Firstly few commands to get you up & running:

– Get names of tablespaces: “select name from v$tablespace;”

– Get names of disk groups: “select name from v$asm_diskgroup;”

– Get names of data files: “select name from v$datafile;”

In my case it was a big file tablespace, which only option is to resize, not to add more data files, so I did the following:

ALTER TABLESPACE tablespace_name RESIZE 40G;

To check for the size, run the following query:

SELECT tablespace_name,file_name, bytes/1024/1024 SIZE_MBYTES
FROM dba_data_files
WHERE tablespace_name IN (‘SIEBELDATA’, ‘SIEBELINDEX’)
ORDER BY tablespace_name