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  1. Core Server
  2. SERVER-56017

Fix invariant failure in SlotBasedStageBuilder::buildSort()

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      Open the mongo shell and run the following commands:

      > db.coll.createIndex({y: 1, x: 1})
      > db.coll.find({y: {$gt: 0}, x: {$gte: 20}}, {_id: 0, y: 1, x: 1}).sort({x:-1}).limit(2)

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      Open the mongo shell and run the following commands: > db.coll.createIndex({y: 1, x: 1}) > db.coll.find({y: {$gt: 0}, x: {$gte: 20}}, {_id: 0, y: 1, x: 1}).sort({x:-1}).limit(2)
    • Query Execution 2021-04-19, Query Execution 2021-05-03

      Around line 829 of "src/mongo/db/query/sbe_stage_builder.cpp", there is an invariant at the top of the buildSort() method.

      Here is a valid plan that can cause this invariant() to fail:

      > db.coll.createIndex({y: 1, x: 1})
      > db.coll.find({y: {$gt: 0}, x: {$gte: 20}}, {_id: 0, y: 1, x: 1}).sort({x:-1}).limit(2)

      The "limit(2)" in the query above forces the QueryPlanner to generate a PROJECTION_COVERED / SORT / IXSCAN plan, where the input to sort stage is coming directly from the index keys.

            Assignee:
            nikita.lapkov@mongodb.com Nikita Lapkov (Inactive)
            Reporter:
            andrew.paroski@mongodb.com Drew Paroski
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              Created:
              Updated:
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