frontend: Continuous new connections to the frontend

[StrikeW]

Describe the bug

There are continuous new connections to the frontend, but I didn't issue any query to RW yet.

Error message/log

ubuntu@ip-172-31-18-200:~$ docker logs -f --tail 20 frontend-node-0
2023-10-17T06:21:37.947230938Z  INFO pgwire::pg_server: New connection: 127.0.0.1:53388
2023-10-17T06:21:39.053806249Z  INFO pgwire::pg_server: New connection: 127.0.0.1:55060
2023-10-17T06:21:40.162289131Z  INFO pgwire::pg_server: New connection: 127.0.0.1:55076
2023-10-17T06:21:41.277674271Z  INFO pgwire::pg_server: New connection: 127.0.0.1:55082
2023-10-17T06:21:42.426251715Z  INFO pgwire::pg_server: New connection: 127.0.0.1:55092
2023-10-17T06:21:43.228862846Z  INFO risingwave_frontend::scheduler::snapshot: unpin snapshot with RPC min_epoch=5261787275067392
2023-10-17T06:21:43.54943322Z  INFO pgwire::pg_server: New connection: 127.0.0.1:55104
2023-10-17T06:21:44.637976302Z  INFO pgwire::pg_server: New connection: 127.0.0.1:55116
2023-10-17T06:21:45.80773817Z  INFO pgwire::pg_server: New connection: 127.0.0.1:55132
2023-10-17T06:21:46.917714507Z  INFO pgwire::pg_server: New connection: 127.0.0.1:55134
2023-10-17T06:21:48.03394383Z  INFO pgwire::pg_server: New connection: 127.0.0.1:55150
2023-10-17T06:21:49.163603396Z  INFO pgwire::pg_server: New connection: 127.0.0.1:38680
2023-10-17T06:21:50.298328693Z  INFO pgwire::pg_server: New connection: 127.0.0.1:38686
2023-10-17T06:21:51.421938785Z  INFO pgwire::pg_server: New connection: 127.0.0.1:38690
2023-10-17T06:21:52.527349792Z  INFO pgwire::pg_server: New connection: 127.0.0.1:38696
2023-10-17T06:21:53.228733046Z  INFO risingwave_frontend::scheduler::snapshot: unpin snapshot with RPC min_epoch=5261787930427392
2023-10-17T06:21:53.669984684Z  INFO pgwire::pg_server: New connection: 127.0.0.1:38710
2023-10-17T06:21:54.805995021Z  INFO pgwire::pg_server: New connection: 127.0.0.1:38718
2023-10-17T06:21:55.941883556Z  INFO pgwire::pg_server: New connection: 127.0.0.1:38728
2023-10-17T06:21:57.061743671Z  INFO pgwire::pg_server: New connection: 127.0.0.1:38738
2023-10-17T06:21:58.174052447Z  INFO pgwire::pg_server: New connection: 127.0.0.1:38754
2023-10-17T06:21:59.299327313Z  INFO pgwire::pg_server: New connection: 127.0.0.1:58074
2023-10-17T06:22:00.437811222Z  INFO pgwire::pg_server: New connection: 127.0.0.1:58086
2023-10-17T06:22:01.591573363Z  INFO pgwire::pg_server: New connection: 127.0.0.1:58102
2023-10-17T06:22:02.726824374Z  INFO pgwire::pg_server: New connection: 127.0.0.1:58104
2023-10-17T06:22:03.228990757Z  INFO risingwave_frontend::scheduler::snapshot: unpin snapshot with RPC min_epoch=5261788585787392
2023-10-17T06:22:03.822428937Z  INFO pgwire::pg_server: New connection: 127.0.0.1:58112
2023-10-17T06:22:04.948228401Z  INFO pgwire::pg_server: New connection: 127.0.0.1:58114
2023-10-17T06:22:06.077847649Z  INFO pgwire::pg_server: New connection: 127.0.0.1:58124
2023-10-17T06:22:07.197658349Z  INFO pgwire::pg_server: New connection: 127.0.0.1:58128
2023-10-17T06:22:08.329699137Z  INFO pgwire::pg_server: New connection: 127.0.0.1:58136
2023-10-17T06:22:09.449949924Z  INFO pgwire::pg_server: New connection: 127.0.0.1:42442
2023-10-17T06:22:10.570176468Z  INFO pgwire::pg_server: New connection: 127.0.0.1:42444
2023-10-17T06:22:11.709943169Z  INFO pgwire::pg_server: New connection: 127.0.0.1:42454
2023-10-17T06:22:12.83365675Z  INFO pgwire::pg_server: New connection: 127.0.0.1:42468
2023-10-17T06:22:13.228951804Z  INFO risingwave_frontend::scheduler::snapshot: unpin snapshot with RPC min_epoch=5261789241147392
2023-10-17T06:22:13.98196021Z  INFO pgwire::pg_server: New connection: 127.0.0.1:42480
2023-10-17T06:22:15.110604834Z  INFO pgwire::pg_server: New connection: 127.0.0.1:42484
2023-10-17T06:22:16.2466518Z  INFO pgwire::pg_server: New connection: 127.0.0.1:42496
2023-10-17T06:22:17.375405428Z  INFO pgwire::pg_server: New connection: 127.0.0.1:42504
2023-10-17T06:22:18.493798241Z  INFO pgwire::pg_server: New connection: 127.0.0.1:54298
2023-10-17T06:22:19.636058591Z  INFO pgwire::pg_server: New connection: 127.0.0.1:54304
2023-10-17T06:22:20.75061193Z  INFO pgwire::pg_server: New connection: 127.0.0.1:54318
2023-10-17T06:22:21.886142222Z  INFO pgwire::pg_server: New connection: 127.0.0.1:54326
2023-10-17T06:22:23.023578922Z  INFO pgwire::pg_server: New connection: 127.0.0.1:54332
2023-10-17T06:22:23.228785369Z  INFO risingwave_frontend::scheduler::snapshot: unpin snapshot with RPC min_epoch=5261789896441856
2023-10-17T06:22:24.14209099Z  INFO pgwire::pg_server: New connection: 127.0.0.1:54334
2023-10-17T06:22:25.267264419Z  INFO pgwire::pg_server: New connection: 127.0.0.1:54338
2023-10-17T06:22:26.39374741Z  INFO pgwire::pg_server: New connection: 127.0.0.1:54350

To Reproduce

It is not related to the script of the citus-cdc integration test. Since the docker compose of ad-ctr case can also reproduce the problem.

Expected behavior

No response

How did you deploy RisingWave?

risingwave/integration_tests/citus-cdc/docker-compose.yml

The version of RisingWave

nightly-20231016

Additional context

No response

[chenzl25]

This is a health check from the docker compose.

    healthcheck:
      test:
        - CMD-SHELL
        - bash -c 'printf \"GET / HTTP/1.1\n\n\" > /dev/tcp/127.0.0.1/4566; exit $$?;'
      interval: 1s
      timeout: 5s
      retries: 5