Anti-Starvation Promotion

Last updated 2026-10-21

This page explains how go-queue lifts long-waiting Low and Normal tasks so a steady stream of urgent work cannot starve them.

Promotion Rules

Each time a worker calls Pop, promoteLocked scans the whole heap and lifts long-waiting tasks one level (core/pending.go:111).

With the default Config.Timeout = 30s, a Low task becomes Normal after 30s, and a Normal task becomes High after 60s.

Boundaries

• Wait time counts from startAt, which resets on retry
• Immediate, High, and Retry never promote
• A promoted Low task keeps its original startAt, so once it also passes the Normal threshold it moves on to High
• Thresholds read only Config.Timeout, never a preset's Timeout
• Promotion only runs on Pop, so no promotion checks happen while every worker is busy
• Promotion changes the order only; the timeout fixed at Enqueue stays the same
• Each promotion emits a Debug-level task.promoted event, see Log Events