PG 數據庫啓動

DEBUG:  loaded library "imcs"
DEBUG:  find_in_dynamic_libpath: trying "/opt/pgsql/lib/plugin_debugger"
DEBUG:  find_in_dynamic_libpath: trying "/opt/pgsql/lib/plugin_debugger.so"
DEBUG:  loaded library "plugin_debugger"
DEBUG:  invoking IpcMemoryCreate(size=8737193984)
DEBUG:  mmap with MAP_HUGETLB failed, huge pages disabled: Cannot allocate memory
FATAL:  could not map anonymous shared memory: Cannot allocate memory
HINT:  This error usually means that PostgreSQL's request for a shared memory segment exceeded available memory, swap space, or huge pages. To reduce the request size (currently 8737193984 bytes), reduce PostgreSQL's shared memory usage, perhaps by reducing shared_buffers or max_connections.
DEBUG:  shmem_exit(1): 0 before_shmem_exit callbacks to make
DEBUG:  shmem_exit(1): 0 on_shmem_exit callbacks to make
DEBUG:  proc_exit(1): 2 callbacks to make
DEBUG:  exit(1)
DEBUG:  shmem_exit(-1): 0 before_shmem_exit callbacks to make
DEBUG:  shmem_exit(-1): 0 on_shmem_exit callbacks to make
DEBUG:  proc_exit(-1): 0 callbacks to make

DEBUG:  invoking IpcMemoryCreate(size=8737193984)
DEBUG:  mmap with MAP_HUGETLB failed, huge pages disabled: Cannot allocate memory
DEBUG:  SlruScanDirectory invoking callback on pg_notify/0000
DEBUG:  removing file "pg_notify/0000"
DEBUG:  dynamic shared memory system will support 128 segments
DEBUG:  created dynamic shared memory control segment 1804289383 (1036 bytes)
DEBUG:  max_safe_fds = 985, usable_fds = 1000, already_open = 5
LOG:  redirecting log output to logging collector process

數據庫啓動 #ifdef EXEC_BACKEND if (argc > 1 && strncmp(argv[1], "--fork", 6) == 0) SubPostmasterMain(argc, argv); /* does not return */

main --> EXEC_BACKEND SubPostmasterMain --CreateSharedMemoryAndSemaphores -- PGSharedMemoryCreate(Size size, bool makePrivate, int port, PGShmemHeader **shim)

SlruScanDirectory