Uncaught Exception When Terminating Query by PID – server conn crashed? Error

Hi Neon team,

We are currently implementing a service that allows the frontend to cancel long-running queries by calling an API endpoint that terminates the query using its PostgreSQL PID (via pg_terminate_backend). However, we consistently encounter an uncaught exception from the Neon client when this happens.

❗ Problem
Whenever the query is forcefully terminated using pg_terminate_backend, we receive the following error from the Neon client library:

Uncaught Exception: error: server conn crashed? at bn.parseErrorMessage (C:\Users\xxx\Documents\GitHub\project\node_modules\@neondatabase\serverless\index.js:949:41) at bn.handlePacket (C:\Users\xxx\Documents\GitHub\project\node_modules\@neondatabase\serverless\index.js:917:75) at bn.parse (C:\Users\xxx\Documents\GitHub\project\node_modules\@neondatabase\serverless\index.js:905:36) at S.<anonymous> (C:\Users\xxx\Documents\GitHub\project\node_modules\@neondatabase\serverless\index.js:956:16) at S.emit (C:\Users\xxx\Documents\GitHub\project\node_modules\@neondatabase\serverless\index.js:316:79) at WebSocket.<anonymous> (C:\Users\xxx\Documents\GitHub\project\node_modules\@neondatabase\serverless\index.js:398:19)

Context :
We are using the @neondatabase/serverless package to connect to our Neon PostgreSQL database.

When the frontend decides that a query is no longer needed (e.g. the user navigates away), it sends a request to our backend to terminate the running query.

The backend issues a SELECT pg_terminate_backend() against the database.

Immediately after that, the Neon client throws an uncaught error and crashes the Node.js process.

🛠️ Expected Behavior
We expect the client to gracefully handle the server-side termination of a query (via pg_terminate_backend) and return a structured error, rather than crashing the process.

✅ Reproduction Steps
Start a long-running query via a Node.js backend using @neondatabase/serverless.

From another request (e.g. triggered by the frontend), call pg_terminate_backend() on that query.

Observe the uncaught exception and stack trace in the Node.js server logs.

📦 Environment

@neondatabase/serverless version: 1.0.0

Node.js version: 24.0.0

Platform: Windows 11

Neon DB: Serverless

🙏 Request
It would be great if the Neon client could catch and properly handle this error scenario, ideally exposing a clear error message that the query was terminated, instead of throwing an uncaught exception.

Thanks in advance!

Reproduce the long-running query cancellation using @neondatabase/serverless and SELECT pg_terminate_backend(), then inspect the failure path reported in node_modules/@neondatabase/serverless/index.js. Verify how the client handles the terminated connection and confirm that the process no longer receives an uncaught exception and exposes a structured termination error.