Can anyone help me to resolve the following issue?.

I am using the CONNECT BY PRIOR Clause in my Query. But i am getting resluts after atleast 10 min in the SQL Prompt..

When i am tring to execute my procedure for 5 lakhs records Many times i am getting the error as ERROR: -- ORA-30928: Connect by filtering phase runs out of temp tablespace... evethough We are having 8 GB as Temp tablespace..