How to Migrate MySQL to PostgreSQL: A Step-by-Step Guide

Switching databases is no small task. But more teams are now moving from MySQL to PostgreSQL—and for good reasons. PostgreSQL offers more advanced features, better compliance, and strong support for complex data types.

If you’re exploring PostgreSQL migration consulting, you’re already on the right track. This guide walks through each step of the migration process, breaking down the journey into simple, actionable tasks.

We’ll also touch on performance tuning, schema conversion, and some tips competitors don’t always cover. Whether you’re just getting started or in the thick of migration, this guide will help.

What is MySQL?

MySQL is a widely used open-source relational database management system (RDBMS). It’s known for being lightweight, easy to use, and compatible with most applications.
It’s been around for decades and is often the default choice for web applications, especially in LAMP stacks (Linux, Apache, MySQL, PHP).

Advantages of Using MySQL

• Easy to set up and configure
• Great community support
• Works well for read-heavy workloads
• Integrated with many popular tools and CMS platforms

Disadvantages of MySQL

• Limited support for complex queries and data types
• Fewer advanced features like full ACID compliance
• Not as extensible as PostgreSQL
• Can struggle with large-scale data analytics

What is PostgreSQL(Postgres) ?

PostgreSQL is an open-source RDBMS known for its advanced features, strict compliance with SQL standards, and powerful performance capabilities.
It’s ideal for high-volume applications and those that require custom data types, stored procedures, or extensive indexing.

Advantages of Using PostgreSQL

• Full ACID compliance for reliable transactions
• Supports advanced indexing and full-text search
• Works with complex data types like JSON, arrays, and hstore
• Highly extensible with custom functions and extensions

Disadvantages of PostgreSQL

• Steeper learning curve for new users
• Slightly heavier setup and configuration
• Not always the best choice for lightweight, simple apps

Why Migrate from MySQL to PostgreSQL?

There are several reasons teams look to PostgreSQL migration consulting when making the switch:

• Better support for modern data types and functions
• Improved data integrity and consistency
• Easier to scale in cloud-native environments
• Enhanced performance for analytical workloads

In short, if your app or system is growing in complexity, PostgreSQL gives you more room to grow.

Data Migration vs. Data Replication

These terms are often confused, but they mean different things:

• Data migration is a one-time process where you move data from one system (MySQL) to another (PostgreSQL).
• Data replication means keeping both databases in sync continuously, often used during live cutovers or hybrid deployments.

In most projects, data migration is done first. Replication may be used temporarily during the transition for zero-downtime switchovers.

Why Migrate to PostgreSQL?

Before jumping in, it’s worth understanding why businesses are making the switch:

• PostgreSQL is open source with strong community support.
• It supports advanced SQL compliance, like full joins and window functions.
• You get better handling of JSON, arrays, and custom data types.
• It’s highly extensible-perfect for growing needs.

For developers working on complex apps or analytics, PostgreSQL often outshines MySQL.

Step 1: Assess Your Current Environment

The first step in any successful migration is discovery. What are you working with?

Start by asking:

• What MySQL version are we using?
• How many schemas, tables, and stored procedures exist?
• Do we use any MySQL-specific features?

This helps you understand the level of effort needed. If you’re also considering SQL Server migration consulting, the same prep applies.

Step 2: Choose the Right Tools

Migration tools save time and reduce errors. Some popular ones include:

• pgloader: Automates schema and data migration.
• AWS Schema Conversion Tool: Great for cloud-native migrations.
• Ora2Pg: Works well for advanced transformations.
• DBConvert: User-friendly with GUI for non-coders.

Choose the tool that matches your technical comfort level and project complexity.

Step 3: Convert the Schema

This is where things get a little technical. MySQL and PostgreSQL use different data types and functions.

For example:

• TINYINT in MySQL should become SMALLINT in PostgreSQL.
• AUTO_INCREMENT changes to SERIAL or GENERATED.

Use tools like pgloader or AWS SCT to automate this. But always review the results manually. Sometimes functions or triggers won’t convert correctly and need rewriting.

If you’re working with PostgreSQL migration consulting experts, this step usually gets the most attention due to its impact on performance and compatibility.

Step 4: Migrate the Data

Once your schema is ready, it’s time to move the actual data.

Here’s how to do it smoothly:

• Dump your MySQL data using mysqldump or mydumper.
• Load it into PostgreSQL using pgloader or psql.
• Use transactional imports for large tables to avoid partial loads.

Always test a sample set first before running full migrations. This minimizes risks and lets you validate integrity.

Step 5: Test Everything

Testing isn’t just a checklist. It’s a critical stage that ensures your new PostgreSQL setup is production-ready.

Focus on:

• Data integrity (no missing records)
• Query performance (especially joins and aggregates)
• Application functionality (does everything still work?)

Test both functional and performance aspects. Run typical workflows and edge cases. If something feels off, this is the time to catch it.

Step 6: Update Your Application Code

Your app likely has SQL queries hardcoded. These may behave differently in PostgreSQL.

Look for:

• SQL syntax differences (like string concatenation or LIMIT clauses)
• Use of MySQL-specific functions (NOW(), IFNULL())
• ORM or database driver configurations

PostgreSQL is more strict about standards. It won’t silently ignore errors, which can be a good thing once you adjust your code.

Step 7: Go Live with Confidence

When everything tests clean, you’re ready to switch.

Plan a smooth cutover:

• Schedule during low-traffic hours.
• Take full backups before go-live.
• Monitor logs and performance after switchover.

Have a rollback plan ready—just in case. It’s unlikely you’ll need it, but being prepared keeps the pressure low.

Common Challenges (And How to Beat Them)

Here are a few bumps you might hit – and how to handle them:

• Character set issues: MySQL might store text differently. Use UTF-8 in both systems to avoid conversion bugs.
• Stored procedures: PostgreSQL uses PL/pgSQL, which differs from MySQL’s syntax. You may need to rewrite them.
• Timezone inconsistencies: PostgreSQL handles time zones more strictly. Always set a standard timezone for your app.

These challenges are why many businesses turn to PostgreSQL migration consulting for hands-on help. A smooth migration requires attention to these details.

Bonus Tip: Optimize After Migration

Don’t stop at “it works.”

After going live:

• Add indexes to speed up queries.
• Use EXPLAIN ANALYZE to find slow operations.
• Monitor with tools like pgAdmin or DataDog.

Also, clean up unused tables or outdated structures during the transition. It’s the perfect time to declutter.

Read Also – PostgreSQL: 6 Reasons Why You Should Use & When To Use? 

Conclusion

Migrating from MySQL to PostgreSQL can feel overwhelming—but it doesn’t have to be. With the right steps, tools, and mindset, you can transition smoothly and unlock the power of PostgreSQL.

If you’re ready for a secure, scalable, and smart migration, we’re here to help. At.ralantech.com, we offer expert PostgreSQL migration consulting services that take the guesswork out of the process and ensure a high-performance future for your business.

FAQs

1. What is the best way to migrate a Postgres database?
The best way to migrate a PostgreSQL database is by using tools like pgdump and pg_restore for full exports and imports. For minimal downtime, replication-based tools like pglogical or third-party services can also be used. It depends on your data size, business needs, and downtime tolerance.

2. How do I move a PostgreSQL database to another computer?
You can move a PostgreSQL database by creating a dump file with pgdump, transferring it to the new machine, and then restoring it using pg_restore. Make sure both systems are running compatible PostgreSQL versions and test the connection configurations post-transfer.

3. What is Postgres vacuuming?
Vacuuming in PostgreSQL is the process of cleaning up outdated rows left behind after updates and deletes. It helps reclaim storage and keep query performance strong. PostgreSQL supports both manual and automatic vacuuming through the VACUUM and auto vacuum processes.

4. How many types of migration are there in SQL Server?
There are mainly three types: in-place migration, side-by-side migration, and cloud migration. Each type varies in complexity and downtime based on how the data and services are transferred to the target environment.

5. What are the 3 types of replication in SQL Server?
The three types are:

• Snapshot replication – Takes a point-in-time snapshot of data.
• Transactional replication – Syncs changes in near real-time.
• Merge replication – Allows data to be updated at both source and target, ideal for distributed systems.