12c分区增强功能，新功能（文档ID 1568010.1）

Posted 2021-03-22 zylong-sys

12c Partitioning Enhancements, New Features (Doc ID 1568010.1)

APPLIES TO:

Oracle Database - Enterprise Edition - Version 12.1.0.1 and later
Oracle Database Cloud Schema Service - Version N/A and later
Oracle Database Exadata Express Cloud Service - Version N/A and later
Oracle Database Exadata Cloud Machine - Version N/A and later
Oracle Cloud Infrastructure - Database Service - Version N/A and later
Information in this document applies to any platform.

PURPOSE

The document provides references to the 12c partition specific features, enhancements.  该文档提供了对12c分区特定功能，增强功能的引用

DETAILS

Oracle Database 12c is offering enhanced composite partitioning strategies and vastly improved partition maintenance operations.  Oracle Database 12c提供了增强的复合分区策略，并大大改善了分区维护操作

Enhanced composite partitioning strategies  增强的复合分区策略

Combination of the Interval Partitioning and Reference Partitioning, interval partitioned parent table with reference partitioned child table:  区间分区和引用分区的组合，区间分区的父表与引用分区的子表

Note 1519042.1 How to Create Interval-Reference Partitioned Tables in Oracle 12c  如何在Oracle 12c中创建间隔参考分区表

Combination of Reference Partitioning with virtual column-based Partitioning is supported.  支持将参考分区与基于虚拟列的分区结合使用。

Interval as subpartitioning strategy for any top-level partitioning method (*-Interval) is still not supported.  仍然不支持将间隔作为任何顶级分区方法的子分区策略(*-Interval)

Numerous improvements to partition maintenance operations  分区维护操作的许多改进

Online Partition move  在线分区移动

ALTER TABLE...MOVE PARTITION ... ONLINE statement or ALTER TABLE...MOVE SUBPARTITION ... ONLINE statement moves a table partition or subpartition so that DML operations can continue to run uninterrupted on the partition or subpartition that is being moved.

ALTER TABLE...MOVE PARTITION ... ONLINE 语句或 ALTER TABLE...MOVE SUBPARTITION ... ONLINE 语句可移动表分区或子分区，以便DML操作可以在要移动的分区或子分区上继续不间断地运行

See Note 1584032.1 for more details.  有关更多详细信息，请参见Note 1584032.1

Multiple partitions can be added, dropped, truncated, merged with one DDL command:  可以使用一个DDL命令添加，删除，截断或合并多个分区：

Note 1482456.1 Adding multiple partitions in Oracle 12C  在Oracle 12C中添加多个分区

Note 1482264.1 How to Drop/Truncate multiple partitions in Oracle 12C  如何在Oracle 12C中删除/截断多个分区

Note 1482263.1 How to Merge multiple partitions in Oracle 12C.  如何在Oracle 12C中合并多个分区

Similarly a partition can be split into multiple partitions in one go:  同样，一个分区可以一次性拆分为多个分区

Note 1482230.1 Splitting a Partition into multiple partitions in Oracle 12C 在Oracle 12C 中将一个分区拆分为多个分区

Optimized Global index maintenance during drop or truncate partition  在删除或截断分区期间优化了全局索引维护

Drop or truncate partition is optimized in Oracle Database 12c, so that these operations do not require any immediate index maintenance to keep all indexes valid, making it fast metadata-only operations.
在Oracle Database 12c中对删除或截断分区进行了优化，因此这些操作不需要任何立即的索引维护即可保持所有索引有效，从而使其成为仅使用元数据的快速操作。

Global index maintenance is decoupled from the DROP and TRUNCATE partition maintenance operation without rendering a global index unusable. Index maintenance is done asynchronously and can be delayed to a later point-in-time, making these drop and truncate partition fast metadata-only operations.
全局索引维护与DROP和TRUNCATE分区维护操作分离，而不会导致全局索引不可用。 索引维护是异步完成的，并且可以延迟到以后的某个时间点，从而使这些删除和截断分区操作成为仅使用元数据的快速操作。

As documentation at "Asynchronous Global Index Maintenance for Dropping and Truncating Partitions" states  "Asynchronous global index maintenance for DROP and TRUNCATE is performed by default; however, the UPDATE INDEXES clause is still required for backward compatibility."

正如“ 删除和截断分区的异步全局索引维护 ”中的文档所述：“ 默认情况下，对DROP和TRUNCATE进行异步全局索引维护；但是，为了向后兼容，仍然需要UPDATE INDEXES子句。”

So the UPDATE [GLOBAL] INDEXES clause still needs to be used in order to avoid rendering the status of global index UNUSABLE. 

因此，仍然需要使用UPDATE [GLOBAL] INDEXES子句，以避免使全局索引的状态变为UNUSABLE。

When the UPDATE [GLOBAL] INDEXES clause is specified in ALTER TABLE ... DROP|TRUNCATE PARTITION ... statement and the "_fast_index_maintenance"=true (default value), then oracle will do the above mentioned optimized index maintenance. You can find example to demonstrate the behaviour in Tutorial: Oracle Database 12c: What‘s New in Partitioning?

当在 ALTER TABLE ... DROP|TRUNCATE PARTITION ... 语句中指定 UPDATE [GLOBAL] INDEXES 子句，并且"_fast_index_maintenance"=true（默认值）时，oracle将执行上述优化的索引维护。您可以在教程中找到示例，以演示该行为：Oracle Database 12c：分区中的新增功能？

Partial indexing  部分索引

Global/Local indexes can be either created on all partitions of a partitioned table, or only on a subset of the partitions of a partitioned table.

全局/局部索引既可以在分区表的所有分区上创建，也可以仅在分区表的分区的子集上创建。

Note 1482460.1 How to create Partial Global Indexes for Partitioned tables in Oracle 12c  如何在Oracle 12c中为分区表创建部分全局索引

Partition Advisor  分区顾问

In 12c the Partition Advisor has been enhanced in several ways.  在12c中，分区顾问以多种方式得到了增强。

The time needed to generate recommendations is reduced, the quality of recommendations has improved, it now also recommends more partitioning options e.g., LIST partitioning.

生成建议所需的时间减少了，建议的质量得到了改善，现在还建议了更多的分区选项，例如LIST分区。

Information Lifecycle Management (ILM) integration  

Partitioning provides a simple and automated way to implement an Information Lifecycle Management (ILM) strategy.

See example Adding ILM ADO policies.

Further information

Tutorial: Oracle Database 12c: What‘s New in Partitioning?

Partitioning with Oracle Database 12c (PDF) white paper

VLDB and Partitioning Guide

REFERENCES

NOTE:1584032.1 - 12C New Feature: Online Move Partition
NOTE:276158.1 - Partitioning Enhancements in Oracle 10g
NOTE:452447.1 - 11g Partitioning Enhancements