conn sa/sa@10_2_0_5
spool c:\000\10g_idx_scrout.txt
@spid

set pagesize 999
set linesize 200
col PLAN_TABLE_OUTPUT for a100

alter session set sql_trace=true;

set timing on

-- cache data
select --+ index(test)
       count(pad)
  from test;

-- we start here
-- default _rowsource_statistics_sampfreq
select --+ index(test)
       count(pad)
  from test;

select * from table(dbms_xplan.display_cursor(null, null, 'allstats last'));

alter session set "_rowsource_statistics_sampfreq"=0;

select --+ index(test)
       count(pad)
  from test;

select * from table(dbms_xplan.display_cursor(null, null, 'allstats last'));


alter session set "_rowsource_statistics_sampfreq"=128;

select --+ index(test)
       count(pad)
  from test;

select * from table(dbms_xplan.display_cursor(null, null, 'allstats last'));

alter session set "_rowsource_statistics_sampfreq"=16;

select --+ index(test)
       count(pad)
  from test;

select * from table(dbms_xplan.display_cursor(null, null, 'allstats last'));

alter session set "_rowsource_statistics_sampfreq"=8;

select --+ index(test)
       count(pad)
  from test;

select * from table(dbms_xplan.display_cursor(null, null, 'allstats last'));

alter session set "_rowsource_statistics_sampfreq"=4;

select --+ index(test)
       count(pad)
  from test;

select * from table(dbms_xplan.display_cursor(null, null, 'allstats last'));

alter session set "_rowsource_statistics_sampfreq"=2;

select --+ index(test)
       count(pad)
  from test;

select * from table(dbms_xplan.display_cursor(null, null, 'allstats last'));

alter session set "_rowsource_statistics_sampfreq"=1;

select --+ index(test)
       count(pad)
  from test;

select * from table(dbms_xplan.display_cursor(null, null, 'allstats last'));

spool off