多选题The OPTIMIZER_USE_PLAN_BASELINES parameter is set to TRUE. The optimizer generates a plan for a SQL statement but does not find a matching plan in the SQL plan baseline. Which two operations are performed by the optimizer in this scenario?()AThe optimi

题目
多选题
The OPTIMIZER_USE_PLAN_BASELINES parameter is set to TRUE. The optimizer generates a plan for a SQL statement but does not find a matching plan in the SQL plan baseline. Which two operations are performed by the optimizer in this scenario?()
A

The optimizer adds the new plan to the plan history.

B

The optimizer selects the new plan for the execution of the SQL statement.

C

The optimizer adds the new plan to the SQL plan baseline as an accepted plan.

D

The optimizer adds the new plan to the SQL plan baseline but not in the ENABLED state.

E

The optimizer costs each of the accepted plans in the SQL plan baseline and picks the one with the lowest cost.

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相似问题和答案

第1题:

View the Exhibit exhibit1 to examine the series of SQL commands. View the Exhibit exhibit2 to examine the plans available in the SQL plan baseline. The baseline in the first row of the Exhibit is created when OPTIMIZER_MODE was set to FIRST_ROWS.Which statement is true if the SQL query in exhibit1 is executed again when the valueof OPTIMIZER_MODE is set to FIRST_ROWS?()

A. The optimizer uses a new plan because none of the plans in the exhibit2 are fixed plans.

B. The optimizer uses the plan in the second row of the exhibit2 because it is an accepted plan.

C. The optimizer uses the plan in the first row of the exhibit2 because it is the latest generated plan.

D. The optimizer uses the plan in the first row of the exhibit2 because OPTIMIZER_MODE was set to FIRST_ROW during its creation.


参考答案:B

第2题:

While deploying a new application module, the software vendor ships the application software along with appropriate SQL plan baselines for the new SQLs being introduced. Which two statements describe the consequences?()

  • A、The plan baselines can be evolved over time to produce better performance.
  • B、The newly generated plans are directly placed into the SQL plan baseline without being verified.
  • C、The new SQL statements initially run with the plans that are known to produce good performance under standard test configuration.
  • D、The optimizer does not generate new plans for the SQL statements for which the SQL plan baseline has been imported.

正确答案:A,C

第3题:

You perform the following activities during the database upgrade from Oracle Database 10g to Oracle Database 11g:1. Capture plans for a SQL workload into a SQL Tuning Set (STS) before upgrade.2. Load these plans from the STS into the SQL plan baseline immediately after the upgrade.What is the reason for performing these activities? ()

A. to minimize plan regression due to the use of a new optimizer version

B. to completely avoid the use of new plans generated by a new optimizer version

C. to prevent plan capturing when the SQL statement is executed after the database upgrade

D. to keep the plan in the plan history so that it can be used when the older version of the optimizer is used


参考答案:A

第4题:

Which three are the valid statements in relation to SQL plan baselines?()

  • A、 The plans can be manually loaded to the SQL plan baseline.
  • B、 The plans in the SQL plan baseline are verified and accepted plans.
  • C、 The plans generated for every SQL statement are stored in the SQL plan baseline by default. 
  • D、 The plan baselines are stored temporarily in the memory as long as the database instance is running.
  • E、 For the SQL plan baselines to be accessible to the optimizer, the SYSAUX tablespace must be online.

正确答案:A,B,E

第5题:

Which two statements about the SQL Management Base (SMB) are true? ()(Choose two.)

  • A、It contains only SQL profiles generated by SQL Tuning Advisor.
  • B、It stores plans generated by the optimizer using a stored outline.
  • C、It is part of the data dictionary and stored in the SYSAUX tablespace.
  • D、It is part of the data dictionary and stored in the SYSTEM tablespace.
  • E、It contains the statement log, the plan history, plan baselines, and SQL profiles.

正确答案:C,E

第6题:

Which three statements are true about SQL plan directives?()

A. They are tied to a specific statement or SQL id.

B. They instruct the maintenance job to collect missing statistics or perform dynamic sampling to generate a more optimal plan.

C. They are used to gather only missing statistics.

D. They are created for a query expression where statistics are missing or the cardinality estimates by the optimizer are incorrect.

E. They instruct the optimizer to create only column group statistics.

F. Improve plan accuracy by persisting both compilation and execution statistics in the SYSAUX tablespace.


参考答案:B, D, E

第7题:

You run the SQL Tuning Advisor (STA) to tune a SQL statement that is part of a fixed SQL plan baseline. The STA generates a SQL profile for the SQL statement, which recommends that you accept the profile. Which statement is true when you accept the suggested SQL profile?()

  • A、The tuned plan is not added to the SQL plan baseline.
  • B、The tuned plan is added to the fixed SQL plan baseline as a fixed plan.
  • C、The tuned plan is added to the fixed SQL plan baseline as a nonfixed plan.
  • D、The tuned plan is added to a new nonfixed SQL plan baseline as a nonfixed plan.

正确答案:C

第8题:

Which two statements about the SQL Management Base (SMB) are true?()

A. It contains only SQL profiles generated by SQL Tuning Advisor.

B. It stores plans generated by the optimizer using a stored outline.

C. It is part of the data dictionary and stored in the SYSAUX tablespace.

D. It is part of the data dictionary and stored in the SYSTEM tablespace.

E. It contains the statement log, the plan history, plan baselines, and SQL profiles.


参考答案:C, E

第9题:

Your system has been upgraded from Oracle Database 10g to Oracle Database 11g. You imported SQL Tuning Sets (STS) from the previous version. After changing the  OPTIMIZER_FEATURE_ENABLE parameter to 10.2.0.4 and running the SQL Performance Analyzer, you observed performance regression for a few SQL statements.  What would you do with these SQL statements?()

  • A、 Set OPTIMIZER_USE_PLAN_BASELINES to FALSE to prevent the use of regressed plans.
  • B、 Capture the plans from the previous version using STS and then load them into the stored outline.
  • C、 Capture the plans from the previous version using STS and then load them into SQL Management Base (SMB)
  • D、 Set OPTIMIZER_CAPTURE_SQL_PLAN_BASELINES to FALSE to prevent the plans from being loaded to the SQL plan baseline.

正确答案:C

第10题:

You want to analyze a SQL Tuning Set (STS) using SQL Performance Analyzer in a test database. Which two statements are true regarding the activities performed during the test execution of SQLs in a SQL Tuning Set?()

  • A、 Every SQL statement in the STS is considered only once for execution.
  • B、 The SQL statements in the STS are executed concurrently to produce the execution plan and execution statistics.
  • C、 The execution plan and execution statistics are computed for each SQL statement in the STS. 
  • D、 The effects of DDL and DML are considered to produce the execution plan and execution statistics.

正确答案:A,C

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