1Z0-054 無料問題集「Oracle Database 11g: Performance Tuning」
The columns CUST_CITY, CUST_STATE_PROVINCE, and COUNTRY_ID are frequently used together in the WHERE clause of the queries. The CUSTOMERS table is a big table with 20 GB of data. You notice that the selectivity for these three columns varies from the selectivity that the optimizer calculates. What would you recommend to influence the selectivity calculated by the optimizer?
正解：A
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There are 500 users of an online transaction processing (OLTP) application that resides in your database. The system had been maintaining an average response rate of 10 seconds as specified by the Service-Level Agreement (SLA).This morning you were informed that for the past four days
the average response time has gone up to 15-20 seconds. No changes have been made to the hardware or networking setup.What is the first thing that you should do to diagnose the cause of the slow response time?
the average response time has gone up to 15-20 seconds. No changes have been made to the hardware or networking setup.What is the first thing that you should do to diagnose the cause of the slow response time?
正解：D
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You used SQL Tuning Advisor for a long-running SQL statement that suggested a SQL profile which can be used by the query subsequently for better execution plan. View the Exhibit. But you want certain user sessions not to use this SQL profile for their queries. How would you implement this?
正解：A
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You have the automatic optimizer statistics gathering enabled for a 24x7 database as part of the automatic maintenance task. You observed that a few tables are being updated regularly, but not being queried often. However statistics are being gathered for these tables automatically and regularly, thereby affecting the database performance. What would you do to increase the interval of statistics collection for these tables so that the statistics collection jobs spend less time during the automatic maintenance task?
正解：B
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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?
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?
正解：B
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You work on an online transaction processing (OLTP) database in which the SALES table has
10,000 rows but only four distinct products are sold.
View the Exhibit named HIST to check data distribution in the table and the histograms on the
table.
Further, you query the SALES table thrice more in the following order:
-query rows having product ID 4
-query rows having product ID 2
-query rows having product ID 4
View the Exhibit named QUERY-n to see the details about these queries.
What do you infer from this?
10,000 rows but only four distinct products are sold.
View the Exhibit named HIST to check data distribution in the table and the histograms on the
table.
Further, you query the SALES table thrice more in the following order:
-query rows having product ID 4
-query rows having product ID 2
-query rows having product ID 4
View the Exhibit named QUERY-n to see the details about these queries.
What do you infer from this?
正解：D
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You are working on an online transaction processing (OLTP) database that runs on a machine having multiple CPUs. The database uses normal file system storage. Examine the following initialization parameters and their respective values for the instance: NAME TYPE VALUE
dbwr_io_slaves integer 0 db_writer_processes integer 1 filesystemio_options string NONE disk_asynch_io boolean TRUE The applications perform small, random I/Os in which each foreground process reads a data block into the buffer cache for updates and the changed blocks are written in batches by the DBWR process. You noticed free buffer waits events for your database. To solve the problem, you increased the size of the buffer cache. But after some time, you notice the same event again.Which three possible actions would you recommend? (Choose three.)
dbwr_io_slaves integer 0 db_writer_processes integer 1 filesystemio_options string NONE disk_asynch_io boolean TRUE The applications perform small, random I/Os in which each foreground process reads a data block into the buffer cache for updates and the changed blocks are written in batches by the DBWR process. You noticed free buffer waits events for your database. To solve the problem, you increased the size of the buffer cache. But after some time, you notice the same event again.Which three possible actions would you recommend? (Choose three.)
正解：A、D、E
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