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  1. Core Server
  2. SERVER-83196

SBE multiplanning may chooses the wrong plan

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    • Icon: Bug Bug
    • Resolution: Unresolved
    • Icon: Major - P3 Major - P3
    • None
    • None
    • None
    • Query Optimization
    • ALL

    Description

      For SBE, we implemented a default limit of 10,000 reads for each candidate plan. This bounds the expense of the trial period cost at 10,000n where n is the number of plans – an important backstop given that we may incidentally trial the “wrong” plan(s) first. However, this limit can be much higher for the Classic multi-planner. As a result, the SBE multi-planner will sometimes do less partial execution than the Classic multi-planner, rendering it unable to distinguish amongst plans when no well-indexed plan exists.

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            backlog-query-optimization Backlog - Query Optimization
            xiaochen.wu@mongodb.com Xiaochen Wu
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              Created:
              Updated: