sharding introduces risk cross_shard_query

shardingIntroduces Riskcross shard query degradation

Source: Pattern·Target: Failure Mode

Summary

Sharding by a specific key makes queries that omit the shard key require fan-out across all shards, degrading latency and consuming connection pool slots proportional to shard count.

Evidence

·sharding: cross-shard joins/aggregates/range scans must scatter-gather at N x single-shard latency (patterns/sharding.yaml tradeoffs)
·cross_shard_query_degradation lists sharding in affects_patterns; fan-out opens N connection-pool slots (failure_modes/cross_shard_query_degradation.yaml)

Evidence grounding

Grounded, 2 supporting items

Queries without the shard key scatter to all shards and gather, incurring N x single-shard latency.