Greetings, I have been running dbms_stats.gather_schema_stats against test/development database for some time and recently added estimate_percent => dbms_stats.auto_sample_size Since which time ORA-06152 errora are generated... BEGIN dbms_stats.gather_schema_stats( ownname => 'EDRS', estimate_percent => dbms_stats.auto_sample_size, method_opt => 'for all columns', cascade => true, options => 'GATHER', degree => 15); END; * ERROR at line 1: ORA-00979: not a GROUP BY expression ORA-06512: at "SYS.DBMS_STATS", line 10502 ORA-06512: at "SYS.DBMS_STATS", line 10996 ORA-06512: at "SYS.DBMS_STATS", line 11183 ORA-06512: at "SYS.DBMS_STATS", line 11237 ORA-06512: at "SYS.DBMS_STATS", line 11214 ORA-06512: at line 1 I suspect it has to do with dbms_stats not knowing how to deal with the stats which have already been collected but that is just a guess. I am not familiar enough with views such as DBA_TAB_MODIFICATIONS to know if information stored there is causing the problems or if deleting and regenerating statistics (I haven't tried that yet) will solve the problem. I would appreciate any insight into the problem. Thanks. Bill Wagman Univ. of California at Davis IET Campus Data Center wjwagman@xxxxxxxxxxx (530) 754-6208 -- //www.freelists.org/webpage/oracle-l