$sequentialCache optimization can interfere with $match pushdown in a $lookup sub-pipeline

XMLWordPrintableJSON

    • Query Optimization
    • Fully Compatible
    • v8.2, v8.1, v8.0
    • 200
    • None
    • None
    • None
    • None
    • None
    • None
    • None

      If an aggregate includes a $lookup on a view using a pipeline with a $match that can be partially supported by an index, and the pipeline uses constants, it is executed in a few milliseconds and using a single index scan on the base collection of the view.
      If the pipeline uses locally defined variables, still assigned to the same constants, the generated plan does a full collection scan, ignoring the predicate

      See attached repro case

        1. lookup_on_view.js
          4 kB

            Assignee:
            David Storch
            Reporter:
            Alberto Massari
            Votes:
            0 Vote for this issue
            Watchers:
            13 Start watching this issue

              Created:
              Updated:
              Resolved: