오라클 프로세스 역할
ora_smon : SMON(System Monitor)
ora_pmon : PMON(Process Monitor)
ora_dbw0 : DBWR(Database Writer)
ora_lgwr : LGWR(Ledo Log Writer)
ora_ckpt : (CKPT : Checkpoint)
ora_reco : (RECO : Recoverer)
ora_s00 : shared server process
ora_d00 : dedicated server process
