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Type:
Bug
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Resolution: Unresolved
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Priority:
Major - P3
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None
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Affects Version/s: None
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Component/s: Aggregation Framework, Sharding
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Labels:
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Query Optimization
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ALL
Running an aggregation which was run on all three shards, when merging shard did a getMore, the logs show that only the merging shard itself shows the appName on the getMore log line (lines pruned for readability):
d20002| 2017-04-04T18:08:45.193-0400 I COMMAND [conn22] getmore test.w appName: "MongoDB Shell" query: { getMore: 7102048335196067288, collection: "w", batchSize: 0 } originatingCommand: { aggregate: "w", pipeline: [ { $match: { _id: { $lt: ObjectId('58e3f9aec65061ce53c8f334') } } }, { $group: { _id: { $const: 0.0 }, a: { $sum: "$a" } } } ], fromRouter: true, cursor: { batchSize: 0 } } planSummary: IXSCAN { _id: 1 } cursorid:7102048335196067288 ntoreturn:0 keysExamined:0 docsExamined:0 cursorExhausted:1 numYields:0 nreturned:0 reslen:20 0ms
d20000| 2017-04-04T18:08:45.194-0400 I COMMAND [conn35] getmore test.w query: { getMore: 6814644449283722003, collection: "w", batchSize: 0 } originatingCommand: { aggregate: "w", pipeline: [ { $match: { _id: { $lt: ObjectId('58e3f9aec65061ce53c8f334') } } }, { $group: { _id: { $const: 0.0 }, a: { $sum: "$a" } } } ], fromRouter: true, cursor: { batchSize: 0 } } planSummary: IXSCAN { _id: 1 } cursorid:6814644449283722003 ntoreturn:0 keysExamined:0 docsExamined:0 cursorExhausted:1 numYields:0 nreturned:0 reslen:20 0ms
d20001| 2017-04-04T18:08:45.194-0400 I COMMAND [conn12] getmore test.w query: { getMore: 8919999956757843669, collection: "w", batchSize: 0 } originatingCommand: { aggregate: "w", pipeline: [ { $match: { _id: { $lt: ObjectId('58e3f9aec65061ce53c8f334') } } }, { $group: { _id: { $const: 0.0 }, a: { $sum: "$a" } } } ], fromRouter: true, cursor: { batchSize: 0 } } planSummary: IXSCAN { _id: 1 } cursorid:8919999956757843669 ntoreturn:0 keysExamined:119 docsExamined:119 cursorExhausted:1 numYields:0 nreturned:1 reslen:49 0ms
d20002| 2017-04-04T18:08:45.194-0400 I COMMAND [conn21] command test.w appName: "MongoDB Shell" command: aggregate { aggregate: "w", pipeline: [ { $mergeCursors: [ { host: "erh-twinb:20000", ns: "test.w", id: 6814644449283722003 }, { host: "erh-twinb:20001", ns: "test.w", id: 8919999956757843669 }, { host: "erh-twinb:20002", ns: "test.w", id: 7102048335196067288 } ] }, { $group: { _id: "$$ROOT._id", a: { $sum: "$$ROOT.a" }, $doingMerge: true } } ], collation: { locale: "simple" }, cursor: {} } keysExamined:0 docsExamined:0 cursorExhausted:1 numYields:0 nreturned:1 reslen:163 protocol:op_command 0ms