Hi Hrishy, You could check this Metalink Note... How To Size UNDO Tablespace For Automatic Undo Management Doc ID: 262066.1 You'll get from the note the query below: SQL> SELECT (UR * (UPS * DBS)) + (DBS * 24) AS "Bytes" FROM (SELECT value AS UR FROM v$parameter WHERE name = 'undo_retention'), (SELECT (SUM(undoblks)/SUM(((end_time - begin_time)*86400))) AS UPS FROM v$undostat), (select block_size as DBS from dba_tablespaces where tablespace_name= (select upper(value) from v$parameter where name = 'undo_tablespace')); - Karl Arao http://karlarao.wordpress.com On Wed, Jul 8, 2009 at 2:50 PM, hrishy <hrishys@xxxxxxxxxxx> wrote: > Hi > > I am trying to size my undo tablepsace by looking at the undo rates.i.e the > column UNDOBLKS in v$undostat. > > Value for undoblks for particular sql is 13841 and my database size is > 8kb.Does this mean that i need to have a undo tablespace size of > > select 8192*13841/1024/1024 from dual > 108Gb ? > > Not the particular sql does a corelated update ofmere 72762 rows and the > figure of 108Gb doesnt make much sense .This is a JDBC app and i dont have > much idea if this sql is in some for loop or something. > > regards > Hrishy > > regards > Hrishy > > >