Tassert in exactCE code

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    • Type: Bug
    • Resolution: Fixed
    • Priority: Minor - P4
    • 8.3.0-rc0
    • Affects Version/s: None
    • Component/s: None
    • Query Optimization
    • Fully Compatible
    • ALL
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      db.foo.drop()
db.foo.insert({})
db.foo.createIndex({a: 1, b: 1})
db.adminCommand({setParameter: 1, internalQueryCBRCEMode: "exactCE"});
db.foo.explain().distinct("b", {a: 1});
// mongo unreachable

       

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        db.foo.drop() db.foo.insert({}) db.foo.createIndex({a: 1, b: 1}) db.adminCommand({setParameter: 1, internalQueryCBRCEMode: "exactCE" }); db.foo.explain().distinct( "b" , {a: 1}); // mongo unreachable  
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      This query generates a STAGE_DISTINCT_SCAN as its leaf node. ExactCE mode does not go through CardinalityEstimator::estimate, which is where we would throw the ErrorCodes::UnsupportedCbrNode error for STAGE_DISTINCT_SCAN. ExactCE doesn't actually do any checks to see if the nodes are eligible for CBR generally.

       

      We should implement such checks so that when ExactCE is used in the CBR fallback to populate the estimate map, we can exit CBR earlier if we encounter an unsupported node.

            Assignee:
            Militsa Sotirova
            Reporter:
            Militsa Sotirova
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              Created:
              Updated:
              Resolved: