From 4d59c483a45f14dc2e015faf4f5aa797005baa42 Mon Sep 17 00:00:00 2001
From: yeya24 <yb532204897@gmail.com>
Date: Tue, 9 Mar 2021 08:38:00 -0500
Subject: [PATCH] check label existence

Signed-off-by: yeya24 <yb532204897@gmail.com>
---
 pkg/compactv2/compactor_test.go | 10 ++++------
 pkg/compactv2/modifiers.go      | 19 ++++++++++++++++---
 2 files changed, 20 insertions(+), 9 deletions(-)

diff --git a/pkg/compactv2/compactor_test.go b/pkg/compactv2/compactor_test.go
index e5c979a0539..46594c434c0 100644
--- a/pkg/compactv2/compactor_test.go
+++ b/pkg/compactv2/compactor_test.go
@@ -377,8 +377,6 @@ func TestCompactor_WriteSeries_e2e(t *testing.T) {
 					},
 				})},
 			expected: []seriesSamples{
-				{lset: labels.Labels{{Name: "a", Value: ""}, {Name: "foo", Value: "bat"}},
-					chunks: [][]sample{{{0, 0}, {1, 1}, {2, 2}}, {{10, 11}, {11, 11}, {20, 20}}}},
 				{lset: labels.Labels{{Name: "a", Value: "1"}},
 					chunks: [][]sample{{{0, 0}, {1, 1}, {2, 2}}, {{10, 11}, {11, 11}, {20, 20}}}},
 				{lset: labels.Labels{{Name: "a", Value: "2"}},
@@ -390,11 +388,11 @@ func TestCompactor_WriteSeries_e2e(t *testing.T) {
 				{lset: labels.Labels{{Name: "foo", Value: "bat"}},
 					chunks: [][]sample{{{0, 0}, {1, 1}, {2, 2}}, {{10, 11}, {11, 11}, {20, 20}}}},
 			},
-			expectedChanges: "Deleted {a=\"2\", foo=\"bar\"} [{0 20}]\nDeleted {a=\"3\", foo=\"baz\"} [{0 20}]\n",
+			expectedChanges: "Deleted {a=\"\", foo=\"bat\"} [{0 20}]\nDeleted {a=\"2\", foo=\"bar\"} [{0 20}]\nDeleted {a=\"3\", foo=\"baz\"} [{0 20}]\n",
 			expectedStats: tsdb.BlockStats{
-				NumSamples: 36,
-				NumSeries:  6,
-				NumChunks:  12,
+				NumSamples: 30,
+				NumSeries:  5,
+				NumChunks:  10,
 			},
 		},
 	} {
diff --git a/pkg/compactv2/modifiers.go b/pkg/compactv2/modifiers.go
index aef4ec065ea..43edaea9320 100644
--- a/pkg/compactv2/modifiers.go
+++ b/pkg/compactv2/modifiers.go
@@ -5,6 +5,7 @@ package compactv2
 
 import (
 	"github.com/pkg/errors"
+	"github.com/prometheus/prometheus/pkg/labels"
 	"github.com/prometheus/prometheus/storage"
 	"github.com/prometheus/prometheus/tsdb"
 	"github.com/prometheus/prometheus/tsdb/chunkenc"
@@ -61,10 +62,11 @@ SeriesLoop:
 	DeletionsLoop:
 		for _, deletions := range d.d.deletions {
 			for _, m := range deletions.Matchers {
-				v := lbls.Get(m.Name)
+				v, exist := getLabelValue(lbls, m.Name)
 
-				// Only if all matchers in the deletion request are matched can we proceed to deletion.
-				if v == "" || !m.Matches(v) {
+				// We skip when the label doesn't exist or not all
+				// matchers in the deletion request are matched can we proceed to deletion.
+				if !exist || !m.Matches(v) {
 					continue DeletionsLoop
 				}
 			}
@@ -107,6 +109,17 @@ SeriesLoop:
 	return false
 }
 
+// getLabelValue get the label value by the given label name and returns
+// the label existence by returning a bool.
+func getLabelValue(ls labels.Labels, name string) (string, bool) {
+	for _, l := range ls {
+		if l.Name == name {
+			return l.Value, true
+		}
+	}
+	return "", false
+}
+
 // intersection returns intersection between interval and range of intervals.
 func intersection(i tombstones.Interval, dranges tombstones.Intervals) tombstones.Intervals {
 	var ret tombstones.Intervals