Full-text search engine

Index billions of documents into an inverted index sharded by document ID, scatter queries across shards in parallel, score candidates with BM25 + static signals (PageRank) + neural re-ranking, and gather the top results with snippets under a tight tail-latency budget.

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Duration 45:00

Requirements checklist

Full-text search over multi-word queries with boolean/phrase matching, returning ranked results with title, URL, and highlighted snippet.Ingest new and updated documents continuously so fresh documents become searchable within seconds to minutes.Multi-stage ranking: fast lexical retrieval (BM25 + static quality score) followed by re-ranking of the top candidates.Search p99 latency under ~150–250 ms despite fanning out across many index shards.High availability: if one shard replica is slow or down, serve partial or hedged results rather than failing the whole query.Scale to tens of billions of documents and ~100k queries/s.

Clarifying questions

How many documents and what average document length?
How fresh must newly published or edited documents be in search results?
Is returning 98% complete results acceptable when a shard times out?
Do we need phrase queries and positional proximity scoring?

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requirements

Suggested time: about 6 minutes. Partial-result degradation vs complete failure under shard slowdowns.

Notes for requirements