Watching for postgres changes always times out

[bringert]

Describe the bug

When subscribing to database changes using supabase-py, I see no events, until after about 10 seconds when I get Channel subscription state: RealtimeSubscribeStates.TIMED_OUT.

To check that it's a python problem and not something else, I tried this js code which works fine:

import { createClient } from '@supabase/supabase-js'

const supabase = createClient(
  process.env.SUPABASE_URL,
  process.env.SUPABASE_SERVICE_ROLE_KEY
)

const channel = supabase
  .channel('schema-db-changes')
  .on(
    'postgres_changes',
    {
      event: '*',
      schema: 'public',
    },
    (payload) => console.log(payload)
  )
  .subscribe()

Reproduction

import asyncio
import supabase
import os


async def watch_db(url, key):
    client = await supabase.acreate_client(url, key)

    def handle_payload(payload):
        print(payload)

    def subscribe_callback(state, error):
        if error:
            print(f"Error subscribing to channel: {error}")
        else:
            print(f"Channel subscription state: {state}")

    channel = client.channel("schema-db-changes")
    channel.on_postgres_changes("*", schema="public", callback=handle_payload)
    await channel.subscribe(subscribe_callback)

    await asyncio.Event().wait()


if __name__ == "__main__":
    asyncio.run(
        watch_db(os.environ["SUPABASE_URL"], os.environ["SUPABASE_SERVICE_ROLE_KEY"])
    )

Steps to reproduce

1. Set env vars SUPABASE_URL and SUPABASE_SERVICE_ROLE_KEY to point to a locally running Supabase instance, mine has supabase/realtime:v2.65.2
2. Install supabase-py 2.24.0 (I also tried with 2.23.2 and got the same result)
3. Run the python code
4. Do some DB insertions

Expected: I first see a SUBCRIBED event and then I see the db events

Observed: I see no events, until after about 10 seconds when I get Channel subscription state: RealtimeSubscribeStates.TIMED_OUT

Library affected

supabase-py

Library version

supabase 2.24.0; supabase/realtime:v2.65.2

Python version

Python 3.13.9; Python 3.14.0 on MacOS Tahoe 26.1

[bringert]

If I switch to using Broadcast instead of Postgres Changes, the subscription works fine, though I still get a spurious RealtimeSubscribeStates.TIMED_OUT state change about 10 seconds after subscribing. After the TIMED_OUT state change, the subscription still works.

So it looks like there are two issues:

1. When using the Python client library to watch for Postgres Changes, there is no RealtimeSubscribeStates.SUBSCRIBED state change, and no change messages are received. The JS client works fine with the same Supabase instance.
2. When using the Python client library to subscribe to any Realtime channel, a spurious (and it seems mostly harmless) RealtimeSubscribeStates.TIMED_OUT state change happens after about 10 seconds.

import asyncio
import supabase
import os

async def watch_db(url: str, key: str) -> None:
    client = await supabase.acreate_client(url, key)

    def handle_payload(payload):
        print(payload)

    def subscribe_callback(state, error):
        if error:
            print(f"Error subscribing to channel: {error}")
        else:
            print(f"Channel subscription state: {state}")

    channel = client.channel(
        "db-changes",
        {
            "config": {
                "private": True,
            }
        },
    )
    channel.on_broadcast("INSERT", handle_payload)
    channel.on_broadcast("UPDATE", handle_payload)
    channel.on_broadcast("DELETE", handle_payload)
    await channel.subscribe(subscribe_callback)

    await asyncio.Event().wait()


if __name__ == "__main__":
    asyncio.run(
        watch_db(os.environ["SUPABASE_URL"], os.environ["SUPABASE_SERVICE_ROLE_KEY"])
    )