Creating Tables Without Segments - Oracle 11g Release 2 New Feature
Understand Deferred Segment CreationBeginning with Oracle Database 11g 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 188.8.131.52, deferred segment creation is not supported for partitioned tables. This restriction is removed in release 184.108.40.206 and later.
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.
To enable deferred segment creation, compatibility must be set to '11.2.0' or higher.
The new clauses for the
TRUE, which defers segment creation. To disable deferred segment creation, set this parameter to
Note that when you create a table with deferred segment creation, the new table appears in the
*_TABLESviews, but no entry for it appears in the
*_SEGMENTSviews until you insert the first row.
You can verify deferred segment creation by viewing the
*_LOBSviews for non-partitioned tables, and in
*_LOB_PARTITIONSviews for partitioned tables.
Reference Source - docs.oracle.com
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