Some Column Values Change To UNKNOWN Or NULL When Querying V$LOGMNR_CONTENTS (Doc ID 1307497.1)

Last updated on SEPTEMBER 23, 2013

Applies to:

Oracle Database - Enterprise Edition - Version 10.2.0.4 to 11.2.0.2 [Release 10.2 to 11.2]
Information in this document applies to any platform.
***Checked for relevance on 23-Sep-2013***

Symptoms

If starting Logminer with DBMS_LOGMNR.START_LOGMNR with DDL_DICT_TRACKING and STARTSCN options and querying V$LOGMNR_CONTENTS multiple times, one can notice that the session or transaction audit columns (such as TX_NAME, USERNAME, OS_USERNAME, MACHINE_NAME, AUDIT_SESSIONID, SESSION#, SERIAL# or SESSION_INFO) will have NULL or UNKNOWN values on second and subsequent query executions but not on first query execution.

For example:

Result from FIRST query execution (correct):

select username, count(*)
from v$logmnr_contents c
group by username
order by username;
 
USERNAME                       COUNT(*)
------------------------------ ----------
TC1                                 23911


Result from SECOND query execution (incorrect):

USERNAME                       COUNT(*)
------------------------------ ----------
UNKNOWN                             23911

Cause

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