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Oracle

1Z0-485 · Question #18

You are measuring the I/O savings provided by storage indexes for Table A. One of your scripts displays the I/O savings as a result of the storage indexes. Which two statements are true? SQL> select…

The correct answer is B. Storage Index data is not on the Cell Server's region index memory structures yet because this C. Since the database was started, no quires were run against this table with the same predicate. cell physical I/O bytes eligible for predicate offload Number of bytes eligible for predicate offload, an indication of smart scan (not D) cell physical I/O bytes saved by storage index Here 0. Number of bytes saved by a storage index; this is a reflection of how many physical…

Smart Scan and Hybrid Columnar Compression

Question

You are measuring the I/O savings provided by storage indexes for Table A. One of your scripts displays the I/O savings as a result of the storage indexes. Which two statements are true? SQL> select count () from transmap.mymap_comp 2 where map_id between 400 and 500; COUNT() --------------------------------------- 103000 Elapsed: 00:00:00.08 SQL> select b.name, a.value/1024/1024 value from vSmystat a, vSstatname b, where b.statistic# = a.statistic# and b.nafne in (cell physical IO bytes eligible for predicate offload', cell physical IO interconnect bytes', cell physical IO bytes saved by storage index', cell physical IO interconnect bytes returned by smart scan') order by 1; Statistic Value (MB) ----------------------------------------------------------------------- ---------------------- ----------------- cell physical IO bytes eligible for predicate offload 2,255 .09 cell physical IO bytes saved by storage index .00 cell physical IO interconnect bytes 1.72 cell physical IO interconnect bytes returned by smart scan 1.68

Options

  • AThe storage indexes were disabled using the disable_storage_INDEX Parameter.
  • BStorage Index data is not on the Cell Server's region index memory structures yet because this
  • CSince the database was started, no quires were run against this table with the same predicate.
  • DThe storage indexes reduced the amount of physical I/O bytes significantly for this query.

How the community answered

(31 responses)
  • A
    10% (3)
  • B
    84% (26)
  • D
    6% (2)

Explanation

  • cell physical I/O bytes eligible for predicate offload Number of bytes eligible for predicate offload, an indication of smart scan * (not D) cell physical I/O bytes saved by storage index Here 0. Number of bytes saved by a storage index; this is a reflection of how many physical disk I/O bytes (and by proxy, requests) were saved due to a storage index eliminating candidate blocks

Topics

#storage indexes#I/O savings statistics#predicate offload bytes#region index memory

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