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Relationship · Complements
fan out on readComplementsfan out on write
Source: Pattern·Target: Pattern

Summary

Fan-out on read and fan-out on write are used together in a hybrid social feed model: normal accounts use fan-out on write for fast reads; high-follower accounts use fan-out on read to avoid write amplification.

Evidence

  • ·fan_out_on_read lists fan_out_on_write in related_patterns and documents the hybrid (threshold ~10k-100k followers, e.g. Twitter/X) (patterns/fan_out_on_read.yaml)
  • ·fan_out_on_write's celebrity problem (30M followers = 30M cache writes/post) is exactly what fan-out-on-read avoids (patterns/fan_out_on_write.yaml tradeoffs)

Evidence grounding

Grounded, 2 supporting items

Large platforms route by follower-count threshold: fan-out-on-write for normal accounts, fan-out-on-read for high-follower accounts.

fan_out_on_read complements fan_out_on_write: DBRaven