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append 与 Highwater 测试

 2008-06-03 12:43:08 来源:WEB开发网   
核心提示: SQL> commit;提交完成,SQL> select dbms_rowid.rowid_block_number(rowid) block# from test_block;BLOCK#-- 194 194 194 194 194 194 194 194 194 194 1

  SQL> commit;
  提交完成。
  SQL> select dbms_rowid.rowid_block_number(rowid) block# from test_block;
  BLOCK#
  ----------
   194
   194
   194
   194
   194
   194
   194
   194
   194
   194
   194
   195
  已选择12行。

看看此时的高水位:

  SQL> alter system dump datafile 11 block 193;
  系统已更改。

193块的内容如下:

  *** 2008-05-30 13:13:54.000
  Start dump data blocks tsn: 11 file#: 11 minblk 193 maxblk 193
  buffer tsn: 11 rdba: 0x02c000c1 (11/193)
  scn: 0x0000.1bf3c7bf seq: 0x01 flg: 0x04 tail: 0xc7bf1001
  frmt: 0x02 chkval: 0x233e type: 0x10=DATA SEGMENT HEADER - UNLIMITED
  Extent Control Header
  -----------------------------------------------------------------
  Extent Header:: spare1: 0   spare2: 0   #extents: 1   #blocks: 7  
  last map 0x00000000 #maps: 0   offset: 4128 
  Highwater:: 0x02c000c4 ext#: 0   blk#: 2   ext size: 7  
  #blocks in seg. hdr's freelists: 1  
  #blocks below: 2  
  mapblk 0x00000000 offset: 0  
   Unlocked
   Map Header:: next 0x00000000 #extents: 1  obj#: 31997 flag: 0x40000000
  Extent Map
  -----------------------------------------------------------------
   0x02c000c2 length: 7  
  nfl = 1, nfb = 1 typ = 1 nxf = 0 ccnt = 1
  SEG LST:: flg: USED  lhd: 0x02c000c2 ltl: 0x02c000c2
  End dump data blocks tsn: 11 file#: 11 minblk 193 maxblk 193
  
  SQL> select to_number('c4', 'xxx') from dual;
  TO_NUMBER('C4','XXX')
  ---------------------
  196

提交后,高水位移动到了第196块。

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Tags:append Highwater

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