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Tip of the Day: How to Mitigate Multi-Block Read Performance on Oracle 10g

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  • 1.  Tip of the Day: How to Mitigate Multi-Block Read Performance on Oracle 10g

    Posted 12-04-2014 05:37:00 PM
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    Ways to mitigate this issue:

    1. Upgrade to a newer version of Linux. (Issue is not present when using Red Hat Linux 6.4)

    2. Force multi-block reads to use direct path rather than scattered read

      1. Set “_serial_direct_read” to TRUE. 

      2. This forces all serial scans that exceed the small table threshold to use direct path read

      3. This forces 11g style read semantics on the 10g databases 

    3. Change the Oracle init parameter “filesystemio_options”

      1. The problem manifests only when this parameter is set to “SETALL”. Using “NONE” or “ASYNC” will mitigate the problem.

      2. “ASYNC” is the preferred setting in the absence of “SETALL”

    Want to read more about this issue and how we got this workaround? Check out this">https://support.delphix.com/hc/en-us/articles/203839946-How-to-Mitigate-Multi-Block-Read-Performance-on-Oracle-10g">this article on our Knowledge Base!