Effortless PostgreSQL Table Partitioning with pg_rewrite

Partitioning PostgreSQL tables has quickly become one of the most popular methods to scale and improve database performance. However, partitioning existing tables without locking your database is often a major pain point.

That’s where pg_rewrite comes in—a simple, elegant tool that allows you to repartition PostgreSQL tables with minimal locking. In this guide, you’ll learn how to install and use it.

🔧 Installing pg_rewrite

To get started, clone the open-source project from GitHub:

Make sure the correct version of pg_config is in your path:

Then build and install the extension:

PostgreSQL Configuration

Update your postgresql.conf with the following settings:

Restart PostgreSQL and verify the extension is loaded:

Then create the extension:

🧪 Creating a Sample Table

Now let’s create a test table that we’ll later partition:

Confirm the data distribution:

Make sure the table has a primary key:

🗂 Setting Up Partitioned Tables

Create your partitioned structure. For this example, we’ll split values into negative and positive ranges:

☝ Make sure the primary key and constraints match the original table, or the rewrite will fail.

🚀 Partitioning with Minimal Locking

Run the rewrite operation:

• t_number: original table

• t_part_number: new partitioned table

• t_old_number: backup of the original (for rollback, if needed)

Check the resulting structure:

You’ll see:

• t_number (now a partitioned table)

• t_old_number (backup of the original table)

• t_part_number_neg, t_part_number_pos (partition tables)

🎉 Why Use pg_rewrite?

Unlike traditional PostgreSQL partitioning, pg_rewrite minimizes locking by using a rewrite strategy. It’s ideal for large tables and production systems where downtime is unacceptable.

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We also offer ready-to-import OpenStreetMap (OSM) data for PostgreSQL on our new GIS site. These dumps are ideal for large PostGIS workloads and take full advantage of partitioning.

Check out the GIS resource page →

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