async-dedup-race-in-streaming-pipelines

Duplicate emissions in streaming pipelines occur when dedup checks run after per-item async work begins, allowing concurrent requests to pass the check simultaneously. Moving dedup reservations to execute synchronously before spawning async work prevents this race condition and ensures strict one-emission-per-key guarantees.

Prevent late WebSocket emissions by reserving dedup slots synchronously before async work starts, then awaiting all in-flight promises with Promise.all before signaling stream completion. This guarantees all async processing finishes and avoids premature closure dropping valid results.

The best way to handle dedup races in SSE streaming dashboards is to implement synchronous dedup reservations before async enrichment, await all promises with Promise.all, and use a shared-resource cache to reuse I/O results across concurrent requests, ensuring each dedup key yields at most one result.

Yes, you need to await all async tasks with Promise.all before closing a WebSocket stream. Premature completion signaling causes late async enrichment results to be dropped when the stream closes, leading to invisible UI entries and incorrect counts in streaming pipelines.

Caching shared resources reduces redundant I/O in async streaming pipelines by reusing results across concurrent requests for the same dedup key. This small shared-resource cache minimizes duplicate fetches during per-item async enrichment while maintaining strict dedup guarantees.