彻底搞懂uba地址转换

SQL> update t set owner='killdb.com' where object_id=555;已更新 1 行。SQL> select xidusn,xidslot,xidsqn,ubablk,ubafil,ubarec,START_SCN from v$transaction;    XIDUSN    XIDSLOT     XIDSQN     UBABLK     UBAFIL     UBAREC  START_SCN---------- ---------- ---------- ---------- ---------- ---------- ----------         6         15        916        366          3          6     968248SQL>  select  dbms_rowid.rowid_block_number(rowid) blk# from t  where object_id=555;      BLK#----------       491SQL> select distinct dbms_rowid.rowid_relative_fno(rowid) file# from t;     FILE#----------         5alter system dump datafile 5 block 491;Block header dump:  0x014001eb Object id on Block? Y seg/obj: 0x15a1d  csc: 0x00.ef4ce  itc: 3  flg: E  typ: 1 - DATA     brn: 0  bdba: 0x14001e8 ver: 0x01 opc: 0     inc: 0  exflg: 0 Itl           Xid                  Uba         Flag  Lck        Scn/Fsc0x01   0xffff.000.00000000  0x00000000.0000.00  C---    0  scn 0x0000.000ec6190x02   0x0006.00f.00000394  0x00c0016e.0085.06  ----    1  fsc 0x0000.000000000x03   0x0000.000.00000000  0x00000000.0000.00  ----    0  fsc 0x0000.00000000bdba: 0x014001ebdata_block_dump,data header at 0xfffffd7ffdd34a7c===============tsiz: 0x1f80hsiz: 0x474pbl: 0xfffffd7ffdd34a7c     76543210flag=--------ntab=1nrow=561frre=-1fsbo=0x474fseo=0x799avsp=0x330tosp=0x3300xe:pti[0]      nrow=561        offs=00x12:pri[0]     offs=0x1f760x14:pri[1]     offs=0x1f6c0x16:pri[2]     offs=0x1f620x18:pri[3]     offs=0x1f580x1a:pri[4]     offs=0x1f4e0x1c:pri[5]     offs=0x1f440x1e:pri[6]     offs=0x1f3a0x20:pri[7]     offs=0x1f300x22:pri[8]     offs=0x1f260x24:pri[9]     offs=0x1f1c0x26:pri[10]    offs=0x1f120x28:pri[11]    offs=0x1f080x02   0x0006.00f.00000394  0x00c0016e.0085.06  ----    1  fsc 0x0000.00000000SQL>  select dbms_utility.data_block_address_file(to_number(substr(uba, 3, 8),                                                          'xxxxxxxxxxxx')) as undo_file#,           dbms_utility.data_block_address_block(to_number(substr(uba, 3, 8),                                                           'xxxxxxxxxxxx')) as undo_block,           to_number(substr(uba, 12, 4), 'xxxxxxxxxxxx') undo_sequence,           to_number(substr(uba, 17, 2), 'xxxxxxxxxxxx') undo_record      from (select '0x00c0016e.0085.06' uba from dual);  2    3    4    5    6    7  UNDO_FILE# UNDO_BLOCK UNDO_SEQUENCE UNDO_RECORD---------- ---------- ------------- -----------         3        366           133           6uba = Address of the last undo block used + Sequence + Last Entry in UNDO record mapdump undo header:SQL>  select name from v$rollname where usn=6;NAME------------------------------_SYSSMU6_112126372$alter system dump undo header '_SYSSMU6_112126372$';********************************************************************************Undo Segment:  _SYSSMU6_112126372$ (6)********************************************************************************  Extent Control Header  -----------------------------------------------------------------  Extent Header:: spare1: 0      spare2: 0      #extents: 4      #blocks: 151                  last map  0x00000000  #maps: 0      offset: 4080      Highwater::  0x00c0016f  ext#: 2      blk#: 7      ext size: 8  #blocks in seg. hdr's freelists: 0  #blocks below: 0  mapblk  0x00000000  offset: 2                   Unlocked     Map Header:: next  0x00000000  #extents: 4    obj#: 0      flag: 0x40000000  Extent Map  -----------------------------------------------------------------   0x00c000d1  length: 7   0x00c000d8  length: 8   0x00c00168  length: 8   0x00c00900  length: 128 Retention Table  ----------------------------------------------------------- Extent Number:0  Commit Time: 1408809628 Extent Number:1  Commit Time: 1408809628 Extent Number:2  Commit Time: 1408846934 Extent Number:3  Commit Time: 1408809628  TRN CTL:: seq: 0x0085 chd: 0x000b ctl: 0x0012 inc: 0x00000000 nfb: 0x0001            mgc: 0xb000 xts: 0x0068 flg: 0x0001 opt: 2147483646 (0x7ffffffe)            uba: 0x00c0016f.0085.01 scn: 0x0000.000ebd47Version: 0x01  FREE BLOCK POOL::    uba: 0x00c0016f.0085.01 ext: 0x2  spc: 0x1f84    uba: 0x00000000.0085.02 ext: 0x2  spc: 0x1ee2    uba: 0x00000000.0085.1f ext: 0x2  spc: 0x978    uba: 0x00000000.0000.00 ext: 0x0  spc: 0x0    uba: 0x00000000.0000.00 ext: 0x0  spc: 0x0  TRN TBL::  index  state cflags  wrap#    uel         scn            dba            parent-xid    nub     stmt_num    cmt  ------------------------------------------------------------------------------------------------   0x0a    9    0x00  0x0394  0x0012  0x0000.000ec5eb  0x00c0016d  0x0000.000.00000000  0x00000001   0x00000000  1408814848   0x0b    9    0x00  0x0393  0x0015  0x0000.000ebd59  0x00c0016c  0x0000.000.00000000  0x00000001   0x00000000  1408810230   0x0c    9    0x00  0x0394  0x0006  0x0000.000ec5e8  0x00c0016e  0x0000.000.00000000  0x00000001   0x00000000  1408814848   0x0d    9    0x00  0x0393  0x0019  0x0000.000ec24e  0x00c0016c  0x0000.000.00000000  0x00000001   0x00000000  1408813250   0x0e    9    0x00  0x0394  0x000c  0x0000.000ec5ae  0x00c0016d  0x0000.000.00000000  0x00000001   0x00000000  1408814750   0x0f   10    0x80  0x0394  0x0002  0x0000.000ec638  0x00c0016e  0x0000.000.00000000  0x00000001   0x00000000  0  usn: 6  sp1:0x00000000 sp2:0x00000000 sp3:0x00000000 sp4:0x00000000  sp5:0x00000000 sp6:0x00000000 sp7:0x00000000 sp8:0x00000000  EXT TRN TBL::这里的dba=0x00c0016e和uba=0x00c0016e.0085.06 一致。