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Which two statements are true about the use and monitoring of Buffer Cache Hit ratios and their value in tuning Database I/O performance?

A.

The performance of workloads that primarily generate full table scans and fast full index scans are always affected by the cache hit ratio.

B.

A 99% cache hit ratio can be observed for database instances which have very poor I/O performance.

C.

The buffer cache advisory view v$db_cache_advice provides advice on cache hit ratios appropriate for the instance workload.

D.

Both the RECYCLE and KEEP buffer caches should always have a very high cache hit ratio.

E.

A 60% cache hit ratio can be observed for database instances which have very good I/O performance.

Examine this statement and its corresponding execution plan:

Which phase introduces the CONCATENATION step?

A.

SQL Semantic Check

B.

SQL Execution

C.

SQL Row Source Generation

D.

SQL Transformation

E.

SQL Adaptive Execution

Which three types of statistics are captured by statspack with snap level 6?

A.

Parent and child latches

B.

Parent and child latches

C.

Optimizer execution plans

D.

Plan usage data

E.

Enqueue statistics

F.

Segment-level statistics

You must configure and enable Database Smart Flash Cache for a database.

You configure these flash devices:

Examine these parameter settings:

What must be configured so that the database uses these devices for the Database Smart Flash Cache?

A.

Set DB_FLASH_CACHE_SIZE to 192G and MEMORY_TARGET to 256G.

B.

Set DB_FLASH_CACHE_SIZE parameter to 192G.

C.

Disable Automatic Memory Management and set SGA_TARGET to 256G.

D.

Set DB_FLASH_CACHE_SIZE to 256G and change device /dev/sdk to 128G.

E.

Set DB_FLASH_CACHE_SIZE parameter to 128G, 64G.

You must write a statement that returns the ten most recent sales. Examine this statement:

Users complain that the query executes too slowly. Examine the statement's current execution plan:

What must you do to reduce the execution time and why?

A.

Create an index on SALES.TIME_ID to force the return of rows in the order specified by the ORDER BY clause.

B.

Replace the FETCH FIRST clause with ROWNUM to enable the use of an index on SALES.

C.

Collect a new set of statistics on PRODUCT, CUSTOMERS, and SALES because the current stats are inaccurate.

D.

Enable Adaptive Plans so that Oracle can change the Join method as well as the Join order for this query.

E.

Create an index on SALES.CUST_ID to force an INDEX RANGE SCAN on this index followed by a NESTED LOOP join between CUSTOMERS and SALES.

Multiple sessions are inserting data concurrently into a table that has an LOB column.

At some point in time, one of the sessions cannot find available space in the LOB segment and needs to allocate a new extent.

Which wait event will be raised in the other sessions that need space in the LOB column?

A.

enq: SQ - contention

B.

enq: TM - contention

C.

enq: HW - contention

D.

enq: TX - allocate ITL entry