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6 Replies Latest reply: May 23, 2013 6:33 AM by startup RSS

Difference between Offloading and Smart scan

706543 Newbie
Currently Being Moderated
Hi All,

I am not clear with the word, Offloading and Smart scan.

I know the term, offloading refers moving the process to storage server instead of database server which includes column projection, predicate filter, storage indexes. etc.

then what does the term Smart scan.

Kindly explain.
  • 1. Re: Difference between Offloading and Smart scan
    UweHesse Expert
    Currently Being Moderated
    There is more that can be offloaded to the cells than only Smart Scan.
    Offloading in Exadata means that the cells do something that the Database Nodes would have to do on another platform.

    Doing SQL filtering (Smart Scan) is the most important offloading, but there is more. For example the cells can do
    TDE decryption and HCC decompression also.

    Kind regards
    Uwe Hesse

    "Don't believe it, test it!"
    http://uhesse.com
  • 2. Re: Difference between Offloading and Smart scan
    LaserSoft Journeyer
    Currently Being Moderated
    Hi Friend

    Cell Offloading:
    =========
    The storage in the Exadata Database Machine is not just dumb storage. 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.

    In Traditional system storage will not have these features.


    Smart Scan:
    =========

    In a traditional Oracle database, when a user selects a row or even a single column in a row, the entire block containing that row is fetched from the disk to the buffer cache, and the selected row is then extracted from the block and presented to the user’s session.

    The Exadata Database Machine can pull the specific rows from the disks directly and send them to the database nodes. This functionality is known as Smart Scan. It results in huge savings in I/O.

    Basically it will reduce the I/O between Compute Nodes (i.e Database Nodes) and Storage Servers although it is 40 Gbps between these two.

    Hope it helps....


    Thanks
    LaserSoft
  • 3. Re: Difference between Offloading and Smart scan
    706543 Newbie
    Currently Being Moderated
    Hi,

    Thanks a lot for the detailed info.

    Regards,
    Sivakumar
  • 4. Re: Difference between Offloading and Smart scan
    startup Explorer
    Currently Being Moderated
    HI,

    offloading is feature that comes with up software with Stroage cell.we can Enable or disable by parameter cell_offloading_processing that filters data at storage level i.e done up with this offloading. we call the technical term as ' SMART SCAN' as concept of doing cell projection,filtering..etc .
  • 5. Re: Difference between Offloading and Smart scan
    Dan.Norris Employee ACE
    Currently Being Moderated
    startup wrote:
    HI,

    offloading is feature that comes with up software with Stroage cell.we can Enable or disable by parameter cell_offloading_processing that filters data at storage level i.e done up with this offloading. we call the technical term as ' SMART SCAN' as concept of doing cell projection,filtering..etc .
    I can't think of a case where you'd disable offload processing except in some experimental tests. I hope that no one is doing that as a matter of course--it's one of the biggest benefits and key features of Exadata Storage.
  • 6. Re: Difference between Offloading and Smart scan
    startup Explorer
    Currently Being Moderated
    Hi Norris,

    As Offloading is vital concept at stroage level for Exadata. Even though We had disabled this feature since a month, due to Storage level I/O issuses.

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