{"id":474,"date":"2013-12-22T23:51:03","date_gmt":"2013-12-22T15:51:03","guid":{"rendered":"http:\/\/www.gpfeng.com\/?p=474"},"modified":"2013-12-23T11:50:22","modified_gmt":"2013-12-23T03:50:22","slug":"innodb-native-aio%e6%ba%90%e7%a0%81%e5%88%86%e6%9e%90","status":"publish","type":"post","link":"http:\/\/www.gpfeng.com\/?p=474","title":{"rendered":"InnoDB\u4f7f\u7528linux native aio\u6e90\u7801\u5206\u6790"},"content":{"rendered":"

\u597d\u8bb0\u6027\u4e0d\u5982\u70c2\u7b14\u5934\uff0c\u8fd9\u7bc7\u6587\u7ae0\u662f\u4e00\u4e2a\u5b66\u4e60\u548c\u603b\u7ed3\uff0c\u5305\u62eclinux native aio API\u4ecb\u7ecd\u4ee5\u53caInnoDB\u4e2d\u5982\u4f55\u4f7f\u7528native aio<\/p>\n

\u5f02\u6b65io<\/h3>\n

linux\u4e0a\u5f02\u6b65io\u6709\u4e24\u5957API\uff0cposix aio\u548cnative aio\uff0c\u5176\u4e2dnative aio\u5177\u6709\u66f4\u597d\u7684\u6027\u80fd\uff0c\u4f46\u8981\u6c42\u6587\u4ef6\u6253\u5f00\u65b9\u5f0f\u5fc5\u987b\u662fO_DIRECT\uff0c\u7b80\u5355\u5217\u4e0b\u4e24\u5957API\u7684\u63a5\u53e3\uff1a
\n

\n\r\n\r\n
posix aio<\/caption>\n
function<\/th>\ndesc<\/th>\n<\/tr>\n<\/thead>\n
aio_read<\/td>\n\u53d1\u8d77\u4e00\u4e2a\u5f02\u6b65\u8bfb\u8bf7\u6c42<\/td>\n<\/tr>\n\r\n
aio_write<\/td>\n\u53d1\u8d77\u4e00\u4e2a\u5f02\u6b65\u5199\u8bf7\u6c42<\/td>\n<\/tr>\n\r\n
aio_return<\/td>\n\u963b\u585e\u7b49\u5f85\u5f02\u6b65io\u8bf7\u6c42\u8fd4\u56de<\/td>\n<\/tr>\n\r\n
aio_error<\/td>\n\u68c0\u67e5\u5f02\u6b65io\u8fd4\u56de\u7ed3\u679c<\/td>\n<\/tr>\n\r\n
aio_suspend<\/td>\n\u6302\u8d77\u8c03\u7528\u8fdb\u7a0b\uff0c\u76f4\u5230\u4e00\u4e2a\u6216\u591a\u4e2a\u5f02\u6b65\u8bf7\u6c42\u5df2\u7ecf\u5b8c\u6210\uff08\u6216\u5931\u8d25\uff09<\/td>\n<\/tr>\n\r\n
aio_cancel<\/td>\n\u53d6\u6d88\u5f02\u6b65io<\/td>\n<\/tr>\n\r\n
lio_listio<\/td>\n\u53d1\u8d77\u4e00\u7cfb\u5217\u5f02\u6b65io\u8bf7\u6c42<\/td>\n<\/tr>\n<\/tbody><\/table><\/div>
\n
\n\r\n\r\n
native aio<\/caption>\n
function<\/th>\ndesc<\/th>\n<\/tr>\n<\/thead>\n
io_setup<\/td>\n\u521b\u5efa\u5f02\u6b65io\u4e0a\u4e0b\u6587<\/td>\n<\/tr>\n\r\n
io_submit<\/td>\n\u53d1\u8d77\u4e00\u4e2a\u5f02\u6b65io\u8bf7\u6c42<\/td>\n<\/tr>\n\r\n
io_getevents<\/td>\n\u963b\u585e\u7b49\u5f85\u5f02\u6b65io\u8bf7\u6c42\u8fd4\u56de<\/td>\n<\/tr>\n\r\n
io_cancel<\/td>\n\u53d6\u6d88\u5f02\u6b65io<\/td>\n<\/tr>\n\r\n
io_destroy<\/td>\n\u9500\u6bc1\u5f02\u6b65io\u4e0a\u4e0b\u6587<\/td>\n<\/tr>\n<\/tbody><\/table><\/div><\/p>\n

\u672c\u6587\u4e0d\u6253\u7b97\u7ee7\u7eed\u4ecb\u7ecdposix aio\u76f8\u5173\u5185\u5bb9\uff0c\u5c06\u91cd\u70b9\u96c6\u4e2d\u5728native aio\u4e0a\uff0c\u5217\u51fa\u51fd\u6570\u539f\u578b\uff1a<\/p>\n

1. int io_setup<\/strong>(int maxevents, io_context_t *ctxp);
\n|- \u521b\u5efa\u5f02\u6b65io\u4e0a\u4e0b\u6587\uff0c\u5176\u4e2dio_context_t\u662f\u53e5\u67c4\uff0c\u5177\u4f53\u5b9e\u73b0\u65f6\u5e94\u8be5\u5bf9\u5e94\u4e00\u4e2a\u6574\u6570\uff0cmaxevents\u9650\u5236\u4e86\u53ef\u4ee5\u540c\u65f6\u63d0\u4ea4\u7684\u5f02\u6b65io\u6570\u91cf<\/p>\n

2. long io_submit<\/strong>(aio_context_t ctx_id, long nr, struct iocb **iocbpp);
\n|- \u63d0\u4ea4\u5f02\u6b65io\u8bf7\u6c42\uff0c\u8bf7\u6c42\u53ef\u4ee5\u662f\u8bfb\u6216\u8005\u5199\uff0cnr\u662fiocbpp\u6570\u7ec4\u7684\u5927\u5c0f\uff0cio\u8bf7\u6c42\u5165\u961f\u540e\u5373\u523b\u8fd4\u56de<\/p>\n

3. long io_getevents<\/strong>(aio_context_t ctx_id, long min_nr, long nr, struct io_event *events, struct timespec *timeout)
\n|- \u63d0\u4f9b\u4e00\u4e2aio_event\u6570\u7ec4\u7ed9\u5185\u6838\u6765copy\u5b8c\u6210\u7684io\u8bf7\u6c42\uff0c\u6570\u7ec4\u7684\u5927\u5c0f\u662fio_setup\u65f6\u6307\u5b9a\u7684maxevents\uff0c\u963b\u585e\u7b49\u5f85\u81f3\u5c11min_nr\u4e2aio\u8bf7\u6c42\u8fd4\u56de\uff0c\u5982\u679ctimeout\u975eNULL\uff0c\u8d85\u65f6\u540e\u5373\u523b\u8fd4\u56de\uff0c\u8fd4\u56de\u503c\u4e3a\u5b8c\u6210\u7684io\u8bf7\u6c42\u4e2a\u6570<\/p>\n

4. int io_destroy<\/strong>(io_context_t ctx);
\n|- \u9500\u6bc1\u5f02\u6b65io\u4e0a\u4e0b\u6587\uff0c\u5982\u679c\u8fd8\u6709\u672a\u5b8c\u6210\u7684io\uff0c\u53d6\u6d88\u8fd9\u4e9bio<\/p>\n

5. long io_cancel<\/strong>(aio_context_t ctx_id, struct iocb *iocb, struct io_event *result);
\n|- \u53d6\u6d88\u4e00\u4e2a\u5f02\u6b65io\u8bf7\u6c42\uff0c\u7ed3\u679c\u653e\u5230result\u4e2d<\/p>\n

\u5176\u4e2d\uff1a1~4\u662f\u4e00\u4e2a\u5b8c\u6574\u7684\u5f02\u6b65io\u8c03\u7528\u8fc7\u7a0b\uff1a\u521d\u59cb\u5316context\uff0c\u63d0\u4ea4io\u8bf7\u6c42\uff0c\/*do something else… *\/, \u7b49\u5f85io\u5b8c\u6210\uff0c\u9500\u6bc1contex<\/p>\n

iocb\/io_event<\/h3>\n

io_context_t\u672c\u8d28\u4e0a\u5c31\u662f\u4e00\u4e2a\u53e5\u67c4\uff0c\u5f02\u6b65io\u4e2d\u7528\u5230\u7684\u4e24\u4e2a\u91cd\u8981\u7ed3\u6784\u4f53\u662fiocb\u4e0eio_event\uff0c\u91cd\u70b9\u6df1\u5165\u4e00\u4e0b\uff1a<\/p>\n

iocb\u63cf\u8ff0\u4e86\u4e00\u4e2a\u5f02\u6b65io\u8bf7\u6c42<\/p>\n

\r\nstruct iocb {\r\n  void *data; \/* return in the io completion event *\/\r\n  unsigned key; \/* use in identifying io requests *\/\r\n  short aio_lio_opcode;\r\n  short aio_reqprio;\r\n  int aio_fildes;\r\n  union {\r\n    struct io_iocb_common c;\r\n    struct io_iocb_vector v;\r\n    struct io_iocb_poll poll;\r\n    struct io_iocb_sockaddr saddr;\r\n  } u;\r\n};\r\n\r\nstruct io_iocb_common {\r\n  void *buf;\r\n  unsigned long nbytes;\r\n  long long offset;\r\n  unsigned flags;\r\n  unsigned resfd;\r\n};\r\n<\/pre>\n
\u5176\u4e2d\uff0cdata\u7531\u7528\u6237\u81ea\u5b9a\u4e49\uff0c\u53ef\u4ee5\u4e3a\u56de\u8c03\u51fd\u6570\uff0caio_lio_opcode\u6709\u4e24\u4e2a\u503c\uff1aIOCB_CMD_PREAD\/IOCB_CMD_PWRITE\uff0caio_fildes\u662f\u5bf9\u5e94\u7684\u6587\u4ef6fd\uff0cio_iocb_common\u4e2d\u7684\u6210\u5458\u63cf\u8ff0\u4e86\u8981\u63d0\u4ea4\u7684io\u8bf7\u6c42\u7684\u7ec6\u8282: [buf,nbytes] –> [aio_fildes,offset]<\/p>\n
io_event\u63cf\u8ff0\u4e86\u5f02\u6b65io\u8fd4\u56de\u4fe1\u606f<\/p>\n
\r\nstruct io_event {\r\n  void *data;\r\n  struct iocb *obj;\r\n  unsigned long res;\r\n  unsigned long res2;\r\n};\r\n<\/pre>\n
\u5176\u4e2d\uff0cobj\u6307\u5411\u4e4b\u524d\u63d0\u4ea4\u7684\u5f02\u6b65io\u5bf9\u5e94\u7684iocb\uff0cres\u548cres2\u8868\u793a\u5f02\u6b65io\u5b8c\u6210\u7684\u72b6\u6001<\/p>\n
\u521d\u59cb\u5316iocb\u7ed3\u6784\u4f53\uff08\u5b8f\u5b9a\u4e49\uff09<\/h3>\n
\r\nvoid io_prep_pwrite(struct iocb *iocb, int fd, void *buf, size_t count, long long offset);\r\nvoid io_prep_pread(struct iocb *iocb, int fd, void *buf, size_t count, long long offset);\r\n<\/pre>\n
\u5217\u51faio_prep_pread\u7684code\uff0cio_prep_pwrite\u4e2diocb->aio_lio_opcode = IO_CMD_PWRITE;<\/p>\n
\r\nvoid io_prep_pread(struct iocb *iocb, int fd, void *buf, size_t count, long long offset)\r\n{\r\n  memset(iocb, 0, sizeof(*iocb));\r\n  iocb->aio_fildes = fd;\r\n  iocb->aio_lio_opcode = IO_CMD_PREAD;\r\n  iocb->aio_reqprio = 0;\r\n  iocb->u.c.buf = buf;\r\n  iocb->u.c.nbytes = count;\r\n  iocb->u.c.offset = offset;\r\n}\r\n<\/pre>\n
Innodb native AIO<\/h3>\n
InnoDB\u5728linux native aio\u51fa\u6765\u4e4b\u524d\u66fe\u7ecf\u91c7\u7528simulated aio\u6765\u6a21\u62df\u5f02\u6b65io\uff0c\u4e00\u6b21\u63d0\u4ea4\u591a\u4e2aio\u8bf7\u6c42\u63d0\u9ad8\u6548\u7387\uff0c\u4f46\u662f\u4e0enative aio\u6bd4\u8d77\u6765\uff0c\u6027\u80fd\u8fd8\u4e0d\u591f\u597d\uff0c\u6587\u7ae0\u540e\u7eed\u5185\u5bb9focus\u5728InnoDB\u5982\u4f55\u4f7f\u7528linux native aio\u4e0a\u9762<\/p>\n
\u4e24\u4e2a\u7ed3\u6784\u4f53<\/strong>\uff1aos_aio_slot_struct\/os_aio_array_struct<\/p>\n
os_aio_array_struct<\/h3>\n
\u7ba1\u7406\u4e86\u540c\u4e00\u7c7b\u5f02\u6b65io\uff0cInnoDB\u4e2d\u4e00\u5171\u6709\u56db\u7c7b\u5f02\u6b65io\uff0c\u5206\u522b\u8d1f\u8d23data page\/insert buffer\/redo log\u7684\u5f02\u6b65io<\/p>\n
\r\nstatic os_aio_array_t*     os_aio_read_array     = NULL;     \/*!< Reads *\/\r\nstatic os_aio_array_t*     os_aio_write_array    = NULL;     \/*!< Writes *\/\r\nstatic os_aio_array_t*     os_aio_ibuf_array     = NULL;     \/*!< Insert buffer *\/\r\nstatic os_aio_array_t*     os_aio_log_array      = NULL;     \/*!< Redo log *\/\r\n<\/pre>\n
os_aio_array_struct\u90e8\u5206\u6210\u5458\uff1a<\/p>\n
\r\n\/** The asynchronous i\/o array structure *\/\r\nstruct os_aio_array_struct{\r\n     os_mutex_t     mutex;     \/*!< the mutex protecting the aio array *\/\r\n     ulint          n_slots;\/*!< Total number of slots in the aio\r\n                    array.  This must be divisible by\r\n                    n_threads. *\/\r\n     ulint          n_segments;\r\n                    \/*!< Number of segments in the aio\r\n                    array of pending aio requests. A\r\n                    thread can wait separately for any one\r\n                    of the segments. *\/\r\n     ulint          n_reserved;\r\n                    \/*!< Number of reserved slots in the\r\n                    aio array outside the ibuf segment *\/\r\n     os_aio_slot_t*     slots;     \/*!< Pointer to the slots in the array *\/\r\n\r\n#if defined(LINUX_NATIVE_AIO)\r\n     io_context_t*          aio_ctx;\r\n                    \/* completion queue for IO. There is\r\n                    one such queue per segment. Each thread\r\n                    will work on one ctx exclusively. *\/\r\n     struct io_event*     aio_events;\r\n                    \/* The array to collect completed IOs.\r\n                    There is one such event for each\r\n                    possible pending IO. The size of the\r\n                    array is equal to n_slots. *\/\r\n#endif\r\n};\r\n<\/pre>\n
\u5173\u952e\u6210\u5458\uff1a
\nslots<\/strong>\uff1aos_aio_slot_t\u7c7b\u578b\u6570\u7ec4\uff0c\u6bcf\u4e2a\u5f02\u6b65io\u8fc7\u7a0b\u4e2d\u9700\u8981\u4f7f\u7528\u4e00\u4e2aslot\uff0c\u5b8c\u6210\u540e\u91ca\u653e
\nn_slots<\/strong>\uff1a\u6570\u7ec4slots\u7684\u957f\u5ea6\uff0c\u4ee3\u8868\u6700\u5927peding io\u6570\u76ee
\nn_reserved<\/strong>\uff1a\u5f53\u524dslots\u6570\u7ec4\u4e2d\u5df2\u7ecf\u5360\u7528\u7684slot\u6570\u76ee\uff0c\u5f53n_reserved\u5230\u8fben_slots\uff0c\u63d0\u4ea4\u5f02\u6b65io\u9700\u8981\u7b49\u5f85
\naio_events<\/strong>\uff1aio_event\u7c7b\u578b\u6570\u7ec4\uff0c\u6570\u7ec4\u957f\u5ea6\u4e3an_slots\uff0c\u4fdd\u5b58\u5bf9\u5e94\u5f02\u6b65io\u7684\u8fd4\u56de\u7ed3\u679c\uff08io_getevents\uff09
\nn_segments<\/strong>\uff1aslots\u6570\u7ec4\u88ab\u5206\u6210m\u4e2a\u533a\uff0c\u5355\u4e2a\u533a\u4e2d\u7684\u5f02\u6b65io\uff08n_slots\/n_segments\u4e2a\uff09\u7531\u4e00\u4e2a\u7ebf\u7a0b\u6765\u8bbf\u95ee\u548c\u64cd\u4f5c
\naio_ctx<\/strong>\uff1aio_context_t\u7c7b\u578b\u6570\u7ec4\uff0c\u6570\u7ec4\u957f\u5ea6\u4e3an_segments\uff0c\u6bcf\u4e2aio_context\u5bf9\u5e94slots\u6570\u7ec4\u4e2d\u7684(n_slots\/n_segments)\u4e2aslot\uff0c\u4e00\u4e2aio_context\u88ab\u4e00\u4e2a\u7ebf\u7a0b\u4f7f\u7528<\/p>\n
os_aio_ibuf_array\u4e0eos_aio_log_array\u4e2d\u5305\u542b\u4e00\u4e2asegment\uff08hard code\uff09\uff0cos_aio_read_array\u4e0eos_aio_write_array\u4e2d\u7684segment\u6570\u91cf\u7531innodb_read_io_threads\u4e0einnodb_write_io_threads\u6307\u5b9a\uff08\u9ed8\u8ba4\u90fd\u662f4\uff0c\u542f\u52a8\u540e\u4e0d\u53ef\u4fee\u6539\uff09\uff0c\u7cfb\u7edf\u4f1a\u4e3a\u6bcf\u4e2asegment\u521b\u5efa\u4e00\u4e2a\u540e\u53f0\u7ebf\u7a0b\u7528\u4e8e\u5904\u7406\u5f02\u6b65io\uff0c\u6bcf\u4e2a\u540e\u53f0\uff08linux native aio\uff09\u7ebf\u7a0b\u6700\u591a\u5904\u7406\uff0832*8 = 256\uff09\u4e2apending io\uff0c\u5177\u4f53\u53c2\u8003innodb_start_or_create_for_mysql<\/p>\n
\r\n    io_limit = 8 * SRV_N_PENDING_IOS_PER_THREAD;\r\n    os_aio_init(io_limit,\r\n                srv_n_read_io_threads,\r\n                srv_n_write_io_threads,\r\n                SRV_MAX_N_PENDING_SYNC_IOS);\r\n<\/pre>\n
os_aio_slot_t<\/h3>\n
\u7528\u4e8e\u63d0\u4ea4\u4e00\u4e2a\u5f02\u6b65io\u64cd\u4f5c\uff0c\u90e8\u5206\u6210\u5458\uff1a<\/p>\n
\r\n\/** The asynchronous i\/o array slot structure *\/\r\nstruct os_aio_slot_struct{\r\n     ibool          is_read;     \/*!< TRUE if a read operation *\/\r\n     ulint          pos;          \/*!< index of the slot in the aio array *\/\r\n     ibool          reserved;     \/*!< TRUE if this slot is reserved *\/\r\n     ulint          len;          \/*!< length of the block to read or write *\/\r\n     byte*          buf;          \/*!< buffer used in i\/o *\/\r\n     ulint          type;          \/*!< OS_FILE_READ or OS_FILE_WRITE *\/\r\n     ulint          offset;          \/*!< 32 low bits of file offset in bytes *\/\r\n     ulint          offset_high;     \/*!< 32 high bits of file offset *\/\r\n     os_file_t     file;          \/*!< file where to read or write *\/\r\n     ulint          space_id;\r\n     fil_node_t*     message1;     \/*!< message which is given by the *\/\r\n\r\n#elif defined(LINUX_NATIVE_AIO)\r\n     struct iocb     control;     \/* Linux control block for aio *\/\r\n     int          n_bytes;     \/* bytes written\/read. *\/\r\n     int          ret;          \/* AIO return code *\/\r\n#endif\r\n};\r\n<\/pre>\n
\u5173\u952e\u6210\u5458\uff1a
\npos<\/strong>\uff1a\u5176\u5728\u5bf9\u5e94\u7684sync array\u4e2d\u7684\u4f4d\u7f6e\uff0c\u901a\u8fc7slot->pos\/array->n_segment\u53ef\u4ee5\u5f97\u5230\u5176\u5bf9\u5e94\u7684io_context
\ncontrol<\/strong>\uff1a\u6307\u5411\u4e00\u4e2aiocb\u7ed3\u6784\u4f53\uff0c\u5728\u63d0\u4ea4\u5f02\u6b65io\u65f6\uff0ccontrol->data\u6307\u5411\u8be5slot\uff0cio_getevents\u540e\uff0c\u53ef\u4ee5\u901a\u8fc7event->obj->data\u8bbf\u95eeslot<\/p>\n
\u5f02\u6b65io\u521d\u59cb\u5316\u53ca\u51fd\u6570\u8c03\u7528\u5173\u7cfb<\/h3>\n
\r\ninnodb_start_or_create_for_mysql\r\n\r\n   srv_n_file_io_threads = 2 + srv_n_read_io_threads\r\n                    + srv_n_write_io_threads;\r\n\r\n   os_aio_init()\r\n\r\n   for (i = 0; i < srv_n_file_io_threads; i++) {\r\n        n[i] = i;\r\n        os_thread_create(io_handler_thread, n + i, thread_ids + i);\r\n   }\r\n<\/pre>\n
\u5f02\u6b65io\u540e\u53f0\u7ebf\u7a0b<\/h3>\n
\r\nio_handler_thread\r\n   while (srv_shutdown_state != SRV_SHUTDOWN_EXIT_THREADS) {\r\n        fil_aio_wait(segment);\r\n   }\r\n\r\nfil_aio_wait\r\n   os_aio_linux_handle\r\n   fil_node_complete_io\r\n<\/pre>\n
native aio API\u8c03\u7528\u5806\u6808<\/h3>\n
\r\nos_aio_init --> os_aio_array_create --> os_aio_linux_create_io_ctx --> io_setup\r\n(_fil_io | fil_extend_space_to_desired_size) --> os_aio --> os_aio_func --> os_aio_linux_dispatch --> io_submit\r\nio_handler_thread --> fil_aio_wait --> os_aio_linux_handle --> os_aio_linux_collect --> io_getevents\r\n<\/pre>\n","protected":false},"excerpt":{"rendered":"
\u597d\u8bb0\u6027\u4e0d\u5982\u70c2\u7b14\u5934\uff0c\u8fd9\u7bc7\u6587\u7ae0\u662f\u4e00\u4e2a\u5b66\u4e60\u548c\u603b\u7ed3\uff0c\u5305\u62eclinux native aio API\u4ecb\u7ecd\u4ee5\u53caInnoDB\u4e2d … \u7ee7\u7eed\u9605\u8bfbInnoDB\u4f7f\u7528linux native aio\u6e90\u7801\u5206\u6790<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"jetpack_post_was_ever_published":false,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":true,"jetpack_social_options":{"image_generator_settings":{"template":"highway","enabled":false}}},"categories":[1,2],"tags":[],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_shortlink":"https:\/\/wp.me\/p3tPZp-7E","jetpack_sharing_enabled":true,"jetpack-related-posts":[],"_links":{"self":[{"href":"http:\/\/www.gpfeng.com\/index.php?rest_route=\/wp\/v2\/posts\/474"}],"collection":[{"href":"http:\/\/www.gpfeng.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.gpfeng.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.gpfeng.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/www.gpfeng.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=474"}],"version-history":[{"count":12,"href":"http:\/\/www.gpfeng.com\/index.php?rest_route=\/wp\/v2\/posts\/474\/revisions"}],"predecessor-version":[{"id":477,"href":"http:\/\/www.gpfeng.com\/index.php?rest_route=\/wp\/v2\/posts\/474\/revisions\/477"}],"wp:attachment":[{"href":"http:\/\/www.gpfeng.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=474"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.gpfeng.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=474"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.gpfeng.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=474"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}