【12c】新特性：一文带你详细了解Oracle 12c 数据库的自动数据优化（ADO）
写在前面
Oracle 12c 可以通过热图和自动数据优化（ADO）实现信息生命周期的管理（ILM），上篇介绍了热图，本篇将对自动数据优化进行展开，通过热图和自动数据优化，最终实现信息生命周期管理。
1 自动数据优化工作流程
使用自动数据优化，必须先在系统级别启用热图，通过修改初始化参数heat_map即可，启用热图后，数据库会自动在段上进行热图统计信息的收集，可通过数据字典视图查看热图相关的信息，具体可参考：Oracle 12c Heat Map 热图 。
2 创建策略
策略可以在执行create table或alter table时在行、段、表空间级别进行创建，在满足指定的策略时可以进行数据的自动压缩和移动，从而完成数据的归档。
2.1 策略创建语法
通过下面的语法结构我们可以知道以下内容。
1）ADO主要在两个层面实现数据的优化，分别为
- 压缩
- 存储分层
2）压缩的类型
- ROW STORE COMPRESS BASIC（Bisic压缩）
- ROW STORE COMPRESS ADVCANCED（Advanced压缩）
- COLUMN STORE COMPRESS FOR QUERY LOW/HIGH（HCC Query压缩）
- COLUMN STORE COMPRESS FOR ArCHIVE LOW/HIGH（HCC Archive压缩）
3）压缩作用域
- Tablespace 表空间：默认设置存储对象
- Group 组：目标对象的索引和LOB
- Segment 段：表、分区和子分区
- Row 行：数据行
4）访问模式
- NO ACESS：无INSERT、DELETE、UPDATE、SELECT
- NO MODIFICATION：无INSERT、DELETE、UPDATE
- CREATION：创建段
5）启动时机
- DAY
- MONTH
- YEAR
ilm_clause::=
ilm_policy_clause::=
ilm_compression_policy::=
table_compression::=
ilm_tiering_policy::=
ilm_time_period::=
2.2 示例：演示压缩
0）查看heat_map初始化参数配置
ALEN@PROD2> show parameter heat_map
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
heat_map string ON1）创建测试表，可以看出，数据行为259418，表没有被压缩，表占用空间为11534336 BYTES
ALEN@PROD2> create table sales_ado as select * from sales;
Table created.
ALEN@PROD2> select count(1) from sales_ado;
COUNT(1)
----------
259418
ALEN@PROD2> select t.compression,t.compress_for from user_tables t where t.table_name='SALES_ADO';
COMPRESS COMPRESS_FOR
-------- ------------------------------
DISABLED
ALEN@PROD2> select t.bytes from user_segments t where t.segment_name='SALES_ADO';
BYTES
----------
115343362）创建策略
ALEN@PROD2> alter table sales_ado ilm add policy row store compress advanced segment after 30 days of no modification;
Table altered.3）查看创建的策略
ALEN@PROD2> col policy_name for a10
ALEN@PROD2> col policy_type for a30
ALEN@PROD2> select policy_name,policy_type,enabled,deleted from user_ilmpolicies;
POLICY_NAM POLICY_TYPE ENABLED DELETED
---------- ------------------------------ ------- -------
P102 DATA MOVEMENT YES NO4）查看策略对象
ALEN@PROD2> col object_owner for a10
ALEN@PROD2> col object_name for a20
ALEN@PROD2> set linesize 200
ALEN@PROD2> select policy_name,object_owner,object_name,object_type,inherited_from,enabled,deleted from user_ilmobjects;
POLICY_NAM OBJECT_OWN OBJECT_NAME OBJECT_TYPE INHERITED_FROM ENA DEL
---------- ---------- -------------------- ------------------ -------------------- --- ---
P102 ALEN SALES_ADO TABLE POLICY NOT INHERITED YES NO5）查看热图信息
ALEN@PROD2> select object_name,track_time,segment_write,full_scan,lookup_scan from user_heat_map_seg_histogram where object_name='SALES_ADO';
OBJECT_NAME TRACK_TIME SEG FUL LOO
-------------------- ------------------- --- --- ---
SALES_ADO 2020-05-26 18:59:53 NO YES NO
ALEN@PROD2> select object_name,segment_write_time,segment_read_time,full_scan,lookup_scan from user_heat_map_segment where object_name='SALES_ADO';
OBJECT_NAME SEGMENT_WRITE_TIME SEGMENT_READ_TIME FULL_SCAN LOOKUP_SCAN
-------------------- ------------------- ------------------- ------------------- -------------------
SALES_ADO 2020-05-26 19:01:146）因为策略是30天内没有修改的话，就启用高级压缩，下面进行模拟，将时间向前推33天
SYS@PROD2> exec dbms_ilm_admin.set_heat_map_table('ALEN','SALES_ADO','',sysdate-33,2);
PL/SQL procedure successfully completed.7）再次查看热图信息，可以看出 2020-04-23之后没有对表做修改
ALEN@PROD2> select object_name,track_time,segment_write,full_scan,lookup_scan from user_heat_map_seg_histogram where object_name='SALES_ADO';
OBJECT_NAME TRACK_TIME SEG FUL LOO
-------------------- ------------------- --- --- ---
SALES_ADO 2020-05-26 19:06:38 NO YES NO
SALES_ADO 2020-04-23 19:06:03 NO NO NO
ALEN@PROD2> select object_name,segment_write_time,segment_read_time,full_scan,lookup_scan from user_heat_map_segment where object_name='SALES_ADO';
OBJECT_NAME SEGMENT_WRITE_TIME SEGMENT_READ_TIME FULL_SCAN LOOKUP_SCAN
-------------------- ------------------- ------------------- ------------------- -------------------
SALES_ADO 2020-04-23 19:06:03 2020-05-26 19:06:558）通过第7步可知，30天内对表没有进行修改操作，那么按照策略，会启用压缩，但策略的执行，需要对应的窗口，或时间间隔，下面进行手工触发策略
ALEN@PROD2> set serveroutput on
ALEN@PROD2> declare
v_taskid number;
begin
dbms_ilm.execute_ilm(v_taskid,dbms_ilm.scope_schema,dbms_ilm.ilm_execution_offline);
dbms_output.put_line('Task ID is '||v_taskid);
end;
/
Task ID is 63
PL/SQL procedure successfully completed.9）查看任务的执行情况，可以看出任务执行完成
ALEN@PROD2> select task_id,state,creation_time +0 ct,start_time+0 st,completion_time+0 dt from user_ilmtasks where task_id=63;
TASK_ID STATE CT ST DT
---------- --------- ------------------- ------------------- -------------------
63 COMPLETED 2020-05-26 19:12:44 2020-05-26 19:12:44 2020-05-26 19:12:46
ALEN@PROD2> select task_id,policy_name,object_name,object_type,SELECTED_FOR_EXECUTION,job_name from user_ilmevaluationdetails;
TASK_ID POLICY_NAM OBJECT_NAME OBJECT_TYPE SELECTED_FOR_EXECUTION JOB_NAME
---------- ---------- -------------------- ------------------ ---------------------------------------- ----------
63 P102 SALES_ADO TABLE SELECTED FOR EXECUTION ILMJOB60810）检查策略执行后，表是否压缩，以及压缩比率
ALEN@PROD2> select t.compression,t.compress_for from user_tables t where t.table_name='SALES_ADO';
COMPRESS COMPRESS_FOR
-------- ------------------------------
ENABLED ADVANCED
ALEN@PROD2> select t.bytes from user_segments t where t.segment_name='SALES_ADO';
BYTES
----------
4194304可以看出，执行策略后，表进行了高级压缩，4194304/11534336 = 0.36 差不多压缩到原来的三分之一。
2.3 示例：演示存储分层
1）创建表空间，分别用于存放数据以及归档数据
SYS@PROD2> create tablespace ts_data datafile '/u01/app/oracle/oradata/PROD2/ts_data01.dbf' size 13M;
Tablespace created.
SYS@PROD2> create tablespace ts_low_store datafile '/u01/app/oracle/oradata/PROD2/ts_low01.dbf' size 50M;
Tablespace created.2）创建测试表，表段占用空间为11M，占用ts_data表空间的85%
ALEN@PROD2> create table sales_ts_ado tablespace ts_data as select * from sales;
Table created.
ALEN@PROD2> select t.compression,t.compress_for,t.tablespace_name from user_tables t where t.table_name='SALES_TS_ADO';
COMPRESS COMPRESS_FOR TABLESPACE_NAME
-------- ------------------------------ ------------------------------
DISABLED TS_DATA
ALEN@PROD2> select sum(t.bytes)/1024/1024 from user_segments t where t.segment_name='SALES_TS_ADO';
SUM(T.BYTES)/1024/1024
----------------------
113）策略默认参数是表空间使用百分比TBS PERCENT USED达到85时，会进行数据移动，这里为了实验的目的，修改该值为80
SYS@PROD2> exec dbms_ilm_admin.customize_ilm(8,80);
PL/SQL procedure successfully completed.4）创建存储分层策略，当表空间使用达到80%时，即会进行数据的移动
ALEN@PROD2> alter table sales_ts_ado ilm add policy tier to ts_low_store;
Table altered.5）查看策略
ALEN@PROD2> select policy_name,object_owner,object_name,object_type,inherited_from,enabled,deleted from user_ilmobjects;
POLICY_NAM OBJECT_OWN OBJECT_NAME OBJECT_TYPE INHERITED_FROM ENA DEL
---------- ---------- -------------------- ------------------ -------------------- --- ---
P102 ALEN SALES_ADO TABLE POLICY NOT INHERITED NO NO
P142 ALEN SALES_TS_ADO TABLE POLICY NOT INHERITED YES NO6）手工触发策略
ALEN@PROD2> declare
v_taskid number;
begin
dbms_ilm.execute_ilm(v_taskid,dbms_ilm.scope_schema,dbms_ilm.ilm_execution_offline);
dbms_output.put_line('Task ID is '||v_taskid);
end;
/
Task ID is 84
PL/SQL procedure successfully completed.7）查看任务执行情况，验证策略执行结果
ALEN@PROD2> select task_id,state,creation_time +0 ct,start_time+0 st,completion_time+0 dt from user_ilmtasks where task_id=84;
TASK_ID STATE CT ST DT
---------- --------- ------------------- ------------------- -------------------
84 COMPLETED 2020-05-26 20:25:19 2020-05-26 20:25:19 2020-05-26 20:25:21
ALEN@PROD2> select t.compression,t.compress_for,t.tablespace_name from user_tables t where t.table_name='SALES_TS_ADO';
COMPRESS COMPRESS_FOR TABLESPACE_NAME
-------- ------------------------------ ------------------------------
DISABLED TS_LOW_STORE可以看到，执行策略后，表段对应的表空间由TS_DATA移到了TS_LOW_STORE，从而自动完成了数据的存储分层移动。
3 管理策略
3.1 禁用/启用策略
ALEN@PROD2> alter table sales_ado ilm disable policy P102;
Table altered.
ALEN@PROD2> alter table sales_ado ilm enable policy P102;
Table altered.3.2 删除策略
ALEN@PROD2> alter table sales_ado ilm delete policy P102;
Table altered.3.3 管理ADO参数
1）查看ADO参数
ALEN@PROD2> select * from dba_ilmparameters;
NAME VALUE
------------------------------ ----------
ENABLED 1
RETENTION TIME 30
JOB LIMIT 2
EXECUTION MODE 2
EXECUTION INTERVAL 15
TBS PERCENT USED 80
TBS PERCENT FREE 25
POLICY TIME 1
8 rows selected.2）修改参数，使用dbms_ilm_admin.customize_ilm
ALEN@PROD2> conn / as sysdba
Connected.
SYS@PROD2> exec dbms_ilm_admin.customize_ilm(parameter =>11 , value => 0);
PL/SQL procedure successfully completed.4 监控策略
策略的监控主要通过数据字典视图，分别如下：
1）dba / user_ilmdatamovementpolicies
展示和ILM策略相关的数据移动信息。
2）dba / user_ilmtasks
展示ILM执行的任务信息。
3）dba / user_ilmevaluationdetails
展示ILM任务的评估信息。
4）dba / user_ilmobjects
展示策略和对象信息。
5）dba / user_ilmpolicies
展示策略信息。
6）dba / user_ilmresults
展示数据移动相关的作业信息。
7）dba_ilmparameters
展示ADO相关的参数信息。
以上就是自动数据优化相关的介绍和演示。
