create table data_r(c1) as with g as (select * from dual connect by level <= 1000) select dbms_random.value(1, 5000000) from g, g, g where rownum <= 5e6;
create table data_s(c1) as with g as (select * from dual connect by level <= 1000) select rownum from g, g, g where rownum <= 5e6;
create table t1 (c1 number);
create index i1 on t1(c1);
create table t2 (c1 number);
create index i2 on t2(c1) unusable;

SQL> select sn.name, s.value from v$mystat s join v$statname sn on (s.statistic# = sn.statistic#) where sn.name like 'leaf node%splits';

NAME                                VALUE
------------------------------ ----------
leaf node splits                        0
leaf node 90-10 splits                  0

Elapsed: 00:00:00.00
SQL> insert into t1 select * from data_r;

5000000 rows created.

Elapsed: 00:00:47.64
SQL> commit;

Commit complete.

Elapsed: 00:00:00.00
SQL> select sn.name, s.value from v$mystat s join v$statname sn on (s.statistic# = sn.statistic#) where sn.name like 'leaf node%splits';

NAME                                VALUE
------------------------------ ----------
leaf node splits                    29992
leaf node 90-10 splits                  0

Elapsed: 00:00:00.00
SQL>

SQL> conn bp/bp
Connected.
SQL> select sn.name, s.value from v$mystat s join v$statname sn on (s.statistic# = sn.statistic#) where sn.name like 'leaf node%splits';

NAME                                VALUE
------------------------------ ----------
leaf node splits                        0
leaf node 90-10 splits                  0

Elapsed: 00:00:00.01
SQL> insert into t2 select * from data_r;

5000000 rows created.

Elapsed: 00:00:03.29
SQL> alter index i2 rebuild;

Index altered.

Elapsed: 00:00:05.18

SQL> select sn.name, s.value from v$mystat s join v$statname sn on (s.statistic# = sn.statistic#) where sn.name like 'leaf node%splits';

NAME                                VALUE
------------------------------ ----------
leaf node splits                        0
leaf node 90-10 splits                  0


truncate table t1;
truncate table t2;
alter index i2 unusable;


SQL> select sn.name, s.value from v$mystat s join v$statname sn on (s.statistic# = sn.statistic#) where sn.name like 'leaf node%splits';

NAME                                                                  VALUE
---------------------------------------------------------------- ----------
leaf node splits                                                          0
leaf node 90-10 splits                                                    0

Elapsed: 00:00:00.00
SQL>

SQL> truncate table t1;

Table truncated.

Elapsed: 00:00:00.46
SQL> truncate table t2;

Table truncated.

Elapsed: 00:00:00.43
SQL> alter index i2 unusable;

Index altered.

Elapsed: 00:00:00.02

Connected.
SQL> select sn.name, s.value from v$mystat s join v$statname sn on (s.statistic# = sn.statistic#) where sn.name like 'leaf node%splits';

NAME                                VALUE
------------------------------ ----------
leaf node splits                        0
leaf node 90-10 splits                  0

Elapsed: 00:00:00.00
SQL> insert into t1 select * from data_s order by 1;

5000000 rows created.

Elapsed: 00:00:10.37
SQL> commit;

Commit complete.

Elapsed: 00:00:00.02
SQL> select sn.name, s.value from v$mystat s join v$statname sn on (s.statistic# = sn.statistic#) where sn.name like 'leaf node%splits';

NAME                                VALUE
------------------------------ ----------
leaf node splits                    10509
leaf node 90-10 splits              10509

Elapsed: 00:00:00.01

SQL> conn bp/bp
Connected.
SQL> select sn.name, s.value from v$mystat s join v$statname sn on (s.statistic# = sn.statistic#) where sn.name like 'leaf node%splits';

NAME                                VALUE
------------------------------ ----------
leaf node splits                        0
leaf node 90-10 splits                  0

Elapsed: 00:00:00.00
SQL> insert into t2 select * from data_s order by 1;

5000000 rows created.

Elapsed: 00:00:04.00
SQL> alter index i2 rebuild;

Index altered.

Elapsed: 00:00:03.34
SQL> commit;

Commit complete.

Elapsed: 00:00:00.00
SQL> select sn.name, s.value from v$mystat s join v$statname sn on (s.statistic# = sn.statistic#) where sn.name like 'leaf node%splits';

NAME                                VALUE
------------------------------ ----------
leaf node splits                        0
leaf node 90-10 splits                  0

Elapsed: 00:00:00.01