PlanetScale Postgres Import Fails or Is Slow

How to fix it

Try these in order — the most common fix is first.

1. 1. Run the Migration Assessment Tool

   Copy steps
   1. Run the Discovery Tool on your source
   2. Upload the report to the assessment tool and fix flagged blockers
   Did this fix it? Yes No

2. 2. Deploy the schema first

   Copy steps
   1. Create the schema on PlanetScale before data copy
   2. Wait for index recreation and sequence sync (can take hours)
   Did this fix it? Yes No

3. 3. Use DMS for large databases

   Copy steps
   1. Follow the PlanetScale DMS guide
   2. Cut over after replication catches up
   Did this fix it? Yes No

Symptoms

Import stalls, errors on sequences/foreign keys, or large tables copy for days.

Why it happens

• Source on an older Postgres version than 17/18
• Unsupported extension
• Plain logical replication too slow on huge tables

This guide also covers

• planetscale postgres import
• migrate to planetscale postgres

The same problem in other apps

All not loading, error messages & connection guides →

• Supabase Max Client Connections Reached (Supabase)

Other PlanetScale errors

• PlanetScale Transaction Pool Connection Limit Exceeded
• PlanetScale Foreign Key Constraints Not Working
• PlanetScale Safe Migrations: DDL Statement Rejected
• PlanetScale Prisma Connection Errors
• PlanetScale Query Exceeded Row or Time Limit
• PlanetScale Postgres Extension Not Available
• PlanetScale Unexpected Bill: Storage, Backups and Transfer
• PlanetScale Connection Errors During Outage