At a company I used to work for, I would frequently get asked, “There’s 200 GB free in the tablespace. Why can’t you just shrink it?”
First, the tablespace consists of many data files and there are objects at the end of the data file, preventing the shrink.
There’s probably over a dozen post out there about the subject matter; however, I believe this method is much simpler and will let you be the judge.
Find the data files to shrink, provide the size to shrink to, a list of tables will be provided to be moved.
After the move, rebuild all UNUSABLE indexes. Don’t forget, this is an offline operation.
Find data files for tablespace
SQL> set pages 10000 SQL> select tablespace_name, file_id, bytes/1048576 mb from dba_data_files where tablespace_name = '&_tbs' order by 1,2 asc ; 2 3 Enter value for _tbs: USERS old 2: where tablespace_name = '&_tbs' order by 1,2 asc new 2: where tablespace_name = 'USERS' order by 1,2 asc TABLESPACE_NAME FILE_ID MB ------------------------------ ---------- ---------- USERS 4 23824 USERS 7 24576 USERS 8 23684 USERS 9 20480 USERS 10 20480 USERS 11 20450 USERS 12 20439 USERS 14 20353 USERS 15 20480 USERS 17 20480 USERS 19 20480 USERS 20 20480 USERS 21 20480 USERS 31 20453 USERS 34 20450 USERS 36 18315 USERS 39 20480 USERS 41 20467 USERS 43 20161 USERS 44 20353 USERS 48 20458 USERS 50 10240 USERS 51 10941 USERS 54 11003 USERS 57 10240 USERS 61 10193 USERS 62 10117 USERS 64 10240 USERS 66 10240 USERS 68 28449 USERS 69 10240 USERS 70 10178 USERS 71 10240 USERS 76 25000 USERS 83 24556 USERS 86 10218 USERS 87 13994 USERS 88 8721 38 rows selected. Elapsed: 00:00:00.05
Identify file_id and final size
SQL> SET SERVEROUTPUT ON
SQL> DECLARE
2 V_FILE_ID NUMBER;
3 V_BLOCK_SIZE NUMBER;
4 V_RESIZE_SIZE NUMBER;
5 BEGIN
6 V_FILE_ID := &_FILE_ID;
7 V_RESIZE_SIZE := &_RESIZE_FILE_TO_MB;
8
9 SELECT BLOCK_SIZE INTO V_BLOCK_SIZE FROM V$DATAFILE WHERE FILE# = V_FILE_ID;
10
11 DBMS_OUTPUT.PUT_LINE('.');
12 DBMS_OUTPUT.PUT_LINE('.');
13 DBMS_OUTPUT.PUT_LINE('.');
14 DBMS_OUTPUT.PUT_LINE('OBJECTS IN FILE '||V_FILE_ID||' THAT MUST MOVE IN ORDER TO RESIZE THE FILE TO '||V_RESIZE_SIZE||' MB');
15 DBMS_OUTPUT.PUT_LINE('===================================================================');
16 DBMS_OUTPUT.PUT_LINE('NON-PARTITIONED OBJECTS');
17 DBMS_OUTPUT.PUT_LINE('===================================================================');
18
19 for my_record in (
20 SELECT DISTINCT(OWNER||'.'||SEGMENT_NAME||' - OBJECT TYPE = '||SEGMENT_TYPE) ONAME
21 FROM DBA_EXTENTS
22 WHERE (block_id + blocks-1)*V_BLOCK_SIZE/1048576 > V_RESIZE_SIZE
23 AND FILE_ID = V_FILE_ID
24 AND SEGMENT_TYPE NOT LIKE '%PARTITION%'
25 ORDER BY 1) LOOP
26 DBMS_OUTPUT.PUT_LINE(my_record.ONAME);
27 END LOOP;
28
29 DBMS_OUTPUT.PUT_LINE('===================================================================');
30 DBMS_OUTPUT.PUT_LINE('PARTITIONED OBJECTS');
31 DBMS_OUTPUT.PUT_LINE('===================================================================');
32
33 for my_record in (
34 SELECT DISTINCT(OWNER||'.'||SEGMENT_NAME||' - PARTITION = '||PARTITION_NAME||' - OBJECT TYPE = '||SEGMENT_TYPE) ONAME
35 FROM DBA_EXTENTS
36 WHERE (block_id + blocks-1)*V_BLOCK_SIZE/1048576 > V_RESIZE_SIZE
37 AND FILE_ID = V_FILE_ID
38 AND SEGMENT_TYPE LIKE '%PARTITION%'
39 ORDER BY 1) LOOP
40 DBMS_OUTPUT.PUT_LINE(my_record.ONAME);
41 END LOOP;
42
43 END;
44 /
Enter value for _file_id: 83
old 6: V_FILE_ID := &_FILE_ID;
new 6: V_FILE_ID := 83;
Enter value for _resize_file_to_mb: 10240
old 7: V_RESIZE_SIZE := &_RESIZE_FILE_TO_MB;
new 7: V_RESIZE_SIZE := 10240;
.
.
.
OBJECTS IN FILE 83 THAT MUST MOVE IN ORDER TO RESIZE THE FILE TO 10240 MB
===================================================================
NON-PARTITIONED OBJECTS
===================================================================
SCHEMA.D_DATA - OBJECT TYPE = TABLE
SCHEMA.LOGIN_LOG - OBJECT TYPE = TABLE
SCHEMA.COMPANY - OBJECT TYPE = TABLE
SCHEMA.ORDER - OBJECT TYPE = TABLE
SCHEMA.FIELD - OBJECT TYPE = TABLE
SCHEMA.REQUEST - OBJECT TYPE = TABLE
SCHEMA.SENDER - OBJECT TYPE = TABLE
SCHEMA.SUMMARY - OBJECT TYPE = TABLE
SCHEMA.TERMINAL - OBJECT TYPE = TABLE
SCHEMA.ORG - OBJECT TYPE = TABLE
SCHEMA.SESSION_LOG - OBJECT TYPE = TABLE
SCHEMA.AGENT - OBJECT TYPE = TABLE
===================================================================
PARTITIONED OBJECTS
===================================================================
PL/SQL procedure successfully completed.
Elapsed: 00:00:00.30
SQL>
When asked about how much space was saved, the answer is 24556-10240=14316 MB
Disclaimer, this has on been run; hence, the actual results is unknown.
SQL script and Reference:
– How to Resize a Datafile (Doc ID 1029252.6)
set pages 10000
select tablespace_name, file_id, bytes/1048576 mb from dba_data_files
where tablespace_name = '&_tbs' order by 1,2 asc
;
SET SERVEROUTPUT ON
DECLARE
V_FILE_ID NUMBER;
V_BLOCK_SIZE NUMBER;
V_RESIZE_SIZE NUMBER;
BEGIN
V_FILE_ID := &_FILE_ID;
V_RESIZE_SIZE := &_RESIZE_FILE_TO_MB;
SELECT BLOCK_SIZE INTO V_BLOCK_SIZE FROM V$DATAFILE WHERE FILE# = V_FILE_ID;
DBMS_OUTPUT.PUT_LINE(‘.’);
DBMS_OUTPUT.PUT_LINE(‘.’);
DBMS_OUTPUT.PUT_LINE(‘.’);
DBMS_OUTPUT.PUT_LINE(‘OBJECTS IN FILE ‘||V_FILE_ID||’ THAT MUST MOVE IN ORDER TO RESIZE THE FILE TO ‘||V_RESIZE_SIZE||’ MB’);
DBMS_OUTPUT.PUT_LINE(‘===================================================================’);
DBMS_OUTPUT.PUT_LINE(‘NON-PARTITIONED OBJECTS’);
DBMS_OUTPUT.PUT_LINE(‘===================================================================’);
for my_record in (
SELECT DISTINCT(OWNER||’.'||SEGMENT_NAME||’ – OBJECT TYPE = ‘||SEGMENT_TYPE) ONAME
FROM DBA_EXTENTS
WHERE (block_id + blocks-1)*V_BLOCK_SIZE/1048576 > V_RESIZE_SIZE
AND FILE_ID = V_FILE_ID
AND SEGMENT_TYPE NOT LIKE ‘%PARTITION%’
ORDER BY 1) LOOP
DBMS_OUTPUT.PUT_LINE(my_record.ONAME);
END LOOP;
DBMS_OUTPUT.PUT_LINE(‘===================================================================’);
DBMS_OUTPUT.PUT_LINE(‘PARTITIONED OBJECTS’);
DBMS_OUTPUT.PUT_LINE(‘===================================================================’);
for my_record in (
SELECT DISTINCT(OWNER||’.'||SEGMENT_NAME||’ – PARTITION = ‘||PARTITION_NAME||’ – OBJECT TYPE = ‘||SEGMENT_TYPE) ONAME
FROM DBA_EXTENTS
WHERE (block_id + blocks-1)*V_BLOCK_SIZE/1048576 > V_RESIZE_SIZE
AND FILE_ID = V_FILE_ID
AND SEGMENT_TYPE LIKE ‘%PARTITION%’
ORDER BY 1) LOOP
DBMS_OUTPUT.PUT_LINE(my_record.ONAME);
END LOOP;
END;
/
