Glossary

Aging: the increase of a waiting task's score over time, preventing starvation.

Attempt: one execution of a task. A task has one or more attempts.

Backlog: tasks ready to run but waiting for a slot.

Class: a priority level: critical, high, normal or low.

Deadline: a soft time by which a task should be done; it raises urgency.

Dead letter: terminal status for a task whose retryable failures used every attempt.

Driver: the async task that owns the engine, executes its actions and feeds back results.

Edge condition: when a dependency is satisfied: on success, on failure or on completion.

Effective score: base score of the class plus aging plus deadline urgency; the highest dispatches first.

Engine / core: the sans-IO state machine (cronoq-core) that makes all scheduling decisions.

Epoch: a counter incremented by each new leader; used for fencing and embedded in task ids.

Executor: the code that runs an attempt in-process.

Fencing: rejecting writes from a leader whose epoch is no longer current.

Fixed start: a time at which a task should begin, backed by a reservation.

Hold: a worker slot kept free for a fixed-start task about to begin.

Key: an optional unique name of a task, used for deduplication and references.

Latest start time (LST): deadline minus estimated duration.

Lease: the identity of one attempt; remote workers heartbeat it to keep it alive.

Lease TTL: how long a lease survives without a heartbeat.

Miss policy: what happens to a fixed-start task that could not start within its tolerance.

Parked: a ready task waiting for a resource, outside the dispatch queue.

Pending: submitted but not running (counted against queue bounds).

Pool: a group of worker slots with one executor, one autoscaling policy and its own bounds.

Reservation: a booked interval of pool capacity for a fixed-start task.

Resource: a shared limit (semaphore or token bucket) that tasks request units of.

Retention window: how long terminal statuses are remembered.

Shed: evicted under overload by a shedding overflow policy.

Slot: capacity to run one attempt at a time.

Snapshot: per-pool state, quality metrics over the sliding window, and counters since start.

Tolerance: how far from its fixed start a task may begin and still count as on time.

Worker: a process connected to cronoq-server that runs leased attempts.