Oracle Database 12c新特性 In-Database Archiving数据库内归档

时间:2023-01-17 13:58:20

【Oracle Database 12c新特性】 In-Database Archiving数据库内归档

Oracle Database 12c中引入了 In-Database Archiving的新特性, 该特性允许用户通过对表上的数据行标记为inactive不活跃的,以归档数据。

 这些inactive的数据行可以通过压缩进一部优化,且对应用来说默认不可见。    可以通过一个session级别的参数来控制数据的可见与否。

 

通过In-Database Archiving数据库内归档郑州电脑上门维修特性可以在单库中存放更长周期的数据, 而损耗很少的应用性能。 归档数据还可以通过压缩来进一步提升备份效能。

 

要管理一张表的In-Database Archiving,必须为表启用ROW ARCHIVAL  并操作ORA_ARCHIVE_STATE 这个隐藏字段 。 此外用户还可以指定session级别的 ROW ARCHIVAL VISIBILITY为ACTIVE  或者ALL。

 

下面为演示示例:

 

/* Set visibility to ACTIVE to display only active rows of a table.*/

ALTER SESSION SET ROW ARCHIVAL VISIBILITY = ACTIVE;

 

CREATE TABLE employees_indbarch

 (employee_id NUMBER(6) NOT NULL,

  first_name VARCHAR2(20), last_name VARCHAR2(25) NOT NULL,

  email VARCHAR2(25) NOT NULL, phone_number VARCHAR2(20),

  hire_date DATE NOT NULL, job_id VARCHAR2(10) NOT NULL, salary  NUMBER(8,2),

  commission_pct NUMBER(2,2), manager_id NUMBER(6), department_id NUMBER(4)) ROW ARCHIVAL;

 

INSERT INTO employees_indbarch(employee_id, first_name, last_name, email,

  hire_date, job_id, salary, manager_id, department_id)

  VALUES (251, 'Scott', 'Tiger', 'scott.tiger@example.com', '21-MAY-2009',

 'IT_PROG', 50000, 103, 60);

 

INSERT INTO employees_indbarch(employee_id, first_name, last_name, email,

  hire_date, job_id, salary, manager_id, department_id)

  VALUES (252, 'Jane', 'Lion', 'jane.lion@example.com', '11-JUN-2009',

  'IT_PROG', 50000, 103, 60);

 

 commit;

 

 /* Show all the columns in the table, including hidden columns */

SELECT SUBSTR(COLUMN_NAME,1,22), SUBSTR(DATA_TYPE,1,20), COLUMN_ID AS COL_ID,

  SEGMENT_COLUMN_ID AS SEG_COL_ID, INTERNAL_COLUMN_ID AS INT_COL_ID, HIDDEN_COLUMN, CHAR_LENGTH

  FROM USER_TAB_COLS WHERE TABLE_NAME='EMPLOYEES_INDBARCH';

 

SELECT SUBSTR(COLUMN_NAME,1,22) NAME, SUBSTR(DATA_TYPE,1,20) DATA_TYPE, COLUMN_ID AS COL_ID,

  SEGMENT_COLUMN_ID AS SEG_COL_ID, INTERNAL_COLUMN_ID AS INT_COL_ID, HIDDEN_COLUMN, CHAR_LENGTH

  FROM USER_TAB_COLS WHERE TABLE_NAME='EMPLOYEES_INDBARCH';

 

NAME                   DATA_TYPE                COL_ID SEG_COL_ID INT_COL_ID HID CHAR_LENGTH

---------------------- -------------------- ---------- ---------- ---------- --- -----------

ORA_ARCHIVE_STATE      VARCHAR2                                 1          1 YES        4000

EMPLOYEE_ID            NUMBER                        1          2          2 NO            0

FIRST_NAME             VARCHAR2                      2          3          3 NO           20

LAST_NAME              VARCHAR2                      3          4          4 NO           25

EMAIL                  VARCHAR2                      4          5          5 NO           25

PHONE_NUMBER           VARCHAR2                      5          6          6 NO           20

HIRE_DATE              DATE                          6          7          7 NO            0

JOB_ID                 VARCHAR2                      7          8          8 NO           10

SALARY                 NUMBER                        8          9          9 NO            0

COMMISSION_PCT         NUMBER                        9         10         10 NO            0

MANAGER_ID             NUMBER                       10         11         11 NO            0

DEPARTMENT_ID          NUMBER                       11         12         12 NO            0

 

/* Decrease the ORA_ARCHIVE_STATE column size to improve formatting in queries */

COLUMN ORA_ARCHIVE_STATE FORMAT a18;

/* The default value for ORA_ARCHIVE_STATE is '0', which means active */

SELECT employee_id, ORA_ARCHIVE_STATE FROM employees_indbarch;

 

EMPLOYEE_ID ORA_ARCHIVE_STATE

----------- ------------------

        251 0

        252 0

 

/* Insert a value into ORA_ARCHIVE_STATE to set inactive */

UPDATE employees_indbarch SET ORA_ARCHIVE_STATE = '20' WHERE employee_id = 252;

 

/* Only active records are in the following query */

SELECT employee_id, ORA_ARCHIVE_STATE FROM employees_indbarch;

 

EMPLOYEE_ID ORA_ARCHIVE_STATE

----------- ------------------

        251 0

 

/* Set visibility to ALL to display all records */

ALTER SESSION SET ROW ARCHIVAL VISIBILITY = ALL;

 

SELECT employee_id, ORA_ARCHIVE_STATE FROM employees_indbarch;

 

EMPLOYEE_ID ORA_ARCHIVE_STATE

----------- ------------------

        251 0

        252 20

 

SQL> desc employees_indbarch

 Name                                      Null?    Type

 ----------------------------------------- -------- ----------------------------

 EMPLOYEE_ID                               NOT NULL NUMBER(6)

 FIRST_NAME                                         VARCHAR2(20)

 LAST_NAME                                 NOT NULL VARCHAR2(25)

 EMAIL                                     NOT NULL VARCHAR2(25)

 PHONE_NUMBER                                       VARCHAR2(20)

 HIRE_DATE                                 NOT NULL DATE

 JOB_ID                                    NOT NULL VARCHAR2(10)

 SALARY                                             NUMBER(8,2)

 COMMISSION_PCT                                     NUMBER(2,2)

 MANAGER_ID                                         NUMBER(6)

 DEPARTMENT_ID                                      NUMBER(4)

 

  1* select COLUMN_NAME,COLUMN_ID,DATA_TYPE from dba_tab_cols where table_name=upper('employees_indbarch')

SQL> /

 

COLUMN_NAME          COLUMN_ID DATA_TYPE

-------------------- --------- --------------------

DEPARTMENT_ID               11 NUMBER

MANAGER_ID                  10 NUMBER

COMMISSION_PCT               9 NUMBER

SALARY                       8 NUMBER

JOB_ID                       7 VARCHAR2

HIRE_DATE                    6 DATE

PHONE_NUMBER                 5 VARCHAR2

EMAIL                        4 VARCHAR2

LAST_NAME                    3 VARCHAR2

FIRST_NAME                   2 VARCHAR2

EMPLOYEE_ID                  1 NUMBER

ORA_ARCHIVE_STATE              VARCHAR2

 

SQL> select dump(ORA_ARCHIVE_STATE,16),dump(EMPLOYEE_ID,16),dbms_rowid.rowid_block_number(rowid),dbms_rowid.rowid_relative_fno(rowid)  from employees_indbarch;

 

DUMP(ORA_ARCHIVE_STA DUMP(EMPLOYEE_ID,16) DBMS_ROWID.ROWID_BLOCK_NUMBER(ROWID) DBMS_ROWID.ROWID_RELATIVE_FNO(ROWID)

-------------------- -------------------- ------------------------------------ ------------------------------------

Typ=1 Len=1: 30      Typ=2 Len=3: c2,3,34                               109465                                    1

Typ=1 Len=2: 32,30   Typ=2 Len=3: c2,3,35                               109465                                    1

 

       SQL> alter system flush buffer_cache;

 

System altered.

 

SQL> alter system dump datafile 1 block 109465;

 

System altered.

 

tl: 73 fb: --H-FL-- lb: 0x0  cc: 12

col  0: [ 1]  30

col  1: [ 3]  c2 03 34

col  2: [ 5]  53 63 6f 74 74

col  3: [ 5]  54 69 67 65 72

col  4: [23]

 73 63 6f 74 74 2e 74 69 67 65 72 40 65 78 61 6d 70 6c 65 2e 63 6f 6d

col  5: *NULL*

col  6: [ 7]  78 6d 05 15 01 01 01

col  7: [ 7]  49 54 5f 50 52 4f 47 

col  8: [ 2]  c3 06

col  9: *NULL*

col 10: [ 3]  c2 02 04

col 11: [ 2]  c1 3d

tab 0, row 1, @0x1ecc

tl: 70 fb: --H-FL-- lb: 0x2  cc: 12

col  0: [ 2]  32 30

col  1: [ 3]  c2 03 35

col  2: [ 4]  4a 61 6e 65

col  3: [ 4]  4c 69 6f 6e

col  4: [21]

 6a 61 6e 65 2e 6c 69 6f 6e 40 65 78 61 6d 70 6c 65 2e 63 6f 6d

col  5: *NULL*

col  6: [ 7]  78 6d 06 0b 01 01 01

col  7: [ 7]  49 54 5f 50 52 4f 47

col  8: [ 2]  c3 06

col  9: *NULL*

col 10: [ 3]  c2 02 04 

col 11: [ 2]  c1 3d

 

 

 

可以看到这里 ORA_ARCHIVE_STATE是实际存放在块里的row piece上的第一个字段,类型为varchar2(4000);
In-Database Archiving的限制:

§  ILM is not supported with OLTP table compression for in-database archiving. Segment-level ILM and compression is supported if partitioned on the ORA_ARCHIVE_STATE column.

 

 

ORA_ARCHIVE_STATE相关:

/* constants specifying ROW ARCHIVAL state */
archive_state_active constant varchar2(1) := ‘0’;
archive_state_archived constant varchar2(1) := ‘1’;

/*
* description – Given a value for the ORA_ARCHIVE_STATE column this
* function returns the mapping for the value.
*
* value – “0”, “1” or other values from the ORA_ARCHIVE_STATE column of
* a row archival enabled table
* returns either “archive_state_active” or “archive_state_archived”
*/