pg-upgrade-internals

To perform a PostgreSQL major version upgrade safely, you must validate cluster compatibility, audit for unsupported extensions, and resolve catalog version conflicts before executing data file relocation. This requires access to the PostgreSQL source tree and cluster control data.

The best way to migrate data files during a PostgreSQL upgrade depends on your needs: evaluate the trade-offs between link, copy, and clone methods to balance speed and safety based on your operational requirements.

PostgreSQL pg_upgrade procedures fail with relfilenumber mismatches due to catalog schema extraction and alignment issues. You must validate compatibility using cluster control data and resolve these upgrade-blocking mismatches before retrying.

Yes, you need access to the PostgreSQL source tree and cluster control data to validate compatibility and resolve upgrade-blocking issues like unlogged tables, extension conflicts, and catalog version mismatches during major version migrations.

No, pg_upgrade will fail if unsupported extensions or unlogged tables exist in your current cluster. You must audit your PostgreSQL cluster and resolve all extension compatibility and catalog version conflicts before starting the major version upgrade.

You should not use the link method for PostgreSQL data file relocation when your operational requirements prioritize data safety over speed, as evaluating trade-offs between link, copy, and clone methods is essential for preventing downtime.