oracle分区表转换之在线重定义（DBMS_REDEFINITION）（oracle 在线重定义）

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；

ABORT_REDEF_TABLE Procedure

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Cleans up errors that occur during the redefinition process and removes all temporary objects created by the reorganization process

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ABORT_ROLLBACK Procedure

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Aborts rollback

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ABORT_UPDATE Procedure

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Aborts an update started with the EXECUTE_UPDATE procedure

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CAN_REDEF_TABLE Procedure

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Determines if a given table can be redefined online

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COPY_TABLE_DEPENDENTS Procedure

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Copies the dependent objects of the original table onto the interim table

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EXECUTE_UPDATE Procedure

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Optimizes the performance of bulk updates to a table

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FINISH_REDEF_TABLE Procedure

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Completes the redefinition process

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REDEF_TABLE Procedure

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Provides a single push-button interface that integrates several redefinition steps

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REGISTER_DEPENDENT_OBJECT Procedure

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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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ROLLBACK Procedure

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Performs rollback

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SET_PARAM Procedure

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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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START_REDEF_TABLE Procedure

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Initiates the redefinition process

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SYNC_INTERIM_TABLE Procedure

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Keeps the interim table synchronized with the original table

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UNREGISTER_DEPENDENT_OBJECT Procedure

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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

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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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