teradata database unable to increase database size in permanent space
Your query and the results don't match, but you're probably right.

This will return the actual available space (modify it accordingly for TBs or 1024**3):

SELECT DatabaseName, 
   CAST(SUM(    MaxPerm                  / 1000**3) AS DEC(9,2)) AS MaxPermGB, 
   CAST(SUM(CurrentPerm                  / 1000**3) AS DEC(9,2)) AS CurrentPermGB, 
   CAST(MAX(CurrentPerm) * (HASHAMP()+1) / 1000**3  AS DEC(9,2)) AS SkewedPermGB, -- due to skewed tables
   MaxPermGB - SkewedPermGB AS AvailablePermGB -- this space can be assigned to other databases
FROM dbc.DiskSpaceV
WHERE MaxPerm &gt; 0
GROUP BY 1
ORDER BY AvailablePermGB DESC


MODIFY DATABASE will only work if enough perm is available in the parent/immediate owner. If this database is not in the 2nd level of the hierarchy dbc is not the direct owner and then it's more complicated. Now you better use Tools -&gt; Move Space, but this might fail if you don't have appropriate access rights.