statistics:sys,table,index,column package:dbms_stats (exec dbms_stats.gather_table_stats('HR','T')) dba_tables dba_indexes v$user_tab_statistics v$user_tab_col_statistics v$segstat_name v$segstat v$segment_statistics para: optimizer_dynamic_sampling dbms_stats.gather_table_stats -> dba_histograms dba_tab_histograms histograms:width-balanced,height-balanced monitor table optimizer cost model:cpu_cost,io_cost,temp_space export import statistics between database
