多选题You notice a high number of waits for the db file scattered read and db file sequential read events in the recent Automatic Database Diagnostic Monitor (ADDM) report. After further investigation, you find that queries are performing too many full table scans and indexes are not being used even though the filter columns are indexed. Identify three possible reasons for this.()AMissing or stale histogram statisticsBUndersized shared poolCHigh clustering factor for the indexesDHigh value for the DB_FILE_MULTIBLOCK_READ_COUNT parameterEOversized buffer cache

多选题
You notice a high number of waits for the db file scattered read and db file sequential read events in the recent Automatic Database Diagnostic Monitor (ADDM) report. After further investigation, you find that queries are performing too many full table scans and indexes are not being used even though the filter columns are indexed. Identify three possible reasons for this.()
A

Missing or stale histogram statistics

B

Undersized shared pool

C

High clustering factor for the indexes

D

High value for the DB_FILE_MULTIBLOCK_READ_COUNT parameter

E

Oversized buffer cache


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You notice a performance change in your production Oracle database and you want to know which change has made this performance difference. You generate the Compare Period Automatic Database Diagnostic Monitor (ADDM) report to further investigation. Which three findings would you get from the report?()A、It detects any configuration change that caused a performance difference in both time periods.B、It identifies any workload change that caused a performance difference in both time periods.C、It detects the top wait events causing performance degradation.D、It shows the resource usage for CPU, memory, and I/O in both time periods.E、It shows the difference in the size of memory pools in both time periods.F、It gives information about statistics collection in both time periods.

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单选题One of the tablespaces is read-only in your database. The loss of all control files forced you to re-create the control file. Which operation do you need to perform after re-creating the control file and opening the database?()A drop and re-create the read-only tablespacesB rename the read-only data files to their correct file namesC change the tablespace status from read/write to read-onlyD re-create the read-only tablespace because it is automatically removed

多选题You notice a performance change in your production Oracle database and you want to know which change has made this performance difference. You generate the Compare Period Automatic Database Diagnostic Monitor (ADDM) report to further investigation. Which three findings would you get from the report?()AIt detects any configuration change that caused a performance difference in both time periods.BIt identifies any workload change that caused a performance difference in both time periods.CIt detects the top wait events causing performance degradation.DIt shows the resource usage for CPU, memory, and I/O in both time periods.EIt shows the difference in the size of memory pools in both time periods.FIt gives information about statistics collection in both time periods.

单选题The loss of the control file forced you to re/x7fcreate the control file. After re/x7fcreating it and opening the database, you find that some of the data files are named as MISSINGnnnnn, where nnnnn is a five/x7fdigit number starting with 0.  What could be the possible reason?()AThese are the data files that are corrupted.BThere is no SYSAUX tablespace in your databaseCThere is a read­only tablespace in your database.DThese are the data files that cannot be recovered.

单选题You find that the execution time of reports in your datawarehouse application is significantly high. You suspect the lack of indexes to be the reason for the degradation in performance. Which advisory component would you refer to, in order to determine the appropriate indexes?()A Memory AdvisorB Segment AdvisorC SQL Access AdvisorD Automatic Workload Repository (AWR)E Automatic Database Diagnostic Monitor (ADDM)

单选题The loss of the control file forced you to re-create the control file. After re-creating it and opening the database, you find that some of the data files are named as MISSINGnnnnn, where nnnnn is a five-digit number starting with 0. What could be the possible reason?()A These are the data files that are corrupted.B There is no SYSAUX tablespace in your databaseC There is a read-only tablespace in your database.D These are the data files that cannot be recovered.

多选题Oracle数据中,下列哪些等待事件将产生大量的IO?()Alog file parallel writeBlatch:cache buffers chainsCdb file sequential readDdb file scattered read