Step-by-Step Guide to Migrating from PostgreSQL 11 to 15 Using pg_upgrade

Step-by-Step Guide to Migrating from PostgreSQL 11 to 15 Using pg_upgrade

To use pg_upgrade for migrating from PostgreSQL 11 to PostgreSQL 15, follow these steps:

  1. Install PostgreSQL 15: Install the new PostgreSQL version alongside the old one without removing PostgreSQL 11.

  2. Prepare the Environment:

    • Stop the PostgreSQL 11 server.
    • Ensure both versions have the same locale and encoding settings.

  3. Run pg_upgrade:

    • Use the pg_upgrade tool provided with PostgreSQL 15.
    • Run it as the same user owning the database processes.
    • Specify the old and new data directories and server binaries.

  4. Example Command:

    pg_upgrade \\\\
  --old-datadir=/var/lib/pgsql/11/data \\\\
  --new-datadir=/var/lib/pgsql/15/data \\\\
  --old-bindir=/usr/lib/postgresql/11/bin \\\\
  --new-bindir=/usr/lib/postgresql/15/bin

  5. Post-Upgrade Steps:

    • Start the PostgreSQL 15 server.
    • Run ANALYZE to update statistics.
    • Check for any deprecated features or compatibility issues.

  6. Testing:

    • Test your applications against the new server.
    • Monitor for performance and stability.

Make sure to backup your data before starting the upgrade process. Additionally, testing the upgrade in a non-production environment first is highly recommended.