Re: Sizing Undo tablespace

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_at_yahoo.co.uk> 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
>
>
>

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