"Streaming-Replication"
- PostgreSQL Replication Topology：async / sync / quorum 在 durability、latency、consistency 上的取捨，與 LSN + replication slot
PostgreSQL streaming replication 不是「sync 或 async」、是 *durability / latency / consistency* 三軸組合 + LSN-based 進度追蹤 + replication slot 治理。本文走 durability / latency / consistency 的取捨模型、async / sync / quorum-based sync 行為對比、LSN + replication slot 機制、配置 step-by-step、production 踩雷（standby lag 暴衝 / sync standby 失聯時 primary commit 卡住 / orphan replication slot / cascading replication 雪崩 / failover 後 timeline 分歧）、跟 Patroni HA + logical replication 整合