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Type:
New Feature
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Resolution: Fixed
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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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None
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Fully Compatible
A query like this:
db.coll.aggregate([
{$group: {
_id: "$meta.a",
mostRecent: {$topN: {
n: 1,
sortBy: {ts: -1},
output: {
ts: "$ts",
measureA: "$measureA",
measureB: "$measureB"
}
}}
}}
])
or
db.coll.aggregate([
{$group: {
_id: "$meta.a",
mostRecent: {$top: {
sortBy: {ts: -1},
output: {
ts: "$ts",
measureA: "$measureA",
measureB: "$measureB"
}
}}
}}
])
Will be rewritten to something like this to get the last point optimization:
db.measurements.aggregate([
{$sort: {"meta.a": 1, "ts": -1}},
{$group: {
_id: "$sensorId”,
ts: {$first: "$ts”},
measureA: {$first: "$measureA"},
measureB: {$first: "$measureB"}
}}
])
- is depended on by
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- Closed
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