Read only transaction

Hi,

        I'm trying to enumerate a table with 3 fields, one of them indexed. I type the following commands *immediately after starting sqlplus monitor*

set transaction read only;
select field from table;

        After about 50,000 responses, I get an error 01555 snapshot too old (rollback segment too small) Why does oracle need rollback space for a read only transaction? Also, if I have exactly one client manipulating a table, can I ask oracle not to use rollback space (auto commit) for a read-write transaction?

Thanks
Rupesh Received on Tue Feb 20 1996 - 00:00:00 CET