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  1. Documentation
  2. DOCS-417

Add doc for option to disable index prefetching

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    • Task
    • Status: Closed
    • Major - P3
    • Resolution: Fixed
    • None
    • mongodb-2.2
    • Server
    • None
    • true

    Description

      Config option for indexPrefetch commandline flag:

      Command line flag --replIndexPrefetch
      Parameter replIndexPrefetch
      values: none, _id_only, all
      "all" is the default if unspecified.


      New parameter replIndexPrefetch.
      Settable via the command line or use setParameter() command on a running server.
      Only valid on a server started with --replSet parameter.
      This allows a user to disable the prefetching of all index pages prior to the application
      of a replicated op on a secondary.
      For most use cases, prefetching all indexes for a given op will provide good performance.
      For use cases that do many in-place updates to documents in a collection with many indexes
      that are unaffected by such updates, using the '_id_only' setting may provide better performance
      than the 'all' setting. The '_id_only' setting only prefetches index pages for the _id index,
      which will always be used to find the document needed to be updated.
      The 'none' setting will be used for debugging only; there should be no production use cases for
      this setting.
      getParameter() supports getting the current value of this parameter.

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              sam.kleinman Sam Kleinman (Inactive)
              andrew.leung@10gen.com Andrew Leung (Inactive)
              Jonathan Dahl Jonathan Dahl
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              Dates

                Created:
                Updated:
                Resolved:
                10 years, 15 weeks ago