ora-01555: snapshot too old

hi,

while loading data from one table having at least 2.5 million records to another oracle table through Informatica mapping, I encountered following problem yesterday:

READER_2_1_1> RR_4035 SQL Error [ORA-01555: snapshot too old: rollback segment number 7with name "_7$" too small

I tried to reduce the commit interval in from 10,000 to 500 and ran the session, but still it did not ran successfully and given above error message. So, I changed the commit interval to 20000 and still it got failed.

So, finally we had asked to our DBA about this, and he ressolved the problem.
Wow, the solution was just to increase the UNDO tablespace for that database where that table is residing.
So, go and ask your DBA to increase the UNDO tablespace.

That's all.