The optimizer statistics are collected automatically.
Only the timed operating system （OS） statistics and plan execution statistics are collected.
The Oracle server dynamically generates the necessary statistics on tables as part of query optimization.
The snapshots for the Automatic Workload Repository （AWR） are not generated automatically.
Snapshots cannot be collected manually by using DBMS_WORKLOAD_REPOSITORY PACKAGE.
第1题：
You are connected to a pluggable database (PDB) as a common user with DBA privileges.The STATISTICS_LEVEL parameter is PDB_MODIFIABLE. You execute the following:SQL > ALTER SYSTEM SET STATISTICS_LEVEL = ALL SID = ‘*’ SCOPE = SPFILE;Which is true about the result of this command?（）
A. The STATISTICS_LEVEL parameter is set to all whenever this PDB is re-opened.
B. The STATISTICS_LEVEL parameter is set to ALL whenever any PDB is reopened.
C. The STATISTICS_LEVEL parameter is set to all whenever the multitenant container database (CDB) is restarted.
D. Nothing happens; because there is no SPFILE for each PDB, the statement is ignored.
第2题：
Your database is functional with peak load for one hour. You want to preserve the performance statistics collected during this period so that they can be used for comparison while analyzing the performance of the database in the future. What action would you take to achieve this task？（）
第3题：
A. Set MEMORY_TARGET to zero
B. Set the STATISTICS_LEVEL parameter to BASIC
C. Set the WORKAREA_SIZE_POLICY parameter to MANUAL
D. Set the PGA_AGGREGATE_TARGET parameter to nonzero value
第4题：
A new report process containing a complex query is written, with high impact on the database. You wantto collect basic statistics about query, such as the level of parallelism, total database time, and the number of I/O requests. For the database instance STATISTICS_LEVEL, the initialization parameter is set to TYPICAL and theCONTROL_MANAGEMENT_PACK_ACCESS parameter is set to DIAGNOSTIC+TUNING. What should you do to accomplish this task?（）
第5题：
Examine the parameter for your database instance: You generated the execution plan for the following query in the plan table and noticed that the nested loop join was done. After actual execution of the query, you notice that the hash join was done in the execution plan: Identify the reason why the optimizer chose different execution plans.（）
第6题：
Examine the parameter for your database instance:You generated the execution plan for the following query in the plan table and noticed that the nested loop join was done. After actual execution of the query, you notice that the hash join was done in the execution plan:Identify the reason why the optimizer chose different execution plans.（）
A. The optimizer used a dynamic plan for the query.
B. The optimizer chose different plans because automatic dynamic sampling was enabled.
C. The optimizer used re-optimization cardinality feedback for the query.
D. The optimizer chose different plan because extended statistics were created for the columns used.
第7题：
The database instance has the following parameter setting： OS_AUTHENT_PREFIX = OPS$ OS_ROLES = FALSE REMOTE_OS_AUTHENT = FALSE REMOTE_OS_ROLES = FALSE TIMED_OS_STATISTICS = 0 You have a local operating system user SKD. You create a database user OPS$SKD， and then assignexternal authentication. The user OPS$SKD has the CREATE SESSION privilege. What would youachieve by the above process（）
第8题：
A. setting the STATISTICS_LEVEL parameter to TYPICAL
B. adding filters to the Automatic Database Diagnostic Monitor (ADDM)
C. enabling Automated Maintenance Task using Oracle Enterprise Manager
D. setting the OPTIMIZER_USE_PENDING_STATISTICS parameter to TRUE
第9题：
In your database，the STATISTICS_LEVEL initialization parameter is set to BASIC. What is the impact of this setting？（）
第10题：
You work as a database administrator for Certkiller .com. Users complain that their query is taking a long time to complete. You suspect the database buffer cache size to be the reason， and you define an alert to be generated when the buffer cache hit metric goes below 85%. When you observe the dynamic performance views， you find that the buffer cache hit ratio is 81% but no alerts are being generated. What could be the reason for this problem？（）