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Oracle事务原理探究2--读书笔记五

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互联网集市收集整理的这篇技术教程文章主要介绍了Oracle事务原理探究2--读书笔记五，小编现在分享给大家，供广大互联网技能从业者学习和参考。文章包含33807字，纯文字阅读大概需要49分钟。

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续上篇...

3. ?数据块访问与undo

? ? ? ? 任何时候当会话查看一个数据块的时候，都需要保证看到的是适当的数据版本。从外部观点来看，这意味着会话不应该看到任何未提交的数据，或许还不应该看到查询开始后修改并提交的数据（取决于事务的隔离级别），这称为数据的读一致性版本。

? ? ? ? 下面我们来谈谈oracle怎么实现读一致性版本的：

3.1 设置场景

? ? ? ? 我们会创建一张表，里面插入3条数据，然后开几个会话对其进行操作

3.1.1 连接oracle，以任何一个用户登录即可，初始化一些格式

  1. execute ?dbms_random.seed(0)??
  2. ??
  3. set ?doc? off ??
  4. doc??
  5. ??
  6. end ?doc? is ?marked? with ?#??
  7. ??
  8. #??
  9. ??
  10. set ?linesize?120??
  11. set ?trimspool? on ??
  12. set ?pagesize?24??
  13. set ?arraysize?25??
  14. ??
  15. --?set?longchunksize?32768 ??
  16. --?set?long?32768 ??
  17. ??
  18. set ?autotrace? off ??
  19. ??
  20. clear?breaks??
  21. ttitle?off??
  22. btitle?off??
  23. ??
  24. column ?owner?format?a15??
  25. column ?segment_name?format?a20??
  26. column ?table_name?format?a20??
  27. column ?index_name?format?a20??
  28. column ?object_name?format?a20??
  29. column ?subobject_name?format?a20??
  30. column ?partition_name?format?a20??
  31. column ?subpartition_name?format?a20??
  32. column ?column_name?format?a20??
  33. column ?column_expression?format?a40?word?wrap??
  34. column ?constraint_name?format?a20??
  35. ??
  36. column ?referenced_name?format?a30??
  37. ??
  38. column ?file_name?format?a60??
  39. ??
  40. column ?low_value?format?a24??
  41. column ?high_value?format?a24??
  42. ??
  43. column ?parent_id_plus_exp???format?999??
  44. column ?id_plus_exp??????format?990??
  45. column ?plan_plus_exp????????format?a90??
  46. column ?object_node_plus_exp?format?a14??
  47. column ?other_plus_exp???????format?a90??
  48. column ?other_tag_plus_exp???format?a29??
  49. ??
  50. column ?access_predicates????format?a80??
  51. column ?filter_predicates????format?a80??
  52. column ?projection???????format?a80??
  53. column ?remarks??????????format?a80??
  54. column ?partition_start??????format?a12??
  55. column ?partition_stop???????format?a12??
  56. column ?partition_id?????format?999??
  57. column ?other_tag????????format?a32??
  58. column ?object_alias?????format?a24??
  59. ??
  60. column ?object_node??????format?a13??
  61. column ??other???????????format?a150??
  62. ??
  63. column ?os_username??????format?a30??
  64. column ?terminal?????????format?a24??
  65. column ?userhost?????????format?a24??
  66. column ?client_id????????format?a24??
  67. ??
  68. column ?statistic_name?format?a35??
  69. ??
  70. column ?namespace?format?a20??
  71. column ?attribute?format?a20??
  72. ??
  73. column ?hint?format?a40??
  74. ??
  75. column ?start_time???format?a25??
  76. column ?end_time?????format?a25??
  77. ??
  78. column ?time_now?noprint?new_value?m_timestamp??
  79. ??
  80. set ?feedback? off ??
  81. ??
  82. select ?to_char(sysdate, ‘hh24miss‘ )?time_now? from ?dual;??
  83. commit ;??
  84. ??
  85. set ?feedback? on ??
  86. ??
  87. set ?timing? off ??
  88. set ?verify? off ??
  89. ??
  90. alter ?session? set ?optimizer_mode?=?all_rows;??
  91. ??
  92. spool?log??

3.1.2 创建表

  1. drop ? table ?t1;??
  2. ??
  3. create ? table ?t1(id?number,?n1?number);??
  4. ??
  5. insert ? into ?t1? values (1,1);??
  6. insert ? into ?t1? values (2,2);??
  7. insert ? into ?t1? values (3,3);??
  8. ??
  9. commit ;??
  10. ??
  11. create ? unique ? index ?t1_i1? on ?t1(id);??
  12. ??
  13. begin ??
  14. ????dbms_stats.gather_table_stats(??
  15. ????????ownname??????=>?user,??
  16. ????????tabname??????=>‘T1‘,??
  17. ????????estimate_percent?=>?100,??
  18. ????????method_opt???=>?‘for?all?columns?size?1‘??
  19. ????);??
  20. end ;??
  21. /??
  22. ??
  23. -- ??
  24. --<span?style="white-space:pre">??</span>For?11g?-?force?to?disc?for?the?dump ??
  25. -- ??
  26. ??
  27. ??
  28. alter ?system? checkpoint ;??

3.1.3 创建一个存储过程，用来转储一个表使用的第一个数据块。

  1. create ? or ? replace ? procedure ?dump_table_block(??
  2. ????i_tab_name??????in??varchar2,??
  3. ????i_owner?????????in??varchar2????default?sys_context(‘userenv‘,‘session_user‘)??
  4. )??
  5. as ??
  6. ????m_file_id???number;??
  7. ????m_block?????number;??
  8. ????m_process???varchar2(32);??
  9. ??
  10. begin ??
  11. ??
  12. ????execute?immediate??
  13. ????????‘?select?‘?||??
  14. ????????????‘?dbms_rowid.rowid_relative_fno(rowid),?‘?||??
  15. ????????????‘?dbms_rowid.rowid_block_number(rowid)??‘?||??
  16. ????????‘?from?‘?||??
  17. ????????????i_owner?||???
  18. ????????????‘.‘?||??
  19. ????????????i_tab_name?||??
  20. ????????‘?where?‘?||??
  21. ????????????‘?rownum?=?1?‘??
  22. ????????into??
  23. ????????????m_file_id,?m_block??
  24. ????;??
  25. ??
  26. ????execute?immediate??
  27. ????????‘alter?system?dump?datafile?‘?||?m_file_id?||??
  28. ????????‘?block?‘?||?m_block??
  29. ????;??
  30. ??
  31. -- ??
  32. --??For?non-MTS,?work?out?the?trace?file?name ??
  33. -- ??
  34. ??
  35. ????select??
  36. ????????spid??
  37. ????into??
  38. ????????m_process??
  39. ????from??
  40. ????????v$session???se,??
  41. ????????v$process???pr??
  42. ????where??
  43. -- ??
  44. --??????The?first?option?is?the?9.2?version?for?checking?the?SID ??
  45. --??????The?second?is?a?quick?and?dirty?option?for?8.1.7 ??
  46. --??????provided?SYS?has?made?v$mystat?visible?(or?this?is?the?sys?account) ??
  47. -- ??
  48. --??????se.sid?=?(select?dbms_support.mysid?from?dual) ??
  49. ????????se.sid?=?(select?sid?from?v$mystat?where?rownum?=?1)??
  50. ????and?pr.addr?=?se.paddr??
  51. ????;??
  52. ??
  53. ????dbms_output.new_line;??
  54. ????dbms_output.put_line(‘Trace?file?name?includes:?‘?||?m_process);??
  55. ????dbms_output.new_line;??
  56. ??
  57. exception??
  58. ????when?others?then??
  59. ????????dbms_output.new_line;??
  60. ????????dbms_output.put_line(‘Unspecified?error.‘);??
  61. ????????dbms_output.put_line(‘Check?syntax.‘);??
  62. ????????dbms_output.put_line(‘dump_table_block({table_name},[{owner}]‘);??
  63. ????????dbms_output.new_line;??
  64. ????????raise;??
  65. end ;??
  66. .??
  67. /??
  68. ??
  69. show?errors??
  70. ??
  71. drop ? public ?synonym?dump_table_block;??
  72. create ? public ?synonym?dump_table_block? for ?dump_table_block;??
  73. grant ? execute ? on ?dump_table_block? to ? public ;??


3.1.4 转储表t1的第一个数据块

  1. execute ?dump_table_block( ‘t1‘ )??

3.1.5 我们会看到：Trace file name includes: 4292这样的字样，到oracle 的trace目录找到这个跟踪文件，我的电脑入戏所示：

E:\app\Administrator\diag\rdbms\orcl\orcl\trace\orcl_ora_4292.trc, ?双击用记事本打开，可以看到如下内容：

  1. Block?header?dump:??0x00416169??
  2. ?Object?id?on?Block??Y??
  3. ?seg/obj:?0x12e7a??csc:?0x00.326fb7??itc:?2??flg:?O??typ:?1?-?DATA??
  4. ?????fsl:?0??fnx:?0x0?ver:?0x01??
  5. ???
  6. ?Itl???????????Xid??????????????????Uba?????????Flag??Lck????????Scn/Fsc??
  7. 0x01???0x0002.005.000005f5??0x00c00b18.0121.0d??--U-????3??fsc?0x0000.00326fb8??
  8. 0x02???0x0000.000.00000000??0x00000000.0000.00??----????0??fsc?0x0000.00000000??
  9. bdba:?0x00416169??
  10. data_block_dump,data?header?at?0x1e256e5c??
  11. ===============??
  12. tsiz:?0x1fa0??
  13. hsiz:?0x18??
  14. pbl:?0x1e256e5c??
  15. ?????76543210??
  16. flag=--------??
  17. ntab=1??
  18. nrow=3??
  19. frre=-1??
  20. fsbo=0x18??
  21. fseo=0x1f85??
  22. avsp=0x1f6d??
  23. tosp=0x1f6d??
  24. 0xe:pti[0]??nrow=3??offs=0??
  25. 0x12:pri[0]?offs=0x1f97??
  26. 0x14:pri[1]?offs=0x1f8e??
  27. 0x16:pri[2]?offs=0x1f85??
  28. block_row_dump:??
  29. tab?0,?row?0,?@0x1f97??
  30. tl:?9?fb:?--H-FL--?lb:?0x1??cc:?2??
  31. col??0:?[?2]??c1?02??
  32. col??1:?[?2]??c1?02??
  33. tab?0,?row?1,?@0x1f8e??
  34. tl:?9?fb:?--H-FL--?lb:?0x1??cc:?2??
  35. col??0:?[?2]??c1?03??
  36. col??1:?[?2]??c1?03??
  37. tab?0,?row?2,?@0x1f85??
  38. tl:?9?fb:?--H-FL--?lb:?0x1??cc:?2??
  39. col??0:?[?2]??c1?04??
  40. col??1:?[?2]??c1?04??
  41. end_of_block_dump??
  42. End ?dump?data?blocks?tsn:?0?file#:?1?minblk?90473?maxblk?90473??
  43. Start?dump?data?blocks?tsn:?0?file#:1?minblk?90473?maxblk?90473??


3.2 事务列表
? ? ? ? 这一节，简要介绍一下转储出来的数据块中事务槽的信息，上面数据块的事务槽如下：

  1. ?Itl???????????Xid??????????????????Uba?????????Flag??Lck????????Scn/Fsc??
  2. 0x01???0x0002.005.000005f5??0x00c00b18.0121.0d??--U-????3??fsc?0x0000.00326fb8??
  3. 0x02???0x0000.000.00000000??0x00000000.0000.00??----????0??fsc?0x0000.00000000??

Itl：列表的数组索引，该值未真正存储在数据块中，它由执行转储的代码生成。该值用在行的锁字节(lb:)中以显示哪个事务锁住了该行。

Xid: 最近更改该块的事务的事务id，格式是undo段.undo槽.undo序列号.

Uba: undo记录地址，是事务为该块最近生成的undo记录所在块的序列号。

Flag: 标识事务当前状态

? ? ? ? ? ---- ?活动（当Xid中每一个字段为0时表示，无事务）

? ? ? ? ? --U- 上界提交（表明这个事务已经提交，只是还没有清除一些标记）

? ? ? ? ?C---： 已提交并清除（所有标记已清除，比如相关的锁字节都被置0了）

?Lck：块中由该事务锁住的行数

Scn/Fsc：表示提交SCN或者快速提交SCN。

? ? ? ?在我们这个例子中，占用了一个事务槽，flag是--U-表明，事务已经快速提交，但是Lck为3，表明还没有清除锁标记，快速提交的scn是326fb8. Uba指向了最后一条插入的undo记录，这条undo记录会指向上一条插入的undo记录，上一条undo记录指向了上上条插入的undo记录。这样，如果事务失败，或者人工回滚，沿着这条undo链重做就好了。在oracle10g之后，一个数据块的事务槽被硬性规定为169个。（8KB大小的情况下）

3.3 并发操作

我们需要开启4个事务，如下所示：

  1. session1:? update ?t1? set ?n1=101?? where ?id?=?1;??
  2. session2:?update?t1?set?n1=102?where?id?=?2;??
  3. ??????????????????commit;alter?system?checkpoint;??
  4. My?session:?set?transaction?read?only;??
  5. session3:?update?t1?set?n1=99?where?id?=?3;?commit;?alter?system?checkpoint;??
  6. My?session:?select?id,?n1?from?t1;??


我们在自己的会话查询之前，转储一下数据块的结果，不过转储之前执行一下切换检查点命令（alter system checkpoint;），使改变刷新输出到磁盘。

  1. Itl???????????Xid??????????????????Uba?????????Flag??Lck????????Scn/Fsc??
  2. 0x01???0x0009.010.0000062d??0x00c00712.0127.07??--U-????1??fsc?0x0000.0034a241?--flag?U?代表上界提交，意思是这个事务已经提交，只是目前标记还没清理。??
  3. 0x02???0x0005.018.0000062a??0x00c0068a.013f.2f??----????1??fsc?0x0000.00000000?----锁住的是id为1的行，为会话1所锁住的行??
  4. ??
  5. bdba:?0x00416169??
  6. data_block_dump,data?header?at?0x1cd0825c??
  7. ===============??
  8. tsiz:?0x1fa0??
  9. hsiz:?0x18??
  10. pbl:?0x1cd0825c??
  11. ?????76543210??
  12. flag=--------??
  13. ntab=1??
  14. nrow=3??
  15. frre=-1??
  16. fsbo=0x18??
  17. fseo=0x1f71??
  18. avsp=0x1f6b??
  19. tosp=0x1f6b??
  20. ??
  21. block_row_dump:??
  22. tab?0,?row?0,?@0x1f7b??
  23. tl:?10?fb:?--H-FL--?lb:?0x2??cc:?2?--?事务0x2似乎锁住了这一行，其实是锁住了这一行??
  24. col??0:?[?2]??c1?02??
  25. col??1:?[?3]??c2?02?02??
  26. tab?0,?row?1,?@0x1f71??
  27. tl:?10?fb:?--H-FL--?lb:?0x0??cc:?2??
  28. col??0:?[?2]??c1?03??
  29. col??1:?[?3]??c2?02?03??
  30. tab?0,?row?2,?@0x1f85??
  31. tl:?9?fb:?--H-FL--?lb:?0x1??cc:?2?--?事务0x1似乎锁住了这一行，其实没有锁住，只是锁标记没有清除??
  32. col??0:?[?2]??c1?04??
  33. col??1:?[?2]??c1?64??
  34. end_of_block_dump??

?执行查询之后，转储数据块结果(需要先执行alter system checkpoint;)

  1. Itl???????????Xid??????????????????Uba?????????Flag??Lck????????Scn/Fsc??
  2. 0x01???0x0009.010.0000062d??0x00c00712.0127.07??C---????0??scn?0x0000.0034a241?--?flag?C?已提交并清除完成，表明，查询会将已提交的数据清除标记。??
  3. 0x02???0x0005.018.0000062a??0x00c0068a.013f.2f??----????1??fsc?0x0000.00000000?---?锁住的是id为1的行，为会话1所锁住的行??
  4. bdba:?0x00416169??
  5. data_block_dump,data?header?at?0x1cd0825c??
  6. ===============??
  7. tsiz:?0x1fa0??
  8. hsiz:?0x18??
  9. pbl:?0x1cd0825c??
  10. ?????76543210??
  11. flag=--------??
  12. ntab=1??
  13. nrow=3??
  14. frre=-1??
  15. fsbo=0x18??
  16. fseo=0x1f71??
  17. avsp=0x1f6b??
  18. tosp=0x1f6b??
  19. ??
  20. block_row_dump:??
  21. tab?0,?row?0,?@0x1f7b??
  22. tl:?10?fb:?--H-FL--?lb:?0x2??cc:?2?--?事务0x2似乎锁住了这一行，其实是锁住了这一行。??
  23. col??0:?[?2]??c1?02??
  24. col??1:?[?3]??c2?02?02??
  25. tab?0,?row?1,?@0x1f71??
  26. tl:?10?fb:?--H-FL--?lb:?0x0??cc:?2??
  27. col??0:?[?2]??c1?03??
  28. col??1:?[?3]??c2?02?03??
  29. tab?0,?row?2,?@0x1f85??
  30. tl:?9?fb:?--H-FL--?lb:?0x0??cc:?2?--锁标记已经被清除了。??
  31. col??0:?[?2]??c1?04??
  32. col??1:?[?2]??c1?64??
  33. end_of_block_dump??
?

3.4 真实的查询操作

? ? ? ?我们知道，如果我们需要查询一个数据，假设我们是事务1，开始于1:00，于1:05分开始查找A表记录1号。另一个事务2于1:01开始，在1:05分之前将A表记录1号修改了3遍，比如最开始记录1号的值是1，另一个事务将其由1改成2，又改成了3，最后改成了4。另一个事务2于1:10提交的。这样我们的事务1查找的记录1号的值应该为1，但是数据块里面的值已经被修改好几遍了，而且已经变成了4。那么oracle是怎么找到原始值1的呢。下面让我们通过一个小例子来解释这种现象：

? ? ? ?其实，就是讲前面的步骤在执行一下，原谅我直接将上面的命令再拷贝一部分放在下面

3.4.1 准备工作

  1. </pre><pre?code_snippet_id= "571760" ?snippet_file_name= "blog_20150104_10_4627320" ? name = "code" ?class= "sql" > execute ?dbms_random.seed(0)??
  2. ??
  3. set ?doc? off ??
  4. doc??
  5. ??
  6. end ?doc? is ?marked? with ?#??
  7. ??
  8. #??
  9. ??
  10. set ?linesize?120??
  11. set ?trimspool? on ??
  12. set ?pagesize?24??
  13. set ?arraysize?25??
  14. ??
  15. --?set?longchunksize?32768 ??
  16. --?set?long?32768 ??
  17. ??
  18. set ?autotrace? off ??
  19. ??
  20. clear?breaks??
  21. ttitle?off??
  22. btitle?off??
  23. ??
  24. column ?owner?format?a15??
  25. column ?segment_name?format?a20??
  26. column ?table_name?format?a20??
  27. column ?index_name?format?a20??
  28. column ?object_name?format?a20??
  29. column ?subobject_name?format?a20??
  30. column ?partition_name?format?a20??
  31. column ?subpartition_name?format?a20??
  32. column ?column_name?format?a20??
  33. column ?column_expression?format?a40?word?wrap??
  34. column ?constraint_name?format?a20??
  35. ??
  36. column ?referenced_name?format?a30??
  37. ??
  38. column ?file_name?format?a60??
  39. ??
  40. column ?low_value?format?a24??
  41. column ?high_value?format?a24??
  42. ??
  43. column ?parent_id_plus_exp???format?999??
  44. column ?id_plus_exp??????format?990??
  45. column ?plan_plus_exp????????format?a90??
  46. column ?object_node_plus_exp?format?a14??
  47. column ?other_plus_exp???????format?a90??
  48. column ?other_tag_plus_exp???format?a29??
  49. ??
  50. column ?access_predicates????format?a80??
  51. column ?filter_predicates????format?a80??
  52. column ?projection???????format?a80??
  53. column ?remarks??????????format?a80??
  54. column ?partition_start??????format?a12??
  55. column ?partition_stop???????format?a12??
  56. column ?partition_id?????format?999??
  57. column ?other_tag????????format?a32??
  58. column ?object_alias?????format?a24??
  59. ??
  60. column ?object_node??????format?a13??
  61. column ??other???????????format?a150??
  62. ??
  63. column ?os_username??????format?a30??
  64. column ?terminal?????????format?a24??
  65. column ?userhost?????????format?a24??
  66. column ?client_id????????format?a24??
  67. ??
  68. column ?statistic_name?format?a35??
  69. ??
  70. column ?namespace?format?a20??
  71. column ?attribute?format?a20??
  72. ??
  73. column ?hint?format?a40??
  74. ??
  75. column ?start_time???format?a25??
  76. column ?end_time?????format?a25??
  77. ??
  78. column ?time_now?noprint?new_value?m_timestamp??
  79. ??
  80. set ?feedback? off ??
  81. ??
  82. select ?to_char(sysdate, ‘hh24miss‘ )?time_now? from ?dual;??
  83. commit ;??
  84. ??
  85. set ?feedback? on ??
  86. ??
  87. set ?timing? off ??
  88. set ?verify? off ??
  89. ??
  90. alter ?session? set ?optimizer_mode?=?all_rows;??
  91. ??
  92. spool?log??
  93. --?创建表 ??
  94. drop ? table ?t1;??
  95. ??
  96. create ? table ?t1(id?number,?n1?number);??
  97. ??
  98. insert ? into ?t1? values (1,1);??
  99. insert ? into ?t1? values (2,2);??
  100. insert ? into ?t1? values (3,3);??
  101. ??
  102. commit ;??
  103. ??
  104. create ? unique ? index ?t1_i1? on ?t1(id);??
  105. ??
  106. begin ??
  107. ????dbms_stats.gather_table_stats(??
  108. ????????ownname??????=>?user,??
  109. ????????tabname??????=>‘T1‘,??
  110. ????????estimate_percent?=>?100,??
  111. ????????method_opt???=>?‘for?all?columns?size?1‘??
  112. ????);??
  113. end ;??
  114. /??
  115. ??
  116. -- ??
  117. --<span?style="white-space:pre">??</span>For?11g?-?force?to?disc?for?the?dump ??
  118. -- ??
  119. ??
  120. ??
  121. alter ?system? checkpoint ;??
  122. --?创建一个存储过程，用来转储一个表使用的第一个数据块。 ??
  123. create ? or ? replace ? procedure ?dump_table_block(??
  124. ????i_tab_name??????in??varchar2,??
  125. ????i_owner?????????in??varchar2????default?sys_context(‘userenv‘,‘session_user‘)??
  126. )??
  127. as ??
  128. ????m_file_id???number;??
  129. ????m_block?????number;??
  130. ????m_process???varchar2(32);??
  131. ??
  132. begin ??
  133. ??
  134. ????execute?immediate??
  135. ????????‘?select?‘?||??
  136. ????????????‘?dbms_rowid.rowid_relative_fno(rowid),?‘?||??
  137. ????????????‘?dbms_rowid.rowid_block_number(rowid)??‘?||??
  138. ????????‘?from?‘?||??
  139. ????????????i_owner?||???
  140. ????????????‘.‘?||??
  141. ????????????i_tab_name?||??
  142. ????????‘?where?‘?||??
  143. ????????????‘?rownum?=?1?‘??
  144. ????????into??
  145. ????????????m_file_id,?m_block??
  146. ????;??
  147. ??
  148. ????execute?immediate??
  149. ????????‘alter?system?dump?datafile?‘?||?m_file_id?||??
  150. ????????‘?block?‘?||?m_block??
  151. ????;??
  152. ??
  153. -- ??
  154. --??For?non-MTS,?work?out?the?trace?file?name ??
  155. -- ??
  156. ??
  157. ????select??
  158. ????????spid??
  159. ????into??
  160. ????????m_process??
  161. ????from??
  162. ????????v$session???se,??
  163. ????????v$process???pr??
  164. ????where??
  165. -- ??
  166. --??????The?first?option?is?the?9.2?version?for?checking?the?SID ??
  167. --??????The?second?is?a?quick?and?dirty?option?for?8.1.7 ??
  168. --??????provided?SYS?has?made?v$mystat?visible?(or?this?is?the?sys?account) ??
  169. -- ??
  170. --??????se.sid?=?(select?dbms_support.mysid?from?dual) ??
  171. ????????se.sid?=?(select?sid?from?v$mystat?where?rownum?=?1)??
  172. ????and?pr.addr?=?se.paddr??
  173. ????;??
  174. ??
  175. ????dbms_output.new_line;??
  176. ????dbms_output.put_line(‘Trace?file?name?includes:?‘?||?m_process);??
  177. ????dbms_output.new_line;??
  178. ??
  179. exception??
  180. ????when?others?then??
  181. ????????dbms_output.new_line;??
  182. ????????dbms_output.put_line(‘Unspecified?error.‘);??
  183. ????????dbms_output.put_line(‘Check?syntax.‘);??
  184. ????????dbms_output.put_line(‘dump_table_block({table_name},[{owner}]‘);??
  185. ????????dbms_output.new_line;??
  186. ????????raise;??
  187. end ;??
  188. .??
  189. /??
  190. ??
  191. show?errors??
  192. ??
  193. drop ? public ?synonym?dump_table_block;??
  194. create ? public ?synonym?dump_table_block? for ?dump_table_block;??
  195. grant ? execute ? on ?dump_table_block? to ? public ;??

创建一个转储undo块的存储过程

  1. create ? or ? replace ? procedure ?dump_undo_block??
  2. as ??
  3. ????m_xidusn????????number;??
  4. ????m_header_file_id????number;??
  5. ????m_header_block_id???number;??
  6. ????m_start_file_id?????number;??
  7. ????m_start_block_id????number;??
  8. ????m_file_id???????number;??
  9. ????m_block_id??????number;??
  10. ????m_process???????number;??
  11. begin ??
  12. ??
  13. ????select??
  14. ????????xidusn,??
  15. ????????start_ubafil,??
  16. ????????start_ubablk,??
  17. ????????ubafil,???
  18. ????????ubablk??
  19. ????into??
  20. ????????m_xidusn,??
  21. ????????m_start_file_id,??
  22. ????????m_start_block_id,??
  23. ????????m_file_id,??
  24. ????????m_block_id??
  25. ????from??
  26. ????????v$session???ses,??
  27. ????????v$transaction???trx??
  28. ????where??
  29. ????????ses.sid?=?(select?mys.sid?from?V$mystat?mys?where?rownum?=?1)??
  30. ????and?trx.ses_addr?=?ses.saddr??
  31. ????;??
  32. ??
  33. ????select???
  34. ????????file_id,?block_id???
  35. ????into??
  36. ????????m_header_file_id,??
  37. ????????m_header_block_id??
  38. ????from???
  39. ????????dba_rollback_segs???
  40. ????where???
  41. ????????segment_id?=?m_xidusn??
  42. ????;??
  43. ??
  44. ??
  45. ????dbms_output.put_line(‘Header??File:?‘?||?m_header_file_id?||?‘?Header?block:?‘??||?m_header_block_id);??
  46. ????dbms_output.put_line(‘Start???File:?‘?||?m_start_file_id??||?‘?Start?block:?‘???||?m_start_block_id);??
  47. ????dbms_output.put_line(‘Current?File:?‘?||?m_file_id????????||?‘?Current?block:?‘?||?m_block_id);??
  48. ??
  49. ??
  50. ????dbms_system.ksdwrt(1,‘===================‘);??
  51. ????dbms_system.ksdwrt(1,‘Undo?Segment?Header‘);??
  52. ????dbms_system.ksdwrt(1,‘===================‘);??
  53. ??
  54. ????execute?immediate??
  55. ????????‘alter?system?dump?datafile?‘?||?m_header_file_id?||‘?block?‘?||?m_header_block_id;??
  56. ??
  57. ????dbms_system.ksdwrt(1,‘================‘);??
  58. ????dbms_system.ksdwrt(1,‘Undo?Start?block‘);??
  59. ????dbms_system.ksdwrt(1,‘================‘);??
  60. ??
  61. ????execute?immediate??
  62. ????????‘alter?system?dump?datafile?‘?||?m_start_file_id?||‘?block?‘?||?m_start_block_id;??
  63. ??
  64. ????if?m_start_block_id?!=?m_block_id?then??
  65. ??
  66. ????????dbms_system.ksdwrt(1,‘==================‘);??
  67. ????????dbms_system.ksdwrt(1,‘Current?Undo?block‘);??
  68. ????????dbms_system.ksdwrt(1,‘==================‘);??
  69. ??
  70. ????????execute?immediate??
  71. ????????????‘alter?system?dump?datafile?‘?||?m_file_id?||‘?block?‘?||?m_block_id;??
  72. ??
  73. ????end?if;??
  74. ??
  75. ????select??
  76. ????????spid??
  77. ????into??
  78. ????????m_process??
  79. ????from??
  80. ????????v$session???se,??
  81. ????????v$process???pr??
  82. ????where???se.sid?=?(select?sid?from?v$mystat?where?rownum?=?1)??
  83. ????and??
  84. ????????pr.addr?=?se.paddr??
  85. ????;??
  86. ??
  87. ????dbms_output.put_line(‘Trace?file?name?includes:?‘?||?m_process);??
  88. ??
  89. end ;??
  90. /??
  91. ??
  92. grant ? execute ? on ?dump_undo_block? to ? public ;??
  93. ??
  94. drop ??? public ?synonym?dump_undo_block;???
  95. create ? public ?synonym?dump_undo_block? for ?dump_undo_block;??


? ? ? ??

以上步骤只是创建了一个表t1，

? ? ? ?3.4.2 转储表t1的第一个数据块

  1. execute ?dump_table_block( ‘t1‘ )??

? ? ? ? 3.4.3 另外开启一个会话，将id为1的记录n1的值改为101，然后改为102，然后改为103。并记录块的变化和undo块的变化。

  1. select ?*? from ?t1; --清除标记?? ??
  2. alter ?system? checkpoint ; --刷新输出磁盘，执行完等5,6s ??
  3. execute ?dump_table_block( ‘t1‘ ) --转储数据块??<span?style="color:#ff0000;">序号1</span> ??
  4. update ?t1? set ?n1=101? where ?id=1; --第一次更新 ??
  5. alter ?system? checkpoint ; --刷新输出磁盘，执行完等5,6s ??
  6. execute ?dump_table_block( ‘t1‘ ) --转储数据块 ??
  7. execute ?dump_undo_block --转储undo块??<span?style="color:#ff0000;">序号2</span> ??
  8. update ?t1? set ?n1=102? where ?id=1; --第二次更新 ??
  9. alter ?system? checkpoint ; --刷新输出磁盘，执行完等5,6s ??
  10. execute ?dump_table_block( ‘t1‘ ) --转储数据块 ??
  11. execute ?dump_undo_block --转储undo块??<span?style="color:#ff0000;">序号3</span> ??
  12. update ?t1? set ?n1=103? where ?id=1; --第三次更新 ??
  13. alter ?system? checkpoint ; --刷新输出磁盘，执行完等5,6s ??
  14. execute ?dump_table_block( ‘t1‘ ) --转储数据块 ??
  15. execute ?dump_undo_block --转储undo块??<span?style="color:#ff0000;">序号4</span> ??

? ? ? ?3.4.4 找到转储出来的日志文件

? ? ? ?序号1 执行完后

  1. Itl???????????Xid??????????????????Uba?????????Flag??Lck????????Scn/Fsc??
  2. 0x01???0x0003.015.0000065c??0x00c009af.01e8.1c??--U-????3??fsc?0x0000.0035e07c?--理论上，这里的标记应该被清除了??
  3. 0x02???0x0000.000.00000000??0x00000000.0000.00??----????0??fsc?0x0000.00000000??
  4. bdba:?0x00416169??
  5. data_block_dump,data?header?at?0x1ce9705c??

? ? 标记没有清掉，不知道为什么

序号2 执行完后
数据块转储结果

  1. ***?2015-01-04?22:52:48.506??
  2. Start?dump?data?blocks?tsn:?0?file#:1?minblk?90473?maxblk?90473??
  3. Block?dump?from?cache:??
  4. Dump?of?buffer?cache?at?level?4?for?tsn=0,?rdba=4284777??
  5. ??
  6. Itl???????????Xid??????????????????Uba?????????Flag??Lck????????Scn/Fsc??
  7. 0x01???0x0003.015.0000065c??0x00c009af.01e8.1c??C---????0??scn?0x0000.0035e07c?--标记被清除了??
  8. 0x02???0x0004.00b.00000595??0x00c02694.0109.1d??----????1??fsc?0x0000.00000000?--锁住了修改的行??
  9. bdba:?0x00416169??
  10. data_block_dump,data?header?at?0x1ce9705c??

undo块转储结果

  1. ***?2015-01-04?22:53:40.834??
  2. ===================??
  3. Undo?Segment?Header??
  4. ===================??
  5. Start?dump?data?blocks?tsn:?2?file#:3?minblk?176?maxblk?176??
  6. Block?dump?from?cache:??
  7. Dump?of?buffer?cache?at?level?4?for?tsn=2,?rdba=12583088??
  8. .....??
  9. TRN?TBL::??
  10. ???
  11. ??index??state?cflags??wrap#????uel?????????scn????????????dba????????????parent-xid????nub?????stmt_num????cmt??
  12. ??------------------------------------------------------------------------------------------------??
  13. ???0x00????9????0x00??0x0593??0x000c??0x0000.0035df6c??0x00c02693??0x0000.000.00000000??0x00000002???0x00000000??1420382305??
  14. ???0x01????9????0x00??0x056d??0x001e??0x0000.0035dcd1??0x00c02692??0x0000.000.00000000??0x00000001???0x00000000??1420381360??
  15. ???0x02????9????0x00??0x0591??0x0005??0x0000.0035de9e??0x00c02692??0x0000.000.00000000??0x00000001???0x00000000??1420381960??
  16. ???0x03????9????0x00??0x0594??0x0018??0x0000.0035e16f??0x00c02694??0x0000.000.00000000??0x00000001???0x00000000??1420382905??
  17. ???0x04????9????0x00??0x0594??0x001f??0x0000.0035e189??0x00c02694??0x0000.000.00000000??0x00000001???0x00000000??1420382905??
  18. ???0x05????9????0x00??0x0594??0x0009??0x0000.0035deed??0x00c02692??0x0000.000.00000000??0x00000001???0x00000000??1420382080??
  19. ???0x06????9????0x00??0x0594??0x0019??0x0000.0035e080??0x00c02694??0x0000.000.00000000??0x00000001???0x00000000??1420382629??
  20. ???0x07????9????0x00??0x0593??0x0002??0x0000.0035de5e??0x00c02692??0x0000.000.00000000??0x00000001???0x00000000??1420381815??
  21. ???0x08????9????0x00??0x0594??0x000a??0x0000.0035e089??0x00c02693??0x0000.000.00000000??0x00000001???0x00000000??1420382629??
  22. ???0x09????9????0x00??0x0592??0x001d??0x0000.0035df03??0x00c02692??0x0000.000.00000000??0x00000001???0x00000000??1420382080??
  23. ???0x0a????9????0x00??0x0593??0x0011??0x0000.0035e0b8??0x00c02694??0x0000.000.00000000??0x00000001???0x00000000??1420382639??
  24. ???0x0b???10????0x80??0x0595??0x0003??0x0000.00000000??0x00c02694??0x0000.000.00000000??0x00000001???0x00000000??0?<span?style="color:#ff0000;">--跟数据块的事务槽对上了</span>??
  25. ???0x0c????9????0x00??0x0594??0x001c??0x0000.0035dfad??0x00c02693??0x0000.000.00000000??0x00000001???0x00000000??1420382440??
  26. ???0x0d????9????0x00??0x0592??0x0014??0x0000.0035ddac??0x00c02692??0x0000.000.00000000??0x00000001???0x00000000??1420381705??
  27. ?.....??
  28. *-----------------------------??
  29. *?Rec?#0x1d??slt:?0x0b??objn:?77560(0x00012ef8)??objd:?77560??tblspc:?0(0x00000000)??
  30. *???????Layer:??11?(Row)???opc:?1???rci?0x00?????
  31. Undo?type:??Regular?undo????Begin?trans????Last?buffer?split:??No???
  32. Temp ?Object:?? No ???
  33. Tablespace?Undo:??No???
  34. rdba:?0x00000000Ext?idx:?0??
  35. flg2:?0??
  36. *-----------------------------??
  37. uba:?0x00c02694.0109.1c?ctl?max?scn:?0x0000.0035dc32?prv?tx?scn:?0x0000.0035dc72??
  38. txn?start?scn:?scn:?0x0000.0035e1d6?logon?user:?0??
  39. ?prev?brb:?12592785?prev?bcl:?0??
  40. KDO?undo?record:??
  41. KTB?Redo???
  42. op:?0x03??ver:?0x01????
  43. compat?bit:?4?(post-11)?padding:?0??
  44. op:?Z??
  45. KDO?Op?code:?URP?row?dependencies?Disabled??
  46. ??xtype:?XA?flags:?0x00000000??bdba:?0x00416169??hdba:?0x00416168??
  47. itli:?2??ispac:?0??maxfr:?4863??
  48. tabn:?0?slot:?0(0x0)?flag:?0x2c?lock:?0?ckix:?0??
  49. ncol:?2?nnew:?1?size:?-1??
  50. col??1:?[?2]??c1?02<span?style="color:#ff0000;">--?这是数据块事务槽uba的地址指向的undo记录，c1?02?代表着1，说明修改前是1.</span>??

序号3执行完后

数据块转储结果

  1. ***?2015-01-04?23:06:25.105??
  2. Block?dump?from?cache:??
  3. Dump?of?buffer?cache?at?level?4?for?tsn=0,?rdba=4284777??
  4. .....??
  5. Itl???????????Xid??????????????????Uba?????????Flag??Lck????????Scn/Fsc??
  6. 0x01???0x0003.015.0000065c??0x00c009af.01e8.1c??C---????0??scn?0x0000.0035e07c??
  7. 0x02???0x0004.00b.00000595??0x00c02694.0109.1e??----????1??fsc?0x0000.00000000??--uba?变了，由?0x00c02694.0109.1d?变成了??0x00c02694.0109.1e??
  8. </span>bdba:?0x00416169??
  9. data_block_dump,data?header?at?0x1ce9705c??
  10. .....??
  11. block_row_dump:??
  12. tab?0,?row?0,?@0x1f7b??
  13. tl:?10?fb:?--H-FL--?lb:?0x2??cc:?2??
  14. col??0:?[?2]??c1?02??
  15. col??1:?[?3]??c2?02?03??
  16. tab?0,?row?1,?@0x1f8e??
  17. tl:?9?fb:?--H-FL--?lb:?0x0??cc:?2??
  18. col??0:?[?2]??c1?03??
  19. col??1:?[?2]??c1?03??
  20. tab?0,?row?2,?@0x1f85??
  21. tl:?9?fb:?--H-FL--?lb:?0x0??cc:?2??
  22. col??0:?[?2]??c1?04??
  23. col??1:?[?2]??c1?04??
  24. end_of_block_dump??

undo块转储结果

  1. ***?2015-01-04?23:06:31.347??
  2. ===================??
  3. Undo?Segment?Header??
  4. ===================??
  5. Start?dump?data?blocks?tsn:?2?file#:3?minblk?176?maxblk?176??
  6. Block?dump?from?cache:??
  7. Dump?of?buffer?cache?at?level?4?for?tsn=2,?rdba=12583088??
  8. ....??
  9. ??
  10. ??index??state?cflags??wrap#????uel?????????scn????????????dba????????????parent-xid????nub?????stmt_num????cmt??
  11. ??------------------------------------------------------------------------------------------------??
  12. ???0x00????9????0x00??0x0593??0x000c??0x0000.0035df6c??0x00c02693??0x0000.000.00000000??0x00000002???0x00000000??1420382305??
  13. ???0x01????9????0x00??0x056d??0x001e??0x0000.0035dcd1??0x00c02692??0x0000.000.00000000??0x00000001???0x00000000??1420381360??
  14. ???0x02????9????0x00??0x0591??0x0005??0x0000.0035de9e??0x00c02692??0x0000.000.00000000??0x00000001???0x00000000??1420381960??
  15. ???0x03????9????0x00??0x0594??0x0018??0x0000.0035e16f??0x00c02694??0x0000.000.00000000??0x00000001???0x00000000??1420382905??
  16. ???0x04????9????0x00??0x0594??0x001f??0x0000.0035e189??0x00c02694??0x0000.000.00000000??0x00000001???0x00000000??1420382905??
  17. ???0x05????9????0x00??0x0594??0x0009??0x0000.0035deed??0x00c02692??0x0000.000.00000000??0x00000001???0x00000000??1420382080??
  18. ???0x06????9????0x00??0x0594??0x0019??0x0000.0035e080??0x00c02694??0x0000.000.00000000??0x00000001???0x00000000??1420382629??
  19. ???0x07????9????0x00??0x0593??0x0002??0x0000.0035de5e??0x00c02692??0x0000.000.00000000??0x00000001???0x00000000??1420381815??
  20. ???0x08????9????0x00??0x0594??0x000a??0x0000.0035e089??0x00c02693??0x0000.000.00000000??0x00000001???0x00000000??1420382629??
  21. ???0x09????9????0x00??0x0592??0x001d??0x0000.0035df03??0x00c02692??0x0000.000.00000000??0x00000001???0x00000000??1420382080??
  22. ???0x0a????9????0x00??0x0593??0x0011??0x0000.0035e0b8??0x00c02694??0x0000.000.00000000??0x00000001???0x00000000??1420382639??
  23. ???0x0b???10????0x80??0x0595??0x0003??0x0000.00000000??0x00c02694??0x0000.000.00000000??0x00000001???0x00000000??0??
  24. ???0x0c????9????0x00??0x0594??0x001c??0x0000.0035dfad??0x00c02693??0x0000.000.00000000??0x00000001???0x00000000??1420382440??
  25. ???0x0d????9????0x00??0x0592??0x0014??0x0000.0035ddac??0x00c02692??0x0000.000.00000000??0x00000001???0x00000000??1420381705??
  26. ?.......??
  27. *-----------------------------??
  28. *?Rec?#0x1d??slt:?0x0b??objn:?77560(0x00012ef8)??objd:?77560??tblspc:?0(0x00000000)??
  29. *???????Layer:??11?(Row)???opc:?1???rci?0x00?????
  30. Undo?type:??Regular?undo????Begin?trans????Last?buffer?split:??No???
  31. Temp ?Object:?? No ???
  32. Tablespace?Undo:??No???
  33. rdba:?0x00000000Ext?idx:?0??
  34. flg2:?0??
  35. *-----------------------------??
  36. uba:?0x00c02694.0109.1c?ctl?max?scn:?0x0000.0035dc32?prv?tx?scn:?0x0000.0035dc72??
  37. txn?start?scn:?scn:?0x0000.0035e1d6?logon?user:?0??
  38. ?prev?brb:?12592785?prev?bcl:?0??
  39. KDO?undo?record:??
  40. KTB?Redo???
  41. op:?0x03??ver:?0x01????
  42. compat?bit:?4?(post-11)?padding:?0??
  43. op:?Z??
  44. KDO?Op?code:?URP?row?dependencies?Disabled??
  45. ??xtype:?XA?flags:?0x00000000??bdba:?0x00416169??hdba:?0x00416168??
  46. itli:?2??ispac:?0??maxfr:?4863??
  47. tabn:?0?slot:?0(0x0)?flag:?0x2c?lock:?0?ckix:?0??
  48. ncol:?2?nnew:?1?size:?-1??
  49. col??1:?[?2]??c1?02???
  50. ???
  51. *-----------------------------??
  52. *?Rec?#0x1e??slt:?0x0b??objn:?77560(0x00012ef8)??objd:?77560??tblspc:?0(0x00000000)??
  53. *???????Layer:??11?(Row)???opc:?1???rci?0x1d?????
  54. Undo?type:??Regular?undo???Last?buffer?split:??No???
  55. Temp ?Object:?? No ???
  56. Tablespace?Undo:??No???
  57. rdba:?0x00000000??
  58. *-----------------------------??
  59. KDO?undo?record:??
  60. KTB?Redo???
  61. op:?0x02??ver:?0x01????
  62. compat?bit:?4?(post-11)?padding:?0??
  63. op:?C??uba:?0x00c02694.0109.1d?--指向前一个undo记录??
  64. KDO?Op?code:?URP?row?dependencies?Disabled??
  65. ??xtype:?XAxtype?KDO_KDOM2?flags:?0x00000080??bdba:?0x00416169??hdba:?0x00416168??
  66. itli:?2??ispac:?0??maxfr:?4863??
  67. tabn:?0?slot:?0(0x0)?flag:?0x2c?lock:?2?ckix:?0??
  68. ncol:?2?nnew:?1?size:?0??
  69. Vector?content:???
  70. col??1:?[?3]??c2?02?02?--?这是数据块事务槽uba的地址指向的undo记录，c2?02?02?代表着101，说明修改前是101??

序号4执行完后

数据块转储结果

  1. ***?2015-01-04?23:13:22.306??
  2. Start?dump?data?blocks?tsn:?0?file#:1?minblk?90473?maxblk?90473??
  3. Block?dump?from?cache:??
  4. Dump?of?buffer?cache?at?level?4?for?tsn=0,?rdba=4284777??
  5. ....??
  6. ?Itl???????????Xid??????????????????Uba?????????Flag??Lck????????Scn/Fsc??
  7. 0x01???0x0003.015.0000065c??0x00c009af.01e8.1c??C---????0??scn?0x0000.0035e07c??
  8. 0x02???0x0004.00b.00000595??0x00c02694.0109.1f??----????1??fsc?0x0000.00000000?--uba?变了，由?0x00c02694.0109.1e?变成了??0x00c02694.0109.1f??
  9. bdba:?0x00416169??
  10. ....??
  11. block_row_dump:??
  12. tab?0,?row?0,?@0x1f7b??
  13. tl:?10?fb:?--H-FL--?lb:?0x2??cc:?2??
  14. col??0:?[?2]??c1?02??
  15. col??1:?[?3]??c2?02?04??
  16. tab?0,?row?1,?@0x1f8e??
  17. tl:?9?fb:?--H-FL--?lb:?0x0??cc:?2??
  18. col??0:?[?2]??c1?03??
  19. col??1:?[?2]??c1?03??
  20. tab?0,?row?2,?@0x1f85??
  21. tl:?9?fb:?--H-FL--?lb:?0x0??cc:?2??
  22. col??0:?[?2]??c1?04??
  23. col??1:?[?2]??c1?04??
  24. end_of_block_dump??

undo块转储结果

  1. ***?2015-01-04?23:13:31.622??
  2. ===================??
  3. Undo?Segment?Header??
  4. ===================??
  5. Start?dump?data?blocks?tsn:?2?file#:3?minblk?176?maxblk?176??
  6. Block?dump?from?cache:??
  7. Dump?of?buffer?cache?at?level?4?for?tsn=2,?rdba=12583088??
  8. ....??
  9. ?index??state?cflags??wrap#????uel?????????scn????????????dba????????????parent-xid????nub?????stmt_num????cmt??
  10. ??------------------------------------------------------------------------------------------------??
  11. ???0x00????9????0x00??0x0593??0x000c??0x0000.0035df6c??0x00c02693??0x0000.000.00000000??0x00000002???0x00000000??1420382305??
  12. ???0x01????9????0x00??0x056d??0x001e??0x0000.0035dcd1??0x00c02692??0x0000.000.00000000??0x00000001???0x00000000??1420381360??
  13. ???0x02????9????0x00??0x0591??0x0005??0x0000.0035de9e??0x00c02692??0x0000.000.00000000??0x00000001???0x00000000??1420381960??
  14. ???0x03????9????0x00??0x0594??0x0018??0x0000.0035e16f??0x00c02694??0x0000.000.00000000??0x00000001???0x00000000??1420382905??
  15. ???0x04????9????0x00??0x0594??0x001f??0x0000.0035e189??0x00c02694??0x0000.000.00000000??0x00000001???0x00000000??1420382905??
  16. ???0x05????9????0x00??0x0594??0x0009??0x0000.0035deed??0x00c02692??0x0000.000.00000000??0x00000001???0x00000000??1420382080??
  17. ???0x06????9????0x00??0x0594??0x0019??0x0000.0035e080??0x00c02694??0x0000.000.00000000??0x00000001???0x00000000??1420382629??
  18. ???0x07????9????0x00??0x0593??0x0002??0x0000.0035de5e??0x00c02692??0x0000.000.00000000??0x00000001???0x00000000??1420381815??
  19. ???0x08????9????0x00??0x0594??0x000a??0x0000.0035e089??0x00c02693??0x0000.000.00000000??0x00000001???0x00000000??1420382629??
  20. ???0x09????9????0x00??0x0592??0x001d??0x0000.0035df03??0x00c02692??0x0000.000.00000000??0x00000001???0x00000000??1420382080??
  21. ???0x0a????9????0x00??0x0593??0x0011??0x0000.0035e0b8??0x00c02694??0x0000.000.00000000??0x00000001???0x00000000??1420382639??
  22. ???0x0b???10????0x80??0x0595??0x0003??0x0000.00000000??0x00c02694??0x0000.000.00000000??0x00000001???0x00000000??0??
  23. ???0x0c????9????0x00??0x0594??0x001c??0x0000.0035dfad??0x00c02693??0x0000.000.00000000??0x00000001???0x00000000??1420382440??
  24. ???0x0d????9????0x00??0x0592??0x0014??0x0000.0035ddac??0x00c02692??0x0000.000.00000000??0x00000001???0x00000000??1420381705??
  25. .....??
  26. *-----------------------------??
  27. *?Rec?#0x1d??slt:?0x0b??objn:?77560(0x00012ef8)??objd:?77560??tblspc:?0(0x00000000)??
  28. *???????Layer:??11?(Row)???opc:?1???rci?0x00?????
  29. Undo?type:??Regular?undo????Begin?trans????Last?buffer?split:??No???
  30. Temp ?Object:?? No ???
  31. Tablespace?Undo:??No???
  32. rdba:?0x00000000Ext?idx:?0??
  33. flg2:?0??
  34. *-----------------------------??
  35. uba:?0x00c02694.0109.1c?ctl?max?scn:?0x0000.0035dc32?prv?tx?scn:?0x0000.0035dc72??
  36. txn?start?scn:?scn:?0x0000.0035e1d6?logon?user:?0??
  37. ?prev?brb:?12592785?prev?bcl:?0??
  38. KDO?undo?record:??
  39. KTB?Redo???
  40. op:?0x03??ver:?0x01????
  41. compat?bit:?4?(post-11)?padding:?0??
  42. op:?Z??
  43. KDO?Op?code:?URP?row?dependencies?Disabled??
  44. ??xtype:?XA?flags:?0x00000000??bdba:?0x00416169??hdba:?0x00416168??
  45. itli:?2??ispac:?0??maxfr:?4863??
  46. tabn:?0?slot:?0(0x0)?flag:?0x2c?lock:?0?ckix:?0??
  47. ncol:?2?nnew:?1?size:?-1??
  48. col??1:?[?2]??c1?02??
  49. ???
  50. *-----------------------------??
  51. *?Rec?#0x1e??slt:?0x0b??objn:?77560(0x00012ef8)??objd:?77560??tblspc:?0(0x00000000)??
  52. *???????Layer:??11?(Row)???opc:?1???rci?0x1d?????
  53. Undo?type:??Regular?undo???Last?buffer?split:??No???
  54. Temp ?Object:?? No ???
  55. Tablespace?Undo:??No???
  56. rdba:?0x00000000??
  57. *-----------------------------??
  58. KDO?undo?record:??
  59. KTB?Redo???
  60. op:?0x02??ver:?0x01????
  61. compat?bit:?4?(post-11)?padding:?0??
  62. op:?C??uba:?0x00c02694.0109.1d--指向前一个undo记录??
  63. KDO?Op?code:?URP?row?dependencies?Disabled??
  64. ??xtype:?XAxtype?KDO_KDOM2?flags:?0x00000080??bdba:?0x00416169??hdba:?0x00416168??
  65. itli:?2??ispac:?0??maxfr:?4863??
  66. tabn:?0?slot:?0(0x0)?flag:?0x2c?lock:?2?ckix:?0??
  67. ncol:?2?nnew:?1?size:?0??
  68. Vector?content:???
  69. col??1:?[?3]??c2?02?02??
  70. ???
  71. *-----------------------------??
  72. *?Rec?#0x1f??slt:?0x0b??objn:?77560(0x00012ef8)??objd:?77560??tblspc:?0(0x00000000)??
  73. *???????Layer:??11?(Row)???opc:?1???rci?0x1e?????
  74. Undo?type:??Regular?undo???Last?buffer?split:??No???
  75. Temp ?Object:?? No ???
  76. Tablespace?Undo:??No???
  77. rdba:?0x00000000??
  78. *-----------------------------??
  79. KDO?undo?record:??
  80. KTB?Redo???
  81. op:?0x02??ver:?0x01????
  82. compat?bit:?4?(post-11)?padding:?0??
  83. op:?C??uba:?0x00c02694.0109.1e?--指向前一个undo记录??
  84. </span>KDO?Op?code:?URP?row?dependencies?Disabled??
  85. ??xtype:?XAxtype?KDO_KDOM2?flags:?0x00000080??bdba:?0x00416169??hdba:?0x00416168??
  86. itli:?2??ispac:?0??maxfr:?4863??
  87. tabn:?0?slot:?0(0x0)?flag:?0x2c?lock:?2?ckix:?0??
  88. ncol:?2?nnew:?1?size:?0??
  89. Vector?content:???
  90. col??1:?[?3]??c2?02?03?--?这是数据块事务槽uba的地址指向的undo记录，c2?02?03代表着102，说明修改前是102.??

原文：http://liwenshui322.iteye.com/blog/2172702

内容总结

以上是互联网集市为您收集整理的Oracle事务原理探究2--读书笔记五全部内容，希望文章能够帮你解决Oracle事务原理探究2--读书笔记五所遇到的程序开发问题。 如果觉得互联网集市技术教程内容还不错，欢迎将互联网集市网站推荐给程序员好友。

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