Examine the Exhibit. ---MISSING----- Which three statements are correct?

Question

Options

• AGlobal Cache Block Access Latency indicates how many block transfers incurred a delay (busy)
• BGlobal Cache Block Access Latency indicates how many block transfers received blocks cached
• CGlobal Cache Block Transfer Rate shows the total aggregated number of blocks received by all
• DGlobal Cache Block Transfer Rate is essentially a profile of how much work is performed in the
• EGlobal Cache Block Transfers and Physical Reads shows the percentage of read operations that
• FGlobal Cache Block Transfers and Physical Reads shows the aggregated number of data blocks

• A
  73% (24)
• B
  18% (6)
• D
  3% (1)
• F
  6% (2)

Explanation

Global Cache Block Access Latency The global cache access latency represents the end-to-end elapsed time for a block request. The request is timed from when the request is initiated until it completes. Cache transfer indicates how many current and CR blocks per block class were received from remote instances, including how many transfers incurred a delay (busy) or an unexpected longer delay (congested). If accessing a database block of any class does not locate a buffered copy in the local cache, a global cache operation is initiated. Before reading a block from disk, an attempt is made to find the block in the buffer cache of another instance. If the block is present in another instance, a version of the block may be shipped. Two different kinds of blocks are distinguished: current and consistent read blocks. The average block receive time represents the end-to-end elapsed time or latency for a block request. Global Cache Block Transfer Rate The global cache block transfer rate shows the total aggregated number of data blocks received by all instances in the cluster by way of an interconnect. If a logical read fails to find a copy of the buffer in the local cache, it attempts to find the buffer in the database cache of a remote instance. If the block is present in another database, it is sent to the current instance. Global Cache Block Transfers and Physical Reads The chart represents the percentage of logical reads that read data from the buffer cache of other instances via Direct Memory Access and from disk. It is essentially a profile of how much work is performed in the local buffer cache, rather than the portion of non-local references that incur some latency overhead. Active Sessions for Cluster Wait Class The chart represents the active sessions for the cluster wait class. You can view the top modules and top SQL for a time period by selecting the time period in the active sessions chart. Oracle Enterprise Manager Online Help

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