I have a sensor on a group of assets that share the same

FreshnessPolicy

which looks like this

FreshnessPolicy(maximum_lag_minutes=24 * 60, cron_schedule="2 15 * * *")

And the sensor looks like this:

build_asset_reconciliation_sensor(
    name="update_atlas",
    asset_selection=AssetSelection.groups("atlas"),
    minimum_interval_seconds=60 * 5,
)

When this was turned on originally, things were fine but now, every tick results in

Sensor function returned an empty result

Which function is this referring to? I'm not exactly sure what I might have changed that would caused this. How do I go about debugging this?

Hi Philippe, if the tick doesn't yield any run requests, the asset reconciliation sensor displays that message. Did you expect the asset reconciliation sensor to kick off runs?

Well, the assets have no upstream dependencies, so I assume that the sensor would generate run when the freshness policy determines them as “stale”. But it’s simply always retuning “empty result”.

@owen know whats going on here?

just to confirm, the expected behavior is that around every 5 hours, a run will be kicked off to refresh those assets, but the sensor is not launching runs at all? I would expect the`Sensor function returned an empty result` message to show up for the vast majority of ticks (the reconciliation sensor executes, by default, every ~30 seconds, and most of those ticks will not launch a run and so will have that message), so the specific behavior that seems concerning is just the fact that it hasn't launched any runs after more than 5 hours

My understanding is that every 5 minutes, it should check if the asset has been refreshed within the past 24 hours after 2:15AM. From memory, this was working fine at the beginning which was on 1.1.10. It has stopped working now, but as mentioned, I'm not sure what else has changed besides upgrading to 1.1.18 and then 1.1.19. Sorry I can't be more specific. I'm no longer planning on using this, but I'm happy to try different things to debug this case if you want.