10g doesn't gather when the system is having less activity - it gathers during the predefind maintenance window, which is defined as every night (10pm-6am?) and all weekend long out of the box. You can either disable the gather_stats_job, or modify it, or modify the maintenance window (e.g. disable weeknights) as needed. If there are no stats on a table, dynamic sampling will be used by default and all_rows will still be used with the dynamic stats. Regards, Brandon Privileged/Confidential Information may be contained in this message or attachments hereto. Please advise immediately if you or your employer do not consent to Internet email for messages of this kind. Opinions, conclusions and other information in this message that do not relate to the official business of this company shall be understood as neither given nor endorsed by it. -- //www.freelists.org/webpage/oracle-l