SQL Trace facility and TKPROF

TKProf is an Oracle database utility used to format SQL Trace output into human readable format. The TKProf executable is located in the ORACLE HOME/bin directory.
The SQL Trace facility and TKPROF let you accurately assess the efficiency of the SQL statements an application runs.

TKPROF reports each statement executed with the resources it has consumed, the number of times it was called, and the number of rows which it processed. 
This information lets you easily locate those statements that are using the greatest resource.

EXEC DBMS_SESSION.set_sql_trace(sql_trace => TRUE);

ALTER SESSION SET SQL_TRACE = TRUE;

ALTER SESSION SET SQL_TRACE = FALSE;

tkprof filename1 filename2 [waits=yes|no] [sort=option] [print=n]
    [aggregate=yes|no] [insert=filename3] [sys=yes|no] [table=schema.table]
    [explain=user/password] [record=filename4] [width=n]