Bytes is greater than maxbytes in dba_data_files

Question

Hi,
In what situation can the size of bytes be greater than the size of maxbytes in the dba_data_files?
select bytes,user_bytes,maxbytes from dba_data_files where bytes > maxbytes
BYTES     USER_BYTES     MAXBYTES
10485760000     10485694464     6392119296
6291456000     6288310272     5242880000
6291456000     6291390464     5242880000
6291456000     6291390464     5242880000
10485760000     10485628928     7340032000
33554432000     33552334848     0
15728640000     15725494272     12582912000
35357982720     35347496960     32212254720
11534336000     11523850240     5242880000
11534336000     11532238848     10485760000
Regards,
CT

Answer 1

It's just mixing methods. Example follows.
SQL> create tablespace bytes datafile 'bytes01.dbf' size 128K
autoextend on maxsize 1000K;
Tablespace created.
SQL> select bytes/1024 kb, maxbytes/1024 maxkb, autoextensible
  2  from dba_data_files where tablespace_name='BYTES';
        KB      MAXKB AUT
       128       1000 YES
SQL> create table dump (a varchar(4000)) tablespace bytes;
Table created.
SQL> insert into dump values ... ;
1 row created.
SQL> insert into dump select a from dump;
SQL> /
32 rows created.
SQL> select bytes/1024 kb, maxbytes/1024 maxkb, autoextensible
  2  from dba_data_files where tablespace_name='BYTES';
        KB      MAXKB AUT
       192       1000 YES
SQL> insert into dump select a from dump;
SQL> /
256 rows created.
SQL> /
insert into dump select a from dump
ERROR at line 1:
ORA-01653: unable to extend table TESTING.DUMP by 8 in tablespace BYTES
SQL> select bytes/1024 kb, maxbytes/1024 maxkb, autoextensible
  2  from dba_data_files where tablespace_name='BYTES';
        KB      MAXKB AUT
       960       1000 YES
SQL> alter database datafile 'bytes01.dbf' resize 1111K;
Database altered.
SQL> select bytes/1024 kb, maxbytes/1024 maxkb, autoextensible
  2  from dba_data_files where tablespace_name='BYTES';
        KB      MAXKB AUT
      1112       1000 YES
SQL>Does this answer op's concern?