Details
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Improvement
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Status: Closed
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Major - P3
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Resolution: Fixed
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None
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None
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Fully Compatible
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Query Optimization 2021-05-03
Description
For a time-series collection, we automatically bucket fields and have a control block with the min and max of each, like so:
{ _id: ObjectId(...),
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control: {
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version: 1, // in case we want to change the format in a later release |
min: { _id: ..., time: ISODate("2020-09-09T16:54:04.174Z"), field0: 0.01, ... }, |
max: { _id: ..., time: ISODate("2020-09-09T16:54:04.450Z"), field0: 0.99, ... }, |
},
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meta: ...,
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data: { _id: { 0:..., 1: ..., ...},
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time: { 0: ISODate("2020-09-09T16:54:04.174Z"), |
1: ISODate("2020-09-09T16:54:04.450Z"), ...}, |
field0: { 0: 0.99, 1: 0.01,...},
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field1: { 2: "high", 42: "low",...}, // Missing fields are omitted |
...}
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}
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For a query over that collection like this:
db.example.aggregate([{$group: {_id: "$meta.x", field0: {$max: "$field0"}}}]) |
We should be able to avoid unpacking or looking at "data" at all.
Attachments
Issue Links
- is related to
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SERVER-55624 Track materialized counts and sums for time-series measurements
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- Backlog
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