engine: fix limitratio to limit the map access and update sort logic #583
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Signed-off-by: Saumya Shah <saumyabshah90@gmail.com>
Signed-off-by: Saumya Shah <saumyabshah90@gmail.com>
Signed-off-by: Saumya Shah <saumyabshah90@gmail.com>
Signed-off-by: Saumya Shah <saumyabshah90@gmail.com>
GiedriusS
reviewed
Jun 6, 2025
engine/sort.go
Outdated
| @@ -155,6 +156,10 @@ func (s aggregateResultSort) comparer(samples *promql.Vector) func(i, j int) boo | |||
| if lblsCmp != 0 { | |||
| return lblsCmp < 0 | |||
| } | |||
|
|
|||
| if s.sortOrder == noValueSort { | |||
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Where is this used? It looks very weird. Maybe we can just avoid calling this function (& sorting) overall?
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https://github.com/thanos-io/promql-engine/blob/main/engine/sort.go#L100C1-L104C5 for limit k/_ratio, we set sortOrder to noValueSort.
Of what I saw, we would need sort if some grouping is used, though sorting sample values would be just extra step as its not needed in two of these aggregations.
Maybe we can just avoid calling this function (& sorting) overall?
Right, but is it ok if order in which samples are, differs? this is just for when some groupings are used for instant queries
Signed-off-by: Saumya Shah <saumyabshah90@gmail.com>
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limit the number of map access calls in limit_ratio, as it won't be needed to check whether to add samples or not.
For instant queries:
limitk, limit_ratio doesn't require to sort values at the end.