This reverts commit 2ddb3596ef.
Various tests are failing in CI after this change; reverting to free up
other work.
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
In https://github.com/prometheus/prometheus/pull/13276 we started reusing float histogram objects to reduce allocations in PromQL.
That PR introduces a bug where histogram pointers gets copied to the beginning of the histograms slice,
but are still kept in the end of the slice. When a new histogram is read into the last element,
it can overwrite a previous element because the pointer is the same.
This commit fixes the issue by moving outdated points to the end of the slice
so that we don't end up with duplicate pointers in the same buffer. In other words,
the slice gets rotated so that old objects can get reused.
Signed-off-by: Filip Petkovski <filip.petkovsky@gmail.com>
This commit reduces the memory needed to query native histogram objects
by reusing existing HPoint instances.
Signed-off-by: Filip Petkovski <filip.petkovsky@gmail.com>
The 'ToFloat' method on integer histograms currently allocates new memory
each time it is called.
This commit adds an optional *FloatHistogram parameter that can be used
to reuse span and bucket slices. It is up to the caller to make sure the
input float histogram is not used anymore after the call.
Signed-off-by: Filip Petkovski <filip.petkovsky@gmail.com>
promql: Improve histogram_quantile calculation for classic buckets
Tiny differences between classic buckets are most likely caused by floating point precision issues. With this commit, relative changes below a certain threshold are ignored. This makes the result of histogram_quantile more meaningful, and also avoids triggering the _input to histogram_quantile needed to be fixed for monotonicity_ annotations in unactionable cases.
This commit also adds explanation of the new adjustment and of the monotonicity annotation to the documentation of `histogram_quantile`.
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Signed-off-by: Jeanette Tan <jeanette.tan@grafana.com>
* Add benchmark for native histograms
This commit adds a PromQL benchmark for queries on native histograms.
Signed-off-by: Filip Petkovski <filip.petkovsky@gmail.com>
This PR adds an Experimental flag to the functions.
This can be used by https://github.com/prometheus/prometheus/pull/13059
but also xrate and other future functions.
Signed-off-by: Julien Pivotto <roidelapluie@o11y.eu>
This function is useful to analyze promQL queries. We want to use this in Mimir to record the time range which the query touches.
I also chose to remove the `Engine` receiver because it was unnecessary, and it makes it easier to use, but happy to refactor that if you disagree.
The function is untested on its own. If you prefer to have unit tests now that its exported, I can look into adding some.
Signed-off-by: Dimitar Dimitrov <dimitar.dimitrov@grafana.com>
* Remove NewPossibleNonCounterInfo until it can be made more efficient, and avoid creating empty annotations as much as possible
Signed-off-by: Jeanette Tan <jeanette.tan@grafana.com>
Return annotations (warnings and infos) from PromQL queries
This generalizes the warnings we have already used before (but only for problems with remote read) as "annotations".
Annotations can be warnings or infos (the latter could be false positives). We do not treat them different in the API for now and return them all as "warnings". It would be easy to distinguish them and return infos separately, should that appear useful in the future.
The new annotations are then used to create a lot of warnings or infos during PromQL evaluations. Partially these are things we have wanted for a long time (e.g. inform the user that they have applied `rate` to a metric that doesn't look like a counter), but the new native histograms have created even more needs for those annotations (e.g. if a query tries to aggregate float numbers with histograms).
The annotations added here are not yet complete. A prominent example would be a warning about a range too short for a rate calculation. But such a warnings is more tricky to create with good fidelity and we will tackle it later.
Another TODO is to take annotations into account when evaluating recording rules.
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Signed-off-by: Jeanette Tan <jeanette.tan@grafana.com>
Make it more likely that contributors will run the benchmark suite.
count_values needs more than 2GB at 1,000 steps, so just run it for 100.
And remove 10-step variant because it doesn't add much to 100 and
1000-step benchmarks.
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
Otherwise we have a highly unusual situation of over 100 chunks
in the headChunks list of each series, which heavily skews
performance.
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
