ORACLE分区表转换之在线重定义（DBMS_REDEFINITION）
【摘要】 一、DBMS_REDEFINITION（在线重定义）参考MOS文档：_How To Partition Existing Table Using DBMS_REDEFINITION (Doc ID 472449.1) _支持的数据库版本：Oracle Database - Enterprise Edition - Version 9.2.0.4 and later在线重定义是通过 物化视...
一、DBMS_REDEFINITION（在线重定义）
参考MOS文档：_How To Partition Existing Table Using DBMS_REDEFINITION (Doc ID 472449.1) _
支持的数据库版本：Oracle Database - Enterprise Edition - Version 9.2.0.4 and later
在线重定义是通过 物化视图 实现的。
使用在线重定义的一些限制条件：
1、必须有足够的表空间来容纳表的两倍数据量。
2、主键列不能被修改。
3、表必须有主键。
4、必须在同一个用户下进行在线重定义。
5、SYS和SYSTEM用户下的表无法进行在线重定义。
6、在线重定义无法采用nologging。
7、如果中间表有新增列，则不能有NOT NULL约束
DBMS_REDEFINITION包：
- ABSORT_REDEF_TABLE：清理重定义的错误和中止重定义；
- CAN_REDEF_TABLE：检查表是否可以进行重定义,存储过程执行成功代表可以进行重定义；
- COPY_TABLE_DEPENDENTS：同步索引和依赖的对象（包括索引、约束、触发器、权限等）；
- FINISH_REDEF_TABLE：完成在线重定义；
- REGISTER_DEPENDENTS_OBJECTS：注册依赖的对象，如索引、约束、触发器等；
- START_REDEF_TABLE：开始在线重定义；
- SYNC_INTERIM_TABLE：增量同步数据；
- UNREGISTER_DEPENDENT_OBJECT：不注册依赖的对象，如索引、约束、触发器等；
| Subprogram | Description |
|---|---|
|
Cleans up errors that occur during the redefinition process and removes all temporary objects created by the reorganization process
|
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Aborts rollback
|
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|
Aborts an update started with the EXECUTE_UPDATE procedure
|
|
|
Determines if a given table can be redefined online
|
|
COPY_TABLE_DEPENDENTS Procedure
|
Copies the dependent objects of the original table onto the interim table
|
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|
Optimizes the performance of bulk updates to a table
|
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Completes the redefinition process
|
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Provides a single push-button interface that integrates several redefinition steps
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REGISTER_DEPENDENT_OBJECT Procedure
|
Registers a dependent object (index, trigger, constraint or materialized view log) on the table being redefined and the corresponding dependent object on the interim table
|
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|
Performs rollback
|
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|
Sets a new value for a specified parameter used by the redefinition process identified by a redefinition ID
|
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Initiates the redefinition process
|
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Keeps the interim table synchronized with the original table
|
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UNREGISTER_DEPENDENT_OBJECT Procedure
|
Unregisters a dependent object (index, trigger, constraint or materialized view log) on the table being redefined and the corresponding dependent object on the interim table
|
CREATE OR REPLACE PACKAGE SYS.dbms_redefinition AUTHID CURRENT_USER IS
------------
-- OVERVIEW
--
-- This package provides the API to perform an online, out-of-place
-- redefinition of a table
--- =========
--- CONSTANTS
--- =========
-- Constants for the options_flag parameter of start_redef_table
cons_use_pk CONSTANT PLS_INTEGER := 1;
cons_use_rowid CONSTANT PLS_INTEGER := 2;
-- Constants used for the object types in the register_dependent_object
cons_index CONSTANT PLS_INTEGER := 2;
cons_constraint CONSTANT PLS_INTEGER := 3;
cons_trigger CONSTANT PLS_INTEGER := 4;
cons_mvlog CONSTANT PLS_INTEGER := 10;
-- constants used to specify the method of copying indexes
cons_orig_params CONSTANT PLS_INTEGER := 1;
PRAGMA SUPPLEMENTAL_LOG_DATA(default, AUTO_WITH_COMMIT);
-- NAME: can_redef_table - check if given table can be re-defined
-- INPUTS: uname - table owner name
-- tname - table name
-- options_flag - flag indicating user options to use
-- part_name - partition name
PROCEDURE can_redef_table(uname IN VARCHAR2,
tname IN VARCHAR2,
options_flag IN PLS_INTEGER := 1,
part_name IN VARCHAR2 := NULL);
PRAGMA SUPPLEMENTAL_LOG_DATA(can_redef_table, NONE);
-- NAME: start_redef_table - start the online re-organization
-- INPUTS: uname - schema name
-- orig_table - name of table to be re-organized
-- int_table - name of interim table
-- col_mapping - select list col mapping
-- options_flag - flag indicating user options to use
-- orderby_cols - comma separated list of order by columns
-- followed by the optional ascending/descending
-- keyword
-- part_name - name of the partition to be redefined
PROCEDURE start_redef_table(uname IN VARCHAR2,
orig_table IN VARCHAR2,
int_table IN VARCHAR2,
col_mapping IN VARCHAR2 := NULL,
options_flag IN BINARY_INTEGER := 1,
orderby_cols IN VARCHAR2 := NULL,
part_name IN VARCHAR2 := NULL);
-- NAME: finish_redef_table - complete the online re-organization
-- INPUTS: uname - schema name
-- orig_table - name of table to be re-organized
-- int_table - name of interim table
-- part_name - name of the partition being redefined
PROCEDURE finish_redef_table(uname IN VARCHAR2,
orig_table IN VARCHAR2,
int_table IN VARCHAR2,
part_name IN VARCHAR2 := NULL);
-- NAME: abort_redef_table - clean up after errors or abort the
-- online re-organization
-- INPUTS: uname - schema name
-- orig_table - name of table to be re-organized
-- int_table - name of interim table
-- part_name - name of the partition being redefined
PROCEDURE abort_redef_table(uname IN VARCHAR2,
orig_table IN VARCHAR2,
int_table IN VARCHAR2,
part_name IN VARCHAR2 := NULL);
-- NAME: sync_interim_table - synchronize interim table with the original
-- table
-- INPUTS: uname - schema name
-- orig_table - name of table to be re-organized
-- int_table - name of interim table
-- part_name - name of the partition being redefined
PROCEDURE sync_interim_table(uname IN VARCHAR2,
orig_table IN VARCHAR2,
int_table IN VARCHAR2,
part_name IN VARCHAR2 := NULL);
-- NAME: register_dependent_object - register dependent object
--
-- INPUTS: uname - schema name
-- orig_table - name of table to be re-organized
-- int_table - name of interim table
-- dep_type - type of the dependent object
-- dep_owner - name of the dependent object owner
-- dep_orig_name- name of the dependent object defined on table
-- being re-organized
-- dep_int_name - name of the corressponding dependent object on
-- the interim table
PROCEDURE register_dependent_object(uname IN VARCHAR2,
orig_table IN VARCHAR2,
int_table IN VARCHAR2,
dep_type IN PLS_INTEGER,
dep_owner IN VARCHAR2,
dep_orig_name IN VARCHAR2,
dep_int_name IN VARCHAR2);
-- NAME: unregister_dependent_object - unregister dependent object
--
-- INPUTS: uname - schema name
-- orig_table - name of table to be re-organized
-- int_table - name of interim table
-- dep_type - type of the dependent object
-- dep_owner - name of the dependent object owner
-- dep_orig_name- name of the dependent object defined on table
-- being re-organized
-- dep_int_name - name of the corressponding dependent object on
-- the interim table
PROCEDURE unregister_dependent_object(uname IN VARCHAR2,
orig_table IN VARCHAR2,
int_table IN VARCHAR2,
dep_type IN PLS_INTEGER,
dep_owner IN VARCHAR2,
dep_orig_name IN VARCHAR2,
dep_int_name IN VARCHAR2);
-- NAME: copy_table_dependents
--
-- INPUTS: uname - schema name
-- orig_table - name of table to be re-organized
-- int_table - name of interim table
-- copy_indexes - integer value indicating whether to
-- copy indexes
-- 0 - don't copy
-- 1 - copy using storage params/tablespace
-- of original index
-- copy_triggers - TRUE implies copy triggers, FALSE otherwise
-- copy_constraints - TRUE implies copy constraints, FALSE
-- otherwise
-- copy_privileges - TRUE implies copy privileges, FALSE
-- otherwise
-- ignore errors - TRUE implies continue after errors, FALSE
-- otherwise
-- num_errors - number of errors that occurred while
-- cloning ddl
-- copy_statistics - TRUE implies copy table statistics, FALSE
-- otherwise.
-- If copy_indexes is 1, copy index
-- related statistics, 0 otherwise.
-- copy_mvlog - TRUE implies copy table's MV log, FALSE
-- otherwise.
PROCEDURE copy_table_dependents(uname IN VARCHAR2,
orig_table IN VARCHAR2,
int_table IN VARCHAR2,
copy_indexes IN PLS_INTEGER := 1,
copy_triggers IN BOOLEAN := TRUE,
copy_constraints IN BOOLEAN := TRUE,
copy_privileges IN BOOLEAN := TRUE,
ignore_errors IN BOOLEAN := FALSE,
num_errors OUT PLS_INTEGER,
copy_statistics IN BOOLEAN := FALSE,
copy_mvlog IN BOOLEAN := FALSE);
END;
二、在线重定义表的步骤
**1.**创建未分区的表，如果存在，就不需要操作。
--前置准备：创建用户，表空间，授权用户。
SQL> create tablespace PARTITION;
SQL> create user par identified by par;
SQL> grant dba to par;
--创建表,索引，授权，同义词
SQL> conn par/par
Connected.
-- Create table
create table student(
s_id number(8) PRIMARY KEY,
s_name varchar2(20) not null,
s_sex varchar2(8),
s_birdate date,
constraint u_1 unique(s_name),
constraint c_1 check (s_sex in ('MALE','FEMALE')))
tablespace PARTITION;
-- Add comments to the table
comment on table STUDENT is '学生表';
-- Add comments to the columns
comment on column STUDENT.s_name is '姓名';
comment on column STUDENT.s_sex is '性别';
comment on column STUDENT.s_birdate is '出生日期';
-- Create/Recreate indexes
create index S_NAME_IDX on STUDENT (S_NAME, S_SEX) tablespace PARTITION;
-- Create SYNONYM
CREATE SYNONYM stu FOR student;
-- Grant/Revoke object privileges
grant select, insert, delete on STUDENT to SCOTT;
--查看表结构
SQL> desc stu
Name Null? Type
----------------------------------------- -------- ----------------------------
S_ID NOT NULL NUMBER(8)
S_NAME NOT NULL VARCHAR2(20)
S_SEX VARCHAR2(8)
S_BIRDATE DATE
--插入数据
begin
for i in 0 .. 24 loop
insert into student values
(i,
'student_' || i,
decode(mod(i, 2), 0, 'MALE', 'FEMALE'),
add_months(to_date('2019-1-1', 'yyyy-mm-dd'), i));
end loop;
commit;
end;
/
2.确认表是否存在主键，表空间是否足够，收集表统计信息。
--查看表主键
SQL> select cu.* from user_cons_columns cu, user_constraints au where cu.constraint_name = au.constraint_name and au.constraint_type = 'P' and au.table_name = 'STUDENT';
--查看表大小和表空间
--查看表空间
SQL> select tablespace_name from dba_segments where segment_type= 'TABLE' and segment_name='STUDENT' and owner='PAR';
--查看表大小
SQL> select sum(bytes/1024/1024) from dba_segments where segment_type= 'TABLE' and segment_name='STUDENT' and owner='PAR';
--查看表空间
select tbs_used_info.tablespace_name,
tbs_used_info.alloc_mb,
tbs_used_info.used_mb,
tbs_used_info.max_mb,
tbs_used_info.free_of_max_mb,
tbs_used_info.used_of_max || '%' used_of_max_pct
from (select a.tablespace_name,
round(a.bytes_alloc / 1024 / 1024) alloc_mb,
round((a.bytes_alloc - nvl(b.bytes_free,
0)) / 1024 / 1024) used_mb,
round((a.bytes_alloc - nvl(b.bytes_free,
0)) * 100 / a.maxbytes) used_of_max,
round((a.maxbytes - a.bytes_alloc + nvl(b.bytes_free,
0)) / 1048576) free_of_max_mb,
round(a.maxbytes / 1048576) max_mb
from (select f.tablespace_name,
sum(f.bytes) bytes_alloc,
sum(decode(f.autoextensible,
'YES',
f.maxbytes,
'NO',
f.bytes)) maxbytes
from dba_data_files f
group by tablespace_name) a,
(select f.tablespace_name,
sum(f.bytes) bytes_free
from dba_free_space f
group by tablespace_name) b
where a.tablespace_name = b.tablespace_name(+)) tbs_used_info
order by tbs_used_info.used_of_max desc;
--如果表空间不够，提前增加表空间大小
alter tablespace PARTITION add datafile;
--收集统计信息(可忽略)
EXEC DBMS_STATS.gather_table_stats('PAR', 'STUDENT', cascade => TRUE);
3.调用DBMS_REDEFINITION.CAN_REDEF_TABLE()过程，确认表是否满足重定义的条件。
SQL> EXEC Dbms_Redefinition.can_redef_table('PAR', 'STUDENT');
PL/SQL procedure successfully completed.
4.在用一个用户中建立一个空的中间表，根据重定义后你期望得到的结构建立中间表。比如：采用分区表（间隔分区），增加了COLUMN等。
在中间表上建立触发器、索引和约束，并进行相应的授权。任何包含中间表的完整性约束应将状态置为disabled。(此步骤也可以放在同步数据后操作)
--创建间隔分区(增加列s_phone)
create table STUDENT_PAR
(
s_id NUMBER(8) not null,
s_name VARCHAR2(20) not null,
s_sex VARCHAR2(8),
s_birdate DATE,
s_phone number
)
tablespace PARTITION
PARTITION BY RANGE(s_birdate)
INTERVAL (NUMTOYMINTERVAL(1,'MONTH')) STORE IN (partition)
(PARTITION STUDENT_201901 VALUES LESS THAN (TO_DATE('2019-02-01 00:00:00', 'SYYYY-MM-DD HH24:MI:SS', 'NLS_CALENDAR=GREGORIAN')));
--临时中间表上创建如下：
--创建主键约束
alter table STUDENT_PAR add primary key (S_ID) using index tablespace PARTITION;
--创建唯一索引约束
alter table STUDENT_PAR add constraint U_1_PAR unique (S_NAME) using index tablespace PARTITION;
--创建check约束
alter table STUDENT_PAR add constraint C_1_PAR check (s_sex in ('MALE','FEMALE'));
--创建索引
CREATE INDEX S_NAME_IDX_PAR ON STUDENT_PAR (S_NAME,S_SEX) tablespace PARTITION;
--创建同义词
CREATE SYNONYM stu_par FOR STUDENT_PAR;
--添加描述
COMMENT ON TABLE STUDENT_PAR IS '学生表';
COMMENT ON COLUMN STUDENT_PAR.s_name IS '姓名';
COMMENT ON COLUMN STUDENT_PAR.s_sex IS '性别';
COMMENT ON COLUMN STUDENT_PAR.s_birdate IS '出生日期';
--授权
GRANT SELECT,INSERT,DELETE ON STUDENT_PAR TO scott;
5.调用DBMS_REDEFINITION.START_REDEF_TABLE()过程，并提供下列参数：被重定义的表的名称、中间表的名称、列的映射规则、重定义方法。
如果映射方法没有提供，则认为所有包括在中间表中的列用于表的重定义。如果给出了映射方法，则只考虑映射方法中给出的列。如果没有给出重定义方法，则默认使用主键方式。
SQL> BEGIN
DBMS_REDEFINITION.start_redef_table(
uname => 'PAR',
orig_table => 'STUDENT',
int_table => 'STUDENT_PAR');
END;
/
PL/SQL procedure successfully completed.
6.（可选）在创建索引之前将新表与临时名称同步。
Notes：如果在执行DBMS_REDEFINITION.START_REDEF_TABLE()过程和执行DBMS_REDEFINITION.FINISH_REDEF_TABLE()过程直接在重定义表上执行了大量的DML操作，那么可以选择执行一次或多次的SYNC_INTERIM_TABLE()过程，此操作可以减少最后一步执行FINISH_REDEF_TABLE()过程时的锁定时间。
--模拟业务不停，DML表数据写入
insert into STUDENT values(25,'student_25','MALE',to_date('2020-8-1', 'yyyy-mm-dd'));
update student set s_sex='FEMALE' where s_id = 20;
commit;
--比对student和student_par数据
select s_id,s_name,s_sex,s_birdate from student
minus
select s_id,s_name,s_sex,s_birdate from student_par;
S_ID S_NAME S_SEX S_BIRDATE
---------- -------------------- -------- ------------------
20 student_20 FEMALE 01-SEP-20
25 student_25 MALE 01-AUG-20
--同步数据到临时表
BEGIN
dbms_redefinition.sync_interim_table(
uname => 'PAR',
orig_table => 'STUDENT',
int_table => 'STUDENT_PAR');
END;
/
--数据已全部同步到临时表
select s_id,s_name,s_sex,s_birdate from student
minus
select s_id,s_name,s_sex,s_birdate from student_par;
no rows selected
7.执行DBMS_REDEFINITION.FINISH_REDEF_TABLE()过程完成表的重定义。这个过程中，原始表会被独占模式锁定一小段时间，具体时间和表的数据量有关。
执行完FINISH_REDEF_TABLE()过程后，原始表重定义后具有了中间表的属性、索引、约束、授权和触发器。中间表上disabled的约束在原始表上处于enabled状态。
--收集par table的统计信息
EXEC DBMS_STATS.gather_table_stats('PAR', 'STUDENT_PAR', cascade => TRUE);
--结束在线重定义过程
BEGIN
dbms_redefinition.finish_redef_table(
uname => 'PAR',
orig_table => 'STUDENT',
int_table => 'STUDENT_PAR');
END;
/
SQL> select table_name，PARTITION_NAME from user_tab_partitions where table_name in ('STUDENT','STUDENT_PAR');
SQL> select table_name,index_name from user_indexes where table_name in ('STUDENT','STUDENT_PAR');
此时，临时表（及其索引）已成为“真实”表，并且它们的名称已在名称词典中切换。
8.重命名所有约束和索引以匹配原始名称
--drop中间表或者rename原来的约束
a.drop table STUDENT_PAR;
b.
ALTER TABLE STUDENT_PAR RENAME CONSTRAINT U_1 TO U_1_20210411;
ALTER TABLE STUDENT_PAR RENAME CONSTRAINT C_1 TO C_1_20210411;
ALTER INDEX S_NAME_IDX RENAME TO S_NAME_IDX_20210411;
ALTER INDEX U_1 RENAME TO U_1_20210411;
--rename 新分区表的约束和索引
ALTER TABLE STUDENT RENAME CONSTRAINT U_1_PAR TO U_1;
ALTER TABLE STUDENT RENAME CONSTRAINT C_1_PAR TO C_1;
ALTER INDEX S_NAME_IDX_PAR RENAME TO S_NAME_IDX;
ALTER INDEX U_1_PAR RENAME TO U_1;
--查看索引，约束名称是否正确
select table_name,index_name from user_indexes where table_name in ('STUDENT','STUDENT_PAR') order by table_name;
TABLE_NAME INDEX_NAME
------------------------------ ------------------------------
STUDENT S_NAME_IDX
STUDENT SYS_C0011401
STUDENT U_1
STUDENT_PAR S_NAME_IDX_20210411
STUDENT_PAR U_1_20210411
STUDENT_PAR SYS_C0011395
SQL> desc stu
Name Null? Type
----------------------------------------- -------- ----------------------------
S_ID NOT NULL NUMBER(8)
S_NAME NOT NULL VARCHAR2(20)
S_SEX VARCHAR2(8)
S_BIRDATE DATE
S_PHONE NUMBER
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