"Linearizability"
- Spanner Consistency Models 對照：external consistency vs serializability vs linearizability external consistency、serializability、linearizability 是三個常被混用的概念。本文先精確定義三者差異、再用 line-rate scaling 對照表（PG SSI / CockroachDB / Spanner / Aurora DSQL）回答為什麼 Spanner 不只是『更強的 serializable』、最後用 9.C10 揭露的 cross-region quorum 100-200ms 物理硬限解釋『強一致 + 全球部署』的真實 cost