在Teradata中查找所有未压缩的表

Question

Is there a way to find all the uncompressed tables in teradata ?

So far I am doing it manually by using

SHOW TABLE <TABLE_NAME>

and checking if a column has COMPRESS keyword. This gets a lot tedious if I have 100s of tables.

Is there a column or table where I can query for such tables something like I can check for Macro -

SELECT * FROM dbc.tables WHERE tablekind='M' AND databasename='database'

Any help is appreciated.

Answer 1

You can find all compressed columns:

select * from dbc.ColumnsV 
where CompressValueList is not null

To get tables without any compress:

SELECT * FROM dbc.TablesV
WHERE TableKind IN ('T', 'O') -- both PI and NoPI tables
AND (DatabaseName, TableName) NOT IN 
 (
   SELECT DatabaseName, TableName 
   FROM dbc.columnsv
   WHERE CompressValueList IS NOT NULL
 )

Answer 2

As you mentioned, compression is more a "column thing" rather than a "table thing", so you'd better check in the column metadata:

That's a possible query (to be improved):

  select  t.tablename, sum(case when compressvaluelist is null then 0 else 1 end) compressed_cols, count(*) cols  
    from dbc.ColumnsV c join dbc.TablesV t on (c.tablename=t.tablename and c.databasename=t.databasename) 
   where t.databasename='<databasename>'
     and t.tablekind in ('T','O')
   group by 1    
  having compressed_cols=0

Answer 3

You can use dbc table columns for that . Compressible = 'C' will give you those values.

select databasename,tablename,columnname,compressible
from dbc.columns
where compressible in ('A','C')

by the way in y our query why you are choosing tablekind='M', it will not return details of table but will return detail of macro.