Persistent "Overdue for a major GC" warning on hasura startup

### Version Information

Server Version: 2.2.2

### Environment

OSS

### What is the expected behaviour?

Not sure? Garbage collection should work?

### What is the current behaviour?

A hasura instance that's seen significant queries is now constantly telling us "Overdue for a major GC: forcing one even though we don't appear to be idle"

This message appears once a minute. It also appears even after a service restart.

### How to reproduce the issue?

1. ???
2. message "Overdue for a major GC: forcing one even though we don't appear to be idle" appears once a minute
3. restart hasura
4. same message keeps appearing

### Please provide any traces or logs that could help here.

```
{"timestamp":"2022-03-24T17:33:24.000+0000","level":"info","type":"startup","detail":{"kind":"migrations-startup","info":"database url for migrations is set by HASURA_GRAPHQL_DATABASE_URL"}}
{"timestamp":"2022-03-24T17:33:24.000+0000","level":"info","type":"startup","detail":{"kind":"migrations-startup","info":"migrations server port env var is not set, defaulting to 9691"}}
{"timestamp":"2022-03-24T17:33:24.000+0000","level":"info","type":"startup","detail":{"kind":"migrations-startup","info":"server timeout is not set, defaulting to 30 seconds"}}
{"timestamp":"2022-03-24T17:33:24.000+0000","level":"info","type":"startup","detail":{"kind":"migrations-startup","info":"starting graphql engine temporarily on port 9691"}}
{"timestamp":"2022-03-24T17:33:24.000+0000","level":"info","type":"startup","detail":{"kind":"migrations-startup","info":"waiting 30 for 9691 to be ready"}}
{"timestamp":"2022-03-24T17:33:44.000+0000","level":"info","type":"startup","detail":{"kind":"migrations-startup","info":"port 9691 is ready"}}
{"timestamp":"2022-03-24T17:33:44.000+0000","level":"info","type":"startup","detail":{"kind":"migrations-startup","info":"env var HASURA_GRAPHQL_MIGRATIONS_DIR is not set, defaulting to /hasura-migrations"}}
{"timestamp":"2022-03-24T17:33:44.000+0000","level":"info","type":"startup","detail":{"kind":"migrations-startup","info":"env var HASURA_GRAPHQL_METADATA_DIR is not set, defaulting to /hasura-metadata"}}
{"timestamp":"2022-03-24T17:33:44.000+0000","level":"info","type":"startup","detail":{"kind":"migrations-apply","info":"directory /hasura-migrations does not exist, skipping migrations"}}
{"timestamp":"2022-03-24T17:33:44.000+0000","level":"info","type":"startup","detail":{"kind":"migrations-apply","info":"directory /hasura-metadata does not exist, skipping metadata"}}
{"timestamp":"2022-03-24T17:33:44.000+0000","level":"info","type":"startup","detail":{"kind":"migrations-shutdown","info":"killing temporary server"}}
{"timestamp":"2022-03-24T17:33:44.000+0000","level":"info","type":"startup","detail":{"kind":"migrations-shutdown","info":"graphql-engine will now start in normal mode"}}
{"type":"unstructured","timestamp":"2022-03-24T17:36:07.105+0000","level":"warn","detail":"Overdue for a major GC: forcing one even though we don't appear to be idle"}
{"type":"unstructured","timestamp":"2022-03-24T17:37:10.279+0000","level":"warn","detail":"Overdue for a major GC: forcing one even though we don't appear to be idle"}
{"type":"unstructured","timestamp":"2022-03-24T17:38:13.281+0000","level":"warn","detail":"Overdue for a major GC: forcing one even though we don't appear to be idle"}
```

### If the bug is confirmed, would you be willing to submit a PR?

no