SQL> set autot traceonly stat --Flusshing the Buffer cache so there will be no traces from the last test. SQL> alter system flush buffer_cache; System altered. SQL> select /*+ cache */ sum(num1) from pmds.tab1; Statistics ---------------------------------------------------------- 0 recursive calls 0 db block gets 6019 consistent gets 6015 physical reads <---------- 0 redo size 532 bytes sent via SQL*Net to client 523 bytes received via SQL*Net from client 2 SQL*Net roundtrips to/from client 0 sorts (memory) 0 sorts (disk) 1 rows processed SQL> / Statistics ---------------------------------------------------------- 0 recursive calls 0 db block gets 6019 consistent gets 6010 physical reads <---------- 0 redo size 532 bytes sent via SQL*Net to client 523 bytes received via SQL*Net from client 2 SQL*Net roundtrips to/from client 0 sorts (memory) 0 sorts (disk) 1 rows processed SQL> / Statistics ---------------------------------------------------------- 0 recursive calls 0 db block gets 6019 consistent gets 6010 physical reads <---------- 0 redo size 532 bytes sent via SQL*Net to client 523 bytes received via SQL*Net from client 2 SQL*Net roundtrips to/from client 0 sorts (memory) 0 sorts (disk) 1 rows processed --Setting the Event in the session level SQL> alter session set events '10949 trace name context forever, level 1'; Session altered. --The first execution will perform Physical reads SQL> select /*+ cache */ sum(num1) from pmds.tab1; Statistics ---------------------------------------------------------- 0 recursive calls 0 db block gets 6024 consistent gets 6010 physical reads <---------- 0 redo size 532 bytes sent via SQL*Net to client 523 bytes received via SQL*Net from client 2 SQL*Net roundtrips to/from client 0 sorts (memory) 0 sorts (disk) 1 rows processed --From the second run, there are no Physical reads. SQL> / Statistics ---------------------------------------------------------- 0 recursive calls 0 db block gets 6024 consistent gets 0 physical reads <---------- 0 redo size 532 bytes sent via SQL*Net to client 523 bytes received via SQL*Net from client 2 SQL*Net roundtrips to/from client 0 sorts (memory) 0 sorts (disk) 1 rows processed SQL> / Statistics ---------------------------------------------------------- 0 recursive calls 0 db block gets 6024 consistent gets 0 physical reads <---------- 0 redo size 532 bytes sent via SQL*Net to client 523 bytes received via SQL*Net from client 2 SQL*Net roundtrips to/from client 0 sorts (memory) 0 sorts (disk) 1 rows processed