Rotating partitions

 

You can use the ALTER TABLE statement to rotate any logical partition to become the last partition. Rotating partitions is supported for partitioned (non-universal) table spaces and range-partitioned table spaces, but not for partition-by-growth table spaces.

About this task

Recommendation: When you create a partitioned table space, you do not need to allocate extra partitions for expected growth. Instead, you can use the ALTER TABLE ADD PARTITION statement to add partitions as needed. If rotating partitions is appropriate for your application, use the ALTER TABLE ROTATE PARTITION statement to avoid adding another partition.

Nullable partitioning columns: DB2® lets you use nullable columns as partitioning columns. But with table-controlled partitioning, DB2 can restrict the insertion of null values into a table with nullable partitioning columns, depending on the order of the partitioning key. After a rotate operation, if the partitioning key is ascending, DB2 prevents an INSERT of a row with a null value for the key column. If the partitioning key is descending, DB2 allows an INSERT of a row with a null value for the key column. The row is inserted into the first partition.

Procedure

To rotate a partition to be the last partition:

  1. Issue the ALTER TABLE statement and specify the ROTATE PARTITION option.
  2. Optional: Run the RUNSTATS utility.

Example

For example, assume that the partition structure of the table space is sufficient through the year 2006. The following table shows a representation of the table space through the year 2006. When another partition is needed for the year 2007, you determined that the data for 1996 is no longer needed. You want to recycle the partition for the year 1996 to hold the transactions for the year 2007.

Table 1. An excerpt of a partitioned table space
Partition Limit value Data set name that backs the partition
P008 12/31/2004 catname.DSNDBx.dbname.psname.I0001.A008
P009 12/31/2005 catname.DSNDBx.dbname.psname.I0001.A009
P010 12/31/2006 catname.DSNDBx.dbname.psname.I0001.A010

To rotate the first partition for table TRANS to be the last partition, issue the following statement:

ALTER TABLE TRANS ROTATE PARTITION FIRST TO LAST
ENDING AT ('12/31/2007') RESET;

For a table with limit values in ascending order, the data in the ENDING AT clause must be higher than the limit value for previous partitions. DB2 chooses the first partition to be the partition with the lowest limit value.

For a table with limit values in descending order, the data must be lower than the limit value for previous partitions. DB2 chooses the first partition to be the partition with the highest limit value.

The RESET keyword specifies that the existing data in the first logical partition is deleted, and no delete triggers are activated. Because the oldest (or first) partition is P001, DB2 assigns the new limit value to P001. This partition holds all rows in the range between the new limit value of 12/31/2007 and the previous limit value of 12/31/2006. The RESET operation deletes all existing data. You can use the partition immediately after the ALTER completes. The partition is not placed in REORG-pending (REORP) status, if the table is large, or if the last partition before the rotation is empty.

The following table shows a representation of the table space after the first partition is rotated to become the last partition.

Table 2. Rotating the first partition to be the last partition
Partition Limit value Data set name that backs the partition
P002 12/31/1997 catname.DSNDBx.dbname.psname.I0001.A002
P003 12/31/1998 catname.DSNDBx.dbname.psname.I0001.A003
P004 12/31/1999 catname.DSNDBx.dbname.psname.I0001.A004
P005 12/31/2000 catname.DSNDBx.dbname.psname.I0001.A005
P006 12/31/2001 catname.DSNDBx.dbname.psname.I0001.A006
P007 12/31/2002 catname.DSNDBx.dbname.psname.I0001.A007
P008 12/31/2003 catname.DSNDBx.dbname.psname.I0001.A008
P009 12/31/2004 catname.DSNDBx.dbname.psname.I0001.A009
P010 12/31/2005 catname.DSNDBx.dbname.psname.I0001.A010
P011 12/31/2006 catname.DSNDBx.dbname.psname.I0001.A011
P001 12/31/2007 catname.DSNDBx.dbname.psname.I0001.A001

Rotate partitions in DB2 on z的更多相关文章

  1. DB2 for z: system catalog tables

    http://www.ibm.com/support/knowledgecenter/SSEPEK_10.0.0/com.ibm.db2z10.doc.sqlref/src/tpc/db2z_cata ...

  2. 在DB2 for z/os上创建指定pagesize的数据库

    ASNTDIFF的diff table有一列类型为varchar 15000,z上创建db默认的pagesize是4K,无法创建table,所以需要创建一个大pagesize的database. db ...

  3. Index on DB2 for z/OS: DB2 for z/OS 的索引

    可以创建在任何表上的索引: Unique Index:An index that ensures that the value in a particular column or set of col ...

  4. DB2 for Z/os Statement prepare

    The PREPARE statement creates an executable SQL statement from a string form of the statement. The c ...

  5. DB2 bind on z/os

    BIND and REBIND options for packages and plans There are several options you can use for binding or ...

  6. OGG for DB2 z/OS 12.2版本发布

    2016-04-15 Oracle发布了GoldenGate for DB2 z/OS  12.2.0.1.2.可以从OTN或eDelivery下载,该版本是ogg for DB2 z/OS的第一个1 ...

  7. 免费数据库(SQLite、Berkeley DB、PostgreSQL、MySQL、Firebird、mSQL、MSDE、DB2 Express-C、Oracle XE)

    SQLite数据库是中小站点CMS的最佳选择 SQLite 是一个类似Access的轻量级数据库系统,但是更小.更快.容量更大,并发更高.为什么说 SQLite 最适合做 CMS (内容管理系统)呢? ...

  8. DB2调优摘要

    感谢原博主 http://yishueitian326.blog.163.com/blog/static/2858637520106695733719/ 性 能是关系到随需应变型应用程序成功与否的关键 ...

  9. (转)调优 DB2 UDB v8.1 及其数据库的最佳实践

    原文:https://www.ibm.com/developerworks/cn/data/library/techarticles/dm-0404mcarthur/index.html 简介 性能是 ...

随机推荐

  1. android常见问题(一)

    一:文本的颜色选择器: 在res目录下面创建color文件夹,在color文件夹下面创建font_style_colors.xml文件<?xml version="1.0" ...

  2. UNITY3d在移动设备上的一些优化实战(一)-概述

    转自:UNITY3d在移动设备上的一些优化实战(一)-概述 http://blog.csdn.net/leonwei/article/details/39233921 项目进入了中期之后,就需要对程序 ...

  3. SMT 的基本流程?SMT的工艺流程?SMT的设备操作?

    一.SMT工艺流程------单面组装工艺来料检测 --> 丝印焊膏(点贴片胶)--> 贴片 --> 烘干(固化) --> 回流焊接 --> 清洗 --> 检测 - ...

  4. Linux system 函数的一些注意事项

    在日常的代码编程中 , 我们可以利用system  函数去调用一些我们自己想调用的命令 , 并获取他的返回值. 函数的原型如下: int system(const char *command); 上一 ...

  5. json_decode()和json_encode()的使用方法

    json_decode对JSON格式的字符串进行编码 json_encode对变量进行 JSON 编码 JS中对JSON的解析 一.JSON字符串转换为JSON对象     要运用上面的str1,必须 ...

  6. java复制文件

    package com.test.tes; import java.io.File; import java.io.FileInputStream; import java.io.FileOutput ...

  7. 为MongoDB创建一个Windows服务

    一:选型,根据机器的操作系统类型来选择合适的版本,使用下面的命令行查询机器的操作系统版本 wmic os get osarchitecture 二:下载并安装 附上下载链接 点击安装包,我这里是把文件 ...

  8. HTML锚点参考

    锚点参考 <ul class="banner-pic"> <li style="background: url(../Content/images/ne ...

  9. sharepoint2013隐藏左侧导航栏更换新的

    $("#zz16_V4QuickLaunchMenu").hide()//隐藏 更换新的 <script type="text/javascript" s ...

  10. spring + myBatis 常见错误:@Autowired注解失败

    今天配置spring+myBatis的时候,使用注解@Autowired把持久层dao注入service层的时候总是报错. 查了好久才发现,居然是配置文件路径写错了.basepackge的路径一定要正 ...