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原创 Linux操作系统 作者:simkyo 时间:2013-08-29 10:38:50 0 删除 编辑
注意:Oracle只支持2中类型的全局分区索引:
           range partitioned 和 Hash Partitioned.
官网的说明如下:
Global Partitioned Indexes
       Oracle offers two types of global partitioned index: range partitioned and hash partitioned.
(1)Global Range Partitioned Indexes
       Global range partitioned indexes are flexible in that the degree of partitioning and the partitioning key are independent from the table's partitioning method. They are commonly used for OLTP environments and offer efficient access to any individual record.
       The highest partition of a global index must have a partition bound, all of whose values are MAXVALUE. This ensures that all rows in the underlying table can be represented in the index. Global prefixed indexes can be unique or nonunique.
       You cannot add a partition to a global index because the highest partition always has a partition bound of MAXVALUE. If you wish to add a new highest partition, use the ALTER INDEX SPLIT PARTITION statement. If a global index partition is empty, you can explicitly drop it by issuing the ALTER INDEX DROP PARTITION statement. If a global index partition contains data, dropping the partition causes the next highest partition to be marked unusable. You cannot drop the highest partition in a global index.
(2)Global Hash Partitioned Indexes
       Global hash partitioned indexes improve performance by spreading out contention when the index is monotonically growing. In other words, most of the index insertions occur only on the right edge of an index.
(3)Maintenance of Global Partitioned Indexes
       By default, the following operations on partitions on a heap-organized table mark all global indexes as unusable:
ADD (HASH)
COALESCE (HASH)
DROP EXCHANGE MERGE MOVE SPLIT TRUNCATE
示例1 全局索引,全局索引对所有分区类型都支持:
sql> create index ix_custaddr_ global_id on custaddr(id) global;
索引已创建。

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