There are several views in the data
dictionary that display database free space. We have to start by defining
free space:
There are several salient DBA views for
displaying free space in Oracle:
-
dba_free_space
-
dba_data_files
-
dba_tablespaces
For a
free poster of these Oracle space
views, click here. Here is a simple script to display Oracle free
space within the data file space. Note the in-line view where
dba_data_files is joined into dba_free_space:
SELECT
a.tablespace_name,
a.file_name,
a.bytes allocated_bytes,
b.free_bytes
FROM
dba_data_files a,
(SELECT file_id, SUM(bytes) free_bytes
FROM dba_free_space b GROUP BY file_id) b
WHERE
a.file_id=b.file_id
ORDER BY
a.tablespace_name;
This shows the allocated and free bytes within the data files, but it DOES not
show available free space on the OS filesystem:
TABLESPACE_NAME
FILE_NAME ALLOCATED_BYTES FREE_BYTES
--------------------
------------------------- --------------- --------------
TBS_LOCALS
/u01/app/oradata/devdb/de 20,971,520 20,774,912
vdb/devdb_tbs_locals_01.d
bf
Note that there are many other ways to create
tablespace reports. This method create an intermediate view to doisplay
free space:
Rem free_space.sql
rem run this script
first, to create the free_space view;
drOP VIEW SYS.FREE_SPACE;
CREATE VIEW
SYS.FREE_SPACE AS
SELECT
TABLESPACE_NAME TABLESPACE,
FILE_ID,
COUNT(*) PIECES,
SUM(BYTES) FREE_BYTES,
SUM(BLOCKS) FREE_BLOCKS,
MAX(BYTES) LARGEST_BYTES,
MAX(BLOCKS) LARGEST_BLKS
FROM
SYS.DBA_FREE_SPACE
GROUP BY TABLESPACE_NAME, FILE_ID;
This is the next script:
rem tsfree.sql - Shows all free space within
tablespaces.
Prompt be sure that you have run free_space.sql prior to
this script
clear breaks;
clear computes;
set verify off;
set pagesize 66;
set linesize 79;
set newpage 0;
column temp_col
new_value spool_file noprint;
column today new_value datevar noprint;
column TABLESPACE_NAME FORMAT A15 HEADING 'Tablespace';
COLUMN PIECES FORMAT 9,999 HEADING 'Tablespace|Pieces';
COLUMN FILE_MBYTES FORMAT 99,999 HEADING 'Tablespace|Mbytes';
cOLUMN FREE_MBYTES FORMAT 99,999 HEADING 'Free|Mbytes';
COLUMN CONTIGUOUS_FREE_MBYTES FORMAT 99,999 HEADING 'Contiguous|Free|Mbytes';
COLUMN PCT_FREE FORMAT 999 HEADING 'Percent|FREE';
COLUMN PCT_CONTIGUOUS_FREE FORMAT 999 HEADING 'Percent|FREE|Contiguous';
ttitle left datevar
right sql.pno -
center ' Instance Data File Storage' SKIP 1 -
center ' in ORACLE Megabytes (1048576 bytes)' -
skip skip;
BREAK ON REPORT
COMPUTE SUM OF FILE_MBYTES ON REPORT
select
to_char(sysdate,'mm/dd/yy') today,
TABLESPACE_NAME,
PIECES,
(D.BYTES/1048576) FILE_MBYTES,
(F.FREE_BYTES/1048576) FREE_MBYTES,
((F.FREE_BLOCKS / D.BLOCKS) * 100) PCT_FREE,
(F.LARGEST_BYTES/1048576) CONTIGUOUS_FREE_MBYTES,
((F.LARGEST_BLKS / D.BLOCKS) * 100) PCT_CONTIGUOUS_FREE
from SYS.DBA_DATA_FILES D, SYS.FREE_SPACE F
where D.STATUS = 'AVAILABLE' AND
D.FILE_ID= F.FILE_ID AND
D.TABLESPACE_NAME = F.TABLESPACE
order by TABLESPACE_NAME;
Here is the report from this script.
Tablespace
Pieces Mbytes Mbytes FREE Mbytes Contiguous
--------------- ---------- ---------- ------- ------- ---------- ----------
MASTER1_DETAILS 1 18 2 10 2 10
MASTER1_DETAILS 1 20 20 100 20 100
MASTER2_DETAILS 1 2 1 65 1 65
MASTER3_DETAILS 1 5 5 95 5 95
MASTER4_DETAILS 2 3 1 36 1 35
RBS_ONE 11 490 380 78 280 57
RBS_TWO 11 490 379 77 279 57
SYSTEM 17 60 45 76 45 75
TEMP 1 650 650 100 650 100
TOOLS 2 15 9 61 8 55
USERS 41 100 31 31 4 4
----------
13,255
This report is useful for finding the largest sized
chunk of free space within a tablespace.
Click here for the complete
Oracle script collection.
