得到XDES Entry中状态
/**********************************************************************//** Gets the state of an xdes. @return state */ UNIV_INLINE ulint xdes_get_state( /*===========*/ const xdes_t* descr, /*!< in: descriptor */ mtr_t* mtr) /*!< in: mtr handle */ { ulint state; ut_ad(descr && mtr); ut_ad(mtr_memo_contains_page(mtr, descr, MTR_MEMO_PAGE_X_FIX)); state = mtr_read_ulint(descr + XDES_STATE, MLOG_4BYTES, mtr); ut_ad(state - < XDES_FSEG); return(state); }