diff --git a/oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/query/MetricQueryService.java b/oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/query/MetricQueryService.java
index 1b10baf32b51e5f2dce6d477fa29351213d20e95..cd83c2f20495167403b8111df8c28c7f7dc7d880 100644
--- a/oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/query/MetricQueryService.java
+++ b/oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/query/MetricQueryService.java
@@ -31,6 +31,7 @@ import org.apache.skywalking.oap.server.core.storage.annotation.ValueColumnIds;
 import org.apache.skywalking.oap.server.core.storage.query.IMetricQueryDAO;
 import org.apache.skywalking.oap.server.library.module.*;
 import org.apache.skywalking.oap.server.library.module.Service;
+import org.apache.skywalking.oap.server.library.util.CollectionUtils;
 import org.slf4j.*;
 
 /**
@@ -56,6 +57,10 @@ public class MetricQueryService implements Service {
 
     public IntValues getValues(final String indName, final List<String> ids, final Step step, final long startTB,
         final long endTB) throws IOException {
+        if (CollectionUtils.isEmpty(ids)) {
+            throw new RuntimeException("IDs can't be null");
+        }
+
         Where where = new Where();
         KeyValues intKeyValues = new KeyValues();
         intKeyValues.setKey(Indicator.ENTITY_ID);
diff --git a/oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/register/EndpointInventory.java b/oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/register/EndpointInventory.java
index 029e19232ba1bfa1741dd88da34b5c19c85ecb01..3d330f86e18a152b3b0ead326bfbad6c4e348d6f 100644
--- a/oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/register/EndpointInventory.java
+++ b/oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/register/EndpointInventory.java
@@ -18,15 +18,19 @@
 
 package org.apache.skywalking.oap.server.core.register;
 
-import java.util.*;
-import lombok.*;
+import java.util.HashMap;
+import java.util.Map;
+import lombok.Getter;
+import lombok.Setter;
 import org.apache.skywalking.oap.server.core.Const;
 import org.apache.skywalking.oap.server.core.register.annotation.InventoryType;
 import org.apache.skywalking.oap.server.core.remote.annotation.StreamData;
 import org.apache.skywalking.oap.server.core.remote.grpc.proto.RemoteData;
 import org.apache.skywalking.oap.server.core.source.Scope;
 import org.apache.skywalking.oap.server.core.storage.StorageBuilder;
-import org.apache.skywalking.oap.server.core.storage.annotation.*;
+import org.apache.skywalking.oap.server.core.storage.annotation.Column;
+import org.apache.skywalking.oap.server.core.storage.annotation.StorageEntity;
+import org.apache.skywalking.oap.server.library.util.StringUtils;
 
 /**
  * @author peng-yongsheng
@@ -87,7 +91,7 @@ public class EndpointInventory extends RegisterSource {
         remoteBuilder.addDataLongs(getRegisterTime());
         remoteBuilder.addDataLongs(getHeartbeatTime());
 
-        remoteBuilder.addDataStrings(name);
+        remoteBuilder.addDataStrings(StringUtils.getOrDefault(name, Const.EMPTY_STRING));
         return remoteBuilder;
     }
 
diff --git a/oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/register/NetworkAddressInventory.java b/oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/register/NetworkAddressInventory.java
index 2ac68160afeae8590d09767641fe1bad26d5824a..cf465b68c3b2cd75a31bac2624d99458495495b9 100644
--- a/oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/register/NetworkAddressInventory.java
+++ b/oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/register/NetworkAddressInventory.java
@@ -27,6 +27,7 @@ import org.apache.skywalking.oap.server.core.remote.grpc.proto.RemoteData;
 import org.apache.skywalking.oap.server.core.source.Scope;
 import org.apache.skywalking.oap.server.core.storage.StorageBuilder;
 import org.apache.skywalking.oap.server.core.storage.annotation.*;
+import org.apache.skywalking.oap.server.library.util.StringUtils;
 
 /**
  * @author peng-yongsheng
@@ -87,7 +88,7 @@ public class NetworkAddressInventory extends RegisterSource {
         remoteBuilder.addDataLongs(getRegisterTime());
         remoteBuilder.addDataLongs(getHeartbeatTime());
 
-        remoteBuilder.addDataStrings(name);
+        remoteBuilder.addDataStrings(StringUtils.getOrDefault(name, Const.EMPTY_STRING));
         return remoteBuilder;
     }
 
diff --git a/oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/register/ServiceInstanceInventory.java b/oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/register/ServiceInstanceInventory.java
index a4760176956eabe7098f70d191864492848de1dd..519a7d2e35d2abf3d1bd69b8e43a391d57dd9a72 100644
--- a/oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/register/ServiceInstanceInventory.java
+++ b/oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/register/ServiceInstanceInventory.java
@@ -30,6 +30,7 @@ import org.apache.skywalking.oap.server.core.source.Scope;
 import org.apache.skywalking.oap.server.core.storage.StorageBuilder;
 import org.apache.skywalking.oap.server.core.storage.annotation.*;
 import org.apache.skywalking.oap.server.library.util.BooleanUtils;
+import org.apache.skywalking.oap.server.library.util.StringUtils;
 
 /**
  * @author peng-yongsheng
@@ -122,11 +123,11 @@ public class ServiceInstanceInventory extends RegisterSource {
         remoteBuilder.addDataLongs(getRegisterTime());
         remoteBuilder.addDataLongs(getHeartbeatTime());
 
-        remoteBuilder.addDataStrings(name);
-        remoteBuilder.addDataStrings(osName);
-        remoteBuilder.addDataStrings(hostName);
-        remoteBuilder.addDataStrings(ipv4s);
-        remoteBuilder.addDataStrings(instanceUUID);
+        remoteBuilder.addDataStrings(StringUtils.getOrDefault(name, Const.EMPTY_STRING));
+        remoteBuilder.addDataStrings(StringUtils.getOrDefault(osName, Const.EMPTY_STRING));
+        remoteBuilder.addDataStrings(StringUtils.getOrDefault(hostName, Const.EMPTY_STRING));
+        remoteBuilder.addDataStrings(StringUtils.getOrDefault(ipv4s, Const.EMPTY_STRING));
+        remoteBuilder.addDataStrings(StringUtils.getOrDefault(instanceUUID, Const.EMPTY_STRING));
         return remoteBuilder;
     }
 
diff --git a/oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/register/ServiceInventory.java b/oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/register/ServiceInventory.java
index 460e0b97cc2bf1cea38af54d62922522aa45b5bf..c2c219975c2821113a44bfa9b68b0af88c4f8e5b 100644
--- a/oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/register/ServiceInventory.java
+++ b/oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/register/ServiceInventory.java
@@ -28,6 +28,7 @@ import org.apache.skywalking.oap.server.core.source.Scope;
 import org.apache.skywalking.oap.server.core.storage.StorageBuilder;
 import org.apache.skywalking.oap.server.core.storage.annotation.*;
 import org.apache.skywalking.oap.server.library.util.BooleanUtils;
+import org.apache.skywalking.oap.server.library.util.StringUtils;
 
 /**
  * @author peng-yongsheng
@@ -105,7 +106,7 @@ public class ServiceInventory extends RegisterSource {
         remoteBuilder.addDataLongs(getHeartbeatTime());
         remoteBuilder.addDataLongs(getMappingLastUpdateTime());
 
-        remoteBuilder.addDataStrings(name);
+        remoteBuilder.addDataStrings(StringUtils.getOrDefault(name, Const.EMPTY_STRING));
         return remoteBuilder;
     }
 
diff --git a/oap-server/server-library/library-util/src/main/java/org/apache/skywalking/oap/server/library/util/StringUtils.java b/oap-server/server-library/library-util/src/main/java/org/apache/skywalking/oap/server/library/util/StringUtils.java
index 34d84ca1ba5b3f2cbcb2c4bc7cc971f4696c3252..2d425c46b933028e504110c6f8f01fa98aad88a2 100644
--- a/oap-server/server-library/library-util/src/main/java/org/apache/skywalking/oap/server/library/util/StringUtils.java
+++ b/oap-server/server-library/library-util/src/main/java/org/apache/skywalking/oap/server/library/util/StringUtils.java
@@ -32,4 +32,8 @@ public class StringUtils {
     public static boolean isNotEmpty(Object str) {
         return !isEmpty(str);
     }
+
+    public static String getOrDefault(String value, String defaultValue) {
+        return value == null ? defaultValue : value;
+    }
 }