* add custom buckets to native histogram model
* simple copy for custom bounds
* return errors for unsupported add/sub operations
* add test cases for string and update appendhistogram in scrape to account for new schema
* check fields which are supposed to be unused but may affect results in equals
* allow appending custom buckets histograms regardless of max schema
Signed-off-by: Jeanette Tan <jeanette.tan@grafana.com>
The slices package is added to the standard library in Go 1.21;
we need to import from the exp area to maintain compatibility with Go 1.20.
Signed-off-by: tyltr <tylitianrui@126.com>
Add `ReduceResolution` method to `Histogram` and `FloatHistogram`
This takes the original `mergeToSchema` function and turns it into a more generic `reduceResolution` function, which is the building block for the new methods.
The methods will help with addressing #12864.
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Signed-off-by: Ziqi Zhao <zhaoziqi9146@gmail.com>
The bucket receiving math.MaxFloat64 observations now has
math.MaxFloat64 as upper bound, while the bucket after it (the last
possible bucket) has +Inf.
This also adds a test for getBound and moves the getBound code to
generic.go (where it should have been in the first place).
Signed-off-by: beorn7 <beorn@grafana.com>
