Oracle 1Z0-027 Online Practice Questions and Exam Preparation

Oracle 1Z0-027 Online Questions & Answers

• Question 71:

  You are evaluating the performanceof a SQLstatementthat accessesa very large table, and have run the following queryproducingthe output shown:

  

  For which two reasons would the; "physical read total bytes" statistic be greater than the "cell physical IO bytes eligible for predicate offload" statistic?

  A. There is an index on the column used in the where clause, causing "cell multiblock physical reads" to be requested by the database instance, resulting in additional I/O for blocks in the cells.
  B. The table is an IOT and has an overflow segment, causing "cell multiblock physical reads" to be requested by the database instance, resulting in additional I/O for block in the cells.
  C. There is an uncommitted transaction that has modified some of the table blocks, causing some "cell single block physical reads" to be requested by the database instance, resulting in additional I/O for block in the cells.
  D. The table is an indexed clustered table, causing "cell single block physical reads" to be requested by the database instance, resulting in additional I/O forblocks in the cells.
  E. There are migrated rows in the table, causing some "cell single block physical reads" to be requested by the database instance, resulting in additional I/O for blocks in the cells.
  B. The table is an IOT and has an overflow segment, causing "cell multiblock physical reads" to be requested by the database instance, resulting in additional I/O for block in the cells.
  E. There are migrated rows in the table, causing some "cell single block physical reads" to be requested by the database instance, resulting in additional I/O for blocks in the cells.

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  Note:

  * physical read total bytes: the size of the segment to read is known by the database, and must be read entirely from the database's perspective. *cell physical IO bytes eligible for predicate offload: this statistic shows the amount of data which

  the cell server is able to process on behalf of the database, instead of the database processing and the cell server just delivering blocks. *Cell physical IO bytes eligible for predicate offload --- This number should be high The higher the

  number more MB/GB is filtered out at the cell level itself rather sending it to the buffer cache to filter the rows.

  *In this case, all bytes are processed on the cellserver (cell physical IO bytes eligible for predicate offload=physical read total bytes)

  *Cell Offloading:The storage cells are intelligent enough to process some workload inside them, saving the database nodes from that work. This process is referred to as cell offloading.

• Question 72:

  You plan to migrate an existing production database supporting online transaction processing (OLTP) workloads to the Exadata Database Machine. The database currently supports an application requiring fast response times, which satisfies stringent requirements, and most of the application queries use index access to the tables in the application schema.

  For which case would you consider dropping indexes to allow Smart Scans to occur?

  A. Drop non-constraint indexes if Smart Scan occurs instead of an index access path on the corresponding table.
  B. Drop non-constraint indexesif Smart Scan performs better than index unique scans on the corresponding table.
  C. Drop non-constraint indexes if Smart Scan performs better than index range scans on the corresponding table.
  D. Drop non-constraint Indexes if Smart Scan performs better than any index scans on the corresponding table.
  D. Drop non-constraint Indexes if Smart Scan performs better than any index scans on the corresponding table.