Binary fuse filters compress string-to-uint64 lookups from 56 bytes/key to 9 bytes/key with 3x faster latency on immutable datasets.
June 10, 2026
Summary
For large read-only lookup tables (logging IDs, config mappings, feature flags), this trades one-time construction cost for sustained memory efficiency and cache locality gains—critical when map size exceeds L3 cache. Reduces operational memory footprint without code rewrites.
Why it matters
For large read-only lookup tables (logging IDs, config mappings, feature flags), this trades one-time construction cost for sustained memory efficiency and cache locality gains—critical when map size exceeds L3 cache. Reduces operational memory footprint without code rewrites.
Implementation verdict
Drops in as constmap.New() with identical API to Go maps. Worth adopting now for immutable string→uint64 mappings over 100k entries; not suitable for frequently modified maps or other value types. Serialize to disk to avoid reconstruction overhead.
Sources
Dev Signal
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