Three built table occupied rollback segment size

The first: create table s as select * the from dba_objects; –
The second: create table s as select * from dba_objects where 1 = 0;
insert / * + append * / into s select * from dba_objects;
Third: create table s as select * from dba_objects where 1 = 0;
insert into s select * from dba_objects;

The first built table REDO 79648
SQL> select a.name, b.value from v $ statname a, v $ mystat b where a.statistic # = b.statistic # and a.name = ‘redo size’;

NAME VALUE
————————————————– ————————
redo size 644392

Elapsed time: 00: 00: 00.01
SQL> create table s as select * from dba_objects;

The table has been created.

Elapsed time: 00: 00: 00.57
SQL> select a.name, b.value from v $ statname a, v $ mystat b where a.statistic # = b.statistic # and a.name = ‘redo size’;

NAME VALUE
————————————————– ————————
redo size 724040

Elapsed time: 00: 00: 00.00
SQL> select 724040-644392 from dual;

724040-644392
————-
79648

2) The second build tables REDO 18528 +2304 = 20832
SQL> select a.name, b.value from v $ statname a, v $ mystat b where a.statistic # = b.statistic # and a.name = ‘redo size’;

NAME VALUE
————————————————– ————————
redo size 502228

Elapsed time: 00: 00: 00.01
SQL> create table s as select * from dba_objects where 1 = 0;

The table has been created.

Elapsed time: 00: 00: 00.11
SQL> select a.name, b.value from v $ statname a, v $ mystat b where a.statistic # = b.statistic # and a.name = ‘redo size’;

NAME VALUE
————————————————– ————————
redo size 520756

Elapsed time: 00: 00: 00.01
SQL> select 520756-502228 from dual;

520756-502228
————-
18528

Elapsed time: 00: 00: 00.01

SQL> select a.name, b.value from v $ statname a, v $ mystat b where a.statistic # = b.statistic # and a.name = ‘redo size’;

NAME VALUE
————————————————– ————————
redo size 930940

Elapsed time: 00: 00: 00.01
SQL> insert / * + append * / into s select * from dba_objects;

Has been created 49900 line.

Elapsed time: 00: 00: 00.60
SQL> select a.name, b.value from v $ statname a, v $ mystat b where a.statistic # = b.statistic # and a.name = ‘redo size’;

NAME VALUE
————————————————– ————————
redo size 933244

Elapsed time: 00: 00: 00.01
SQL> select 933244-930940 from dual;

933244-930940
————-
2304

Third build tables generated redo 5,658,116
SQL> select a.name, b.value from v $ statname a, v $ mystat b where a.statistic # = b.statistic # and a.name = ‘redo size’;

NAME VALUE
————————————————– ————————
redo size 0

Elapsed time: 00: 00: 00.01
SQL> create table s as select * from dba_objects where 1 = 0;

The table has been created.

Elapsed time: 00: 00: 00.22
SQL> insert into s select * from dba_objects;

Has been created 49900 line.

Elapsed time: 00: 00: 00.62
SQL> select a.name, b.value from v $ statname a, v $ mystat b where a.statistic # = b.statistic # and a.name = ‘redo size’;

NAME VALUE
————————————————– ————————
redo size 5658116

Elapsed time: 00: 00: 00.01