Oracle11gR2 does not assign segment when creating a non-Data Object

The experiment found that oracle11gR2 was used to create tables, indexes, and other objects without data. In order to save space, oracle did not allocate segment, but allocated only when there was a dml operation.

The experiment found that oracle11gR2 was used to create tables, indexes, and other objects without data. In order to save space, oracle did not allocate segment, but allocated only when there was a dml operation.

The experiment found that Oracle11gR2 was used to create tables, indexes, and other objects without data. In order to save space, oracle did not allocate segment, but allocated segment only when there was a dml operation, even if dml is rolled back, the allocated segments are not recycled.

A simple experiment is as follows:
SQL> create table test (a number );

Table created.

SQL> create index ind_test on test ();

Index created.

QL> select segment_name, bytes from dba_segments wheresegment_name = 'test' and owner = 'wxlun ';

No rows selected

SQL> insert into test values (1 );

1 row created.

SQL>
SQL> col SEGMENT_NAME for a22
SQL> select segment_name, bytes from dba_segments wheresegment_name in ('test', 'ind _ test') and owner = 'wxlun ';

SEGMENT_NAME
BYTES
--------------------------------
IND_TEST