diff --git a/core/common/TimeUtil.cpp b/core/common/TimeUtil.cpp
index cc2dc4bf24..10754cf742 100644
--- a/core/common/TimeUtil.cpp
+++ b/core/common/TimeUtil.cpp
@@ -302,10 +302,11 @@ void SetLogTime(sls_logs::Log* log, time_t second) {
     log->set_time(second);
 }
 
-void SetLogTimeWithNano(sls_logs::Log* log, time_t second, long nanosecond) {
-    // Usage: set nanosecond first, and then discard at LogProcess@ProcessBufferLegacy
+void SetLogTimeWithNano(sls_logs::Log* log, time_t second, std::optional<uint32_t> nanosecond) {
     log->set_time(second);
-    log->set_time_ns(nanosecond);
+    if (nanosecond) {
+        log->set_time_ns(nanosecond.value());
+    }
 }
 
 LogtailTime GetCurrentLogtailTime() {
diff --git a/core/common/TimeUtil.h b/core/common/TimeUtil.h
index 59a6f3ccfc..24fcb81d2c 100644
--- a/core/common/TimeUtil.h
+++ b/core/common/TimeUtil.h
@@ -16,6 +16,7 @@
 
 #pragma once
 #include <ctime>
+#include <optional>
 #include <string>
 #include <thread>
 
@@ -83,7 +84,7 @@ uint64_t GetPreciseTimestampFromLogtailTime(LogtailTime logTime, const PreciseTi
 
 void SetLogTime(sls_logs::Log* log, time_t second);
 
-void SetLogTimeWithNano(sls_logs::Log* log, time_t second, long nanosecond);
+void SetLogTimeWithNano(sls_logs::Log* log, time_t second, std::optional<uint32_t> nanosecond);
 
 LogtailTime GetCurrentLogtailTime();
 
diff --git a/core/models/LogEvent.cpp b/core/models/LogEvent.cpp
index dc10b34be1..e9b3106bd2 100644
--- a/core/models/LogEvent.cpp
+++ b/core/models/LogEvent.cpp
@@ -131,7 +131,9 @@ Json::Value LogEvent::ToJson() const {
     Json::Value root;
     root["type"] = static_cast<int>(GetType());
     root["timestamp"] = GetTimestamp();
-    root["timestampNanosecond"] = GetTimestampNanosecond();
+    if (GetTimestampNanosecond()) {
+        root["timestampNanosecond"] = static_cast<int32_t>(GetTimestampNanosecond().value());
+    }
     if (!Empty()) {
         Json::Value contents;
         for (const auto& content : *this) {
diff --git a/core/models/MetricEvent.cpp b/core/models/MetricEvent.cpp
index 402882688b..35160b525b 100644
--- a/core/models/MetricEvent.cpp
+++ b/core/models/MetricEvent.cpp
@@ -31,7 +31,9 @@ Json::Value MetricEvent::ToJson() const {
     Json::Value root;
     root["type"] = static_cast<int>(GetType());
     root["timestamp"] = GetTimestamp();
-    root["timestampNanosecond"] = GetTimestampNanosecond();
+    if (GetTimestampNanosecond()) {
+        root["timestampNanosecond"] = static_cast<int32_t>(GetTimestampNanosecond().value());
+    }
     return root;
 }
 
diff --git a/core/models/PipelineEvent.h b/core/models/PipelineEvent.h
index 255ae1357a..044b58fd28 100644
--- a/core/models/PipelineEvent.h
+++ b/core/models/PipelineEvent.h
@@ -22,6 +22,7 @@
 #include <ctime>
 #include <map>
 #include <memory>
+#include <optional>
 #include <string>
 
 #include "models/StringView.h"
@@ -38,12 +39,16 @@ class PipelineEvent {
     virtual ~PipelineEvent() = default;
 
     Type GetType() const { return mType; }
-    time_t GetTimestamp() const { return timestamp; }
-    long GetTimestampNanosecond() const { return timestampNanosecond; }
-    void SetTimestamp(time_t t) { timestamp = t; }
-    void SetTimestamp(time_t t, long ns) {
-        timestamp = t;
-        timestampNanosecond = ns; // Only nanosecond part
+    time_t GetTimestamp() const { return mTimestamp; }
+    std::optional<uint32_t> GetTimestampNanosecond() const { return mTimestampNanosecond; }
+    void SetTimestamp(time_t t) { mTimestamp = t; }
+    void SetTimestamp(time_t t, uint32_t ns) {
+        mTimestamp = t;
+        mTimestampNanosecond = ns; // Only nanosecond part
+    }
+    void SetTimestamp(time_t t, std::optional<uint32_t> ns) {
+        mTimestamp = t;
+        mTimestampNanosecond = ns; // Only nanosecond part
     }
     void ResetPipelineEventGroup(PipelineEventGroup* ptr) { mPipelineEventGroupPtr = ptr; }
     std::shared_ptr<SourceBuffer>& GetSourceBuffer();
@@ -61,8 +66,8 @@ class PipelineEvent {
     PipelineEvent(Type type, PipelineEventGroup* ptr);
 
     Type mType = Type::NONE;
-    time_t timestamp = 0;
-    long timestampNanosecond = 0;
+    time_t mTimestamp = 0;
+    std::optional<uint32_t> mTimestampNanosecond;
     PipelineEventGroup* mPipelineEventGroupPtr = nullptr;
 };
 
diff --git a/core/models/SpanEvent.cpp b/core/models/SpanEvent.cpp
index 108a181b50..ed72e692e1 100644
--- a/core/models/SpanEvent.cpp
+++ b/core/models/SpanEvent.cpp
@@ -31,7 +31,9 @@ Json::Value SpanEvent::ToJson() const {
     Json::Value root;
     root["type"] = static_cast<int>(GetType());
     root["timestamp"] = GetTimestamp();
-    root["timestampNanosecond"] = GetTimestampNanosecond();
+    if (GetTimestampNanosecond()) {
+        root["timestampNanosecond"] = static_cast<int32_t>(GetTimestampNanosecond().value());
+    }
     return root;
 }
 
diff --git a/core/spl/PipelineEventGroupInput.cpp b/core/spl/PipelineEventGroupInput.cpp
index 334e0fe2fd..fce5248ee5 100644
--- a/core/spl/PipelineEventGroupInput.cpp
+++ b/core/spl/PipelineEventGroupInput.cpp
@@ -56,7 +56,7 @@ void PipelineEventGroupInput::getTimeColumns(std::vector<uint32_t>& times,
     for (const auto &event : mLogGroup->GetEvents()) {
         const LogEvent& sourceEvent = event.Cast<LogEvent>();
         times.emplace_back(sourceEvent.GetTimestamp());
-        timeNanos.emplace_back(sourceEvent.GetTimestampNanosecond());
+        timeNanos.emplace_back(sourceEvent.GetTimestampNanosecond() ? sourceEvent.GetTimestampNanosecond().value() : 0);
     }
 }
 
diff --git a/core/unittest/processor/ProcessorParseApsaraNativeUnittest.cpp b/core/unittest/processor/ProcessorParseApsaraNativeUnittest.cpp
index b0f83ab094..b0905cb195 100644
--- a/core/unittest/processor/ProcessorParseApsaraNativeUnittest.cpp
+++ b/core/unittest/processor/ProcessorParseApsaraNativeUnittest.cpp
@@ -492,7 +492,6 @@ void ProcessorParseApsaraNativeUnittest::TestMultipleLines() {
                     "__raw__": "[2023-09-04 13:15"
                 },
                 "timestamp": 12345678901,
-                "timestampNanosecond": 0,
                 "type": 1
             },
             {
@@ -500,7 +499,6 @@ void ProcessorParseApsaraNativeUnittest::TestMultipleLines() {
                     "__raw__": ":50.1]\t[ERROR]\t[1]\t/ilogtail/AppConfigBase.cpp:1\t\tAppConfigBase AppConfigBase:1"
                 },
                 "timestamp": 12345678901,
-                "timestampNanosecond": 0,
                 "type": 1
             },
             {
@@ -864,7 +862,6 @@ void ProcessorParseApsaraNativeUnittest::TestProcessKeyOverwritten() {
                     "rawLog": "value1"
                 },
                 "timestamp": 12345678901,
-                "timestampNanosecond": 0,
                 "type": 1
             }
         ]
@@ -940,7 +937,6 @@ void ProcessorParseApsaraNativeUnittest::TestUploadRawLog() {
                     "rawLog": "value1"
                 },
                 "timestamp": 12345678901,
-                "timestampNanosecond": 0,
                 "type": 1
             }
         ]
@@ -1051,7 +1047,6 @@ void ProcessorParseApsaraNativeUnittest::TestProcessEventKeepUnmatch() {
                     "rawLog" : "value1"
                 },
                 "timestamp" : 12345678901,
-                "timestampNanosecond": 0,
                 "type" : 1
             },
             {
@@ -1060,7 +1055,6 @@ void ProcessorParseApsaraNativeUnittest::TestProcessEventKeepUnmatch() {
                     "rawLog" : "value1"
                 },
                 "timestamp" : 12345678901,
-                "timestampNanosecond": 0,
                 "type" : 1
             },
             {
@@ -1069,7 +1063,6 @@ void ProcessorParseApsaraNativeUnittest::TestProcessEventKeepUnmatch() {
                     "rawLog" : "value1"
                 },
                 "timestamp" : 12345678901,
-                "timestampNanosecond": 0,
                 "type" : 1
             },
             {
@@ -1078,7 +1071,6 @@ void ProcessorParseApsaraNativeUnittest::TestProcessEventKeepUnmatch() {
                     "rawLog" : "value1"
                 },
                 "timestamp" : 12345678901,
-                "timestampNanosecond": 0,
                 "type" : 1
             },
             {
@@ -1087,7 +1079,6 @@ void ProcessorParseApsaraNativeUnittest::TestProcessEventKeepUnmatch() {
                     "rawLog" : "value1"
                 },
                 "timestamp" : 12345678901,
-                "timestampNanosecond": 0,
                 "type" : 1
             }
         ]
@@ -1293,7 +1284,6 @@ void ProcessorParseApsaraNativeUnittest::TestProcessEventMicrosecondUnmatch() {
                     "rawLog": "[2023-09-04 13:18:04"
                 },
                 "timestamp": 12345678901,
-                "timestampNanosecond": 0,
                 "type": 1
             }
         ]
diff --git a/core/unittest/processor/ProcessorParseDelimiterNativeUnittest.cpp b/core/unittest/processor/ProcessorParseDelimiterNativeUnittest.cpp
index 10463509aa..8f6bfbee5d 100644
--- a/core/unittest/processor/ProcessorParseDelimiterNativeUnittest.cpp
+++ b/core/unittest/processor/ProcessorParseDelimiterNativeUnittest.cpp
@@ -86,6 +86,7 @@ void ProcessorParseDelimiterNativeUnittest::TestAllowingShortenedFields() {
                     "content" : "2013-10-31 21:03:49,POST,'PutData?Category=YunOsAccountOpLog',0.024"
                 },
                 "timestamp" : 12345678901,
+                "timestampNanosecond": 0,
                 "type" : 1
             },
             {
@@ -94,6 +95,7 @@ void ProcessorParseDelimiterNativeUnittest::TestAllowingShortenedFields() {
                     "content" : "value1"
                 },
                 "timestamp" : 12345678901,
+                "timestampNanosecond": 0,
                 "type" : 1
             }
         ]
@@ -146,6 +148,7 @@ void ProcessorParseDelimiterNativeUnittest::TestAllowingShortenedFields() {
                     "__file_offset__": 0
                 },
                 "timestamp" : 12345678901,
+                "timestampNanosecond": 0,
                 "type" : 1
             }
         ]
@@ -270,6 +273,7 @@ void ProcessorParseDelimiterNativeUnittest::TestAllowingShortenedFields() {
                     "__file_offset__": 0
                 },
                 "timestamp" : 12345678901,
+                "timestampNanosecond": 0,
                 "type" : 1
             }
         ]
@@ -417,6 +421,7 @@ void ProcessorParseDelimiterNativeUnittest::TestExtend() {
                     "__file_offset__": 0
                 },
                 "timestamp" : 12345678901,
+                "timestampNanosecond": 0,
                 "type" : 1
             }
         ]
@@ -545,6 +550,7 @@ void ProcessorParseDelimiterNativeUnittest::TestExtend() {
                     "__file_offset__": 0
                 },
                 "timestamp" : 12345678901,
+                "timestampNanosecond": 0,
                 "type" : 1
             }
         ]
@@ -676,6 +682,7 @@ void ProcessorParseDelimiterNativeUnittest::TestMultipleLines() {
                     "__file_offset__": 0
                 },
                 "timestamp" : 12345678901,
+                "timestampNanosecond": 0,
                 "type" : 1
             }
         ]
@@ -800,6 +807,7 @@ void ProcessorParseDelimiterNativeUnittest::TestMultipleLines() {
                     "__file_offset__": 0
                 },
                 "timestamp" : 12345678901,
+                "timestampNanosecond": 0,
                 "type" : 1
             }
         ]
@@ -923,6 +931,7 @@ void ProcessorParseDelimiterNativeUnittest::TestMultipleLines() {
                     "__file_offset__": 0
                 },
                 "timestamp" : 12345678901,
+                "timestampNanosecond": 0,
                 "type" : 1
             }
         ]
@@ -1065,6 +1074,7 @@ void ProcessorParseDelimiterNativeUnittest::TestProcessWholeLine() {
                     "content" : "2013-10-31 21:03:49,POST,PutData?Category=YunOsAccountOpLog,0.024"
                 },
                 "timestamp" : 12345678901,
+                "timestampNanosecond": 0,
                 "type" : 1
             },
             {
@@ -1073,6 +1083,7 @@ void ProcessorParseDelimiterNativeUnittest::TestProcessWholeLine() {
                     "content" : "2013-10-31 21:04:49,POST,PutData?Category=YunOsAccountOpLog,0.024"
                 },
                 "timestamp" : 12345678901,
+                "timestampNanosecond": 0,
                 "type" : 1
             }
         ]
@@ -1133,6 +1144,7 @@ void ProcessorParseDelimiterNativeUnittest::TestProcessQuote() {
                     "__file_offset__": 0
                 },
                 "timestamp" : 12345678901,
+                "timestampNanosecond": 0,
                 "type" : 1
             }
         ]
@@ -1285,6 +1297,7 @@ void ProcessorParseDelimiterNativeUnittest::TestProcessQuote() {
                         "content" : "2013-10-31 21:03:49,POST,'PutData?Category=YunOsAccountOpLog',0.024"
                     },
                     "timestamp" : 12345678901,
+                    "timestampNanosecond": 0,
                     "type" : 1
                 },
                 {
@@ -1293,6 +1306,7 @@ void ProcessorParseDelimiterNativeUnittest::TestProcessQuote() {
                         "content" : "2013-10-31 21:03:49,POST,'PutData?Category=YunOsAccountOpLog,0.024"
                     },
                     "timestamp" : 12345678901,
+                    "timestampNanosecond": 0,
                     "type" : 1
                 },
                 {
@@ -1301,6 +1315,7 @@ void ProcessorParseDelimiterNativeUnittest::TestProcessQuote() {
                         "content" : "2013-10-31 21:03:49,POST,'PutData?Category=YunOs'AccountOpLog',0.024"
                     },
                     "timestamp" : 12345678901,
+                    "timestampNanosecond": 0,
                     "type" : 1
                 }
             ]
@@ -1381,6 +1396,7 @@ void ProcessorParseDelimiterNativeUnittest::TestProcessKeyOverwritten() {
                     "content" : "2013-10-31 21:03:49,POST,'PutData?Category=YunOsAccountOpLog',0.024"
                 },
                 "timestamp" : 12345678901,
+                "timestampNanosecond": 0,
                 "type" : 1
             },
             {
@@ -1389,6 +1405,7 @@ void ProcessorParseDelimiterNativeUnittest::TestProcessKeyOverwritten() {
                     "content" : "value1"
                 },
                 "timestamp" : 12345678901,
+                "timestampNanosecond": 0,
                 "type" : 1
             }
         ]
@@ -1460,6 +1477,7 @@ void ProcessorParseDelimiterNativeUnittest::TestUploadRawLog() {
                     "content" : "2013-10-31 21:03:49,POST,'PutData?Category=YunOsAccountOpLog',0.024"
                 },
                 "timestamp" : 12345678901,
+                "timestampNanosecond": 0,
                 "type" : 1
             },
             {
@@ -1468,6 +1486,7 @@ void ProcessorParseDelimiterNativeUnittest::TestUploadRawLog() {
                     "content" : "value1"
                 },
                 "timestamp" : 12345678901,
+                "timestampNanosecond": 0,
                 "type" : 1
             }
         ]
@@ -1565,6 +1584,7 @@ void ProcessorParseDelimiterNativeUnittest::TestProcessEventKeepUnmatch() {
                     "content" : "value1"
                 },
                 "timestamp" : 12345678901,
+                "timestampNanosecond": 0,
                 "type" : 1
             },
             {
@@ -1573,6 +1593,7 @@ void ProcessorParseDelimiterNativeUnittest::TestProcessEventKeepUnmatch() {
                     "content" : "value1"
                 },
                 "timestamp" : 12345678901,
+                "timestampNanosecond": 0,
                 "type" : 1
             },
             {
@@ -1581,6 +1602,7 @@ void ProcessorParseDelimiterNativeUnittest::TestProcessEventKeepUnmatch() {
                     "content" : "value1"
                 },
                 "timestamp" : 12345678901,
+                "timestampNanosecond": 0,
                 "type" : 1
             },
             {
@@ -1589,6 +1611,7 @@ void ProcessorParseDelimiterNativeUnittest::TestProcessEventKeepUnmatch() {
                     "content" : "value1"
                 },
                 "timestamp" : 12345678901,
+                "timestampNanosecond": 0,
                 "type" : 1
             },
             {
@@ -1597,6 +1620,7 @@ void ProcessorParseDelimiterNativeUnittest::TestProcessEventKeepUnmatch() {
                     "content" : "value1"
                 },
                 "timestamp" : 12345678901,
+                "timestampNanosecond": 0,
                 "type" : 1
             }
         ]
@@ -1705,6 +1729,7 @@ void ProcessorParseDelimiterNativeUnittest::TestProcessEventDiscardUnmatch() {
                     "content" : "value1"
                 },
                 "timestamp" : 12345678901,
+                "timestampNanosecond": 0,
                 "type" : 1
             },
             {
@@ -1713,6 +1738,7 @@ void ProcessorParseDelimiterNativeUnittest::TestProcessEventDiscardUnmatch() {
                     "content" : "value1"
                 },
                 "timestamp" : 12345678901,
+                "timestampNanosecond": 0,
                 "type" : 1
             },
             {
@@ -1721,6 +1747,7 @@ void ProcessorParseDelimiterNativeUnittest::TestProcessEventDiscardUnmatch() {
                     "content" : "value1"
                 },
                 "timestamp" : 12345678901,
+                "timestampNanosecond": 0,
                 "type" : 1
             },
             {
@@ -1729,6 +1756,7 @@ void ProcessorParseDelimiterNativeUnittest::TestProcessEventDiscardUnmatch() {
                     "content" : "value1"
                 },
                 "timestamp" : 12345678901,
+                "timestampNanosecond": 0,
                 "type" : 1
             },
             {
@@ -1737,6 +1765,7 @@ void ProcessorParseDelimiterNativeUnittest::TestProcessEventDiscardUnmatch() {
                     "content" : "value1"
                 },
                 "timestamp" : 12345678901,
+                "timestampNanosecond": 0,
                 "type" : 1
             }
         ]
diff --git a/core/unittest/processor/ProcessorParseRegexNativeUnittest.cpp b/core/unittest/processor/ProcessorParseRegexNativeUnittest.cpp
index 3e5f7cf438..60573f4caa 100644
--- a/core/unittest/processor/ProcessorParseRegexNativeUnittest.cpp
+++ b/core/unittest/processor/ProcessorParseRegexNativeUnittest.cpp
@@ -210,7 +210,6 @@ void ProcessorParseRegexNativeUnittest::TestProcessRegex() {
                     "rawLog" : "value1\tvalue2"
                 },
                 "timestamp" : 12345678901,
-                "timestampNanosecond" : 0,
                 "type" : 1
             },
             {
@@ -221,7 +220,6 @@ void ProcessorParseRegexNativeUnittest::TestProcessRegex() {
                     "rawLog" : "value3\tvalue4"
                 },
                 "timestamp" : 12345678901,
-                "timestampNanosecond" : 0,
                 "type" : 1
             }
         ]
@@ -288,7 +286,6 @@ void ProcessorParseRegexNativeUnittest::TestProcessRegexRaw() {
                     "rawLog" : "value1"
                 },
                 "timestamp" : 12345678901,
-                "timestampNanosecond" : 0,
                 "type" : 1
             },
             {
@@ -298,7 +295,6 @@ void ProcessorParseRegexNativeUnittest::TestProcessRegexRaw() {
                     "rawLog" : "value3"
                 },
                 "timestamp" : 12345678901,
-                "timestampNanosecond" : 0,
                 "type" : 1
             }
         ]
@@ -366,7 +362,6 @@ void ProcessorParseRegexNativeUnittest::TestProcessRegexContent() {
                     "rawLog" : "value1\tvalue2"
                 },
                 "timestamp" : 12345678901,
-                "timestampNanosecond" : 0,
                 "type" : 1
             },
             {
@@ -377,7 +372,6 @@ void ProcessorParseRegexNativeUnittest::TestProcessRegexContent() {
                     "rawLog" : "value3\tvalue4"
                 },
                 "timestamp" : 12345678901,
-                "timestampNanosecond" : 0,
                 "type" : 1
             }
         ]