To find the Table Space Size of your table across all AMPs in Teradata

You can find the Table Space Size of your table from Data Dictionary Table DBC.TABLESIZE

Code:
SELECT DATABASENAME, TABLENAME, SUM(CURRENTPERM) 
FROM DBC.TABLESIZE 
WHERE DATABASENAME = ‘<database>’ AND TABLENAME = ‘<table>’ 
GROUP BY DATABASENAME , TABLENAME;