Creating Tables Without Segments - Oracle 11g Release 2 New Feature
Understand Deferred Segment Creation Beginning with Oracle Database 11 g Release 2, when you create heap-organized tables in a locally managed tablespace, the database defers table segment creation until the first row is inserted. In addition, segment creation is deferred for any LOB columns of the table, any indexes created implicitly as part of table creation, and any indexes subsequently explicitly created on the table. Note: In Release 11.2.0.1, deferred segment creation is not supported for partitioned tables. This restriction is removed in release 11.2.0.2 and later. The advantages of this space allocation method are the following: It saves a significant amount of disk space in applications that create hundreds or thousands of tables upon installation, many of which might never be populated. It reduces application installation time. There is a small performance penalty when the first row is inserted, because the new segment must be created at that ...