LOG MINER issue

[mahajanakhil198]

I am trying to use logminer to find out a particular user who deleted something from master table.

I have mined logs using DBMS_LOGMNR_D.build,DBMS_LOGMNR.ADD_LOGFILE and dbms_logmnr.start_logmnr procedures.

But session_info,session#,serial# columns of v$logmnr_contents show NULL,0,0 values respectively. How can I account for the values in these columns? It's urgent.

[mahajanakhil198]

Update is that I have resolved the issue but it is applicable only to log mining done done from now onwards.

The following command did it:

alter database add supplemental log data;


But the execution of this command took a very long time (around an hour or so). I really doubt if it will have any effect on the performance of database in future.
If anybody can throw some light on the side effects of adding supplemental log data, I would highly appreciate.
Though I have gone through the description of column "supplemental_log_data_min" of v$database. But I have not found it much useful. I would keep you all updated if I get to know something.