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  1. Core Server
  2. SERVER-7945

use plan ordering when reporting "winning" plan at the top of explain

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Details

    • Bug
    • Status: Closed
    • Major - P3
    • Resolution: Done
    • None
    • 2.6.0-rc0
    • Querying
    • Fully Compatible
    • ALL

    Description

      In cases where there is no "winning" query plan, one query plan with the highest match count is reported in the explain output (see discussion in SERVER-4150). However, in cases where some query plans are ordered and others are unordered, and a small limit is applied, this may result in an unordered plan being incorrectly reported at the top of explain when the results actually came from an ordered plan. We should take plan ordering and limit completion into account when choosing a plan to report at the top of explain (ExplainClauseInfo::virtualPickedPlan).

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          is depended on by

          Bug - A problem which impairs or prevents the functions of the product. SERVER-7950 MongoDB not using the most optimal index when sorting on 2 keys

          • Major - P3 - Major loss of function.
          • Closed
          is related to

          New Feature - A new feature of the product, which has yet to be developed. SERVER-10026 New query system

          • Major - P3 - Major loss of function.
          • Closed

          Task - A task that needs to be done. SERVER-10565 Re-implement explain() for new execution engine

          • Major - P3 - Major loss of function.
          • Closed
          related to

          Bug - A problem which impairs or prevents the functions of the product. SERVER-8747 In explain output, per plan 'n' count is not updated after an out of order plan wins

          • Major - P3 - Major loss of function.
          • Closed

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              benety.goh@mongodb.com Benety Goh
              aaron Aaron Staple
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              Dates

                Created:
                Updated:
                Resolved: