Prisma ORM, PgBouncer, Supabase stack - what is causing these database connection timeouts on production?

Question

I'm working with a tech stack of Prisma ORM and Postgres on Supabase with PgBouncer enabled. We're also using Google Cloud Run to deploy our Node/Express API.

When looking through logs for production, you will see occurances of the same errors being raised again and again. One such example looks like:

Timed out fetching a new connection from the connection pool. More info: http://pris.ly/d/connection-pool (Current connection pool timeout: 10, connection limit: 1)

I've read up on this page: https://www.prisma.io/docs/concepts/components/prisma-client/working-with-prismaclient/connection-pool.

The timeout of 10 seconds is the Prisma connection pool default and the connection limit of 1 is set via the query parameter of the connection string I use, postgresql://[USER]:[PASSWORD]@localhost:[PORT]/[NAME]?pgbouncer=true&connection_limit=1, given from the docs also: https://www.prisma.io/docs/guides/performance-and-optimization/connection-management/configure-pg-bouncer.

This was done because we thought multiple instances of our API containers would hog the connections to PgBouncer.

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My question is:

1. Have I set up PgBouncer correctly, and if not, how can I look into setting it up properly?
2. As I'm trying to use PgBouncer, does that make my messing around with the connection_limit query parameter pointless? Should I just get rid of that?
3. How can I stop these timeouts from occurring?

What I've tried:

• Removing the connection_limit - this seemed to have little to no effect.
• Reviewing Supabase -> Database -> Roles for connections - of the 60 max connections I see pgbouncer in the list with connections - so I assume this means pgbouncer is working?
• Looking through pg_stat_activity - I'm seeing 2 different client addresses across multiple processes, almost all idle (I assume because pgbouncer is managing them?)
• I'm thinking of increasing the pool timeout from the default of 10, but I don't really want to do that.

Answer 1

1 & 2: Looking at the Prisma docs, you should not be using connection_limit=1 since you're using an external connection pooler, i.e. PgBouncer. Have you tried increasing the connection_limit beyond the Prisma default?

3: There are also some troubleshooting steps here related to the timeout error.