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https://github.com/prometheus/prometheus.git
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836f1db04c
WIP: This needs more tests. It now gets a from and through value, which it may opportunistically use to optimize the retrieval. With possible future range indices, this could be used in a very efficient way. This change merely applies some easy checks, which should nevertheless solve the use case of heavy rule evaluations on servers with a lot of series churn. Idea is the following: - Only archive series that are at least as old as the headChunkTimeout (which was already extremely unlikely to happen). - Then maintain a high watermark for the last archival, i.e. no archived series has a sample more recent than that watermark. - Any query that doesn't reach to a time before that watermark doesn't have to touch the archive index at all. (A production server at Soundcloud with the aforementioned series churn and heavy rule evaluations spends 50% of its CPU time in archive index lookups. Since rule evaluations usually only touch very recent values, most of those lookup should disappear with this change.) - Federation with a very broad label matcher will profit from this, too. As a byproduct, the un-needed MetricForFingerprint method was removed from the Storage interface.
112 lines
2.9 KiB
Go
112 lines
2.9 KiB
Go
// Copyright 2015 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 web
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import (
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"net/http"
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"github.com/golang/protobuf/proto"
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"github.com/prometheus/prometheus/promql"
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"github.com/prometheus/common/expfmt"
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"github.com/prometheus/common/model"
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dto "github.com/prometheus/client_model/go"
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)
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func (h *Handler) federation(w http.ResponseWriter, req *http.Request) {
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h.mtx.RLock()
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defer h.mtx.RUnlock()
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req.ParseForm()
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fps := map[model.Fingerprint]struct{}{}
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for _, s := range req.Form["match[]"] {
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matchers, err := promql.ParseMetricSelector(s)
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if err != nil {
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http.Error(w, err.Error(), http.StatusBadRequest)
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return
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}
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for fp := range h.storage.MetricsForLabelMatchers(
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model.Now().Add(-promql.StalenessDelta), model.Latest,
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matchers...,
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) {
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fps[fp] = struct{}{}
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}
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}
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var (
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minTimestamp = model.Now().Add(-promql.StalenessDelta)
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format = expfmt.Negotiate(req.Header)
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enc = expfmt.NewEncoder(w, format)
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)
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w.Header().Set("Content-Type", string(format))
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protMetric := &dto.Metric{
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Label: []*dto.LabelPair{},
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Untyped: &dto.Untyped{},
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}
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protMetricFam := &dto.MetricFamily{
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Metric: []*dto.Metric{protMetric},
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Type: dto.MetricType_UNTYPED.Enum(),
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}
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for fp := range fps {
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globalUsed := map[model.LabelName]struct{}{}
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s := h.storage.LastSampleForFingerprint(fp)
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// Discard if sample does not exist or lays before the staleness interval.
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if s.Timestamp.Before(minTimestamp) {
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continue
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}
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// Reset label slice.
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protMetric.Label = protMetric.Label[:0]
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for ln, lv := range s.Metric {
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if ln == model.MetricNameLabel {
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protMetricFam.Name = proto.String(string(lv))
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continue
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}
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protMetric.Label = append(protMetric.Label, &dto.LabelPair{
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Name: proto.String(string(ln)),
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Value: proto.String(string(lv)),
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})
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if _, ok := h.externalLabels[ln]; ok {
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globalUsed[ln] = struct{}{}
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}
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}
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// Attach global labels if they do not exist yet.
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for ln, lv := range h.externalLabels {
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if _, ok := globalUsed[ln]; !ok {
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protMetric.Label = append(protMetric.Label, &dto.LabelPair{
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Name: proto.String(string(ln)),
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Value: proto.String(string(lv)),
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})
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}
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}
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protMetric.TimestampMs = proto.Int64(int64(s.Timestamp))
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protMetric.Untyped.Value = proto.Float64(float64(s.Value))
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if err := enc.Encode(protMetricFam); err != nil {
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http.Error(w, err.Error(), http.StatusInternalServerError)
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return
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}
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}
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}
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