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Type:
Task
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Resolution: Won't Fix
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Priority:
Major - P3
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Affects Version/s: None
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Component/s: None
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Labels:None
Currently, there is at least one undocumented query plan stage, "KEEP_MUTATIONS". I have no idea what it's doing. We should probably put a reference for all possible values here.
Output:
shard02:PRIMARY> db.foo.find( { a : 1, b : 1 } ).explain()
{
"queryPlanner" : {
"plannerVersion" : 1,
"parsedQuery" : {
"$and" : [
{
"a" : {
"$eq" : 1
}
},
{
"b" : {
"$eq" : 1
}
}
]
},
"winningPlan" : {
"stage" : "KEEP_MUTATIONS",
"inputStage" : {
"stage" : "FETCH",
"filter" : {
"a" : {
"$eq" : 1
}
},
"inputStage" : {
"stage" : "IXSCAN",
"keyPattern" : {
"b" : 1
},
"isMultiKey" : false,
"direction" : "forward",
"indexBounds" : {
"b" : [
"[1.0, 1.0]"
]
}
}
}
},
"rejectedPlans" : [
{
"stage" : "FETCH",
"inputStage" : {
"stage" : "IXSCAN",
"keyPattern" : {
"a" : 1,
"b" : 1
},
"isMultiKey" : false,
"direction" : "forward",
"indexBounds" : {
"a" : [
"[1.0, 1.0]"
],
"b" : [
"[1.0, 1.0]"
]
}
}
}
]
},
"serverInfo" : {
"host" : "cross-mb-air.local",
"port" : 27021,
"version" : "2.8.0-rc2",
"gitVersion" : "f77869e01a6ed235695a46fad441c0dff15202f6"
},
"ok" : 1
}
This is on 2.8.0-rc2, in the shell. I've got a sharded cluster (3 shards) each with 3 replica sets. I've launched them all with mlaunch v.1.1.7, with, at the bash prompt:
mlaunch init --replicaset --sharded 3