LSN could not be found, neither in the transaction log nor in the backup log

[Naga_vivek]

Hi Team,

We are encountering the following LSN error:

"LSN '<LSN number>' could not be found, neither in the transaction log nor in the backup log"
WARNING_GENERAL Task '<replicate task name>' encountered a recoverable error
ERROR_GENERAL "Stream component '<src name>' terminated
Stream component failed at subtask 0, component '<src name>'
Error executing source loop"

Since the LSN is lost and we cannot retrieve it, we have received two approaches from the Qlik team to fix this issue:

1. Reload the target.
2. Start from the minimum LSN using the following query:

SELECT MIN([Current LSN]) FROM fn_dblog(NULL, NULL);

However, we have concerns about potential data loss, especially with approach 2 (resuming from the minimum LSN). We want to know if there are any ways to fix this issue without running a full load (reloading the target) and without any data loss.

Note: Since we are using Microsoft SQL MI servers, we are unable to recover the lost LSN.

Could you please provide guidance on how to address this issue without data loss?

Thank you
N Vivek

[Dana_Baldwin · Accepted solution]

Hi @Naga_vivek 

I apologize but since you are not able to restore the purged backup TLOG those are your only two options. Without a complete set of transaction logs the task cannot continue CDC without missing data unless you reload the target tables and continue CDC from that point.

Please adjust / increase retention on backup TLOGs to prevent this in the future.

Thanks,

Dana