diff --git a/core/models/MetricEvent.cpp b/core/models/MetricEvent.cpp
index d1ae8e139d..74af28acbc 100644
--- a/core/models/MetricEvent.cpp
+++ b/core/models/MetricEvent.cpp
@@ -16,6 +16,8 @@
 
 #include "models/MetricEvent.h"
 
+#include <algorithm>
+
 using namespace std;
 
 namespace logtail {
@@ -48,7 +50,7 @@ void MetricEvent::SetNameNoCopy(StringView name) {
 }
 
 StringView MetricEvent::GetTag(StringView key) const {
-    auto it = mTags.mInner.find(key);
+    auto it = std::find_if(mTags.mInner.begin(), mTags.mInner.end(), [&key](const auto& p) { return p.first == key; });
     if (it != mTags.mInner.end()) {
         return it->second;
     }
@@ -56,7 +58,8 @@ StringView MetricEvent::GetTag(StringView key) const {
 }
 
 bool MetricEvent::HasTag(StringView key) const {
-    return mTags.mInner.find(key) != mTags.mInner.end();
+    auto it = std::find_if(mTags.mInner.begin(), mTags.mInner.end(), [&key](const auto& p) { return p.first == key; });
+    return it != mTags.mInner.end();
 }
 
 void MetricEvent::SetTag(StringView key, StringView val) {
diff --git a/core/models/MetricEvent.h b/core/models/MetricEvent.h
index da9c47934d..42f0a52552 100644
--- a/core/models/MetricEvent.h
+++ b/core/models/MetricEvent.h
@@ -16,9 +16,14 @@
 
 #pragma once
 
+#include <cstddef>
+
 #include <map>
 #include <string>
+#include <utility>
+#include <vector>
 
+#include "StringView.h"
 #include "common/memory/SourceBuffer.h"
 #include "models/MetricValue.h"
 #include "models/PipelineEvent.h"
@@ -71,20 +76,25 @@ class MetricEvent : public PipelineEvent {
         mValue = UntypedMultiDoubleValues{multiDoubleValues.mValues, this};
     }
 
-    StringView GetTag(StringView key) const;
-    bool HasTag(StringView key) const;
+    [[nodiscard]] StringView GetTag(StringView key) const;
+    [[nodiscard]] bool HasTag(StringView key) const;
     void SetTag(StringView key, StringView val);
     void SetTag(const std::string& key, const std::string& val);
     void SetTagNoCopy(const StringBuffer& key, const StringBuffer& val);
     void SetTagNoCopy(StringView key, StringView val);
+
     void DelTag(StringView key);
+    void EraseIf(const std::function<bool(std::pair<StringView, StringView>)>& condition) { mTags.EraseIf(condition); }
+    void SortTags() { std::sort(mTags.mInner.begin(), mTags.mInner.end()); };
+
+    std::vector<std::pair<StringView, StringView>>::const_iterator TagsBegin() const { return mTags.mInner.begin(); }
+    std::vector<std::pair<StringView, StringView>>::const_iterator TagsEnd() const { return mTags.mInner.end(); }
 
-    std::map<StringView, StringView>::const_iterator TagsBegin() const { return mTags.mInner.begin(); }
-    std::map<StringView, StringView>::const_iterator TagsEnd() const { return mTags.mInner.end(); }
     size_t TagsSize() const { return mTags.mInner.size(); }
 
     size_t DataSize() const override;
 
+
 #ifdef APSARA_UNIT_TEST_MAIN
     Json::Value ToJson(bool enableEventMeta = false) const override;
     bool FromJson(const Json::Value&) override;
@@ -95,7 +105,7 @@ class MetricEvent : public PipelineEvent {
 
     StringView mName;
     MetricValue mValue;
-    SizedMap mTags;
+    SizedVectorTags mTags;
 };
 
 } // namespace logtail
diff --git a/core/models/SizedContainer.h b/core/models/SizedContainer.h
index 9593f76a9e..20bb858cbc 100644
--- a/core/models/SizedContainer.h
+++ b/core/models/SizedContainer.h
@@ -59,4 +59,51 @@ class SizedMap {
     size_t mAllocatedSize = 0;
 };
 
+class SizedVectorTags {
+public:
+    void Insert(StringView key, StringView val) {
+        auto iter = std::find_if(mInner.begin(), mInner.end(), [key](const auto& item) { return item.first == key; });
+        if (iter != mInner.end()) {
+            mAllocatedSize += val.size() - iter->second.size();
+            iter->second = val;
+        } else {
+            mAllocatedSize += key.size() + val.size();
+            mInner.emplace_back(key, val);
+        }
+    }
+
+    void Erase(StringView key) {
+        auto iter = std::find_if(mInner.begin(), mInner.end(), [key](const auto& item) { return item.first == key; });
+        if (iter != mInner.end()) {
+            mAllocatedSize -= (iter->first.size() + iter->second.size());
+            mInner.erase(iter);
+        }
+    }
+
+    void EraseIf(const std::function<bool(std::pair<StringView, StringView>)>& condition) {
+        size_t index = 0;
+        mAllocatedSize = 0;
+        for (const auto& item : mInner) {
+            if (condition(item)) {
+                continue;
+            }
+            mInner[index++] = item;
+            mAllocatedSize += item.first.size() + item.second.size();
+        }
+        mInner.resize(index);
+    }
+
+    size_t DataSize() const { return sizeof(decltype(mInner)) + mAllocatedSize; }
+
+    void Clear() {
+        mInner.clear();
+        mAllocatedSize = 0;
+    }
+
+    std::vector<std::pair<StringView, StringView>> mInner;
+
+private:
+    size_t mAllocatedSize = 0;
+};
+
 } // namespace logtail
diff --git a/core/pipeline/serializer/SLSSerializer.cpp b/core/pipeline/serializer/SLSSerializer.cpp
index 504a1a2b77..7f3e30ccaf 100644
--- a/core/pipeline/serializer/SLSSerializer.cpp
+++ b/core/pipeline/serializer/SLSSerializer.cpp
@@ -235,12 +235,13 @@ bool SLSEventGroupSerializer::Serialize(BatchedEvents&& group, string& res, stri
             break;
         case PipelineEvent::Type::METRIC:
             for (size_t i = 0; i < group.mEvents.size(); ++i) {
-                const auto& e = group.mEvents[i].Cast<MetricEvent>();
+                auto& e = group.mEvents[i].Cast<MetricEvent>();
                 if (e.Is<std::monostate>()) {
                     continue;
                 }
                 serializer.StartToAddLog(logSZ[i]);
                 serializer.AddLogTime(e.GetTimestamp());
+                e.SortTags();
                 serializer.AddLogContentMetricLabel(e, metricEventContentCache[i].second);
                 serializer.AddLogContentMetricTimeNano(e);
                 serializer.AddLogContent(METRIC_RESERVED_KEY_VALUE, metricEventContentCache[i].first);
diff --git a/core/plugin/processor/inner/ProcessorPromRelabelMetricNative.cpp b/core/plugin/processor/inner/ProcessorPromRelabelMetricNative.cpp
index b93fb801e5..1cb8206c98 100644
--- a/core/plugin/processor/inner/ProcessorPromRelabelMetricNative.cpp
+++ b/core/plugin/processor/inner/ProcessorPromRelabelMetricNative.cpp
@@ -19,7 +19,7 @@
 
 #include "json/json.h"
 
-#include "common/Flags.h"
+#include "StringView.h"
 #include "common/StringTools.h"
 #include "models/MetricEvent.h"
 #include "models/PipelineEventGroup.h"
@@ -28,8 +28,6 @@
 
 using namespace std;
 
-DECLARE_FLAG_STRING(_pod_name_);
-
 namespace logtail {
 
 const string ProcessorPromRelabelMetricNative::sName = "processor_prom_relabel_metric_native";
@@ -42,21 +40,18 @@ bool ProcessorPromRelabelMetricNative::Init(const Json::Value& config) {
         return false;
     }
 
-    mLoongCollectorScraper = STRING_FLAG(_pod_name_);
-
     return true;
 }
 
 void ProcessorPromRelabelMetricNative::Process(PipelineEventGroup& metricGroup) {
     // if mMetricRelabelConfigs is empty and honor_labels is true, skip it
     auto targetTags = metricGroup.GetTags();
-    auto toDelete = GetToDeleteTargetLabels(targetTags);
 
     if (!mScrapeConfigPtr->mMetricRelabelConfigs.Empty() || !targetTags.empty()) {
         EventsContainer& events = metricGroup.MutableEvents();
         size_t wIdx = 0;
         for (size_t rIdx = 0; rIdx < events.size(); ++rIdx) {
-            if (ProcessEvent(events[rIdx], targetTags, toDelete)) {
+            if (ProcessEvent(events[rIdx], targetTags)) {
                 if (wIdx != rIdx) {
                     events[wIdx] = std::move(events[rIdx]);
                 }
@@ -66,18 +61,12 @@ void ProcessorPromRelabelMetricNative::Process(PipelineEventGroup& metricGroup)
         events.resize(wIdx);
     }
 
-    // delete mTags when key starts with __
-    for (const auto& k : toDelete) {
-        metricGroup.DelTag(k);
-    }
-
     if (metricGroup.HasMetadata(EventGroupMetaKey::PROMETHEUS_STREAM_TOTAL)) {
         auto autoMetric = prom::AutoMetric();
         UpdateAutoMetrics(metricGroup, autoMetric);
         AddAutoMetrics(metricGroup, autoMetric);
     }
 
-
     // delete all tags
     for (const auto& [k, v] : targetTags) {
         metricGroup.DelTag(k);
@@ -88,75 +77,59 @@ bool ProcessorPromRelabelMetricNative::IsSupportedEvent(const PipelineEventPtr&
     return e.Is<MetricEvent>();
 }
 
-bool ProcessorPromRelabelMetricNative::ProcessEvent(PipelineEventPtr& e,
-                                                    const GroupTags& targetTags,
-                                                    const vector<StringView>& toDelete) {
+bool ProcessorPromRelabelMetricNative::ProcessEvent(PipelineEventPtr& e, const GroupTags& targetTags) {
     if (!IsSupportedEvent(e)) {
         return false;
     }
     auto& sourceEvent = e.Cast<MetricEvent>();
 
     for (const auto& [k, v] : targetTags) {
-        if (sourceEvent.HasTag(k)) {
-            if (!mScrapeConfigPtr->mHonorLabels) {
-                // metric event labels is secondary
-                // if confiliction, then rename it exported_<label_name>
-                auto key = prometheus::EXPORTED_PREFIX + k.to_string();
-                auto b = sourceEvent.GetSourceBuffer()->CopyString(key);
-                sourceEvent.SetTagNoCopy(StringView(b.data, b.size), sourceEvent.GetTag(k));
-                sourceEvent.SetTagNoCopy(k, v);
-            }
-        } else {
-            sourceEvent.SetTagNoCopy(k, v);
-        }
+        AppendLabel(k, v, sourceEvent, mScrapeConfigPtr->mHonorLabels);
     }
 
-    vector<string> toDeleteInRelabel;
     if (!mScrapeConfigPtr->mMetricRelabelConfigs.Empty()
-        && !mScrapeConfigPtr->mMetricRelabelConfigs.Process(sourceEvent, toDeleteInRelabel)) {
+        && !mScrapeConfigPtr->mMetricRelabelConfigs.Process(sourceEvent)) {
         return false;
     }
     // set metricEvent name
     sourceEvent.SetNameNoCopy(sourceEvent.GetTag(prometheus::NAME));
 
-    for (const auto& k : toDelete) {
-        sourceEvent.DelTag(k);
-    }
-    for (const auto& k : toDeleteInRelabel) {
-        sourceEvent.DelTag(k);
-    }
+    sourceEvent.EraseIf([](const std::pair<StringView, StringView>& tag) -> bool {
+        if (tag.first.starts_with("__") && tag.first != prometheus::NAME) {
+            return true;
+        }
+        return false;
+    });
 
     for (const auto& [k, v] : mScrapeConfigPtr->mExternalLabels) {
-        if (sourceEvent.HasTag(k)) {
-            if (!mScrapeConfigPtr->mHonorLabels) {
-                // metric event labels is secondary
-                // if confiliction, then rename it exported_<label_name>
-                auto key = prometheus::EXPORTED_PREFIX + k;
-                auto b = sourceEvent.GetSourceBuffer()->CopyString(key);
-                sourceEvent.SetTagNoCopy(StringView(b.data, b.size), sourceEvent.GetTag(k));
-                sourceEvent.SetTagNoCopy(k, v);
-            }
-        } else {
-            sourceEvent.SetTagNoCopy(k, v);
-        }
+        // the lifetime of mExternalLabels is longer than the sourceEvent
+        AppendLabel(k, v, sourceEvent, mScrapeConfigPtr->mHonorLabels);
     }
 
-    // set metricEvent name
-    sourceEvent.SetTagNoCopy(prometheus::NAME, sourceEvent.GetName());
-
     return true;
 }
 
-vector<StringView> ProcessorPromRelabelMetricNative::GetToDeleteTargetLabels(const GroupTags& targetTags) const {
-    // delete tag which starts with __
-    vector<StringView> toDelete;
-    for (const auto& [k, v] : targetTags) {
-        if (k.starts_with("__")) {
-            toDelete.push_back(k);
+void ProcessorPromRelabelMetricNative::AppendLabel(StringView k, StringView v, MetricEvent& e, bool honorLabels) const {
+    auto tagValue = e.GetTag(k);
+    if (!tagValue.empty()) {
+        if (!honorLabels) {
+            // metric event labels is secondary
+            // if confiliction, then rename it exported_<label_name>
+            auto exportedKey = prometheus::EXPORTED_PREFIX + k.to_string();
+            auto exportedTagValue = e.GetTag(exportedKey);
+            if (!exportedTagValue.empty()) {
+                auto exportedExportedKey = prometheus::EXPORTED_PREFIX + exportedKey;
+                auto sb = e.GetSourceBuffer()->CopyString(exportedExportedKey);
+                e.SetTagNoCopy(StringView(sb.data, sb.size), exportedTagValue);
+            }
+            auto sb = e.GetSourceBuffer()->CopyString(exportedKey);
+            e.SetTagNoCopy(StringView(sb.data, sb.size), tagValue);
+            e.SetTagNoCopy(k, v);
         }
+    } else {
+        e.SetTagNoCopy(k, v);
     }
-    return toDelete;
-}
+};
 
 void ProcessorPromRelabelMetricNative::UpdateAutoMetrics(const PipelineEventGroup& eGroup,
                                                          prom::AutoMetric& autoMetric) const {
@@ -247,7 +220,7 @@ void ProcessorPromRelabelMetricNative::AddMetric(PipelineEventGroup& metricGroup
     metricEvent->SetTimestamp(timestamp, nanoSec);
     metricEvent->SetTag(prometheus::NAME, name);
     for (const auto& [k, v] : targetTags) {
-        metricEvent->SetTag(k, v);
+        metricEvent->SetTagNoCopy(k, v);
     }
 }
 
diff --git a/core/plugin/processor/inner/ProcessorPromRelabelMetricNative.h b/core/plugin/processor/inner/ProcessorPromRelabelMetricNative.h
index 1624532e8c..5f52a0f8d1 100644
--- a/core/plugin/processor/inner/ProcessorPromRelabelMetricNative.h
+++ b/core/plugin/processor/inner/ProcessorPromRelabelMetricNative.h
@@ -50,8 +50,7 @@ class ProcessorPromRelabelMetricNative : public Processor {
     bool IsSupportedEvent(const PipelineEventPtr& e) const override;
 
 private:
-    bool ProcessEvent(PipelineEventPtr& e, const GroupTags& targetTags, const std::vector<StringView>& toDelete);
-    std::vector<StringView> GetToDeleteTargetLabels(const GroupTags& targetTags) const;
+    bool ProcessEvent(PipelineEventPtr& e, const GroupTags& targetTags);
 
     void AddAutoMetrics(PipelineEventGroup& eGroup, const prom::AutoMetric& autoMetric) const;
     void UpdateAutoMetrics(const PipelineEventGroup& eGroup, prom::AutoMetric& autoMetric) const;
@@ -61,9 +60,9 @@ class ProcessorPromRelabelMetricNative : public Processor {
                    time_t timestamp,
                    uint32_t nanoSec,
                    const GroupTags& targetTags) const;
+    void AppendLabel(StringView k, StringView v, MetricEvent& e, bool honorLabels) const;
 
     std::unique_ptr<ScrapeConfig> mScrapeConfigPtr;
-    std::string mLoongCollectorScraper;
 
 #ifdef APSARA_UNIT_TEST_MAIN
     friend class ProcessorPromRelabelMetricNativeUnittest;
diff --git a/core/prometheus/labels/Relabel.cpp b/core/prometheus/labels/Relabel.cpp
index 45d5944a29..661072d029 100644
--- a/core/prometheus/labels/Relabel.cpp
+++ b/core/prometheus/labels/Relabel.cpp
@@ -137,14 +137,13 @@ bool RelabelConfig::Init(const Json::Value& config) {
     return true;
 }
 
-bool RelabelConfig::Process(Labels& l, vector<string>& toDelete) const {
+bool RelabelConfig::Process(Labels& l) const {
     vector<string> values;
     values.reserve(mSourceLabels.size());
     for (const auto& item : mSourceLabels) {
         values.push_back(l.Get(item));
     }
     string val = boost::algorithm::join(values, mSeparator);
-    CollectLabelsToDelete(mTargetLabel, toDelete);
     switch (mAction) {
         case Action::DROP: {
             if (boost::regex_match(val, mRegex)) {
@@ -183,7 +182,6 @@ bool RelabelConfig::Process(Labels& l, vector<string>& toDelete) const {
                 break;
             }
             l.Set(target, string(res));
-            CollectLabelsToDelete(target, toDelete);
             break;
         }
         case Action::LOWERCASE: {
@@ -212,7 +210,6 @@ bool RelabelConfig::Process(Labels& l, vector<string>& toDelete) const {
                     string res
                         = boost::regex_replace(key, mRegex, mReplacement, boost::match_default | boost::format_all);
                     l.Set(res, value);
-                    CollectLabelsToDelete(res, toDelete);
                 }
             });
             break;
@@ -255,12 +252,6 @@ bool RelabelConfig::Process(Labels& l, vector<string>& toDelete) const {
     return true;
 }
 
-void RelabelConfig::CollectLabelsToDelete(const string& labelName, vector<string>& toDelete) const {
-    if (StartWith(labelName, "__")) {
-        toDelete.push_back(labelName);
-    }
-}
-
 bool RelabelConfigList::Init(const Json::Value& relabelConfigs) {
     if (!relabelConfigs.isArray()) {
         return false;
@@ -276,19 +267,19 @@ bool RelabelConfigList::Init(const Json::Value& relabelConfigs) {
     return true;
 }
 
-bool RelabelConfigList::Process(Labels& l, vector<string>& toDelete) const {
+bool RelabelConfigList::Process(Labels& l) const {
     for (const auto& cfg : mRelabelConfigs) {
-        if (!cfg.Process(l, toDelete)) {
+        if (!cfg.Process(l)) {
             return false;
         }
     }
     return true;
 }
 
-bool RelabelConfigList::Process(MetricEvent& event, vector<string>& toDelete) const {
+bool RelabelConfigList::Process(MetricEvent& event) const {
     Labels labels;
     labels.Reset(&event);
-    return Process(labels, toDelete);
+    return Process(labels);
 }
 
 bool RelabelConfigList::Empty() const {
diff --git a/core/prometheus/labels/Relabel.h b/core/prometheus/labels/Relabel.h
index edb06e9828..b712904937 100644
--- a/core/prometheus/labels/Relabel.h
+++ b/core/prometheus/labels/Relabel.h
@@ -47,7 +47,7 @@ class RelabelConfig {
 public:
     RelabelConfig();
     bool Init(const Json::Value&);
-    bool Process(Labels&, std::vector<std::string>& toDelete) const;
+    bool Process(Labels&) const;
 
     // A list of labels from which values are taken and concatenated
     // with the configured separator in order.
@@ -69,14 +69,13 @@ class RelabelConfig {
     std::set<std::string> mMatchList;
 
 private:
-    void CollectLabelsToDelete(const std::string& labelName, std::vector<std::string>& toDelete) const;
 };
 
 class RelabelConfigList {
 public:
     bool Init(const Json::Value& relabelConfigs);
-    bool Process(MetricEvent&, std::vector<std::string>& toDelete) const;
-    bool Process(Labels&, std::vector<std::string>& toDelete) const;
+    bool Process(MetricEvent&) const;
+    bool Process(Labels&) const;
 
     [[nodiscard]] bool Empty() const;
 
@@ -84,7 +83,7 @@ class RelabelConfigList {
     std::vector<RelabelConfig> mRelabelConfigs;
 
 #ifdef APSARA_UNIT_TEST_MAIN
-    friend class RelabelConfigListTest;
+    friend class RelabelConfigUnittest;
     friend class InputPrometheusUnittest;
     friend class ScrapeConfigUnittest;
 #endif
diff --git a/core/prometheus/schedulers/ScrapeConfig.cpp b/core/prometheus/schedulers/ScrapeConfig.cpp
index 33d8a06942..4497db1f95 100644
--- a/core/prometheus/schedulers/ScrapeConfig.cpp
+++ b/core/prometheus/schedulers/ScrapeConfig.cpp
@@ -409,14 +409,23 @@ bool ScrapeConfig::InitExternalLabels(const Json::Value& externalLabels) {
         LOG_ERROR(sLogger, ("external_labels config error", ""));
         return false;
     }
+    set<string> dups;
     for (auto& key : externalLabels.getMemberNames()) {
         if (externalLabels[key].isString()) {
+            if (dups.count(key)) {
+                LOG_ERROR(sLogger, ("duplicated key in external_labels", key));
+                return false;
+            }
+            dups.insert(key);
             mExternalLabels.emplace_back(key, externalLabels[key].asString());
         } else {
             LOG_ERROR(sLogger, ("external_labels config error", ""));
             return false;
         }
     }
+    std::sort(mExternalLabels.begin(), mExternalLabels.end(), [](const auto& lhs, const auto& rhs) {
+        return lhs.first < rhs.first;
+    });
     return true;
 }
 
diff --git a/core/prometheus/schedulers/TargetSubscriberScheduler.cpp b/core/prometheus/schedulers/TargetSubscriberScheduler.cpp
index f3f7647adc..fb308d2ea0 100644
--- a/core/prometheus/schedulers/TargetSubscriberScheduler.cpp
+++ b/core/prometheus/schedulers/TargetSubscriberScheduler.cpp
@@ -195,8 +195,7 @@ TargetSubscriberScheduler::BuildScrapeSchedulerSet(std::vector<Labels>& targetGr
     for (const auto& labels : targetGroups) {
         // Relabel Config
         Labels resultLabel = labels;
-        vector<string> toDelete;
-        if (!mScrapeConfigPtr->mRelabelConfigs.Process(resultLabel, toDelete)) {
+        if (!mScrapeConfigPtr->mRelabelConfigs.Process(resultLabel)) {
             continue;
         }
         resultLabel.RemoveMetaLabels();
diff --git a/core/unittest/processor/ProcessorPromRelabelMetricNativeUnittest.cpp b/core/unittest/processor/ProcessorPromRelabelMetricNativeUnittest.cpp
index 06a0668aa8..5730ccf3a4 100644
--- a/core/unittest/processor/ProcessorPromRelabelMetricNativeUnittest.cpp
+++ b/core/unittest/processor/ProcessorPromRelabelMetricNativeUnittest.cpp
@@ -278,16 +278,15 @@ test_metric8{k1="v1", k3="v2", } 9.9410452992e+10 1715829785083
     eventGroup.SetTag(string("k3"), string("v3"));
     APSARA_TEST_EQUAL((size_t)8, eventGroup.GetEvents().size());
     auto targetTags = eventGroup.GetTags();
-    auto toDelete = processor.GetToDeleteTargetLabels(targetTags);
     // honor_labels is true
-    processor.ProcessEvent(eventGroup.MutableEvents()[0], targetTags, toDelete);
+    processor.ProcessEvent(eventGroup.MutableEvents()[0], targetTags);
     APSARA_TEST_EQUAL("v3", eventGroup.GetEvents().at(0).Cast<MetricEvent>().GetTag(string("k3")));
-    processor.ProcessEvent(eventGroup.MutableEvents()[6], targetTags, toDelete);
+    processor.ProcessEvent(eventGroup.MutableEvents()[6], targetTags);
     APSARA_TEST_EQUAL("2", eventGroup.GetEvents().at(6).Cast<MetricEvent>().GetTag(string("k3")).to_string());
 
     // honor_labels is false
     processor.mScrapeConfigPtr->mHonorLabels = false;
-    processor.ProcessEvent(eventGroup.MutableEvents()[7], targetTags, toDelete);
+    processor.ProcessEvent(eventGroup.MutableEvents()[7], targetTags);
     APSARA_TEST_EQUAL("v3", eventGroup.GetEvents().at(7).Cast<MetricEvent>().GetTag(string("k3")).to_string());
     APSARA_TEST_EQUAL("v2", eventGroup.GetEvents().at(7).Cast<MetricEvent>().GetTag(string("exported_k3")).to_string());
 }
diff --git a/core/unittest/prometheus/RelabelUnittest.cpp b/core/unittest/prometheus/RelabelUnittest.cpp
index f6fdd2edfc..aa7c37cd0b 100644
--- a/core/unittest/prometheus/RelabelUnittest.cpp
+++ b/core/unittest/prometheus/RelabelUnittest.cpp
@@ -14,10 +14,10 @@
  * limitations under the License.
  */
 
-#include <string>
+#include <json/json.h>
 
-#include "boost/regex.hpp"
-#include "json/json.h"
+#include <boost/regex.hpp>
+#include <string>
 
 #include "common/JsonUtil.h"
 #include "prometheus/labels/Relabel.h"
@@ -137,8 +137,7 @@ void RelabelConfigUnittest::TestReplace() {
     APSARA_TEST_TRUE(configList.Init(configJson));
 
     Labels result = labels;
-    vector<string> toDelete;
-    configList.Process(result, toDelete);
+    configList.Process(result);
 
     APSARA_TEST_EQUAL((size_t)3, result.Size());
     APSARA_TEST_EQUAL("172.17.0.3:9100", result.Get("__address__"));
@@ -168,8 +167,7 @@ void RelabelConfigUnittest::TestKeep() {
     configList = RelabelConfigList();
     APSARA_TEST_TRUE(configList.Init(configJson));
     auto result = labels;
-    vector<string> toDelete;
-    configList.Process(result, toDelete);
+    configList.Process(result);
     APSARA_TEST_EQUAL((size_t)2, result.Size());
     APSARA_TEST_EQUAL("172.17.0.3", result.Get("__meta_kubernetes_pod_ip"));
 }
@@ -197,8 +195,7 @@ void RelabelConfigUnittest::TestDrop() {
     configList = RelabelConfigList();
     APSARA_TEST_TRUE(configList.Init(configJson));
     auto result = labels;
-    vector<string> toDelete;
-    APSARA_TEST_FALSE(configList.Process(result, toDelete));
+    APSARA_TEST_FALSE(configList.Process(result));
 }
 
 void RelabelConfigUnittest::TestDropMetric() {
@@ -222,8 +219,8 @@ void RelabelConfigUnittest::TestDropMetric() {
     configList = RelabelConfigList();
     APSARA_TEST_TRUE(configList.Init(configJson));
     auto result = labels;
-    vector<string> toDelete;
-    APSARA_TEST_FALSE(configList.Process(result, toDelete));
+
+    APSARA_TEST_FALSE(configList.Process(result));
 }
 
 void RelabelConfigUnittest::TestDropEqual() {
@@ -251,8 +248,8 @@ void RelabelConfigUnittest::TestDropEqual() {
     configList = RelabelConfigList();
     APSARA_TEST_TRUE(configList.Init(configJson));
     auto result = dropEqualLabels;
-    vector<string> toDelete;
-    APSARA_TEST_FALSE(configList.Process(result, toDelete));
+
+    APSARA_TEST_FALSE(configList.Process(result));
 }
 
 void RelabelConfigUnittest::TestKeepEqual() {
@@ -280,8 +277,8 @@ void RelabelConfigUnittest::TestKeepEqual() {
     configList = RelabelConfigList();
     APSARA_TEST_TRUE(configList.Init(configJson));
     auto result = keepEqualLabels;
-    vector<string> toDelete;
-    configList.Process(result, toDelete);
+
+    configList.Process(result);
     APSARA_TEST_EQUAL((size_t)3, result.Size());
     APSARA_TEST_EQUAL("172.17.0.3", result.Get("__meta_kubernetes_pod_ip"));
 }
@@ -311,8 +308,8 @@ void RelabelConfigUnittest::TestLowerCase() {
     configList = RelabelConfigList();
     APSARA_TEST_TRUE(configList.Init(configJson));
     auto result = lowercaseLabels;
-    vector<string> toDelete;
-    configList.Process(result, toDelete);
+
+    configList.Process(result);
     APSARA_TEST_EQUAL((size_t)3, result.Size());
     APSARA_TEST_EQUAL("node-exporter", result.Get("__meta_kubernetes_pod_label_app"));
 }
@@ -342,8 +339,8 @@ void RelabelConfigUnittest::TestUpperCase() {
     configList = RelabelConfigList();
     APSARA_TEST_TRUE(configList.Init(configJson));
     auto result = uppercaseLabels;
-    vector<string> toDelete;
-    configList.Process(result, toDelete);
+
+    configList.Process(result);
     APSARA_TEST_EQUAL((size_t)3, result.Size());
     APSARA_TEST_EQUAL("NODE-EXPORTER", result.Get("__meta_kubernetes_pod_label_app"));
 }
@@ -375,8 +372,8 @@ void RelabelConfigUnittest::TestHashMod() {
     configList = RelabelConfigList();
     APSARA_TEST_TRUE(configList.Init(configJson));
     auto result = hashmodLabels;
-    vector<string> toDelete;
-    configList.Process(result, toDelete);
+
+    configList.Process(result);
     APSARA_TEST_EQUAL((size_t)4, result.Size());
     APSARA_TEST_TRUE(!result.Get("hash_val").empty());
 }
@@ -401,8 +398,8 @@ void RelabelConfigUnittest::TestLabelMap() {
     configList = RelabelConfigList();
     APSARA_TEST_TRUE(configList.Init(configJson));
     auto result = labels;
-    vector<string> toDelete;
-    configList.Process(result, toDelete);
+
+    configList.Process(result);
     APSARA_TEST_EQUAL((size_t)3, result.Size());
     APSARA_TEST_EQUAL("node-exporter", result.Get("k8s_app"));
 }
@@ -429,8 +426,8 @@ void RelabelConfigUnittest::TestLabelDrop() {
     configList = RelabelConfigList();
     APSARA_TEST_TRUE(configList.Init(configJson));
     auto result = labelDropLabels;
-    vector<string> toDelete;
-    configList.Process(result, toDelete);
+
+    configList.Process(result);
     APSARA_TEST_EQUAL((size_t)1, result.Size());
     APSARA_TEST_EQUAL("172.17.0.3", result.Get("pod_ip"));
 }
@@ -457,8 +454,8 @@ void RelabelConfigUnittest::TestLabelKeep() {
     configList = RelabelConfigList();
     APSARA_TEST_TRUE(configList.Init(configJson));
     auto result = labelKeepLabels;
-    vector<string> toDelete;
-    configList.Process(result, toDelete);
+
+    configList.Process(result);
     APSARA_TEST_EQUAL((size_t)2, result.Size());
     APSARA_TEST_EQUAL("172.17.0.3", result.Get("__meta_kubernetes_pod_ip"));
     APSARA_TEST_EQUAL("node-exporter", result.Get("__meta_kubernetes_pod_label_app"));
@@ -503,8 +500,8 @@ void RelabelConfigUnittest::TestMultiRelabel() {
     configList = RelabelConfigList();
     APSARA_TEST_TRUE(configList.Init(configJson));
     auto result = labels;
-    vector<string> toDelete;
-    APSARA_TEST_TRUE(configList.Process(result, toDelete));
+
+    APSARA_TEST_TRUE(configList.Process(result));
     APSARA_TEST_EQUAL((size_t)3, result.Size());
     APSARA_TEST_EQUAL("172.17.0.3:9100", result.Get("__address__"));
 
@@ -512,7 +509,7 @@ void RelabelConfigUnittest::TestMultiRelabel() {
     configList = RelabelConfigList();
     APSARA_TEST_TRUE(configList.Init(configJson));
     result = labels;
-    APSARA_TEST_TRUE(configList.Process(result, toDelete));
+    APSARA_TEST_TRUE(configList.Process(result));
 }
 
 UNIT_TEST_CASE(ActionConverterUnittest, TestStringToAction)
diff --git a/core/unittest/prometheus/ScrapeConfigUnittest.cpp b/core/unittest/prometheus/ScrapeConfigUnittest.cpp
index 7efa40f17c..5336b685d9 100644
--- a/core/unittest/prometheus/ScrapeConfigUnittest.cpp
+++ b/core/unittest/prometheus/ScrapeConfigUnittest.cpp
@@ -95,8 +95,8 @@ void ScrapeConfigUnittest::TestInit() {
                 }
             ],
             "external_labels": {
-                "test_key1": "test_value1",
-                "test_key2": "test_value2"
+                "test_key2": "test_value2",
+                "test_key1": "test_value1"
             },
             "params" : {
                 "__param_query": [