VTGate context deadline exceeded error when routing queries to MySQL shards

Goal: configure alerts for VTGate context deadline exceeded errors to capture sustained latency spikes while avoiding noise from transient timeouts. Constraint: need to rely on VTGate latency histogram and error rate metrics; uncertainty about whether default thresholds should be static or auto‑adjusted based on traffic patterns, as documentation does not specify an automated tuning mechanism.

Should operators define fixed percentile latency and error‑rate thresholds, or implement a dynamic baseline that adapts to historical load? How can one validate that silencing transient spikes does not mask genuine shard‑unavailability incidents? What monitoring granularity (e.g., per‑shard vs aggregate) provides the best signal‑to‑noise ratio for this error?