You enabled PL/SQL tracing in a user session using the following command:
SQL> EXECUTE DBMS_TRACE.SET_PLSQL_TRACE(DBMS_TRACE.TRACE_ALL_CALLS);
View Exhibit1 to examine the output. After some time, the query produces a different result as shown in Exhibit2.
What is the cause for the change?
A.
The FOO procedure has been executed more than once.
B.
The PLSQL_DEBUG parameter is set to FALSE for the user session.
C.
The FOO procedure has been compiled with the DEBUG option, and executed.
D.
Schema level statistics have been gathered by the database administrator (DBA).
C
C.
DBMS_TRACE
Creating Database Tables to Collect DBMS_TRACE Output
You must create database tables into which the DBMS_TRACE package writes output. Otherwise, the data is not collected. To create these tables, run the script TRACETAB.SQL. The tables this script creates are owned by SYS
https://docs.oracle.com/cd/B28359_01/appdev.111/b28419/d_trace.htm
Create Trace Output Table $ORACLE_HOME/rdbms/admin/tracetab.sql
Rem DESCRIPTION
Rem Create tables for the PL/SQL tracer
create table sys.plsql_trace_runs …
comment on table sys.plsql_trace_runs is ‘Run-specific information for the PL/SQL trace’;
create table sys.plsql_trace_events …
comment on table sys.plsql_trace_events is ‘Accumulated data from all trace runs’;
create sequence sys.plsql_trace_runnumber start with 1 nocache;
psoug.org/reference/dbms_trace.html
C.
Controlling Data Volume
Profiling large applications may produce a large volume of data.
You can control the volume of data collected by enabling specific program units for trace data collection.
You can enable a program unit by compiling it debug.
This can be done in one of two ways:
alter session set plsql_debug=true;
create or replace … /* create the library units – debug information will be generated */
or:
/* recompile specific library unit with debug option */
alter [PROCEDURE | FUNCTION | PACKAGE BODY] compile debug;