Perform a trial run on join plan cache hit and make replanning decision

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    • Type: Improvement
    • Resolution: Unresolved
    • Priority: Major - P3
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    • Affects Version/s: None
    • Component/s: None
    • Query Optimization
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      SERVER-136737, implemented the logic around inserting baseline metrics into the join plan cache entry. On a cache hit, these metrics (numReads, numIntermediateRowsProduced and numSpills) from the TrialRunTracker should be used to make a decision on whether to initiate replanning for the query. The plan from the cache will be run under a trial period for N number of docs (tuneable) and its metrics will be recorded.

      The replanning decision will be based on:

      1. Did the query start spilling when previously it did not?
      2. Did numReads exceed k * baseline.numReads?
      3. Did numIntermediateRowsProduced exceed k * baseline.numIntermediateRowsProduced?

      k will be tuneable parameter.

            Assignee:
            Naafiyan Ahmed
            Reporter:
            Naafiyan Ahmed
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              Created:
              Updated: