BigFile Tablespaces (BFT)
BFTs are supported only for locally managed
tablespaces with ASM segments and locally managed UNDO and
TEMPORARY tablespaces. When BFTs are used with Oracle Managed
Files, data files become completely transparent to the DBA and
no reference is needed for them. BFT makes a tablespace
logically equivalent to a data file allowing operations in
earlier releases to be performed on tablespaces.
BFTs should be used only with
the logical volume
manager,
with ASM supporting
dynamically extensible logical volumes,
and with systems
that support striping to prevent negative consequences on RMAN
backup parallelization and parallel query execution. BFT should
not be used when there is a limited free disk space available.
ROWIDs of rows that belong to BFTs do not
contain a relative file number but the block number. A bigfile
tablespace has only one datafile, and always has a relative file number of 1024.
There is no need to include this filenumber in the ROWID. The
block numbers are relative to their tablespace and are unique
with in tablespace. The only supported ways to retrieve the
ROWID component is to use the dbms_rowid package.
The default tablespace type is a persistent
database parameter in the data dictionary. If this parameter is
not set by either the CREATE DATABASE or ALTER DATABASE command,
the default will be SMALLFILE. Two new keywords,
