生产数据库，一张表，一亿多行数据，绝大部分查询按月为维度做时间范围查
询，未分区状态下，查询IO量大，计划以分区截剪的方式减少IO量，提升前前台查询性能
将未分区的oXX_XXt_owner.id_oXXXdx_mX表以（stat_XXcle）字段为分区键，以在定义的方式转换成按月分区表的时间范围分区表，利且在线重定义的特性，保留权限的不漏赋以及极少时间的影响生产。
(1) 数据库若是双节点，只需在其中一个节点的数据库上实施。
(2) 实施中部分命令执行时间较长，命令一旦执行后请不要中断命令的执行一条命令执行完毕后，不能再次重复执行该命令。
(3) 执行命令的数据库用户需要为sys或者system用户。
CREATE TABLE OXX_XXT_OWNER.ID_OXXXDX_MX_TMP
(
iXx_data_id VARCHAR2 (42),
oXg_no VARCHAR2 (16),
iXx_id VARCHAR2 (24),
iXx_code VARCHAR2 (16),
PXRIOD VARCHAR2 (8),
stat_XXcle VARCHAR2 (16),
……
)
TABLESPACE OXXXIEW
PARTITION BY RANGE
(STAT_XXCLE)
(
PARTITION ONXXDX_MIN VALUES LESS THAN (‘20140101‘),
PARTITION ONXXDX_2014_01 VALUES LESS THAN (‘20140201‘),
PARTITION ONXXDX_2014_02 VALUES LESS THAN (‘20140301‘),
PARTITION ONXXDX_2014_03 VALUES LESS THAN (‘20140401‘),
……
PARTITION ONXXDX_2018_02 VALUES LESS THAN (‘20180301‘),
PARTITION ONXXDX_2018_03 VALUES LESS THAN (‘20180401‘),
PARTITION ONXXDX_2018_04 VALUES LESS THAN (‘20180501‘),
PARTITION ONXXDX_2018_05 VALUES LESS THAN (‘20180601‘),
PARTITION ONXXDX_2018_06 VALUES LESS THAN (‘20180701‘),
PARTITION ONXXDX_2018_07 VALUES LESS THAN (‘20180801‘),
PARTITION ONXXDX_2018_08 VALUES LESS THAN (‘20180901‘),
PARTITION ONXXDX_2018_09 VALUES LESS THAN (‘20181001‘),
PARTITION ONXXDX_2018_10 VALUES LESS THAN (‘20181101‘),
PARTITION ONXXDX_2018_11 VALUES LESS THAN (‘20181201‘),
PARTITION ONXXDX_2018_12 VALUES LESS THAN (‘20190101‘),
PARTITION ONXXDX_MAX VALUES LESS THAN (MAXVALUE));
若执行完以下步骤3.2.3开始 表在线重定义，在执行3.2.4,3.2.5,3.2.6时报错，命令不能执行，则执行以下命令回退 表在线重定义，并中断整个表的实施过程。
BEGIN
DBMS_REDEFINITION.ABORT_REDEF_TABLE(
UNAME => ‘OXX_XXT_OWNER‘,
ORIG_TABLE => ‘ID_OXXXDX_MX‘,
INT_TABLE => ‘ID_OXXXDX_MX_TMP‘);
END;
/
BEGIN
DBMS_REDEFINITION.CAN_REDEF_TABLE(
UNAME => ‘OXX_XXT_OWNER‘,
TNAME => ‘ID_OXXXDX_MX‘,
OPTIONS_FLAG => DBMS_REDEFINITION.CONS_USE_PK);
END;
/
BEGIN
DBMS_REDEFINITION.START_REDEF_TABLE(
UNAME => ‘OXX_XXT_OWNER‘,
ORIG_TABLE => ‘ID_OXXXDX_MX‘,
INT_TABLE => ‘ID_OXXXDX_MX_TMP‘,
OPTIONS_FLAG => DBMS_REDEFINITION.CONS_USE_PK);
END;
/
DECLARE
num_errors PLS_INTEGER;
BEGIN
DBMS_REDEFINITION.COPY_TABLE_DEPENDENTS(
‘OXX_XXT_OWNER‘,
‘ID_OXXXDX_MX‘,
‘ID_OXXXDX_MX_TMP‘,
DBMS_REDEFINITION.CONS_ORIG_PARAMS,
TRUE,
TRUE,
TRUE,
TRUE,
num_errors);
END;
/
BEGIN
DBMS_REDEFINITION.SYNC_INTERIM_TABLE(‘OXX_XXT_OWNER‘,
‘ID_OXXXDX_MX‘,
‘ID_OXXXDX_MX_TMP‘);
END;
/
BEGIN
DBMS_REDEFINITION.FINISH_REDEF_TABLE(
UNAME => ‘OXX_XXT_OWNER‘,
ORIG_TABLE => ‘ID_OXXXDX_MX‘,
INT_TABLE => ‘ID_OXXXDX_MX_TMP‘);
END;
/
comment on column OXX_XXT_OWNER.ID_OXXXDX_MX.dim_code1
is ‘XX代码1‘;
DROP INDEX OXX_XXT_OWNER. IDX_ID_OXXXDX_MX
DROP INDEX OXX_XXT_OWNER.IDX_ID_OXXXDX_MX2;
DROP INDEX OXX_XXT_OWNER.IDX_ID_OXXXDX_MX3
CREATE UNIQUE INDEX OXX_XXT_OWNER.IDX_ID_OXXXDX_MX
ON OXX_XXT_OWNER.ID_OXXXDX_MX (OXG_NO,
IXX_CODE,
……
SXPPLY_TYPE,
DXTA_SRC)
TABLESPACE TBS_XXN_DT
LOCAL;
CREATE INDEX OXX_XXT_OWNER.IDX_ID_OXXXDX_MX2
ON OXX_XXT_OWNER.ID_OXXXDX_MX (STAT_XXCLE)
TABLESPACE TBS_XXN_DT
LOCAL;
CREATE INDEX OXX_XXT_OWNER.IDX_ID_OXXXDX_MX3
ON OXX_XXT_OWNER.ID_OXXXDX_MX (OXG_NO, STAT_XXCLE)
TABLESPACE TBS_XXN_DT
LOCAL;
BEGIN
DBMS_STATS.gather_table_stats (ownname => ‘OXX_XXT_OWNER‘,
tabname => ‘ID_OXXXDX_MX‘,
estimate_percent => 20,
degree => 8,
cascade => TRUE);
END;
/
ALTER TABLE OXX_XXT_OWNER.ID_OXXXDX_MX ENABLE ROW MOVEMENT;
执行如下sql语句：
SELECT *
FROM dba_tab_partitions
WHERE table_owner = ‘OXX_XXT_OWNER‘ AND table_name = ‘ID_OXXXDX_MX‘
若返回结果不为空 则说明执行成功。
本文作者：黎俊杰（网名：踩点），从事”系统架构、操作系统、存储设备、数据库、中间件、应用程序“六个层面系统性的性能优化工作
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原文：http://blog.csdn.net/ljunjie82/article/details/43677725