Database Reference
In-Depth Information
comment='text'
is an optional comment you can associate with this setting of the parameter.
The comment will appear in the
UPDATE_COMMENT
field of the
V$PARAMETER
view. If you use
the option to save the change to the
SPFILE
, the comment will be written into the
SPFILE
and
preserved across server restarts as well, so future restarts of the database will see the comment.
•
•
deferred
specifies whether the system change takes place for subsequent sessions only
(not currently established sessions, including the one making the change). By default,
the
ALTER SYSTEM
command will take effect immediately, but some parameters can't be changed
immediately—they can be changed only for newly established sessions. We can use the
following query to see what parameters mandate the use of
deferred
:
EODA@ORA12CR1> select name
2 from v$parameter
3 where issys_modifiable='DEFERRED'
4 /
NAME
------------------------------
backup_tape_io_slaves
recyclebin
audit_file_dest
object_cache_optimal_size
object_cache_max_size_percent
sort_area_size
sort_area_retained_size
olap_page_pool_size
8 rows selected.
■
Your results may differ; from version to version, the list of which parameters may be set online—but must be
deferred—can and will change.
Note
The code shows that
SORT_AREA_SIZE
is modifiable at the system level, but only in a deferred manner. The
following code shows what happens if we try to modify its value with and without the deferred option:
EODA@ORA12CR1> alter system set sort_area_size = 65536;
alter system set sort_area_size = 65536
*
ERROR at line 1:
ORA-02096: specified initialization parameter is not modifiable with this
option
EODA@ORA12CR1> alter system set sort_area_size = 65536 deferred;
System altered.
