What format should the start and end LSN parameters be to sys.fn_dblog?

Question

When I execute

SELECT [Current LSN]
FROM sys.fn_dblog(NULL,NULL)

The LSN values are presented in the format

'000000CB:00000055:0002'

However when I try and pass the start and end LSN parameters explicitly to fn_dblog in that format

SELECT *
FROM   sys.fn_dblog('000000CB:00000055:0002', '000000CC:00000088:000A') 

I get an error, saying...

Msg 9005, Level 16, State 3, Line 1 Either start LSN or end LSN specified in OpenRowset(DBLog, ...) is invalid.

Why doesn't this work and what format do they need to be in?

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I did some studies based on this site about LSN and log files... but, or I got an error, or, when I execute the command with the two parameters, I just got 2 rows of informations... I considerate that is intresting, because, when I use a program to read the data-log, I got all the information's.

How I can make to read all the data and informations of log using SQL ?

Answer 1

FYI: As of SQL Server 12 (I haven't tested others but as far back as SQL 2000 by the looks), you can add '0x' to the beginning of the LSN text.

SELECT TOP 1 [Current LSN] FROM fn_dblog('0x000000CB:00000055:0002',null)

Obviously if the query returns with no errors and the same LSN in the result then you should be good to go.

Credit to Art of SQL