Flashback 15GB table as of timestamp takes over 21 and not ending

Hi,

Last Friday I was reqyested to support an application issue. They run a sql on one 15gb table which supposed to update 1 row but they updated most of rows and commited this change. They requested me for a help and I suggested to run "flashback table xxxx as of timestampe 'before the change';". Table size is 15GB and it has 4 or 5 indexes with sizes bout 5GB each of one. This flashback command lasted over 4 hours and didn't finish. As we didn't had time I proposed to create backup table as "create table xxx_back as select *