PostmasterMain   |- - reset_shared    创建共享内存和信号量     |- - CreateSharedMemoryAndSemaphores         |- - PGSharedMemoryCreate            |- - PGReserveSemaphores            |- - SpinlockSemaInit               |- - CreateLWLocks                |- - InitShmemIndex                |- - dsm_shmem_init         |- - XLOGShmemInit         |- - CLOGShmemInit         |- - CommitTsShmemInit         |- - SUBTRANSShmemInit         |- - MultiXactShmemInit         |- - InitBufferPool         |- - InitLocks         |- - InitPredicateLocks         |- - InitProcGlobal         |- - CreateSharedProcArray         |- - CreateSharedBackendStatus         |- - TwoPhaseShmemInit         |- - BackgroundWorkerShmemInit         |- - CreateSharedInvalidationState         |- - PMSignalShmemInit         |- - ProcSignalShmemInit         |- - CheckpointerShmemInit         |- - AutoVacuumShmemInit         |- - ReplicationSlotsShmemInit         |- - ReplicationOriginShmemInit         |- - WalSndShmemInit         |- - WalRcvShmemInit         |- - PgArchShmemInit         |- - ApplyLauncherShmemInit         |- - SnapMgrInit         |- - BTreeShmemInit         |- - SyncScanShmemInit         |- - AsyncShmemInit