MQE: Ensure we never skip buckets for histogram_stddev and histogram_stdvar - #16486
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cc @krajorama |
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| * [BUGFIX] MQE: Fix an issue where series were joined in binary operations using the wrong labels when `group_left()`/`group_right()` were used in combination with `ignoring()`. This bug manifested as valid queries returning an error `grouping labels must ensure unique matches`. #16387 | ||
| * [BUGFIX] MQE: Fix queries and rules containing a subquery whose range is shorter than its step (e.g. `foo[10m:3d]`) failing with `last bucket must not be before first bucket`. #16442 | ||
| * [BUGFIX] MQE: Fix `sum_over_time()` over native histograms losing precision when experimental range vector splitting is enabled. The Kahan compensation of each split range was discarded instead of being carried over to the other split ranges. #16455 | ||
| * [BUGFIX] MQE: Never skip decoding histogram buckets for `histogram_stddev` and `histogram_stdvar`. #16486 |
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nit: Can you clarify what issue this would have caused for users? Incorrect results?
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Updated, is it okay now?
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What this PR does
See title. This doesn't change most queries as we already don't skip the buckets by default, just making the intended behaviour explicit and adding tests to cover it to prevent inadvertent changes to this behaviour later. This matches what we do in Prometheus.
However, it does change queries where either
histogram_stddevorhistogram_stdvaris nested underhistogram_count,histogram_sumorhistogram_avg(for examplehistogram_sum(h * histogram_stddev(h))), as the inner selector could return histograms without buckets, causing these functions to return 0. Added this edge case in a test and updated the changelog.Which issue(s) this PR fixes or relates to
Parallel to upstream PR: prometheus/prometheus#19521
Checklist
CHANGELOG.mdupdated - the order of entries should be[CHANGE],[FEATURE],[ENHANCEMENT],[BUGFIX]. If changelog entry is not needed, please add thechangelog-not-neededlabel to the PR.about-versioning.mdupdated with experimental features.