1, 第一個塊(offset=0x0)

0x00 - 0x03: 未知

0x04 - 0x07: 日志文件的塊大小

0x08 - 0x0b: 日志文件的塊數

0x0c - 0x0e: 平臺標識串

2, 第二個塊(offset = block_size)

0x00 - 0x03: 日志序列號

0x04 - 0x07: 日志文件塊號

0x08 - 0x0b: 未知

0x0b - 0x0f: 未知

0x10 - 0x13: dbms軟件版本號

0x14 - 0x17: 日志文件版本號

0x18 - 0x1b: dbid

0x1c - 0x23: db name

0x24 - 0x27: control sequence

0x28 - 0x2b: 日志文件的塊數

0x2c - 0x2f: 日志文件的塊大小

0x30 - 0x31: 日志組序號

0x32 - 0x33: 文件類型

0x5c - 0x9a: 日志文件說明

0x9b - 0x9b: 未知

0x9c - 0x9e: 下一個可用塊(next avaiable block)

0xa0 - 0xa3: reset logs count

0xa4 - 0xa7: reset scn base

0xa8 - 0xa9: reset scn wrap

0xa4 - 0xb9: low scn number

0xba - 0xbf: low scn time

0xc0 - 0xc5: next scn number

0xc6 - 0xcb: next scn time

3, 第3-n個block

0x00 - 0x03: 日志序列號

0x04 - 0x07: 日志文件塊號

0x08 - 0x0b: log時間

0x0c - 0x0d: 第一條記錄的偏移, 0表示沒有記錄

0x0e - 0x0f: 未知(應當是chkval之類的)

<<日志記錄>>

{

0x00 - 0x03: 日志記錄長度, 加上第一條記錄的偏移為第二條記錄的偏移

0x04 - 0x04: valid標志

0x05 - 0x05: subscn (oracle 9i, 8i保留)

0x06 - 0x07: scn wrap

0x08 - 0x0b: scn base

<>

{

0x0c - 0x0c: operation layer

0x0d - 0x0d: operation code

0x0e - 0x0f: change # cls

0x10 - 0x11: change # afn

0x12 - 0x13: change # type

0x14 - 0x17: change # dba

0x18 - 0x1d: change # scn

0x1e - ....: redo data

}

}

4, operation layer & operation code

layer = 5 (transaction undo)

op code = 3 (rollout a transaction begin)

= 4 (commit transaction/transaction table update - no undo record)

= 7 (begin transaction/transaction table update)

= 8 (mark transaction as dead)

layer = 11 (row access)

op code = 1 interpret undo record

= 2 insert row piece

= 3 drop row piece

= 4 lock row piece

= 5 update row piece

= 6 overwrite row piece

= 7 manipulate first column

= 8 change forward address

= 9 change cluster key index

= 10 set key links

= 11 quick multi-insert (insert ... select ...)

= 12 quick multi-delete

= 13 toggle block header flags