SPM: SMB space usage (810418176) exceeds 10.000000% of SYSAUX size (6492782592).

SQL Plan baselines are strored in the tablespace SYSAUX and by default, at most 10 percent of the tablespace can be used for this purpose. You can get the current value throught the data dictionary view DBA_SQL_MANAGEMENT_CONFIG.

SQL> select parameter value 
from dba_sql_management_config 
where parameter_name='SPACE_BUDGET_PERCENT';


PARAMETER_VALUE
---------------
         10

When this default value (default threshold) is exceeded, a warning message gets written in the alert log of the database, it is not any error but just a warning so don't bothered about it. If it occurs intermittently, you can change(increase) its default value using the procedure CONFIG in the package DBMS_SPM.

Supported values for its threshold is between 1 percent to 50 percent. Below example illustrate how to change it to 20 percent.

If PARAMETER_VALUE is set to NULL then default value is restored, i.e. 10 percent.

SQL> dbms_spm.configure(
parameter_name => 'space_budget_percent',
parameter_value => 20
);

After successful execution of procedure restart your oracle instance and now you will notice that there would be no more such entry in your alert log file.

SQL> shutdown immediate;
Database closed.
Database dismounted.
ORACLE instance shut down.

SQL> startup mount
ORACLE instance started.
Total System Global Area 5361582080 bytes
Fixed Size                  2185112 bytes
Variable Size            1728055400 bytes
Database Buffers         3623878656 bytes
Redo Buffers                7462912 bytes
Database mounted.

SQL> alter database open;
Database altered.

Hope it wold help someone....!!