Oracle 1Z Oracle Database 11g Performance Tuning.

Transcription

1 Oracle 1Z0-054 Oracle Database 11g Performance Tuning

2 C. Query v$session to gather statistics of the individual sessions for the workload created by the jobs. D. Create services for the applications, create job class associated with the service, and then create jobs by using the job classes. Answer: D QUESTION: 180 You created two services HR and FINANCE on a single instance database. These services are used by the middle-tier applications to connect to the database by using connection pools. The applications have various modules and you asked the developers to invoke the DBMS_APPLICATION_INFO.SET_MODULE procedure to set the module name and action in the code for the application.as part of performance management, you want to gather statistics for these modules and see the amount of workload created by these modules.what would you recommend to accomplish the task? A. Using the DBMS_MONITOR.SERV_MOD_ACT_STAT_ENABLE procedure to collect statistics for a module and querying the V$SERVICE_EVENT view B. Using the DBMS_MONITOR.SERV_MOD_ACT_STAT_ENABLE procedure to collect statistics for a module and querying the V$SERVICE_STATS view C. Using the DBMS_MONITOR.SERV_MOD_ACT_STAT_ENABLE procedure to collect statistics for a module and querying the V$SERV_MOD_ACT_STATS view D. Querying the V$SERVICE_STATS view because the statistics for the modules are collected automatically when you invoke the DBMS_APPLICATION_INFO.SET_MODULE procedure Answer: C QUESTION: 181 Your database has the ACCTG service configured for an accounting application that runs on a middle tier. The application has three modules LEDGER, ACCOUNTS, and BILLING. You enabled tracing at the service level by executing the following command: SQL> exec DBMS_MONITOR.SERV_MOD_ACT_TRACE_ENABLE('ACCTG'); Which statement is true? A. A single trace file would be created for all the sessions for the service. B. Three trace files would be created for the three modules in the application. C. The trace file would not be created because the module name is not specified. D. A trace file is created for each session that uses the service, regardless of the module and action. Answer: D QUESTION:

3 Your database has the ACCTG service configured for an accounting application running on a middle tier. These service is used by the middle-tier applications to connect to the database by using connection pools. The application has three modules LEDGER, ACCOUNTS, and BILLING. You asked the developers to invoke the DBMS_APPLICATION_INFO.SET_MODULE procedure to set the module name and action in the code for the application. You enabled tracing at the service level by executing the following command: SQL> exec DBMS_MONITOR.SERV_MOD_ACT_TRACE_ENABLE('ACCTG'); You want to consolidate the trace output from the trace files created based on module.which is the appropriate solution for this? A. Using trace files as input for the tkprof utility to consolidate the tracing of sessions for a module B. Using the trace file as input for the trcsess utility to consolidate and process the output for a module C. Using the trcsess utility to consolidate all trace files into a single output file, which can then be processed by the tkprof utility D. Using the trace file as input for the trcsess utility and creating output files that can directly be used by the users for performance or debugging purposes Answer: C QUESTION: 183 You noticed a high number of SQL statements with the same PLAN_HASH_VALUES. View Exhibit1 to see the details. View Exhibit2 to see the details of the SQL text for the statements. 115

4 What do you infer from the results? A. The statements are using the same cursor. B. The statements are not using the same cursor. C. Removing the bind variable would improve performance. D. The cursor for the statement is aging out of the shared pool very quickly. Answer: B QUESTION: 184 You are managing an online transaction processing (OLTP) application database. Some users on the system are reporting degradation in the performance of SQL statements. To diagnose the problem, you want to identify the SQL statements that are expensive on system resources. What would you recommend to accomplish the task? (Choose all that apply.) A. running SQL Access Advisor B. running SQL Performance Analyzer C. querying the V$SQLSTATS and V$SQL_PLAN views to get the information D. creating an Automatic Workload Repository (AWR) report for the problematic period Answer: C,D QUESTION: 185 View the Exhibit and examine the statistics of a SQL statement. Which two conclusions can you draw from the statistics? (Choose two.) A. The SQL statement has high logical I/O. B. The SQL statement has high CPU usage. 116

5 C. The SQL statement has high physical I/O. D. The SQL statement has long sort operations. Answer: A,B QUESTION: 186 You are managing an online transaction processing (OLTP) system. Many users complain about the slow response time. You investigated and found that in the Top 5 events, direct path read accounts for 73.2% of the total wait time.which two are the possible reasons for the high direct path read time? (Choose two.) A. The I/O subsystem is slow. B. The SQL statements are using high CPU. C. The SQL statement has a long parsing time. D. The SQL statements are performing a large number of physical and logical reads. Answer: A,D QUESTION: 187 You identified poorly performing SQL by analyzing the V$SQL and V$SQLSTATS views. You want to investigate the plans for these SQL statements. Which two methods can you use to pull out the execution plan from the library cache for the already executed SQL? (Choose two.) A. Query V$SQL_PLAN to view the execution plan. B. Query DBA_HIST_SQL_PLAN to view the execution plan. C. Copy and paste the SQL text from the V$SQL view and use EXPLAIN PLAN to generate the execution plan. D. Use the dbms_xplan.display_cursor function with the SQL ID and child number to generate the execution plan. Answer: A,D QUESTION: 188 You identified a SQL statement with SQL ID 9g485acn2n30m, which is expensive on the resources. To view the execution plan for the statement, you executed the following command: SQL> SELECT * FROM TABLE(dbms_xplan.display_cursor('9g485acn2n30m',1)); What would this command accomplish? A. It formats and displays the contents of the execution plan for the cursor with the SQL_ID '9g485acn2n30m' from the library cache. B. It formats and displays the contents of the execution plan but does not guarantee accuracy if the SQL statement has bind variables. 117

6 C. It formats and displays the contents of the execution plan but does not guarantee that the same execution plan would be executed. D. It formats and displays the contents of the execution plan for the cursor with the SQL_ID '9g485acn2n30m' from the DBA_HIST_SQL_PLAN view. Answer: A QUESTION: 189 You identified poorly performing SQL statements that use bind variables. You want to examine the execution plans for the most recently executed statements for further diagnosis. Which method would you recommend to view the execution plans? A. SQL*Plus Autotrace B. the dbms.xplan package C. EXPLAIN PLAN for SQL statements D. the SQL trace utility to generate trace files and read the formatted output using the tkprof utility Answer: B QUESTION: 190 Examine the SQL statement given below: SQL> EXPLAIN PLAN for SELECT department_name,count(*) FROM hr.employees e, hr.departments d WHERE e.department_id=d.department_id GROUP BY d.department_name; To view the execution plan for the statement, you queried plan_table. View the Exhibit and examine the execution plan. Which two statements are true about the execution plan? (Choose two.) A. The execution plan is displayed for the executed SQL statement. B. The EXPLAIN PLAN command does not actually execute the statement. C. The row with the id column having a value of 4 is the first step executed in the execution plan. D. The row with the id column having a value of 0 is the first step executed in the execution plan. 118

7 Answer: B,C QUESTION: 191 You enabled tracing for a session by executing the following command: SQL>SET AUTOTRACE TRACEONLY; You issued a SQL query in the same session. Which two statements are true? (Choose two.) A. It generates only a report on the execution path used by the SQL optimizer. B. Trace for the statement would be created without displaying the query output. C. It generates only the statement execution statistics without executing the query. D. It generates a report on the execution path used by the SQL optimizer and the statement execution statistics. Answer: B,D QUESTION: 192 Examine the values for the following initialization parameters: STATISTICS_LEVEL = TYPICAL TIMED_STATISTICS = true You are managing an online transaction processing (OLTP) system. Application users notice that some queries have poor response time. You determine that queries from session ID 27, serial number 60, for user OE are heavy-resource consumers.to investigate further, you enabled tracing for the session by executing the following command: SQL> EXECUTE dbms_system.set_sql_trace_in_session (27, 60, true); Which statement is true? A. The tkprof output file for the trace generated would display only the timed statistics for the SQL statements. B. The tkprof output file for the trace generated would display statistics for all the sessions created by the user OE. C. The tkprof output file for the trace generated would display bind variable values if bind variables are used in the queries executed in the session. D. The tkprof output file for the trace generated would not display bind variable values if bind variables are used in the queries executed in the session. Answer: D 119

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