Polling

成熟的系统通常采用Webhook加轮询兜底的双重机制来确保任务状态获取的可靠性

Polling is n8n actively calling an external API at fixed intervals to check for changes; it suits services that do not support Webhook, but it has latency and consumes API quota.

Compared with polling, the hook mechanism has lower latency and lower overhead.

Polling is when a system actively queries each data source at fixed intervals for updates; compared with event-driven real-time push, it is simpler to implement but has latency, and frequent queries consume considerable compute.

Polling is inefficient, and as the number of agents grows, frequent checks waste resources.

Early multi-agent implementations mostly used fire-and-forget semantics, with sub-agent results collected via polling, callbacks or separate session channels, and no shared execution trace between parent and child.

Pacing is controlled by two parameters working together—"recent videos" and "maximum replies per round"—and the polling interval can be set to half an hour or one hour.

Event-driven synchronization can significantly reduce idle-spinning costs in agent orchestration, but it depends on reliable parsing of terminal state; if a certain harness's output format is nonstandard, the monitor may miss or misjudge the state.

Compared with polling, a Webhook does not require the receiver to repeatedly query the data source at fixed intervals, so latency is lower and resource overhead is smaller.

In polling scenarios for slow AI jobs, idempotency means every status query changes neither the job state nor triggers a new generation, so the client can safely refresh at high frequency.

Polling means the client actively queries job status from the server at fixed intervals; it is simple to implement and broadly compatible, but generates many wasted requests and has latency, while subscription uses server push via WebSocket or SSE and is highly real-time but requires maintaining long connections, which is less friendly to mobile and weak networks.

The article recommends using polling as the primary approach for slow AI jobs, supplemented by a backoff strategy (gradually lengthening the interval) to balance real-time responsiveness and server load.

There is no faster notification method than polling when bidding, so agents can only poll open intents at fixed intervals and do other things in between.

The video generation API uses a polling mechanism: it first returns a polling URL, the client checks the status every 15 seconds, and once complete, downloads the video content from a signed URL.

The polling approach has low implementation cost, but frequent empty polling brings invalid load; long polling can reduce idle spinning, yet it is still limited by connection timeouts and interruptions at the proxy layer, and for scenarios where a reply only comes after three hours, the polling window setting itself is a challenge.

Polling is the receiver periodically querying the source system on its own; it is more reliable but has latency and additional overhead.

Polling at a fixed interval has two problems: when there are many tasks it causes a large number of invalid requests that consume quota and may even trigger rate limiting; when tasks take a long time it may lengthen the total waiting time

After NVMe SSDs became fast enough to respond at the microsecond level, the storage industry adopted polling instead of interrupts, having the CPU actively and frequently check the completion queue, sacrificing idle-time energy efficiency for determinism and throughput at low latency.

Polling is when a program repeatedly queries an external data source or API at fixed intervals to determine whether the state has changed; its advantage is simplicity and not depending on the other party supporting callbacks, and its cost is generating invalid requests and introducing latency.

When the data source supports Webhook, Webhook should be used preferentially, and only when it does not support it should one fall back to the polling approach.