PostgreSQL のデッドロック検出アルゴリズムの説明に "soft edge" という記載があります。PostgreSQL 15.3 src/backend/storage/lmgr/README 2. If a process A is behind a process B in some lock's wait queue, and their requested locks conflict, then we must say that A waits for B, since ProcLockWakeup will never awaken A before B. This cr…