In a global partitioned index, the keys in a particular index partition may refer to rows stored in multiple underlying table partitions or subpartitions. A global index can be range or hash partitioned, though it can be defined on any type of partitioned table.
A global index is created by specifying the GLOBAL attribute. The database administrator is responsible for defining the initial partitioning of a global index at creation and for maintaining the partitioning over time. Index partitions can be merged or split as necessary.
Normally, a global index is not equipartitioned with the underlying table. There is nothing to prevent an index from being equipartitioned with the underlying table, but Oracle does not take advantage of the equipartitioning when generating query plans or executing partition maintenance operations. So an index that is equipartitioned with the underlying table should be created as LOCAL.
A global partitioned index contains a single B-tree with entries for all rows in all partitions. Each index partition may contain keys that refer to many different partitions or subpartitions in the table.
The highest partition of a global index must have a partition bound that includes all values that are MAXVALUE. This insures that all rows in the underlying table can be represented in the index.
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