从Oracle8开始，提供了从分区交换的功能，如一个分区或子分区与一个非分区表交换、一个hash分区与另一个表的hash子分区交换等等，详细的交换方式可以参考官方文档。
基本语法：ALTER TABLE...EXCHANGE PARTITION
实验环境：11.2.0.4
zx@ORCL>select * from v$version; BANNER ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit Production PL/SQL Release 11.2.0.4.0 - Production CORE 11.2.0.4.0 Production TNS for Linux: Version 11.2.0.4.0 - Production NLSRTL Version 11.2.0.4.0 - Production
一、测试分区交换
创建测试表
--分区表 zx@ORCL>create table t1 2 ( id number(2), 3 name varchar2(15)) 4 tablespace tt 5 partition by range (id) 6 (partition p1 values less than (10), 7 partition p2 values less than (20), 8 partition p3 values less than (30)); Table created. --非分区表 zx@ORCL>create table t2 (id number(2), name varchar2(15)) tablespace users; Table created. --插入测试数据 zx@ORCL>insert into t1 values (1, ‘1‘); 1 row created. zx@ORCL>insert into t1 values (11, ‘11‘); 1 row created. zx@ORCL>insert into t1 values (21, ‘21‘); 1 row created. zx@ORCL>insert into t2 values (2, ‘2‘); 1 row created. zx@ORCL>commit; Commit complete. zx@ORCL>select * from t1; ID NAME ---------- --------------------------------------------- 1 1 11 11 21 21 zx@ORCL>select * from t2; ID NAME ---------- --------------------------------------------- 2 2 --查看表存储表空间 --t2在USERS表空间，t1各个分区都在TT表空间 zx@ORCL>col segment_name for a20 zx@ORCL>col partition_name for a15 zx@ORCL>col tablespace_name for a15 zx@ORCL>select segment_name,partition_name,tablespace_name from dba_segments where segment_name in (‘T1‘,‘T2‘); SEGMENT_NAME PARTITION_NAME TABLESPACE_NAME -------------------- --------------- --------------- T2 USERS T1 P3 TT T1 P2 TT T1 P1 TT --查看各表的extent信息 zx@ORCL>select SEGMENT_NAME,BLOCK_ID,BLOCKS,TABLESPACE_NAME from dba_extents where segment_name=‘T2‘; SEGMENT_NAME BLOCK_ID BLOCKS TABLESPACE_NAME -------------------- ---------- ---------- --------------- T2 192 8 USERS zx@ORCL>select SEGMENT_NAME,PARTITION_NAME,BLOCK_ID,BLOCKS,TABLESPACE_NAME from dba_extents where segment_name=‘T1‘; SEGMENT_NAME PARTITION_NAME BLOCK_ID BLOCKS TABLESPACE_NAME -------------------- --------------- ---------- ---------- --------------- T1 P2 21376 1024 TT T1 P3 22400 1024 TT T1 P1 20352 1024 TT
t1分区p1与t2表交换分区
--分区 zx@ORCL>alter table t1 exchange partition p1 with table t2; Table altered. zx@ORCL>select * from t2; ID NAME ---------- --------------------------------------------- 1 1 zx@ORCL>select * from t1; ID NAME ---------- --------------------------------------------- 2 2 11 11 21 21
可以看到p1分区里的数据交换到了t2表里，而t2表里里的数据也存储到了t1表中。再次查看各表所在的表空间和extent
--查看表空间 zx@ORCL>select segment_name,partition_name,tablespace_name from dba_segments where segment_name in (‘T1‘,‘T2‘); SEGMENT_NAME PARTITION_NAME TABLESPACE_NAME -------------------- --------------- --------------- T2 TT T1 P3 TT T1 P2 TT T1 P1 USERS --查看extent zx@ORCL>select SEGMENT_NAME,BLOCK_ID,BLOCKS,TABLESPACE_NAME from dba_extents where segment_name=‘T2‘; SEGMENT_NAME BLOCK_ID BLOCKS TABLESPACE_NAME -------------------- ---------- ---------- --------------- T2 20352 1024 TT zx@ORCL>select SEGMENT_NAME,PARTITION_NAME,BLOCK_ID,BLOCKS,TABLESPACE_NAME from dba_extents where segment_name=‘T1‘; SEGMENT_NAME PARTITION_NAME BLOCK_ID BLOCKS TABLESPACE_NAME -------------------- --------------- ---------- ---------- --------------- T1 P1 192 8 USERS T1 P2 21376 1024 TT T1 P3 22400 1024 TT
从结果看到T2已经到了TT表空间，而T1的P1分区移动到了USERS表空间，而且P1分区与T2表的extent也做了交换，可以推断实际表里的数据没有移动位置，只是把数据字典里的相关信息做了更换。
二、再看看交换分区对于分区表的索引的影响
在分区表中创建索引
--全局索引 zx@ORCL>create index idx_t1_id on t1(id) ; Index created. --分区索引 zx@ORCL>create index idx_t1_name on t1(name) local; Index created. zx@ORCL>select index_name,status from user_indexes where index_name like ‘IDX_T1%‘; INDEX_NAME STATUS ------------------------------------------------------------------------------------------ ------------------------ IDX_T1_ID VALID IDX_T1_NAME N/A zx@ORCL>select index_name,partition_name,status from user_ind_partitions where index_name like ‘IDX_T1%‘; INDEX_NAME PARTITION_NAME STATUS ------------------------------------------------------------------------------------------ --------------- ------------------------ IDX_T1_NAME P1 USABLE IDX_T1_NAME P2 USABLE IDX_T1_NAME P3 USABLE
交换分区查看是否对索引有影响
zx@ORCL>alter table t1 exchange partition p1 with table t2; Table altered. zx@ORCL>select index_name,status from user_indexes where index_name like ‘IDX_T1%‘; INDEX_NAME STATUS ------------------------------------------------------------------------------------------ ------------------------ IDX_T1_NAME N/A IDX_T1_ID UNUSABLE zx@ORCL>select index_name,partition_name,status from user_ind_partitions where index_name like ‘IDX_T1%‘; INDEX_NAME PARTITION_NAME STATUS ------------------------------------------------------------------------------------------ --------------- ------------------------ IDX_T1_NAME P1 UNUSABLE IDX_T1_NAME P2 USABLE IDX_T1_NAME P3 USABLE
看到全局索引IDX_T1_ID失效了，分区P1对应的分区索引也失效了，但其他分区的分区没有受到影响
交换分区时加入 UPDATE INDEXES子句
zx@ORCL>alter index idx_t1_id rebuild; Index altered. zx@ORCL>alter index idx_t1_name rebuild partition p1; Index altered. zx@ORCL>select index_name,status from user_indexes where index_name like ‘IDX_T1%‘; INDEX_NAME STATUS ------------------------------------------------------------------------------------------ ------------------------ IDX_T1_NAME N/A IDX_T1_ID VALID zx@ORCL>select index_name,partition_name,status from user_ind_partitions where index_name like ‘IDX_T1%‘; INDEX_NAME PARTITION_NAME STATUS ------------------------------------------------------------------------------------------ --------------- ------------------------ IDX_T1_NAME P1 USABLE IDX_T1_NAME P2 USABLE IDX_T1_NAME P3 USABLE zx@ORCL>alter table t1 exchange partition p1 with table t2 update indexes ; Table altered. zx@ORCL>select index_name,status from user_indexes where index_name like ‘IDX_T1%‘; INDEX_NAME STATUS ------------------------------------------------------------------------------------------ ------------------------ IDX_T1_NAME N/A IDX_T1_ID VALID zx@ORCL>select index_name,partition_name,status from user_ind_partitions where index_name like ‘IDX_T1%‘; INDEX_NAME PARTITION_NAME STATUS ------------------------------------------------------------------------------------------ --------------- ------------------------ IDX_T1_NAME P1 UNUSABLE IDX_T1_NAME P2 USABLE IDX_T1_NAME P3 USABLE
可以看到全局索引没有受影响，但是分区索引仍然失效。
更多信息参考官方文档：http://docs.oracle.com/cd/E11882_01/server.112/e25523/part_admin002.htm#i1107555
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原文地址：http://hbxztc.blog.51cto.com/1587495/1892937
