"Bdr"
- PostgreSQL BDR / Multi-Master：active-active 寫入的 3 種路徑跟 conflict 治理 PG 預設是 single-primary、active-active 多寫入入口需要 *BDR (EDB)* / *pgEdge* / *Bucardo* 等 extension。本文走 3 種 multi-master 方案對比、conflict detection + resolution model、async vs sync 取捨、配置 step-by-step（pgEdge 為主）、5 production 踩雷（last-write-wins data loss / sequence collision / DDL replication / conflict log 治理 / failover 後 timeline 分歧）、跟 MySQL Group Replication sibling 對比