From f1f66fbed1f41cbf34f600de112efe2a612facde Mon Sep 17 00:00:00 2001
From: Zexi Li <zexi.li@icloud.com>
Date: Mon, 12 Jan 2026 17:27:32 +0800
Subject: [PATCH] feat(monitor): delta reducer (#24063)

---
 pkg/apis/monitor/reducer.go                   |  3 +-
 pkg/apis/monitor/unifiedmonitor_query.go      |  1 +
 pkg/monitor/alerting/conditions/evaluator.go  |  4 +--
 .../alerting/conditions/mathreducer.go        |  2 ++
 pkg/monitor/alerting/conditions/reducer.go    | 29 +++++++++++++++++++
 pkg/monitor/dbinit/measurements/system.go     |  3 ++
 6 files changed, 39 insertions(+), 3 deletions(-)

diff --git a/pkg/apis/monitor/reducer.go b/pkg/apis/monitor/reducer.go
index 38cecaed08..a2a57171b2 100644
--- a/pkg/apis/monitor/reducer.go
+++ b/pkg/apis/monitor/reducer.go
@@ -27,6 +27,7 @@ const (
 	REDUCER_LAST           ReducerType = "last"
 	REDUCER_MEDIAN         ReducerType = "median"
 	REDUCER_DIFF           ReducerType = "diff"
+	REDUCER_DELTA          ReducerType = "delta"
 	REDUCER_PERCENT_DIFF   ReducerType = "percent_diff"
 	REDUCER_COUNT_NON_NULL ReducerType = "count_non_null"
 	REDUCER_PERCENTILE     ReducerType = "percentile"
@@ -37,7 +38,7 @@ var ValidateReducerTypes = sets.NewString()
 func init() {
 	for _, rt := range []ReducerType{REDUCER_AVG, REDUCER_SUM, REDUCER_MIN,
 		REDUCER_MAX, REDUCER_COUNT, REDUCER_LAST, REDUCER_MEDIAN, REDUCER_DIFF,
-		REDUCER_PERCENT_DIFF, REDUCER_COUNT_NON_NULL, REDUCER_PERCENTILE} {
+		REDUCER_DELTA, REDUCER_PERCENT_DIFF, REDUCER_COUNT_NON_NULL, REDUCER_PERCENTILE} {
 		ValidateReducerTypes.Insert(string(rt))
 	}
 }
diff --git a/pkg/apis/monitor/unifiedmonitor_query.go b/pkg/apis/monitor/unifiedmonitor_query.go
index 295a36d99e..01f0e1124b 100644
--- a/pkg/apis/monitor/unifiedmonitor_query.go
+++ b/pkg/apis/monitor/unifiedmonitor_query.go
@@ -62,6 +62,7 @@ var (
 		"last":         "Latest value",
 		"median":       "median",
 		"diff":         "The difference between the latest value and the oldest value. The judgment basis value must be legal",
+		"delta":        "The signed difference between the latest value and the oldest value (can be positive or negative)",
 		"percent_diff": "The difference between the new value and the old value,based on the percentage of the old value",
 	}
 )
diff --git a/pkg/monitor/alerting/conditions/evaluator.go b/pkg/monitor/alerting/conditions/evaluator.go
index 398874aa12..c9bb5f41f7 100644
--- a/pkg/monitor/alerting/conditions/evaluator.go
+++ b/pkg/monitor/alerting/conditions/evaluator.go
@@ -63,11 +63,11 @@ func (e *thresholdEvaluator) Eval(reducedValue *float64) bool {
 	val := *reducedValue
 	switch e.Type {
 	case "gt":
-		return val >= e.Threshold
+		return val > e.Threshold
 	case "eq":
 		return val == e.Threshold
 	case "lt":
-		return val <= e.Threshold
+		return val < e.Threshold
 	}
 
 	return false
diff --git a/pkg/monitor/alerting/conditions/mathreducer.go b/pkg/monitor/alerting/conditions/mathreducer.go
index 42ddee25ea..0f0f0fdd6c 100644
--- a/pkg/monitor/alerting/conditions/mathreducer.go
+++ b/pkg/monitor/alerting/conditions/mathreducer.go
@@ -148,6 +148,8 @@ func (s *mathReducer) Reduce(series *monitor.TimeSeries) (*float64, []string) {
 		}
 	case "diff":
 		allNull, value = calculateDiff(series, allNull, value, diff)
+	case "delta":
+		allNull, value = calculateDelta(series, allNull, value)
 	case "percent_diff":
 		allNull, value = calculateDiff(series, allNull, value, percentDiff)
 	case "count_non_null":
diff --git a/pkg/monitor/alerting/conditions/reducer.go b/pkg/monitor/alerting/conditions/reducer.go
index 4e64df0073..317155bd8d 100644
--- a/pkg/monitor/alerting/conditions/reducer.go
+++ b/pkg/monitor/alerting/conditions/reducer.go
@@ -137,6 +137,8 @@ func (s *queryReducer) Reduce(series *monitor.TimeSeries) (*float64, []string) {
 		}
 	case monitor.REDUCER_DIFF:
 		allNull, value = calculateDiff(series, allNull, value, diff)
+	case monitor.REDUCER_DELTA:
+		allNull, value = calculateDelta(series, allNull, value)
 	case monitor.REDUCER_PERCENT_DIFF:
 		allNull, value = calculateDiff(series, allNull, value, percentDiff)
 	case monitor.REDUCER_COUNT_NON_NULL:
@@ -226,6 +228,33 @@ var percentDiff = func(newest, oldest float64) float64 {
 	return (newest - oldest) / oldest * 100
 }
 
+func calculateDelta(series *monitor.TimeSeries, allNull bool, value float64) (bool, float64) {
+	var (
+		points = series.Points
+		first  float64
+		i      int
+	)
+	// get the newest point
+	for i = len(points) - 1; i >= 0; i-- {
+		if points[i].IsValid() {
+			allNull = false
+			first = points[i].Value()
+			break
+		}
+	}
+	if i >= 1 {
+		// get the oldest point
+		for i := 0; i < len(points); i++ {
+			if points[i].IsValid() {
+				allNull = false
+				value = first - points[i].Value()
+				break
+			}
+		}
+	}
+	return allNull, value
+}
+
 func NewAlertReducer(cond *monitor.Condition) (Reducer, error) {
 	if len(cond.Operators) == 0 {
 		return newSimpleReducer(cond), nil
diff --git a/pkg/monitor/dbinit/measurements/system.go b/pkg/monitor/dbinit/measurements/system.go
index a685ae176b..b397325c40 100644
--- a/pkg/monitor/dbinit/measurements/system.go
+++ b/pkg/monitor/dbinit/measurements/system.go
@@ -42,5 +42,8 @@ var system = SMeasurement{
 		{
 			"load15_pcore", "Loadavg load15 per cpu core", monitor.METRIC_UNIT_NULL,
 		},
+		{
+			"uptime", "System uptime", monitor.METRIC_UNIT_NULL,
+		},
 	},
 }