Aggregation on secondary server is not using the same index as the primary

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    • Type: Bug
    • Resolution: Incomplete
    • Priority: Major - P3
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    • Affects Version/s: 3.6.1
    • Component/s: Aggregation Framework
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      On our development server, I upgraded from 3.6.0 to 3.6.1, and one of our aggregation queries started taking about 30s. I ran the profiler on both the primary and secondary, and noticed that it was using a different index on the secondary. On the primary, the correct index is used, on the secondary, it is not. I could solve this problem by adding an additional index, but this is not ideal. The results from the profiling on the primary (fast.js) and secondary (slow.js) are attached.

        1. slow.js
          5 kB
        2. secondary_without_new_index.log
          11 kB
        3. secondary_with_new_index.log
          9 kB
        4. primary_without_new_index.log
          9 kB
        5. indexDetails.png
          indexDetails.png
          31 kB
        6. fast.js
          5 kB
        7. explain_secondary_without_new_index.txt
          105 kB
        8. explain_secondary_with_new_index.txt
          105 kB
        9. explain_primary_without_new_index.txt
          38 kB

            Assignee:
            Mark Agarunov (Inactive)
            Reporter:
            Travis Brown
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              Created:
              Updated:
              Resolved: