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Type:
Bug
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Resolution: Works as Designed
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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: None
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Labels:
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ALL
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QE 2021-09-20
Attempting to use killCursors to kill an idleCursor will output that the cursorId isn't found despite being present in currentOp on a sharded replicaset.
When this behavior occurs on an unsharded replica set, the idleCursor is correctly identified and deleted.
Looking closely at the currentOp on an unsharded and sharded cluster, the difference is the sharded cluster idleCursor includes a cursor.originatingCommand.$audit field, whereas it's absent in the idleCursor operation on an unsharded cluster.
Observed output:
{
"cursorsKilled" : [ ],
"cursorsNotFound" : [
NumberLong("2835470530442257976")
],
"cursorsAlive" : [ ],
"cursorsUnknown" : [ ],
"ok" : 1,
"operationTime" : Timestamp(1631130082, 1),
"$clusterTime" : {
"clusterTime" : Timestamp(1631130082, 1),
"signature" : {
"hash" : BinData(0,"PTeTErvUUsQjtD5TL7HxEWBfkLE="),
"keyId" : NumberLong("7005639500034473987")
}
}
}
currentOp on sharded cluster:
{
"shard" : "shard01",
"type" : "idleCursor",
"host" : "Edwins-MBP.cable.rcn.com:27018",
"ns" : "test.test_col",
"lsid" : {
"id" : UUID("e0d86751-ae27-4711-90d4-58182f15dd38"),
"uid" : BinData(0,"eOZyqfHfiVpfviPDWgAERmzNFnUp8UBdlWKN50Fv9fo=")
},
"planSummary" : "COLLSCAN",
"cursor" : {
"cursorId" : NumberLong("2835470530442257976"),
"createdDate" : ISODate("2021-09-08T19:41:03.243Z"),
"lastAccessDate" : ISODate("2021-09-08T19:41:03.243Z"),
"nDocsReturned" : NumberLong(101),
"nBatchesReturned" : NumberLong(1),
"noCursorTimeout" : false,
"tailable" : false,
"awaitData" : false,
"originatingCommand" : {
"find" : "test_col",
"readConcern" : {
"provenance" : "implicitDefault"
},
"runtimeConstants" : {
"localNow" : ISODate("2021-09-08T19:41:03.243Z"),
"clusterTime" : Timestamp(1631130063, 11259)
},
"_use44SortKeys" : true,
"shardVersion" : [
Timestamp(0, 0),
ObjectId("000000000000000000000000")
],
"databaseVersion" : {
"uuid" : UUID("9ae75994-3008-42f8-8771-c1ed457a8c1c"),
"lastMod" : 1
},
"clientOperationKey" : UUID("ec06493f-4d94-4973-850c-04bba4a63d0f"),
"lsid" : {
"id" : UUID("e0d86751-ae27-4711-90d4-58182f15dd38"),
"uid" : BinData(0,"eOZyqfHfiVpfviPDWgAERmzNFnUp8UBdlWKN50Fv9fo=")
},
"$clusterTime" : {
"clusterTime" : Timestamp(1631130063, 11259),
"signature" : {
"hash" : BinData(0,"xn16OBRLaxcrTFxyj3rOltF6EKw="),
"keyId" : NumberLong("7005639500034473987")
}
},
"$audit" : {
"$impersonatedUsers" : [
{
"user" : "user",
"db" : "admin"
}
],
"$impersonatedRoles" : [
{
"role" : "dbAdminAnyDatabase",
"db" : "admin"
},
{
"role" : "userAdminAnyDatabase",
"db" : "admin"
},
{
"role" : "readWriteAnyDatabase",
"db" : "admin"
},
{
"role" : "clusterAdmin",
"db" : "admin"
}
]
},
"$client" : {
"application" : {
"name" : "MongoDB Shell"
},
"driver" : {
"name" : "MongoDB Internal Client",
"version" : "4.4.8"
},
"os" : {
"type" : "Darwin",
"name" : "Mac OS X",
"architecture" : "x86_64",
"version" : "20.5.0"
},
"mongos" : {
"host" : "Edwins-MBP.cable.rcn.com:27017",
"client" : "127.0.0.1:50963",
"version" : "4.4.8"
}
},
"$configServerState" : {
"opTime" : {
"ts" : Timestamp(1631130062, 1),
"t" : NumberLong(2)
}
},
"$db" : "test"
}
}
}
currentOp on a different, unsharded cluster. This operation can be killed by the killCursors command.
{
"type" : "idleCursor",
"host" : "Edwins-MBP.cable.rcn.com:27017",
"ns" : "test.test_col",
"lsid" : {
"id" : UUID("3e710e06-4f2f-478a-9729-3593997d0e06"),
"uid" : BinData(0,"eOZyqfHfiVpfviPDWgAERmzNFnUp8UBdlWKN50Fv9fo=")
},
"planSummary" : "COLLSCAN",
"cursor" : {
"cursorId" : NumberLong("6473309381379159077"),
"createdDate" : ISODate("2021-09-08T18:16:31.965Z"),
"lastAccessDate" : ISODate("2021-09-08T18:16:31.965Z"),
"nDocsReturned" : NumberLong(101),
"nBatchesReturned" : NumberLong(1),
"noCursorTimeout" : false,
"tailable" : false,
"awaitData" : false,
"originatingCommand" : {
"find" : "test_col",
"filter" : {
},
"lsid" : {
"id" : UUID("3e710e06-4f2f-478a-9729-3593997d0e06")
},
"$clusterTime" : {
"clusterTime" : Timestamp(1631122562, 1),
"signature" : {
"hash" : BinData(0,"v0W3OnNwG/AVseVNtpul6k4g+nQ="),
"keyId" : NumberLong("7005607966384586753")
}
},
"$db" : "test"
}
}
}
Repro:
mlaunch init --auth --sharded 1 --replicaset --nodes 2
// insert some docs
bulk = db.getSiblingDB("test").getCollection("test_col").initializeUnorderedBulkOp();
for (let i = 0; i < 20000; i++) {
bulk.insert({ a: i, x: "x".repeat(1024) });
}
bulk.execute();
// create idleCursor
db.getSiblingDB("test").getCollection("test_col").find();
// get idleCursor cursorId
db.getSiblingDB("admin").aggregate([
{ $currentOp: { allUsers: true, idleCursors: true } },
{ $match: { type: "idleCursor" } },
]).toArray().map((o) => o.cursor.cursorId);
// kill cursor
db.getSiblingDB("test").runCommand({ killCursors: "test_col", cursors: [Long("<idleCursorId>")] });