A likely cause in Prefect 2.20 self-hosted is that the older UI/dashboard filters historical runs using

start_time

instead of

expected_start_time

. That means runs can exist in the DB/API, but still not appear in the dashboard if they were: - scheduled but not picked up yet - marked Late - pending/queued for a while - otherwise missing

start_time

This is more of a Prefect 2.x UI behavior/bug than actual data loss. First things to check 1. Do the runs exist via the API? 2. Do those missing runs have

start_time = null

but

expected_start_time

populated? 3. Are you using SQLite or Postgres for the self-hosted server? SQLite can make UI queries much worse on larger datasets. 4. Is this affecting all old runs, or only some states like Scheduled/Late? Quick API test If your server is at

http://<host>:4200

, try:

bash
curl -X POST http://<host>:4200/api/flow_runs/filter \
  -H "Content-Type: application/json" \
  -d '{
    "flow_runs": {
      "expected_start_time": {
        "after_": "2024-01-01T00:00:00Z",
        "before_": "2024-01-02T00:00:00Z"
      }
    },
    "sort": "EXPECTED_START_TIME_DESC",
    "limit": 100
  }'

Then compare with:

bash
curl -X POST http://<host>:4200/api/flow_runs/filter \
  -H "Content-Type: application/json" \
  -d '{
    "flow_runs": {
      "start_time": {
        "after_": "2024-01-01T00:00:00Z",
        "before_": "2024-01-02T00:00:00Z"
      }
    },
    "sort": "START_TIME_DESC",
    "limit": 100
  }'

If the first returns runs and the second does not, that strongly points to this UI/dashboard filtering issue. DB checks For Postgres:

sql
SELECT COUNT(*), state_type, state_name
FROM flow_run
WHERE expected_start_time >= '2024-01-01'
  AND expected_start_time < '2024-01-02'
GROUP BY state_type, state_name
ORDER BY 1 DESC;

Check for runs with no actual start time:

sql
SELECT COUNT(*)
FROM flow_run
WHERE start_time IS NULL
  AND expected_start_time >= '2024-01-01'
  AND expected_start_time < '2024-01-02';

If you want examples:

sql
SELECT id, name, state_name, expected_start_time, start_time, end_time
FROM flow_run
WHERE expected_start_time >= '2024-01-01'
  AND expected_start_time < '2024-01-02'
ORDER BY expected_start_time DESC
LIMIT 20;

Other things to verify - Timezone mismatch: UI/browser timezone vs server UTC can make “previous day” filters look wrong near day boundaries. - Late runs: runs marked

Late

often still have

start_time = NULL

. - Database size/performance: on self-hosted 2.x, especially with SQLite, older dashboard queries can become slow or incomplete. - Logs: check server logs for query timeouts/errors when loading the dashboard. Useful next step Tell me: 1. whether you use Postgres or SQLite 2. whether the missing runs are completed runs or mostly scheduled/late/pending 3. what exact page in the UI is affected (

Dashboard

, flow run list, deployment run history, etc.) If you want, I can help you build a step-by-step debug checklist for your exact setup, or help interpret the output of your API/SQL checks.