Indexes with $or

31/39

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db.cities.createIndex( { country_code: 1 } );
db.cities.find( { *$or*: [|f10000|{country_code: 'NL'}|, |00cc00|{country_code: 'BE'}|] } ).explain();



{
    *"clauses" : [*
        {
            |f10000|"cursor" : "BtreeCursor country_code_1",|
            |f10000|"nscanned" : 256,|
            |f10000|"nscannedObjects" : 256,|
            |f10000|"n" : 256,|
...
            |f10000|"indexBounds" : { "country_code" : [ [ "NL", "NL" ] ] }|
        },
        {
            |00cc00|"cursor" : "BtreeCursor country_code_1",|
            |00cc00|"nscanned" : 184,|
...
            |00cc00|"indexBounds" : { "country_code" : [ [ "BE", "BE" ] ] }|
        }
    ],
    "nscanned" : 440,
    "nscannedObjects" : 440,
    "n" : 440,
    "millis" : 3
}