mirror of https://github.com/prometheus/prometheus
151 lines
4.3 KiB
Go
151 lines
4.3 KiB
Go
// Copyright 2024 The Prometheus Authors
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package promql
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import (
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"github.com/prometheus/prometheus/model/histogram"
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"github.com/prometheus/prometheus/model/value"
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"github.com/prometheus/prometheus/tsdb/chunkenc"
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)
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type histogramStatsIterator struct {
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chunkenc.Iterator
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currentH *histogram.Histogram
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lastH *histogram.Histogram
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currentFH *histogram.FloatHistogram
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lastFH *histogram.FloatHistogram
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}
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// NewHistogramStatsIterator creates an iterator which returns histogram objects
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// which have only their sum and count values populated. The iterator handles
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// counter reset detection internally and sets the counter reset hint accordingly
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// in each returned histogram objects.
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func NewHistogramStatsIterator(it chunkenc.Iterator) chunkenc.Iterator {
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return &histogramStatsIterator{
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Iterator: it,
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currentH: &histogram.Histogram{},
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currentFH: &histogram.FloatHistogram{},
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}
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}
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// AtHistogram returns the next timestamp/histogram pair. The counter reset
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// detection is guaranteed to be correct only when the caller does not switch
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// between AtHistogram and AtFloatHistogram calls.
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func (f *histogramStatsIterator) AtHistogram(h *histogram.Histogram) (int64, *histogram.Histogram) {
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var t int64
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t, f.currentH = f.Iterator.AtHistogram(f.currentH)
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if value.IsStaleNaN(f.currentH.Sum) {
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h = &histogram.Histogram{Sum: f.currentH.Sum}
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return t, h
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}
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if h == nil {
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h = &histogram.Histogram{
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CounterResetHint: f.getResetHint(f.currentH),
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Count: f.currentH.Count,
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Sum: f.currentH.Sum,
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}
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f.setLastH(f.currentH)
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return t, h
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}
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returnValue := histogram.Histogram{
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CounterResetHint: f.getResetHint(f.currentH),
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Count: f.currentH.Count,
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Sum: f.currentH.Sum,
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}
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returnValue.CopyTo(h)
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f.setLastH(f.currentH)
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return t, h
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}
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// AtFloatHistogram returns the next timestamp/float histogram pair. The counter
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// reset detection is guaranteed to be correct only when the caller does not
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// switch between AtHistogram and AtFloatHistogram calls.
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func (f *histogramStatsIterator) AtFloatHistogram(fh *histogram.FloatHistogram) (int64, *histogram.FloatHistogram) {
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var t int64
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t, f.currentFH = f.Iterator.AtFloatHistogram(f.currentFH)
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if value.IsStaleNaN(f.currentFH.Sum) {
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return t, &histogram.FloatHistogram{Sum: f.currentFH.Sum}
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}
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if fh == nil {
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fh = &histogram.FloatHistogram{
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CounterResetHint: f.getFloatResetHint(f.currentFH.CounterResetHint),
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Count: f.currentFH.Count,
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Sum: f.currentFH.Sum,
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}
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f.setLastFH(f.currentFH)
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return t, fh
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}
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returnValue := histogram.FloatHistogram{
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CounterResetHint: f.getFloatResetHint(f.currentFH.CounterResetHint),
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Count: f.currentFH.Count,
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Sum: f.currentFH.Sum,
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}
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returnValue.CopyTo(fh)
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f.setLastFH(f.currentFH)
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return t, fh
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}
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func (f *histogramStatsIterator) setLastH(h *histogram.Histogram) {
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if f.lastH == nil {
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f.lastH = h.Copy()
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} else {
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h.CopyTo(f.lastH)
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}
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}
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func (f *histogramStatsIterator) setLastFH(fh *histogram.FloatHistogram) {
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if f.lastFH == nil {
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f.lastFH = fh.Copy()
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} else {
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fh.CopyTo(f.lastFH)
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}
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}
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func (f *histogramStatsIterator) getFloatResetHint(hint histogram.CounterResetHint) histogram.CounterResetHint {
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if hint != histogram.UnknownCounterReset {
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return hint
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}
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if f.lastFH == nil {
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return histogram.NotCounterReset
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}
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if f.currentFH.DetectReset(f.lastFH) {
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return histogram.CounterReset
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}
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return histogram.NotCounterReset
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}
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func (f *histogramStatsIterator) getResetHint(h *histogram.Histogram) histogram.CounterResetHint {
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if h.CounterResetHint != histogram.UnknownCounterReset {
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return h.CounterResetHint
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}
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if f.lastH == nil {
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return histogram.NotCounterReset
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}
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fh, prevFH := h.ToFloat(nil), f.lastH.ToFloat(nil)
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if fh.DetectReset(prevFH) {
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return histogram.CounterReset
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}
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return histogram.NotCounterReset
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}
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