Oracle分区表——实现更好的性能（oracle增加表分区）

Millions of data records accumulate day by day. Relational databases need to manage and store massive amounts of records in a high performance environment, or the user will be unsatisfied with the system. Partitioning tables can help us achieve better performance.

Partitioning in Oracle is to divide a very large table or index into smaller, more manageable pieces called partitions, which can be stored in different physical locations. These smaller pieces still contain all the data of the original table, but the entries have been rearranged so that related data is stored together. Partitioning significantly improves the performance of queries that involve a range comparison (where a value is sought that falls within a certain range).

For example, if we had to query a large table every day that contained two million rows, we might decide to partition that table at the monthly level. This would create 12 monthly partitions, each of which would contain only 167,000 rows. Since the query engine only needs to search one partition instead of the entire table, our query can be completed much faster.

“Range partitioning” is one of the most widely used types of partitioning in Oracle. With this type of partitioning, a single table or index can be divided into smaller pieces based on the range of values in a specific column—for example, a “date” column.

范例：

在Oracle系统中，分区表有助于提高检索和维护大表的效率。它将一个大表或一个索引分割成更小更容易管理的一些部分，可以存放在不同的物理位置。这些小部分仍然包含原始表中的所有数据，但它们的条目已经被重新排列，使相关的数据存储在一起。分区显著提高了涉及范围比较的查询的性能（其中查找的值位于某个范围内）。

比如，如果我们每天都要查询一个包含200万行的大表，我们可能会决定对该表进行月度分区。这将创建12个月度分区，每个分区只包含167,000行。由于查询引擎只需搜索一个分区而不是整个表，我们的查询可以更快地完成。

“范围分区”是Oracle中最常用的分区类型之一。使用这种类型的分区，单个表或索引可以根据特定列中的值范围被划分成更小的部分，例如“日期” 列。例如，可以按生成日期对表进行分区，分析一个月内上传的数据。

分区表可以使我们的查询变得更快，更有效。除了日期分区外，Oracle还提供了其他不同的分区类型，包括哈希分区、列分区和列表分区，以便最大程度地将数据组织到最适当的分区以改善性能。对于大数据库的管理和优化，分区表可以极大地提高查询效率。

总之，oracle 分区表可以实现更好的性能。它可以有效地将表划分为多个逻辑分区，使查询更有效地使用数据库资源，实现更高的性能。