A few reliable ways: 1. Check the configured DB URL If your server is using PostgreSQL,

PREFECT_SERVER_DATABASE_CONNECTION_URL

should look like

postgresql+asyncpg://...

. If it’s falling back to SQLite, it will look like

sqlite+aiosqlite:///...

, often something like

~/.prefect/prefect.db

. Quick check:

bash
echo $PREFECT_SERVER_DATABASE_CONNECTION_URL
env | grep -i "PREFECT_SERVER_DATABASE\|PREFECT_API_DATABASE"

Or from Python:

bash
python -c "from prefect.settings import get_current_settings; print(get_current_settings().server.database.connection_url)"

2. Check what Prefect resolved at runtime This is the clearest verification:

bash
python -c "
from prefect.settings import get_current_settings
from prefect.server.utilities.database import get_dialect

url = get_current_settings().server.database.connection_url.get_secret_value()
dialect = get_dialect(url)

print(f'Database URL: {url}')
print(f'Dialect: {dialect.name}')
"

You should see either: -

Dialect: postgresql

-

Dialect: sqlite

3. Check for the default SQLite file If Prefect fell back to SQLite, you’ll usually find:

bash
ls -lh ~/.prefect/prefect.db

If that file exists and is being updated while the server is running, that’s a strong sign you’re on SQLite. You can also inspect it:

bash
sqlite3 ~/.prefect/prefect.db ".tables"

4. Inspect your Postgres directly If you expect Postgres, connect to it and see whether Prefect tables exist:

bash
psql -h <host> -U <user> -d <database_name> -c "\dt"

If you see Prefect tables there, your server is likely using Postgres. 5. Watch server behavior/logs SQLite has some special behavior in Prefect: - request limiting middleware is applied to reduce SQLite lock contention - you may see SQLite-style locking symptoms under load - multi-worker server setups are not appropriate with SQLite Postgres won’t use that SQLite-specific path. Most important thing to know In Prefect 3.x, if you don’t explicitly configure the server DB, Prefect defaults to SQLite. So the simplest answer is: - if

connection_url

resolves to

postgresql+asyncpg://...

→ you’re on Postgres - if it resolves to

sqlite+aiosqlite:///...

→ you’re on SQLite fallback Recommended quick diagnostic

bash
python -c "
from prefect.settings import get_current_settings
from prefect.server.utilities.database import get_dialect

settings = get_current_settings()
url = settings.server.database.connection_url.get_secret_value()
print('Resolved DB URL:', url)
print('Resolved DB dialect:', get_dialect(url).name)
"

Relevant docs: - Self-host Prefect: configure a database - Prefect self-hosting guides If you want, I can also help you check a specific Docker Compose / Helm / environment setup to confirm whether it’s correctly pointing at Postgres.