Tablespace Utilization In Oracle Multitenant Database

February 10, 2021

You must be familiar with checking tablespace utilization in Oracle 11g, here we will discuss about monitoring tablespace in CDB and PDB.

Oracle introduced multitenant architecture from Oracle 12c and in other higher versions like 19c which contains container and pluggable databases CDB and PDB.

There are some new views introduced in 12c multitenant architecture to check size of datafiles and tempfiles tablespace used in CDB and PDB in Oracle database. We have used these views in below below script for monitoring tablespace usage in Oracle.

  • cdb_data_files
  • cdb_segments
  • v$containers
How to shrink Datafiles and Reclaim unused Space in Oracle

Script to Monitor Tablespace Utilization in Oracle 12c, 19c and other higher versions.

set pages 80
 set lin 120
 set echo off
 set feed off
 column PCT format 999.99
 column tablespace format A30
 col container for a30
 select substr(t.tablespace_name,1,30) tablespace,
      round(t.tsbytes/(10241024),0) "ALLOCATED(MB)",      round(nvl(s.segbytes,0)/(10241024),0) "USED(MB)",
      round((nvl(s.segbytes,0)/t.tsbytes)*100,2) PCT,
      lower(vc.name) as container
 from
    (select con_id,tablespace_name,sum(bytes) tsbytes from cdb_data_files group by con_id,tablespace_name) t,
    (select con_id,tablespace_name,sum(bytes) segbytes from cdb_segments group by con_id,tablespace_name) s,
    v$containers vc
 where t.con_id=s.con_id(+)
   and t.tablespace_name=s.tablespace_name(+)
   and t.con_id=vc.con_id
 order by container, tablespace;

TABLESPACE                     ALLOCATED(MB)   USED(MB)     PCT CONTAINER
 -------------                           -------           ------     --------
 SYSAUX                                  1630       1268   77.78 cdb$root
 SYSTEM                                  1250       1244   99.55 cdb$root
 UNDOTBS1                                 545         17    3.18 cdb$root
 USERS                                      8          6   78.33 cdb$root
 APPS_TS_ARCHIVE                         5986        489    8.17 tst31ut
 APPS_TS_INTERFACE                       1041        431   41.43 tst31ut
 APPS_TS_MEDIA                          40394      38294   94.80 tst31ut

Check Tablespace Usage Percentage in Oracle PDB and CDB Database.

set line 200 pages 999
 column name for a10
 column tablespace_name for a15
 column "MAXSIZE (MB)" format 9,999,990.00
 column "ALLOC (MB)" format 9,999,990.00
 column "USED (MB)" format 9,999,990.00
 column "PERC_USED" format 99.00
 select a.con_id,c.name,b.tablespace_name,a.bytes_alloc/(10241024) "MAXSIZE (MB)", nvl(a.physical_bytes,0)/(10241024) "ALLOC (MB)" ,nvl(b.tot_used,0)/(10241024) "USED (MB)" ,(nvl(b.tot_used,0)/a.bytes_alloc)100 "PERC_USED"
 from
 (select con_id,tablespace_name, sum(bytes) physical_bytes,sum(decode(autoextensible,'NO',bytes,'YES',maxbytes)) bytes_alloc
 from cdb_data_files group by con_id,tablespace_name ) a,
 (select con_id,tablespace_name, sum(bytes) tot_used from cdb_segments group by con_id,tablespace_name ) b,
 (select name,con_id from v$containers) c
 where a.con_id= b.con_id and a.con_id = c.con_id and a.tablespace_name = b.tablespace_name (+)
 order by 1,3;
CON_ID NAME       TABLESPACE_NAME  MAXSIZE (MB)    ALLOC (MB)     USED (MB) PERC_USED
---------------  ------------   -----------   ----------------   --------------
1 CDB$ROOT   SYSAUX              32,767.98      1,630.00      1,274.00      3.89
          1 CDB$ROOT   SYSTEM              32,767.98      1,250.00      1,244.38      3.80
          1 CDB$ROOT   UNDOTBS1            32,767.98        545.00         17.25       .05
          1 CDB$ROOT   USERS               32,767.98          7.50          5.88       .02
          3 tst31ut    APPS_TS_ARCHIVE     21,346.00      5,986.00        489.25      2.29
          3 tst31ut    APPS_TS_INTERFA      1,041.00      1,041.00        431.25     41.43

To Check how much Space Used in Oracle 

select sum(BYTES)/1024/1024/1024 from cdb_segments;
SUM(BYTES)/1024/1024/1024
-----------------
310.454269  

select CON_ID,sum(BYTES)/1024/1024/1024 from cdb_segments group by CON_ID;
CON_ID SUM(BYTES)/1024/1024/1024
-------    --------------
1                2.47595215    -CDB Size
 3                307.978317    -PDB Size

To Check Datafile Size in Oracle

 col FILE_NAME for a55
 set lines 200
 select FILE_NAME,BYTES/1024/1024/1024, MAXBYTES/1024/1024/1024,AUTOEXTENSIBLE from cdb_data_files where TABLESPACE_NAME='APPS_TS_MEDIA';
 FILE_NAME                                               BYTES/1024/1024/1024 MAXBYTES/1024/1024/1024 AUT
 
 /scratch/u01/E-BIZ/db/apps_st/data/a_media01.dbf                  1.41210938                       0 NO
 /scratch/u01/E-BIZ/db/apps_st/data/a_media03.dbf                  18.8696289                      20 YES
 /scratch/u01/E-BIZ/db/apps_st/data/a_media02.dbf                  19.1652832                      30 YES

Conclusion: Above script is used to check tablespace details in Oracle including tablespace size, freespace, percentage used etc.

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