prepared statement \"s0\" already exists

Bug description

I’m connecting to Supabase with their connection pooling enabled and I’m seeing the following 500 errors after multiple refreshes of the same page, until eventually it forces me to have to restart my server.

Supabase Connection Pooling

Connection String (Pool Mode = Transaction): postgres://postgres:[YOUR-PASSWORD]@[host].supabase.co:6543/postgres

With Supabase’s connection pooling I still see the 500 error that is shown below.

Prisma PGBouncer

Connection String: "postgresql://postgres:[PASSWORD]@[HOST].supabase.co:5432/postgres?pgbouncer=true"

With Prisma’s PG Bouncer I am still getting the same error after multiple refreshes of the same page. This is very problematic because very quickly I am getting these errors. Even when testing locally.

Error:

"PrismaClientUnknownRequestError: Error occurred during query execution:
ConnectorError(ConnectorError { user_facing_error: None, kind: QueryError(Error { kind: Db, cause: Some(
DbError { severity: \"ERROR\", parsed_severity: Some(Error), code: SqlState(\"42P05\"), 
message: \"prepared statement \\"s0\\" already exists\", detail: None, hint: None, position: None, where_: None, schema: None, table: None, column: None, datatype: None, constraint: None, file: Some(\"prepare.c\"), line: Some(447), routine: Some(\"StorePreparedStatement\") 
}) }) })\n}"

How to reproduce

Expected behavior

Prisma queries should be executed normally when connected to a pgbouncer pool or to supabase’s connection pooling.

Prisma information

"@prisma/client": "^3.5.0",

Environment & setup

• OS: Mac OS 12.0.1
• Database: PostgreSQL 12
• Node.js version: v16.3.0

Prisma Version

3.5.0

[dan-turner]

@woniesong92 I just encountered this same issue and stumbled upon this issue via googling the error

What I’ve found is, if you’ve ever accidentally connected to the without ?pgbouncer=true added to the connection string, you will keep getting this error (even after adding ?pgbouncer=true) until you restart the Supabase project.

TL;RD; Never connect to Supabase without ?pgbouncer=true. If you do by accident, restart the Supabase project.

[janpio]

This problem turned out to ultimately be caused by usage of a pooled connection string (port 6543 at Supabase) without supplying pgbouncer=true. When that was added, the error went away.

But the cause for this is a bit more complicated: @juanzgc has a Next.js app where he is using a .env.local file. When using the Prisma CLI, only the .env file is loaded, and not the .env.local. Hence Juan created a .env with a copy of the database. Then he later messed around with things, and thinking that Prisma would only use .env, only added pgbouncer=true to the connection string there. But his Next.js app on startup loads both .env.local and .env, which meant that Prisma in the end was not using the value from .env but .env.local instead - which was missing the pgbouncer=true. The weird thing now is that if you only have a .env.local file, Prisma still complains about an env var not being set when running queries inside the Next.js app, although that clearly loaded the env var when starting. This is what caused him to be in this weird position where it was easy to get this wrong.