查看SQL Server操作日志

SQL Server提供了一个undocumented的函数fn_dblog可以让我们查看活动的transaction log。

语法如下：

::fn_dblog(@StartingLSN,@EndingLSN)

如果参数都为NULL默认是抓取所有的交易信息。

使用这个函数我们可以查询DML,DDL信息，比如数据删除，修改更新等等。下面我们来看一个数据更新的例子：

create table test(namevarchar(10))

--插入条数据

insert into testvalues('allen test')

go 5


---查询对表Test的修改

select [Transaction Name],Operation,AllocUnitId,AllocUnitName,[Begin Time]fromfn_dblog(null,null)

where AllocUnitName ='dbo.test'andOperation='LOP_INSERT_ROWS'

----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

NULLLOP_INSERT_ROWS72057594040090624 dbo.test NULL

NULLLOP_INSERT_ROWS72057594040090624 dbo.test NULL

NULLLOP_INSERT_ROWS72057594040090624 dbo.test NULL

NULLLOP_INSERT_ROWS72057594040090624 dbo.test NULL

NULLLOP_INSERT_ROWS72057594040090624 dbo.test

--删除表

drop table test

----从Log中查询对表的删除

select [Transaction Name],Operation,AllocUnitId,AllocUnitName,[Begin Time]fromfn_dblog(null,null)

where [Transaction Name] = 'DROPOBJ'

----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

DROPOBJLOP_BEGIN_XACT NULL NULL

--查询Page Split

select Operation, AllocUnitName,COUNT(*)asNumberofIncidents

from ::fn_dblog(null,null)

where Operation =N'LOP_DELETE_SPLIT'

group byOperation, AllocUnitName

注意：从fn_dblog 查出来的LSN是不能直接作为参数的，需要将16进制转化为numeric：

The LSN we havefrom the log dump above is 0000009d:0000021e:0001.To convert it:

Take the rightmost 4 characters (2-byte log record     number) and convert to a 5-character decimal number, including leading     zeroes, to get stringA
Take the middle number (4-byte log block number) and     convert to a 10-character decimal number, including leading zeroes, to get     stringB
Take the leftmost number (4-byte VLF sequence number)     and convert to a decimal number, with no leading zeroes, to get stringC
The LSN string we need is stringC + stringB + stringA
So0000009d:0000021e:0001 becomes '157' + '0000000542'+ '00001' ='157000000054200001'.（来自SQLSkills）

 

可以参考下面的脚本：

 

DECLARE @pageID$ NVARCHAR(23), @pageIDNVARCHAR(50), @sqlCmdNVARCHAR(4000);

SET @pageID$ ='0001:0000004d'--- PageID

 

SELECT @pageID =

CONVERT(VARCHAR(4),CONVERT(INT,CONVERT(VARBINARY,

SUBSTRING(@pageID$, 0, 5), 2)))

+ ',' +

CONVERT(VARCHAR(8),CONVERT(INT,CONVERT(VARBINARY,

SUBSTRING(@pageID$, 6, 8), 2)))

 

---查看Page内容

SET @sqlCmd = 'DBCC PAGE (''Crack_Me'','+ @pageID + ',3) WITH TABLERESULTS'

EXECUTE(@sqlCmd)

另外这个函数只能对当前活动的Log生效，如果Log备份之后就无法读取了，我们需要用另外一个函数（fn_dump_dblog http://blog.csdn.net/smithliu328/article/details/7817540）从备份中读取。上面也只是能够看到数据被修改，但是无法做到恢复数据。

目前网上有人做了一些脚本可以实现恢复，我现在正在做测试，如果能够成功的话后面会把脚本发出来。

https://blog.csdn.net/kevinsqlserver/article/details/7800628