Category: tablespace

What are the features of BIGFILE Tablespace in Oracle Database?

Bigfile Tablespace is introduced from Oracle 10g.A bigfile tablespace is a tablespace with a single, but very large (up to 4G blocks) datafile.


The benefits of bigfile tablespaces are the following:

A bigfile tablespace with 8K blocks can contain a 32 terabyte datafile. A bigfile tablespace with 32K blocks can contain a 128 terabyte datafile. The maximum number of datafiles in an Oracle Database is limited (usually to 64K files). Therefore, bigfile tablespaces can significantly enhance the storage capacity of an Oracle Database.



Bigfile tablespaces can reduce the number of datafiles needed for a database. 
An additional benefit is that the DB_FILES initialization parameter and MAXDATAFILES parameter of the CREATE DATABASE and CREATE CONTROLFILE statements can be adjusted to reduce the amount of SGA space required for datafile information and the size of the control file.


Bigfile tablespaces simplify database management by providing datafile transparency. 
SQL syntax for the ALTER TABLESPACE statement lets you perform operations on tablespaces, 
rather than the underlying individual datafiles.


Bigfile tablespaces are intended to be used with Automatic Storage Management (ASM) or other logical volume managers that supports striping or RAID, and dynamically extensible logical volumes.


Avoid creating bigfile tablespaces on a system that does not support striping because of negative implications for parallel query execution and RMAN backup parallelization.




Creating a Bigfile Tablespace




To create a bigfile tablespace, specify the BIGFILE keyword of the CREATE TABLESPACE statement (CREATE BIGFILE TABLESPACE …)


CREATE BIGFILE TABLESPACE bigtbs 
    DATAFILE ‘/u02/oracle/data/bigtbs01.dbf’ SIZE 50G
…




Identifying a Bigfile Tablespace


The following views contain a BIGFILE column that identifies a tablespace as a bigfile tablespace:


DBA_TABLESPACES


USER_TABLESPACES


V$TABLESPACE

ORA-32771: Cannot Add File To Bigfile Tablespace

When trying to add a datafile to a tablespace , got the error – ORA-32771: cannot add file to bigfile tablespace.


SQL> ALTER TABLESPACE BIG_TBSP1 add datafile ‘+DATA/df01.dbf’ size 130G;
ALTER TABLESPACE BIG_TBSP1 add datafile ‘+DATA/df01.dbf’ size 130G;
*
ERROR at line 1:
ORA-32771: cannot add file to bigfile tablespace


SOLUTION:


A bigfile tablespace can contain only one datafile and no other datafile can be added to that.


SQL> select BIGFILE from dba_tablespaces where tablespace_name=’BIG_TBSP1’;


BIGFILE
———————– —
YES


How to increase space in Bigfile Tablespace?




BIGFILE tablespace stores its data in a single datafile with a much larger capacity.


We can resize the size of the datafile in BIGFILE tablespace using ALTER DATABASE Command




ALTER DATABASE DATAFILE ‘/+DATA/df0101.dbf’ RESIZE 180G;


Since BIGFILE Tablespace has only one datafile, there is no need to identify the datafile and increase its size.
We can use ALTER TABLESPACE command to resize at the tablespace level.


ALTER TABLESPACE BIG_TBSP1 RESIZE 180G;