Ora-01555

[ams-jamali]

Hi,

Iam using oracle9.2 and suse linux.Iam getting repeatedly this error but i have enough space in undo tablespace nearly 800mb and it was already kept in autoextend on.

Wed Feb 14 07:11:53 2007
ORA-01555 caused by SQL statement below (Query Duration=1158 sec, SCN: 0x0000.3544a4a3):
Wed Feb 14 07:11:53 2007
SELECT activ_n
FROM STR_A
WHERE is_del = 'Y' AND delete_date = '4-jan-1876'
Wed Feb 14 07:11:53 2007
Errors in file /mnt/db/oracle/admin/raid2/bdump/raid20_j00_2653.trc:
ORA-12012: error on auto execute of job 1
ORA-01555: snapshot too old: rollback segment number 12 with name "_SYSSMU12$" too small
ORA-06512: at line 1

in pfile it was like this,
undo_management=AUTO
undo_retention=10800

What necessary steps should be taken i don't know whether i should increase retention period or not. pls help.

Thanks in advance.