1、查看segment advisor 方法一： select * fromtable(dbms_space.asa_recommendations(TRUE,FALSE,FALSE)); dbms_space.asa_recommentdations的三个参数： all_runs TURE返回历次运行的结果，FALSE则返回最近一次运行的结果 show_manual TURE返回手工执行se
1、查看segment advisor
方法一：
select * fromtable(dbms_space.asa_recommendations('TRUE','FALSE','FALSE'));
dbms_space.asa_recommentdations的三个参数：
all_runs TURE返回历次运行的结果，FALSE则返回最近一次运行的结果
show_manual TURE返回手工执行segment advisor的执行结果，FALSE返回自动执行的segment advisor的执行结果
show_finding TURE仅显示结果不显示建议，FALSE显示结果和建议
方法二：
select f.task_name,
execution_start,
o.attr2,
o.type,
o.attr3,
f.message,
f.more_info
from dba_advisor_executions e,
dba_advisor_findings f,
dba_advisor_objects o
where o.task_id = f.task_id
and o.object_id = f.object_id
and f.task_id = e.task_id
and e.advisor_name = 'Segment Advisor'
order by f.task_name;
segment advisor会自动的定期执行，查看其执行情况的视图是dba_auto_segadv_summary
查看ora advisor的视图
dba_advisor_executions
dba_advisor_findings
dba_advisor_objects
2、手工生成segment advisor
查看advisor name
select * fromdba_advisor_definitions;
ADVISOR_IDADVISOR_NAME PROPERTY
---------------------------------------- ----------
1 ADDM 1
2 SQL Access Advisor 271
3 Undo Advisor 1
4 SQL Tuning Advisor 935
5 Segment Advisor 67
6 SQL Workload Manager 0
7 Tune MView 31
8 SQL Performance Analyzer 935
9 SQL Repair Advisor 679
10 Compression Advisor 3
生成segmentadvisor
DECLARE
my_task_id number;
obj_id number;
my_task_name varchar2(100);
my_task_desc varchar2(500);
BEGIN
my_task_name := 'BIG_TABLE Advice';
my_task_desc := 'Manual Segment Advisor Run';
-- Step 1创建一个任务
dbms_advisor.create_task(advisor_name =>'Segment Advisor',
task_id => my_task_id,
task_name => my_task_name,
task_desc => my_task_desc);
-- Step 2为这个任务分配一个对象
dbms_advisor.create_object(task_name => my_task_name,
object_type =>'TABLE',
attr1 => 'SYSTEM',
attr2 => 'AL_APPLY',
attr3 => NULL,
attr4 => NULL,
attr5 => NULL,
object_id => obj_id);
-- Step 3设置任务参数
dbms_advisor.set_task_parameter(task_name=> my_task_name,
parameter=> 'recommend_all',
value => 'TRUE');
-- Step 4执行这个任务
dbms_advisor.execute_task(my_task_name);
END;
/
说明：
Table 14-2 DBMS_ADVISOR packageprocedures relevant to the Segment Advisor
Package Procedure Name | Description |
CREATE_TASK | Use this procedure to create the Segment Advisor task. Specify 'Segment Advisor' as the value of the ADVISOR_NAME parameter. |
CREATE_OBJECT | Use this procedure to identify the target object for segment space advice. The parameter values of this procedure depend upon the object type. Table 14-3 lists the parameter values for each type of object. Note: To request advice on an IOT overflow segment, use an object type of TABLE, TABLE PARTITION, or TABLE SUBPARTITION. Use the following query to find the overflow segment for an IOT and to determine the overflow segment table name to use with CREATE_OBJECT: select table_name, iot_name, iot_type from dba_tables; |
SET_TASK_PARAMETER | Use this procedure to describe the segment advice that you need. Table 14-4 shows the relevant input parameters of this procedure. Parameters not listed here are not used by the Segment Advisor. |
EXECUTE_TASK | Use this procedure to execute the Segment Advisor task. |
Table 14-3 Input forDBMS_ADVISOR.CREATE_OBJECT
Input Parameter | ||||
OBJECT_TYPE | ATTR1 | ATTR2 | ATTR3 | ATTR4 |
TABLESPACE | tablespace name | NULL | NULL | Unused. Specify NULL. |
TABLE | schema name | table name | NULL | Unused. Specify NULL. |
INDEX | schema name | index name | NULL | Unused. Specify NULL. |
TABLE PARTITION | schema name | table name | table partition name | Unused. Specify NULL. |
INDEX PARTITION | schema name | index name | index partition name | Unused. Specify NULL. |
TABLE SUBPARTITION | schema name | table name | table subpartition name | Unused. Specify NULL. |
INDEX SUBPARTITION | schema name | index name | index subpartition name | Unused. Specify NULL. |
LOB | schema name | segment name | NULL | Unused. Specify NULL. |
LOB PARTITION | schema name | segment name | lob partition name | Unused. Specify NULL. |
LOB SUBPARTITION | schema name | segment name | lob subpartition name | Unused. Specify NULL. |
Table 14-4 Input forDBMS_ADVISOR.SET_TASK_PARAMETER
Input Parameter | Description | Possible Values | Default Value |
time_limit | The time limit for the Segment Advisor run, specified in seconds. | Any number of seconds | UNLIMITED |
recommend_all | Whether the Segment Advisor should generate findings for all segments. | TRUE: Findings are generated on all segments specified, whether or not space reclamation is recommended. FALSE: Findings are generated only for those objects that generate recommendations for space reclamation. | TRUE |
Example:
variable id number;
begin
declare
name varchar2(100);
descr varchar2(500);
obj_id number;
begin
name:='Manual_Employees';
descr:='Segment Advisor Example';
dbms_advisor.create_task (
advisor_name => 'Segment Advisor',
task_id => :id,
task_name => name,
task_desc => descr);
dbms_advisor.create_object (
task_name => name,
object_type => 'TABLE',
attr1 => 'HR',
attr2 => 'EMPLOYEES',
attr3 => NULL,
attr4 => NULL,
attr5 => NULL,
object_id => obj_id);
dbms_advisor.set_task_parameter(
task_name => name,
parameter => 'recommend_all',
value => 'TRUE');
dbms_advisor.execute_task(name);
end;
end;
/
查看segmentadvisor结果
SELECT
'Segment Advice --------------------------'||chr(10) ||
'TABLESPACE_NAME : ' || tablespace_name || chr(10) ||
'SEGMENT_OWNER : ' || segment_owner || chr(10) ||
'SEGMENT_NAME : ' || segment_name || chr(10) ||
'ALLOCATED_SPACE : ' || allocated_space || chr(10) ||
'RECLAIMABLE_SPACE: ' || reclaimable_space ||chr(10) ||
'RECOMMENDATIONS : ' || recommendations || chr(10) ||
'SOLUTION 1 : ' || c1 || chr(10) ||
'SOLUTION 2 : ' || c2 || chr(10) ||
'SOLUTION 3 : ' || c3 Advice
FROM
TABLE(dbms_space.asa_recommendations('TRUE','TRUE', 'FALSE'));
或者：
SELECT
'Task Name : ' || f.task_name || chr(10) ||
'Segment Name : ' || o.attr2 || chr(10) ||
'Segment Type : ' || o.type || chr(10) ||
'Partition Name : ' || o.attr3 || chr(10) ||
'Message : ' || f.message || chr(10) ||
'More Info : ' || f.more_info TASK_ADVICE
FROMdba_advisor_findings f
,dba_advisor_objects o
WHERE o.task_id =f.task_id
AND o.object_id =f.object_id
AND f.task_name like'BIG_TABLE Advice'
ORDER BYf.task_name;
删除segmentadvisor
execdbms_advisor.delete_task('BIG_TABLE Advice');
释放未使用的表的空间
alter tabletablename enable rowmovement;
alter tabletablename shrink spcace;
alter table tablename shrink spcace cascade;(级联收缩索引空间)
alter table tablename shrink spcace compact;(只整理碎片，不调整高水位线)--如果整理碎片和降低高水位话费时间会很长，用于分开操作