[BUG] Metrics labels not written to GreptimeDB but present in VictoriaMetrics (HertzBeat 1.8.0)

[mingzeh]

Is there an existing issue for this?

• I have searched the existing issues

Current Behavior

When using GreptimeDB as the time-series database in HertzBeat 1.8.0, the metrics labels of monitoring tasks are not written into the database.
However, when switching to VictoriaMetrics, the labels are written correctly.

VictoriaMetrics (labels are present)

→ Custom labels are correctly stored and can be queried.

---

GreptimeDB (labels are missing)

→ Custom labels are NOT written into the database.

Expected Behavior

Metrics labels should be written consistently regardless of the selected time-series database backend.

Steps To Reproduce

1. Deploy HertzBeat 1.8.0

2. Configure GreptimeDB as the storage backend

3. Create a monitoring task with labels

4. Check stored metrics in GreptimeDB → labels missing

5. Switch to VictoriaMetrics

6. Check metrics again → labels exist

Environment

HertzBeat version(s): v1.8.0

Time-series DB:
  GreptimeDB (issue occurs)
  VictoriaMetrics (works as expected)

Debug logs

No response

Anything else?

No response