Viewing tablespace information in Oracle Database

The following data dictionary and dynamic performance views provide useful information about the tablespaces of a DATABASE.

The following are just a few examples of using some of these views.

Example 1: listing TABLESPACES and default storage parameters:

To list the names and default storage parameters of all tablespaces in a database, use the following query on the dba_tablespaces view:

Sql>select tablespace_name "tablespace",
Initial_extent "initial_ext",
Next_extent "next_ext",
Min_extents "min_ext",
Max_extents "max_ext",
Pct_increase
From dba_tablespaces;

Tablespace   initial_ext    next_ext     min_ext      max_ext       pct_increase 
——–             ———          ——–            ——-     ——–             ———-
Rbs                1048576     1048576         2               40               0
System           106496      106496           1               99               1
Temp              106496      106496           1               99              0
Testtbs            57344        16384            2              10                1
Users               57344        57344            1               99                1

Example 2: listing the datafiles and associated tablespaces of a database:

To list the names, sizes, and associated tablespaces of a database, enter the following query on the dba_data_files view:

Sql>select  file_name, blocks, tablespace_name  from dba_data_files;

File_name                                              blocks        tablespace_name
—————-                                          ——–          —————–
/u02/oracle/iddb3/dbf/rbs01.dbf               1536                    rbs
/u02/oracle/iddb3/dbf/system01.dbf        6586                   system
/u02/oracle/iddb3/dbf/temp01.dbf            6400                  temp
/u02/oracle/iddb3/dbf/testtbs01.dbf         6400                   testtbs
/u02/oracle/iddb3/dbf/users01.dbf             384                    users

Checkout Oracle DBA Interview Questions

Example 3: displaying statistics for free space (extents) of each tablespace:

To produce statistics about free extents and coalescing activity for each tablespace in the database, enter the following query:

Sql>select tablespace_name "tablespace", file_id, count(*) "pieces", max(blocks) "maximum",   
 min(blocks) "minimum", avg(blocks) "average", sum(blocks) "total"
 From dba_free_space  group by tablespace_name, file_id;

Tablespace    file_id      pieces     maximum     minimum   average    total
———–     ——            ——-       ———-        ———-        ——–   —-
Rbs                    2             1            955             955             955           955
System              1              1             119               119            119             119
Temp                 4              1          6399            6399        6399           6399
Testtbs              5              5           6364               3            1278            6390
Users                3               1             363               363            363            363

Pieces shows the number of free space extents in the tablespace file, maximum and minimum show the largest and smallest contiguous area of space in database blocks, average shows the average size in blocks of a free space extent, and total shows the amount of free space in each tablespace file in blocks. This query is useful when you are going to create a new object or you know that a segment is about to extend, and you want to make sure that there is enough space in the containing tablespace.