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  1. Core Server
  2. SERVER-70617

Allow use of column indexes for count queries

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    • Type: Icon: Task Task
    • Resolution: Fixed
    • Priority: Icon: Major - P3 Major - P3
    • 6.3.0-rc0
    • Affects Version/s: None
    • Component/s: None
    • None
    • Fully Compatible
    • 100

      Currently, count queries do not use SBE. This prevents any count-like query from using the column index, such as 

      db.order_lineitem.aggregate(
[
    {
        $match: {
            $and: [
                { "order.o_orderdate": { $gte: ISODate("1992-01-01") } },
                { "order.o_orderdate": { $lte: ISODate("1996-01-01") } },
                { l_discount: { $gte: 0.1 } },
                { l_discount: { $lte: 0.3 } }
            ],
            l_quantity: {
                $lte: 25
            }
        },
    },
    {
        $group: {
                _id: 1,
                count: {
                    $sum: 1
                }
            }
        }
    ]
)

      This ticket is to allow queries to use SBE for counts when an eligible column index is available. Doing this in a somewhat clean way will be tricky, because we have to choose the engine based on what indexes are available.

            Assignee:
            alyssa.clark@mongodb.com Alyssa Clark
            Reporter:
            ian.boros@mongodb.com Ian Boros
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              Created:
              Updated:
              Resolved: