If for some reason your database size
approaches eight exabytes, you may want to consider either some table archiving or splitting the
database into multiple databases based on function. With even the largest commercial Oracle
databases in the petabyte (PB) range in 2007, you may very well not bump up against the 8EB
limit any time in the near future!
546 Oracle Database 11g DBA Handbook
Creating and Modifying Bigfile Tablespaces
Here is an example of creating a bigfile tablespace in a non-ASM environment:
SQL> create bigfile tablespace dmarts
2 datafile '+DATA' size 2500g
3 autoextend on next 500g maxsize unlimited
4 extent management local autoallocate
5 segment space management auto;
Tablespace created.
In the example, you can see that extent management and segment space management are
explicitly set, even though auto is the default for segment space management; bigfile tablespaces
must be created as locally managed with automatic segment space management. Because the
default allocation policy for both bigfile and smallfile tablespaces is autoallocate, you don??™t
need to specify it either. As a rule of thumb, autoallocate is best for tablespaces whose table
usage and growth patterns are indeterminate; as I??™ve pointed out in Chapter 5, you use uniform
extent management only if you know the precise amount of space you need for each object in
the tablespace as well as the number and size of extents.
Even though the datafile for this bigfile tablespace is set to autoextend indefinitely, the disk
volume where the datafile resides may be limited in space; when this occurs, the tablespace may
need to be relocated to a different disk volume.
Pages:
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818