Deferred Segment Creation in Oracle 11gR2

在Oracle Database 11gR2中,创建新的表,将不会自动创建Segment,只有在表中正式地插入第一条记录的时候,Segment才会被创建,这就是“Deferred Segment Creation”新功能。

参看官方文档

1.9.2.5 Segment Creation on Demand

The initial segment creation for nonpartitioned tables and indexes can be delayed until data is first inserted into an object.

Several prepackaged applications are delivered with large schemas containing many tables and indexes. Depending on the module usage, only a subset of these objects are really being used. With delayed segment creation, empty database objects do not consume any space, reducing the installation footprint and speeding up the installation.

详细的测试可以参看Christian Antognini的文章

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