From 5e75c389e657ad95de23a278388abd914a123fd4 Mon Sep 17 00:00:00 2001
From: Aliaksandr Valialkin <valyala@gmail.com>
Date: Mon, 2 Nov 2020 02:09:27 +0200
Subject: [PATCH] app/vmselect/promql: allow dropping trailing sample only for
`default_rollup` function
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/850
---
app/vmselect/promql/rollup.go | 27 +++++++++++++++++----------
1 file changed, 17 insertions(+), 10 deletions(-)
diff --git a/app/vmselect/promql/rollup.go b/app/vmselect/promql/rollup.go
index e3cada6df0..44d5fca636 100644
--- a/app/vmselect/promql/rollup.go
+++ b/app/vmselect/promql/rollup.go
@@ -258,15 +258,16 @@ func getRollupConfigs(name string, rf rollupFunc, expr metricsql.Expr, start, en
}
newRollupConfig := func(rf rollupFunc, tagValue string) *rollupConfig {
return &rollupConfig{
- TagValue: tagValue,
- Func: rf,
- Start: start,
- End: end,
- Step: step,
- Window: window,
- MayAdjustWindow: !rollupFuncsCannotAdjustWindow[name],
- LookbackDelta: lookbackDelta,
- Timestamps: sharedTimestamps,
+ TagValue: tagValue,
+ Func: rf,
+ Start: start,
+ End: end,
+ Step: step,
+ Window: window,
+ MayAdjustWindow: !rollupFuncsCannotAdjustWindow[name],
+ CanDropLastSample: name == "default_rollup",
+ LookbackDelta: lookbackDelta,
+ Timestamps: sharedTimestamps,
}
}
appendRollupConfigs := func(dst []*rollupConfig) []*rollupConfig {
@@ -370,6 +371,11 @@ type rollupConfig struct {
// when using window smaller than 2 x scrape_interval.
MayAdjustWindow bool
+ // Whether the last sample can be dropped during rollup calculations.
+ // The last sample can be dropped for `default_rollup()` function only.
+ // See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/748 .
+ CanDropLastSample bool
+
Timestamps []int64
// LoookbackDelta is the analog to `-query.lookback-delta` from Prometheus world.
@@ -501,6 +507,7 @@ func (rc *rollupConfig) doInternal(dstValues []float64, tsm *timeseriesMap, valu
ni := 0
nj := 0
stalenessInterval := int64(float64(scrapeInterval) * 0.9)
+ canDropLastSample := rc.CanDropLastSample
for _, tEnd := range rc.Timestamps {
tStart := tEnd - window
ni = seekFirstTimestampIdxAfter(timestamps[i:], tStart, ni)
@@ -519,7 +526,7 @@ func (rc *rollupConfig) doInternal(dstValues []float64, tsm *timeseriesMap, valu
}
rfa.values = values[i:j]
rfa.timestamps = timestamps[i:j]
- if j == len(timestamps) && j > 0 && (tEnd-timestamps[j-1] > stalenessInterval || i == j && len(timestamps) == 1) && rc.End-tEnd >= 2*rc.Step {
+ if canDropLastSample && j == len(timestamps) && j > 0 && (tEnd-timestamps[j-1] > stalenessInterval || i == j && len(timestamps) == 1) && rc.End-tEnd >= 2*rc.Step {
// Drop trailing data points in the following cases:
// - if the distance between the last raw sample and tEnd exceeds stalenessInterval
// - if time series contains only a single raw sample