PlanetScale Transaction Pool Connection Limit Exceeded

How to fix it

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

1. 1. Keep transactions short

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   1. Break transactions longer than 20 seconds into smaller ones
   2. Commit or roll back in a finally block
   3. Avoid user input or network calls inside a transaction
   Did this fix it? Yes No

2. 2. Tune your connection pool

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   1. Set the pool size gradually (Prisma: connection_limit in the URL)
   2. Reuse one client per process instead of per request
   Did this fix it? Yes No

3. 3. Upgrade cluster size

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   1. Open the database > Cluster configuration
   2. Pick a larger SKU, since the transaction pool limit varies by instance type
   Did this fix it? Yes No

Symptoms

Error: vttablet: rpc error: code = ResourceExhausted desc = transaction pool connection limit exceeded.

Why it happens

• Long-running or never-closed transactions
• Client pool larger than the instance's transaction pool
• Serverless functions opening many connections

This guide also covers

• planetscale transaction pool connection limit exceeded
• planetscale too many connections

The same problem in other apps

All plan limits, paywalls & watermarks guides →

• Supabase Edge Function 546 WORKER_LIMIT Error (Supabase)

Other PlanetScale errors

• 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 Import Fails or Is Slow
• PlanetScale Postgres Extension Not Available
• PlanetScale Unexpected Bill: Storage, Backups and Transfer
• PlanetScale Connection Errors During Outage