Earlier note claimed max_queue_time / target_queue_time were no-ops
because the worker's internal wait_time property filters sessions out.
That filter only affects per-worker rejection on a given handler — the
autoscaler doesn't see the property and computes its own queue-time
estimate from cur_load / max_perf, which *does* include sessions.
With defaults around 30s, an occupied null worker (cur_load=100,
max_perf=100, implied queue=1s) still looks "available" to the
autoscaler, so a third reservation gets queued on an existing worker
via repeated 429-retries instead of triggering scale-up.
Fix: set max_queue_time = 0 and target_queue_time = 0 on the endpoint.
Any in-flight load marks the worker "full" for routing, and any
observed queue time triggers immediate scale-up.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>