UNDO tbs requirement

Question

How would I know what is the required UNDO tbs space for a job to run successfully.
I cannot view the code of the job.
How can I calculate the UNDO tbs requirement for that particular job.
Following is the error I am facing while running that job :
*** Starting go_ifs_gb_publish_data_det.sh at Fri Feb 12 14:13:21 EST 2010.
BEGIN fdw.gb_rpt_publish_data; END;
ERROR at line 1:
ORA-30036: unable to extend segment by 4 in undo tablespace 'UNDOTBS'
ORA-06512: at "FDW.GB_RPT_PUBLISH_DATA", line 140
ORA-06512: at line 1
Job Failed: go_ifs_gb_publish_data_det Error Code: 84
*** go_ifs_gb_publish_data_det.sh Ending at Fri Feb 12 20:49:56 EST 2010.

Answer 1

There is no thumb rule for setting size of the undo for any trasaction or transactions.
few suggestions : monitor for few days in peak time of usage of undo and adjust as per requirement.
: try to do a intermediate commit for transaction instead of running long transactions.
Below query will give you some help in tuning the undo tablespace and retention ( Check the feasiblity , as said there is no thumb rule )
SELECT d.undo_size/(1024*1024) "ACTUAL UNDO SIZE [MByte]",
SUBSTR(e.value,1,25) "UNDO RETENTION [Sec]",
(TO_NUMBER(e.value) * TO_NUMBER(f.value) *
g.undo_block_per_sec) / (1024*1024)
"NEEDED UNDO SIZE [MByte]"
FROM (
SELECT SUM(a.bytes) undo_size
FROM v$datafile a,
v$tablespace b,
dba_tablespaces c
WHERE c.contents = 'UNDO'
AND c.status = 'ONLINE'
AND b.name = c.tablespace_name
AND a.ts# = b.ts#
) d,
v$parameter e,
v$parameter f,
SELECT MAX(undoblks/((end_time-begin_time)*3600*24))
undo_block_per_sec
FROM v$undostat
) g
WHERE e.name = 'undo_retention'
AND f.name = 'db_block_size'
Regards,
Anil Malkai
if it is help ful or answered your query mark it as answered.
Edited by: Anil Malkai on Feb 15, 2010 3:32 AM