 1995 and acquired by Sun Microsystems in 2008, then Oracle in 2010. It’s the “M” in the LAMP stack (Linux, Apache, MySQL, PHP) — the database that shared hosting was built around. MySQL prioritizes speed, simplicity, and broad compatibility over strict standards adherence. It’s the most widely deployed open-source database in the world, powering WordPress, Drupal, Joomla, Magento, and virtually every PHP application ever written.

A notable fork: MariaDB was created in 2009 by MySQL’s original developers after Oracle’s acquisition, as a drop-in replacement for MySQL. It’s now used by many hosting providers instead of — or alongside — MySQL proper. For most web applications, MySQL and MariaDB are interchangeable; MariaDB has some additional features and is developed more openly. When this guide says “MySQL,” the same generally applies to MariaDB.

PostgreSQL

PostgreSQL (often called Postgres) has a longer history — it evolved from a UC Berkeley research project starting in 1986, with the first open-source release in 1996. Where MySQL prioritizes ease and speed, PostgreSQL prioritizes correctness, standards compliance, and feature completeness. It’s the choice of developers who want a database that does exactly what the SQL standard says it should, with no shortcuts and no surprises.

PostgreSQL has been steadily gaining ground in recent years — it’s been ranked the most admired and desired database in Stack Overflow’s developer survey for multiple years running, and its adoption in modern application development has accelerated significantly as developers build more complex data models and need advanced features that MySQL historically lacked.

2. How They Actually Differ

Beyond the marketing narratives, MySQL and PostgreSQL make genuinely different technical choices. Here’s what those differences mean in practice.

The ACID Compliance Question

ACID stands for Atomicity, Consistency, Isolation, Durability — the properties that guarantee database transactions are processed reliably. Both databases support ACID-compliant transactions with their default storage configurations. MySQL’s InnoDB engine (the default since MySQL 5.5) is fully ACID-compliant. PostgreSQL has been fully ACID-compliant from the beginning — it was designed that way at the architectural level rather than retrofitted.

Object-Relational vs. Purely Relational

MySQL is a relational database. PostgreSQL is an object-relational database — it supports custom data types, table inheritance, function overloading, and other object-oriented concepts that pure relational databases don’t have. For most web applications this distinction is invisible. For complex data modeling, PostgreSQL’s extensibility is a genuine advantage.

Write Behavior Differences

One historical difference that tripped up many developers: MySQL (in older configurations) would silently truncate data that didn’t fit its column type, or substitute default values, rather than returning an error. PostgreSQL rejects data that violates constraints, returning an error instead. This makes PostgreSQL more predictable and safer from data integrity problems, but it means code written loosely for MySQL may fail on PostgreSQL until the edge cases are handled. Modern MySQL with strict mode enabled closes much of this gap.

3. Performance Compared

Performance comparisons between MySQL and PostgreSQL are contentious because the answer genuinely depends on the workload. There is no universal winner.

Read-Heavy Workloads (Blogs, Cached Websites)

MySQL has traditionally been faster for simple, high-volume read operations — particularly when queries are straightforward SELECT statements against well-indexed tables with caching enabled. This is the workload that most shared hosting sites run, and it’s why MySQL became the dominant hosting database. The simplicity of the InnoDB engine’s read path, combined with MySQL’s query cache (in older versions) and external caching tools like Redis, gives it an edge here.

Complex Query Performance

PostgreSQL’s query planner is more sophisticated than MySQL’s. For complex queries — multiple JOINs, subqueries, window functions, aggregations across large datasets — PostgreSQL frequently produces better query plans and runs faster. This matters for analytics-style queries, reporting applications, and anything that requires the database to do heavy computation rather than simple lookups.

Write-Heavy and Concurrent Workloads

PostgreSQL’s MVCC implementation handles high-concurrency write scenarios well, particularly when multiple processes are simultaneously reading and writing different rows. MySQL’s InnoDB handles this competently too, but PostgreSQL’s approach to locking tends to cause fewer bottlenecks in write-intensive applications. For applications like real-time collaborative tools, transaction processing systems, or multi-tenant SaaS applications with many concurrent writes, PostgreSQL’s concurrency model often produces better results.

Indexing Capabilities

PostgreSQL has a more extensive indexing toolkit: B-tree (standard), GiST (for geometric data, full-text search, range queries), GIN (for full-text search, JSONB, array containment), BRIN (for large tables with natural sort order), and SP-GiST. MySQL supports B-tree and full-text indexes. PostgreSQL’s additional index types unlock performance optimizations for specific data patterns that MySQL simply can’t match.

4. SQL Compliance and Advanced Features

SQL Standards Compliance

PostgreSQL is the closest any open-source database comes to full SQL standard compliance. It supports Common Table Expressions (CTEs), window functions, lateral joins, range types, and numerous other SQL standard features that MySQL added late or implemented differently. Developers who know SQL deeply tend to prefer PostgreSQL because it behaves the way the standard says it should.

MySQL has improved significantly in recent versions — MySQL 8.0 added window functions, CTEs, and many other long-missing features. But there are still behaviors where MySQL diverges from the SQL standard in ways that can cause subtle bugs, particularly around NULL handling, GROUP BY behavior, and string comparison defaults.

Stored Procedures and Functions

Both databases support stored procedures and user-defined functions. PostgreSQL goes further — it supports writing stored procedures in multiple languages including PL/pgSQL (its native procedural language), Python, Perl, Tcl, and others via extensions. This flexibility makes PostgreSQL a more capable platform for complex server-side logic.

Full-Text Search

Both have built-in full-text search. PostgreSQL’s full-text search is more powerful — it supports multiple languages with proper stemming, ranking, phrase search, and proximity operators, all through native GIN/GiST indexes. MySQL’s full-text search is functional but less sophisticated. For applications needing serious full-text search, Elasticsearch or similar dedicated tools are often used with both databases — but if you need FTS without a separate service, PostgreSQL is the better native choice.

-- Rank products by revenue within each category
SELECT
  product_name,
  category,
  revenue,
  RANK() OVER (PARTITION BY category ORDER BY revenue DESC) AS rank
FROM products;

-- Running total of orders per day
SELECT
  order_date,
  daily_total,
  SUM(daily_total) OVER (ORDER BY order_date) AS running_total
FROM daily_sales;

5. Data Types and JSON Support

PostgreSQL’s Native Data Types

PostgreSQL ships with an impressive array of native data types that MySQL lacks or handles differently:

• Arrays — store multiple values in a single column natively. Query them with array operators and indexes.
• Range types — daterange, tsrange, numrange — store a range of values and query for overlap, containment, and adjacency.
• Network address types — inet, cidr, macaddr — store IP addresses and network ranges with native operators for containment queries.
• UUID — native UUID type with dedicated functions.
• Geometric types — points, lines, circles, polygons — with geometric operators for proximity and containment queries.
• Enumerated types — CREATE TYPE mood AS ENUM (‘sad’, ‘ok’, ‘happy’) — enforced at the database level.
• Composite types — create custom data types that group multiple fields.

JSON and JSONB: PostgreSQL’s Major Advantage

Both databases support JSON columns, but PostgreSQL’s implementation is dramatically more capable. PostgreSQL offers two JSON storage types:

• JSON — stores JSON as text, preserving whitespace and key order, validating structure on insert.
• JSONB — stores JSON in a decomposed binary format that is indexable, queryable with operators, and significantly faster to process for complex queries.

-- Create a table with JSONB column
CREATE TABLE users (
  id SERIAL PRIMARY KEY,
  profile JSONB
);

-- Create a GIN index on the JSONB column for fast queries
CREATE INDEX idx_profile ON users USING GIN (profile);

-- Query JSONB fields directly with operators
SELECT * FROM users
WHERE profile @> '{"subscription": "pro"}';

-- Extract nested values
SELECT profile->>'name', profile->'address'->>'city'
FROM users;

MySQL’s JSON support allows storage and basic querying of JSON data, but it lacks the JSONB binary format, the GIN indexing capability, and the richness of PostgreSQL’s JSON operators. For applications that treat JSON as a first-class data format — storing semi-structured data, API responses, configuration objects — PostgreSQL’s JSONB is one of its strongest differentiators.

6. Hosting Availability

Shared Hosting

MySQL is available on virtually every shared hosting plan in existence. It’s included by default, managed automatically by the host, and accessible through phpMyAdmin or cPanel’s database management interface. You don’t configure it, you don’t administer it, you just create a database and connect to it.

PostgreSQL on shared hosting is rare. A small number of providers include it — some cPanel installations have a PostgreSQL option, and a handful of hosts specifically offer it — but it’s far from standard. If you need PostgreSQL on shared hosting, you’ll need to verify availability with your specific provider rather than assume it’s there.

VPS and Dedicated Servers

On self-managed servers, you choose what you install. Both MySQL/MariaDB and PostgreSQL install trivially on Ubuntu, Debian, Rocky Linux, and other server distributions. The choice is entirely yours and support from the hosting provider is the same — they provide the server, you manage the software stack.

Managed Database Services

Every major cloud provider offers managed versions of both databases:

7. WordPress and PHP Applications

WordPress Requires MySQL (or MariaDB)

WordPress was built on MySQL, stores everything in MySQL, and its database schema, queries, and behavior are written specifically for MySQL. WordPress does not officially support PostgreSQL. There is a third-party plugin called PG4WP that attempts to bridge the gap, but it’s maintained by a small community, frequently lags behind WordPress core updates, and breaks with many plugins that write MySQL-specific queries. Running WordPress on PostgreSQL is a fringe configuration that creates ongoing maintenance problems.

If you’re running WordPress — or planning to — the database decision is MySQL. MariaDB is the other acceptable option and is what many hosts use under the hood instead of MySQL proper.

Other PHP CMS Platforms

The picture is largely the same across the PHP CMS ecosystem:

• Drupal — officially supports both MySQL and PostgreSQL. PostgreSQL is a valid first-class choice for Drupal installations.
• Joomla — officially supports MySQL/MariaDB and PostgreSQL since Joomla 3.x.
• Magento / Adobe Commerce — MySQL/MariaDB only.
• WooCommerce — inherits WordPress’s MySQL requirement.
• PrestaShop — MySQL/MariaDB only.

PHP Frameworks

Modern PHP frameworks are database-agnostic through their ORM layers:

• Laravel / Eloquent — supports MySQL, MariaDB, PostgreSQL, SQLite, and SQL Server natively.
• Symfony / Doctrine — supports all major databases including PostgreSQL with full feature utilization.
• CodeIgniter — supports multiple databases including PostgreSQL.

For greenfield PHP framework applications (Laravel, Symfony), PostgreSQL is a legitimate and increasingly popular choice — the framework handles the abstraction, and you can leverage PostgreSQL’s superior features.

8. Scaling and Replication

MySQL Replication and Scaling

MySQL has a mature replication ecosystem built around its binary log format. Primary-replica (formerly master-slave) replication is well-understood and widely deployed. Tools like ProxySQL, MaxScale, and Vitess (used by PlanetScale) enable sophisticated read/write splitting, connection pooling, and horizontal sharding at scale. MySQL’s replication has been production-tested at enormous scale — including deployments at companies like Facebook and GitHub that have open-sourced many of their MySQL tooling innovations.

PostgreSQL Replication and Scaling

PostgreSQL has streaming replication for high availability and read scaling, and logical replication for more flexible deployment topologies. The Citus extension (now available as Citus Data, also as Azure Cosmos DB for PostgreSQL) enables horizontal sharding of PostgreSQL across multiple nodes. PostgreSQL’s logical replication is more flexible than MySQL’s for certain use cases — you can replicate specific tables or publications rather than the entire database stream.

Connection Pooling

PostgreSQL’s process-per-connection model means each database connection spawns a new OS process, which is more resource-intensive than MySQL’s thread-per-connection model at very high connection counts. For applications with many concurrent connections, PostgreSQL deployments typically use a connection pooler — PgBouncer is the standard choice. This is a slightly more complex setup than MySQL’s threading model, but PgBouncer is mature and widely deployed.

# /etc/pgbouncer/pgbouncer.ini
[databases]
myapp = host=localhost port=5432 dbname=myapp

[pgbouncer]
listen_port = 6432
pool_mode = transaction     # transaction-level pooling
max_client_conn = 1000
default_pool_size = 20

9. Security Features

Authentication Methods

PostgreSQL supports a wider range of authentication methods natively: password-based (md5, scram-sha-256), peer authentication (OS-level user mapping), LDAP, RADIUS, PAM, GSSAPI (Kerberos), certificate-based, and SSPI. The pg_hba.conf file gives granular control over which authentication method applies to which database, user, and IP address combination. This flexibility makes PostgreSQL easier to integrate into complex enterprise security environments.

MySQL’s authentication is simpler and works well for standard deployments, with support for password authentication, LDAP (in enterprise versions), and socket authentication. The separation between MySQL’s community and enterprise editions means some security features — audit logging, for instance — require MySQL Enterprise, while PostgreSQL includes equivalent capabilities in its open-source version.

Row-Level Security (RLS)

PostgreSQL has native Row-Level Security — the ability to define policies that restrict which rows a given user or role can see and modify, enforced transparently at the database level. This is a powerful feature for multi-tenant applications where different users should only ever see their own data.

-- Enable RLS on the orders table
ALTER TABLE orders ENABLE ROW LEVEL SECURITY;

-- Policy: users can only see their own orders
CREATE POLICY user_isolation ON orders
  USING (user_id = current_setting('app.current_user_id')::int);

-- Now any query on orders automatically filters by user
SELECT * FROM orders; -- only returns this user's orders

MySQL lacks native row-level security — equivalent functionality requires application-level filtering or views with WHERE clauses, which are less robust and easier to bypass through programming errors.

10. Ease of Management

Initial Setup and Configuration

MySQL is straightforward to set up — a few commands, run mysql_secure_installation, create a user and database, connect your application. Its defaults work reasonably well for most web applications without extensive tuning. The learning curve from installation to a working application is gentle.

PostgreSQL requires a bit more understanding upfront — particularly around its role-based authentication system, the difference between database superusers and regular roles, and the pg_hba.conf authentication configuration file. These aren’t difficult concepts, but they’re different enough from MySQL that developers familiar with MySQL will need to read documentation rather than rely on intuition.

Management Tools

Both databases have excellent GUI management tools:

• MySQL: phpMyAdmin (ubiquitous in shared hosting), MySQL Workbench, DBeaver, TablePlus
• PostgreSQL: pgAdmin (the standard GUI, powerful but complex), DBeaver, TablePlus, Postico (Mac), Beekeeper Studio

phpMyAdmin’s ubiquity in shared hosting environments means MySQL users rarely need to install anything — it’s just there. PostgreSQL users on self-managed servers need to install pgAdmin or choose an alternative, which is a minor additional setup step.

Backup and Restore

Both databases have robust backup tooling. MySQL uses mysqldump for logical backups and supports physical backup via tools like Percona XtraBackup. PostgreSQL uses pg_dump and pg_dumpall for logical backups, and supports physical backup via pg_basebackup combined with WAL archiving for point-in-time recovery.

# MySQL — export a single database
mysqldump -u root -p mydb > mydb_backup.sql

# MySQL — restore
mysql -u root -p mydb < mydb_backup.sql

# PostgreSQL — export a single database
pg_dump mydb > mydb_backup.sql

# PostgreSQL — restore (custom format, recommended)
pg_dump -Fc mydb > mydb_backup.dump
pg_restore -d mydb mydb_backup.dump

11. Use Case Verdicts

12. The Decision Framework

Work through these questions in order. Stop as soon as you have a clear answer.

Question 1: Does your application require a specific database?

• Running WordPress, WooCommerce, or Magento → MySQL or MariaDB, decision made
• Running a legacy PHP application built for MySQL → MySQL unless you have time and reason to migrate
• Running an ASP.NET application designed for SQL Server → neither, you need SQL Server or Azure SQL
• Running Django, Rails, Laravel, or another framework app → either is fine, continue to Question 2

Question 2: What does your hosting environment support?

• On shared hosting → MySQL — it’s almost certainly all that’s available
• On a VPS or dedicated server → your choice, both install easily on any Linux distribution
• Using a managed database service (AWS, GCP, DigitalOcean) → both are available, choose based on your application’s needs

Question 3: What does your app need from the database?

• Simple CRUD operations, standard relational data → either works well; default to your team’s familiarity
• Complex queries, window functions, advanced SQL → PostgreSQL — the query planner and SQL compliance give you more to work with
• JSONB storage and querying as a core requirement → PostgreSQL JSONB is significantly better
• Row-level security or complex multi-tenant access control → PostgreSQL’s native RLS is the right tool
• Geographic or spatial data → PostgreSQL with PostGIS is the industry standard
• Full-text search without a separate search service → PostgreSQL’s native FTS is more capable

Question 4: What does your team know?

If your team is experienced with one database and not the other, that familiarity has real value. The operational knowledge — backup procedures, performance tuning, replication setup, query optimization — takes time to build. For a team already proficient in MySQL, the productivity cost of switching to PostgreSQL for a new project should be weighed against the specific feature benefits that PostgreSQL would provide. And vice versa: a team that knows PostgreSQL well shouldn’t use MySQL for a new project just because it’s more widely available.