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  1. Core Server
  2. SERVER-61679

$sum accumulator fails in aggregation_wildcard_fuzzer when numeric data set is mixed typed and precision is too wide

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    • Type: Icon: Bug Bug
    • Resolution: Duplicate
    • Priority: Icon: Major - P3 Major - P3
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    • Affects Version/s: None
    • Component/s: None
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      In one window, execute the following.

      $ build/debug/install/bin/mongod --setParameter featureFlagSBEGroupPushdown=true

      In another windows, execute the following.

      $ build/debug/install/bin/mongo
MongoDB Enterprise > db.tt.drop();
true
MongoDB Enterprise > db.tt.insert([{n: NumberLong("9223372036854775807")}, {n: NumberDecimal("1.0")}]);
BulkWriteResult({
	"writeErrors" : [ ],
	"writeConcernErrors" : [ ],
	"nInserted" : 2,
	"nUpserted" : 0,
	"nMatched" : 0,
	"nModified" : 0,
	"nRemoved" : 0,
	"upserted" : [ ]
})
MongoDB Enterprise > db.tt.aggregate([{$group: {_id: null, num : {$sum: {$add: [NumberLong("1000"), "$n"]}}}}]);
{ "_id" : null, "num" : NumberDecimal("9223372036854777808.0") }
MongoDB Enterprise > db.adminCommand({setParameter: 1, internalQueryForceClassicEngine: true});
{ "was" : false, "ok" : 1 }
MongoDB Enterprise > db.tt.aggregate([{$group: {_id: null, num : {$sum: {$add: [NumberLong("1000"), "$n"]}}}}]);
{ "_id" : null, "num" : NumberDecimal("9223372036854776809.0") }
      Show
      In one window, execute the following. $ build/debug/install/bin/mongod --setParameter featureFlagSBEGroupPushdown= true In another windows, execute the following. $ build/debug/install/bin/mongo MongoDB Enterprise > db.tt.drop(); true MongoDB Enterprise > db.tt.insert([{n: NumberLong( "9223372036854775807" )}, {n: NumberDecimal( "1.0" )}]); BulkWriteResult({ "writeErrors" : [ ], "writeConcernErrors" : [ ], "nInserted" : 2, "nUpserted" : 0, "nMatched" : 0, "nModified" : 0, "nRemoved" : 0, "upserted" : [ ] }) MongoDB Enterprise > db.tt.aggregate([{$group: {_id: null , num : {$sum: {$add: [NumberLong( "1000" ), "$n" ]}}}}]); { "_id" : null , "num" : NumberDecimal( "9223372036854777808.0" ) } MongoDB Enterprise > db.adminCommand({setParameter: 1, internalQueryForceClassicEngine: true }); { "was" : false , "ok" : 1 } MongoDB Enterprise > db.tt.aggregate([{$group: {_id: null , num : {$sum: {$add: [NumberLong( "1000" ), "$n" ]}}}}]); { "_id" : null , "num" : NumberDecimal( "9223372036854776809.0" ) }
    • QE 2021-11-29, QE 2021-12-13, QE 2021-12-27, QE 2022-01-10, QE 2022-01-24

      As can be seen in the attached repro script, when a numeric data set is mixed-typed and the precision is too wide so that int64 can't express any intermediate result, the SBE engine result does not agree with the classic engine result. Results are...

      MongoDB Enterprise > db.tt.aggregate([{$group: {_id: null, num : {$sum: {$add: [NumberLong("1000"), "$n"]}}}}]);
{ "_id" : null, "num" : NumberDecimal("9223372036854777808.0") }
MongoDB Enterprise > db.adminCommand({setParameter: 1, internalQueryForceClassicEngine: true});
{ "was" : false, "ok" : 1 }
MongoDB Enterprise > db.tt.aggregate([{$group: {_id: null, num : {$sum: {$add: [NumberLong("1000"), "$n"]}}}}]);
{ "_id" : null, "num" : NumberDecimal("9223372036854776809.0") }

            Assignee:
            yoonsoo.kim@mongodb.com Yoon Soo Kim
            Reporter:
            yoonsoo.kim@mongodb.com Yoon Soo Kim
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              Created:
              Updated:
              Resolved: