I've written a script to gather statistics on each table,schema wise.The script is executed successfully for nearly 18 hrs,while the following line the script,it gives the erro,

SQL> exec dbms_stats.GATHER_TABLE_STATS(ownname=>'TEST',tabname=>'TPMS',cascade=>TRUE,degree=>2);
BEGIN dbms_stats.GATHER_TABLE_STATS(ownname=>'TEST',tabname=>'TPMS',cascade=>TRUE,degree=>2); END;

ERROR at line 1:
ORA-03113: end-of-file on communication channel

Then the remaining script fails with error,

ERROR at line 1:
ORA-03114: not connected to ORACLE

When i tried to re-execute it,it shows the same error.

What i've to do overcome this problem,so that i can execute the remaining script successfully.