How to clear alerts in enterprise manager (database control)

When alert appear in enterprise manager and with some action solve, it may stay in enterprise manager as shown picture:

Here I'll show you how to clear this unnecessary information.
login into database with sysman user and execute this script:

SELECT t.target_name,
       t.target_type,
       collection_timestamp,
       MESSAGE,
          'exec em_severity.delete_current_severity('''
       || t.target_guid
       || ''','''
       || metric_guid
       || ''','''
       || key_value
       || ''')'
          em_severity
  FROM    sysman.mgmt_targets t
       INNER JOIN
          sysman.mgmt_current_severity s
       ON t.target_guid = s.target_guid;

result:

after that run this scripts

SQL> exec em_severity.delete_current_severity('C894D538793FFA3B4727BCBCD84D4925',
'3F2BBE6BF105C0D16A3710F2868B8399','RECOVERY AREA');

PL/SQL procedure successfully completed.

SQL> commit;

Commit complete.

same way you can clear entire alerts.

Where is the location of alert log file in oracle?

We often get questions about how to find alert.log file location in oracle, it's easy to find location of alert.log file, below is two different procedures:

Here is video of these procedures - oracle location of alert log file

1) you can find alert.log location with parameter background_dump_dest.

SQL> select value from v$parameter where name='background_dump_dest';

VALUE
--------------------------------------------------------------------------------
/u0/app/oracle/diag/rdbms/orcl/orcl/trace

-bash-3.2$ cd /u0/app/oracle/diag/rdbms/orcl/orcl/trace
-bash-3.2$ ls
This is alert.log file ----> alert_orcl.log  orcl_j001_25686.trm  orcl_ora_20641.trc

or in SQL *PLUS

SQL> show parameter background_dump_dest

2) To find the location of the diagnostic_dest, you can use the following select

SQL> select value from v$parameter where name='diagnostic_dest';

VALUE
--------------------------------------------------------------------------------
/u0/app/oracle

To know the current ORACLE_SID, you can use following select:

SQL> select instance_name from v$instance;

INSTANCE_NAME
----------------
ORCL

Alert log file consist alert_.log

Therefore my alert log file is : /u0/app/oracle/diag/rdbms/orcl/orcl/trace/alert_orcl.log

good luck.