HardDesign: Web Crawler

A fetcher node crashes after popping a URL from the queue but before completing the crawl. How do you prevent URL loss?

— Tests your understanding of this concept.

Answer Options

AThe URL is lost permanently
BUse in-flight tracking: mark URL as 'crawling' with TTL; if not completed in 5 minutes, return to queue
CUse a transaction log on the fetcher
DDuplicate all URLs in two queues

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This question is from the Design: Web Crawler topic (System Design Cases).

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