diff --git a/src/clients/meta/MetaClient.cpp b/src/clients/meta/MetaClient.cpp
index 55f45eaa0ac..3c6442d415d 100644
--- a/src/clients/meta/MetaClient.cpp
+++ b/src/clients/meta/MetaClient.cpp
@@ -955,6 +955,12 @@ Status MetaClient::handleResponse(const RESP& resp) {
       return Status::Error("Backup table failure!");
     case nebula::cpp2::ErrorCode::E_SESSION_NOT_FOUND:
       return Status::Error("Session not existed!");
+    case nebula::cpp2::ErrorCode::E_SCHEMA_NAME_EXISTS:
+      return Status::Error("Schema with same name exists");
+    case nebula::cpp2::ErrorCode::E_RELATED_INDEX_EXISTS:
+      return Status::Error("Related index exists, please drop index first");
+    case nebula::cpp2::ErrorCode::E_RELATED_SPACE_EXISTS:
+      return Status::Error("There are still space on the host");
     default:
       return Status::Error("Unknown error!");
   }
diff --git a/src/graph/executor/admin/SubmitJobExecutor.cpp b/src/graph/executor/admin/SubmitJobExecutor.cpp
index fbec9898d69..4ad69ea5365 100644
--- a/src/graph/executor/admin/SubmitJobExecutor.cpp
+++ b/src/graph/executor/admin/SubmitJobExecutor.cpp
@@ -151,7 +151,9 @@ nebula::DataSet SubmitJobExecutor::buildShowResultData(
                           apache::thrift::util::enumNameSafe(tsk.get_result()),
                           convertJobTimestampToDateTime(std::move(tsk).get_start_time()),
                           convertJobTimestampToDateTime(std::move(tsk).get_stop_time()),
-                          apache::thrift::util::enumNameSafe(jd.get_code())}));
+                          jd.get_code() == nebula::cpp2::ErrorCode::E_UNKNOWN
+                              ? ""
+                              : apache::thrift::util::enumNameSafe(jd.get_code())}));
     }
     v.emplace_back(Row({folly::sformat("Total:{}", total),
                         folly::sformat("Succeeded:{}", succeeded),
@@ -195,7 +197,9 @@ nebula::DataSet SubmitJobExecutor::buildShowResultData(
           apache::thrift::util::enumNameSafe(taskDesc.get_status()),
           convertJobTimestampToDateTime(taskDesc.get_start_time()),
           convertJobTimestampToDateTime(taskDesc.get_stop_time()),
-          apache::thrift::util::enumNameSafe(taskDesc.get_code()),
+          jd.get_code() == nebula::cpp2::ErrorCode::E_UNKNOWN
+              ? ""
+              : apache::thrift::util::enumNameSafe(jd.get_code()),
       }));
     }
     v.emplace_back(Row({folly::sformat("Total:{}", total),
diff --git a/src/interface/common.thrift b/src/interface/common.thrift
index 1e95be659b8..a703b015280 100644
--- a/src/interface/common.thrift
+++ b/src/interface/common.thrift
@@ -357,6 +357,9 @@ enum ErrorCode {
     E_WRONGCLUSTER                    = -2010,  // Wrong cluster
     E_ZONE_NOT_ENOUGH                 = -2011,  // Listener conflicts
     E_ZONE_IS_EMPTY                   = -2012,  // Host not exist
+    E_SCHEMA_NAME_EXISTS              = -2013,  // Schema name alreay exists
+    E_RELATED_INDEX_EXISTS            = -2014,  // There are stil indexes related to tag or edge, cannot drop it
+    E_RELATED_SPACE_EXISTS            = -2015,  // There are still some spaec on the host, cannot drop it
 
     E_STORE_FAILURE                   = -2021,  // Failed to store data
     E_STORE_SEGMENT_ILLEGAL           = -2022,  // Illegal storage segment
diff --git a/src/meta/processors/schema/CreateEdgeProcessor.cpp b/src/meta/processors/schema/CreateEdgeProcessor.cpp
index e758dd1da3c..c45a67b74ee 100644
--- a/src/meta/processors/schema/CreateEdgeProcessor.cpp
+++ b/src/meta/processors/schema/CreateEdgeProcessor.cpp
@@ -21,7 +21,7 @@ void CreateEdgeProcessor::process(const cpp2::CreateEdgeReq& req) {
     LOG(INFO) << "Failed to create edge `" << edgeName
               << "': some tag with the same name already exists.";
     resp_.id_ref() = to(nebula::value(conflictRet), EntryType::EDGE);
-    handleErrorCode(nebula::cpp2::ErrorCode::E_CONFLICT);
+    handleErrorCode(nebula::cpp2::ErrorCode::E_SCHEMA_NAME_EXISTS);
     onFinished();
     return;
   } else {
diff --git a/src/meta/processors/schema/DropEdgeProcessor.cpp b/src/meta/processors/schema/DropEdgeProcessor.cpp
index 7c07f0a306e..9255223ec59 100644
--- a/src/meta/processors/schema/DropEdgeProcessor.cpp
+++ b/src/meta/processors/schema/DropEdgeProcessor.cpp
@@ -50,7 +50,7 @@ void DropEdgeProcessor::process(const cpp2::DropEdgeReq& req) {
   }
   if (!nebula::value(indexes).empty()) {
     LOG(INFO) << "Drop edge error, index conflict, please delete index first.";
-    handleErrorCode(nebula::cpp2::ErrorCode::E_CONFLICT);
+    handleErrorCode(nebula::cpp2::ErrorCode::E_RELATED_INDEX_EXISTS);
     onFinished();
     return;
   }
@@ -59,7 +59,7 @@ void DropEdgeProcessor::process(const cpp2::DropEdgeReq& req) {
   if (nebula::ok(ftIdxRet)) {
     LOG(INFO) << "Drop edge error, fulltext index conflict, "
               << "please delete fulltext index first.";
-    handleErrorCode(nebula::cpp2::ErrorCode::E_CONFLICT);
+    handleErrorCode(nebula::cpp2::ErrorCode::E_RELATED_INDEX_EXISTS);
     onFinished();
     return;
   }
diff --git a/src/meta/processors/schema/DropTagProcessor.cpp b/src/meta/processors/schema/DropTagProcessor.cpp
index 900454fa3d5..2f3c5c27cb7 100644
--- a/src/meta/processors/schema/DropTagProcessor.cpp
+++ b/src/meta/processors/schema/DropTagProcessor.cpp
@@ -50,7 +50,7 @@ void DropTagProcessor::process(const cpp2::DropTagReq& req) {
   }
   if (!nebula::value(indexes).empty()) {
     LOG(INFO) << "Drop tag error, index conflict, please delete index first.";
-    handleErrorCode(nebula::cpp2::ErrorCode::E_CONFLICT);
+    handleErrorCode(nebula::cpp2::ErrorCode::E_RELATED_INDEX_EXISTS);
     onFinished();
     return;
   }
@@ -59,7 +59,7 @@ void DropTagProcessor::process(const cpp2::DropTagReq& req) {
   if (nebula::ok(ftIdxRet)) {
     LOG(INFO) << "Drop tag error, fulltext index conflict, "
               << "please delete fulltext index first.";
-    handleErrorCode(nebula::cpp2::ErrorCode::E_CONFLICT);
+    handleErrorCode(nebula::cpp2::ErrorCode::E_RELATED_INDEX_EXISTS);
     onFinished();
     return;
   }
diff --git a/src/meta/processors/zone/DropHostsProcessor.cpp b/src/meta/processors/zone/DropHostsProcessor.cpp
index 51323d5ca14..c91aaec1349 100644
--- a/src/meta/processors/zone/DropHostsProcessor.cpp
+++ b/src/meta/processors/zone/DropHostsProcessor.cpp
@@ -54,7 +54,7 @@ void DropHostsProcessor::process(const cpp2::DropHostsReq& req) {
       for (auto& h : partHosts) {
         if (std::find(hosts.begin(), hosts.end(), h) != hosts.end()) {
           LOG(INFO) << h << " is related with partition";
-          code = nebula::cpp2::ErrorCode::E_CONFLICT;
+          code = nebula::cpp2::ErrorCode::E_RELATED_SPACE_EXISTS;
           break;
         }
       }
diff --git a/src/meta/processors/zone/DropZoneProcessor.cpp b/src/meta/processors/zone/DropZoneProcessor.cpp
index ac77d9ab518..22c6f4062ba 100644
--- a/src/meta/processors/zone/DropZoneProcessor.cpp
+++ b/src/meta/processors/zone/DropZoneProcessor.cpp
@@ -86,7 +86,7 @@ nebula::cpp2::ErrorCode DropZoneProcessor::checkSpaceReplicaZone() {
     size_t replicaFactor = properties.get_replica_factor();
     if (replicaFactor == spaceZones.size()) {
       LOG(INFO) << "Space " << spaceId << " replica factor and zone size are the same";
-      code = nebula::cpp2::ErrorCode::E_CONFLICT;
+      code = nebula::cpp2::ErrorCode::E_ZONE_NOT_ENOUGH;
       break;
     }
     iter->next();
@@ -121,7 +121,7 @@ nebula::cpp2::ErrorCode DropZoneProcessor::checkHostPartition(const HostAddr& ad
       for (auto& host : hosts) {
         if (host == address) {
           LOG(INFO) << "Host " << address << " have partition on it";
-          code = nebula::cpp2::ErrorCode::E_CONFLICT;
+          code = nebula::cpp2::ErrorCode::E_RELATED_SPACE_EXISTS;
           break;
         }
       }
diff --git a/src/meta/test/IndexProcessorTest.cpp b/src/meta/test/IndexProcessorTest.cpp
index 4ee6a750077..9a2b199c93f 100644
--- a/src/meta/test/IndexProcessorTest.cpp
+++ b/src/meta/test/IndexProcessorTest.cpp
@@ -1179,7 +1179,7 @@ TEST(IndexProcessorTest, IndexCheckDropEdgeTest) {
     auto f = processor->getFuture();
     processor->process(req);
     auto resp = std::move(f).get();
-    ASSERT_EQ(nebula::cpp2::ErrorCode::E_CONFLICT, resp.get_code());
+    ASSERT_EQ(nebula::cpp2::ErrorCode::E_RELATED_INDEX_EXISTS, resp.get_code());
   }
 }
 
@@ -1211,7 +1211,7 @@ TEST(IndexProcessorTest, IndexCheckDropTagTest) {
     auto f = processor->getFuture();
     processor->process(req);
     auto resp = std::move(f).get();
-    ASSERT_EQ(nebula::cpp2::ErrorCode::E_CONFLICT, resp.get_code());
+    ASSERT_EQ(nebula::cpp2::ErrorCode::E_RELATED_INDEX_EXISTS, resp.get_code());
   }
 }
 
@@ -1934,7 +1934,7 @@ TEST(IndexProcessorTest, DropWithFTIndexTest) {
     auto f = processor->getFuture();
     processor->process(req);
     auto resp = std::move(f).get();
-    ASSERT_EQ(nebula::cpp2::ErrorCode::E_CONFLICT, resp.get_code());
+    ASSERT_EQ(nebula::cpp2::ErrorCode::E_RELATED_INDEX_EXISTS, resp.get_code());
   }
   {
     cpp2::DropEdgeReq req;
@@ -1944,7 +1944,7 @@ TEST(IndexProcessorTest, DropWithFTIndexTest) {
     auto f = processor->getFuture();
     processor->process(req);
     auto resp = std::move(f).get();
-    ASSERT_EQ(nebula::cpp2::ErrorCode::E_CONFLICT, resp.get_code());
+    ASSERT_EQ(nebula::cpp2::ErrorCode::E_RELATED_INDEX_EXISTS, resp.get_code());
   }
 }
 
diff --git a/src/meta/test/ProcessorTest.cpp b/src/meta/test/ProcessorTest.cpp
index 3afc4760b82..66299126eb2 100644
--- a/src/meta/test/ProcessorTest.cpp
+++ b/src/meta/test/ProcessorTest.cpp
@@ -640,7 +640,7 @@ TEST(ProcessorTest, CreateTagTest) {
     auto f = processor->getFuture();
     processor->process(req);
     auto resp = std::move(f).get();
-    ASSERT_EQ(nebula::cpp2::ErrorCode::E_CONFLICT, resp.get_code());
+    ASSERT_EQ(nebula::cpp2::ErrorCode::E_SCHEMA_NAME_EXISTS, resp.get_code());
   }
   {
     // Set schema ttl property
@@ -3596,7 +3596,7 @@ TEST(ProcessorTest, DropHostsTest) {
     auto f = processor->getFuture();
     processor->process(req);
     auto resp = std::move(f).get();
-    ASSERT_EQ(nebula::cpp2::ErrorCode::E_CONFLICT, resp.get_code());
+    ASSERT_EQ(nebula::cpp2::ErrorCode::E_RELATED_SPACE_EXISTS, resp.get_code());
   }
   {
     // Drop hosts which hold partition.
@@ -3607,7 +3607,7 @@ TEST(ProcessorTest, DropHostsTest) {
     auto f = processor->getFuture();
     processor->process(req);
     auto resp = std::move(f).get();
-    ASSERT_EQ(nebula::cpp2::ErrorCode::E_CONFLICT, resp.get_code());
+    ASSERT_EQ(nebula::cpp2::ErrorCode::E_RELATED_SPACE_EXISTS, resp.get_code());
   }
   {
     cpp2::DropSpaceReq req;
@@ -4665,7 +4665,7 @@ TEST(ProcessorTest, DropZoneTest) {
     auto f = processor->getFuture();
     processor->process(req);
     auto resp = std::move(f).get();
-    ASSERT_EQ(nebula::cpp2::ErrorCode::E_CONFLICT, resp.get_code());
+    ASSERT_EQ(nebula::cpp2::ErrorCode::E_ZONE_NOT_ENOUGH, resp.get_code());
   }
   {
     cpp2::DropSpaceReq req;
@@ -4699,7 +4699,7 @@ TEST(ProcessorTest, DropZoneTest) {
     auto f = processor->getFuture();
     processor->process(req);
     auto resp = std::move(f).get();
-    ASSERT_EQ(nebula::cpp2::ErrorCode::E_CONFLICT, resp.get_code());
+    ASSERT_EQ(nebula::cpp2::ErrorCode::E_RELATED_SPACE_EXISTS, resp.get_code());
   }
 }
 
diff --git a/src/storage/admin/StatsTask.cpp b/src/storage/admin/StatsTask.cpp
index 8008df3173d..9b9bb304394 100644
--- a/src/storage/admin/StatsTask.cpp
+++ b/src/storage/admin/StatsTask.cpp
@@ -11,6 +11,11 @@
 #include "common/utils/NebulaKeyUtils.h"
 #include "kvstore/Common.h"
 
+DEFINE_int32(stats_sleep_interval_ms,
+             0,
+             "If interval is greater than 0, sleep a period of time when scanned 1000 records. "
+             "Default value 0 means won't sleep");
+
 namespace nebula {
 namespace storage {
 
@@ -132,6 +137,9 @@ nebula::cpp2::ErrorCode StatsTask::genSubTask(GraphSpaceID spaceId,
   std::unordered_map<PartitionID, int64_t> negativeRelevancy;
   int64_t spaceVertices = 0;
   int64_t spaceEdges = 0;
+  // Once 1000 records are scanned, check if we need to sleep for a while to prevent high pressure
+  // on io, the sleep time is stats_sleep_interval_ms
+  size_t countToSleep = 0;
 
   for (auto tag : tags) {
     tagsVertices[tag.first] = 0;
@@ -167,6 +175,7 @@ nebula::cpp2::ErrorCode StatsTask::genSubTask(GraphSpaceID spaceId,
     }
     tagsVertices[tagId] += 1;
     tagIter->next();
+    sleepIfScannedSomeRecord(++countToSleep);
   }
 
   // Only stats valid edge data, no multi version
@@ -216,10 +225,12 @@ nebula::cpp2::ErrorCode StatsTask::genSubTask(GraphSpaceID spaceId,
       negativeRelevancy[sourceVid % partitionNum + 1]++;
     }
     edgeIter->next();
+    sleepIfScannedSomeRecord(++countToSleep);
   }
   while (vertexIter && vertexIter->valid()) {
     spaceVertices++;
     vertexIter->next();
+    sleepIfScannedSomeRecord(++countToSleep);
   }
   nebula::meta::cpp2::StatsItem statsItem;
 
@@ -334,5 +345,12 @@ void StatsTask::finish(nebula::cpp2::ErrorCode rc) {
   }
 }
 
+void StatsTask::sleepIfScannedSomeRecord(size_t& countToSleep) {
+  if (FLAGS_stats_sleep_interval_ms > 0 && countToSleep >= kRecordsToSleep) {
+    usleep(FLAGS_stats_sleep_interval_ms * 1000);
+    countToSleep = 0;
+  }
+}
+
 }  // namespace storage
 }  // namespace nebula
diff --git a/src/storage/admin/StatsTask.h b/src/storage/admin/StatsTask.h
index 5b618fc0d63..37be1156d29 100644
--- a/src/storage/admin/StatsTask.h
+++ b/src/storage/admin/StatsTask.h
@@ -52,6 +52,8 @@ class StatsTask : public AdminTask {
  private:
   nebula::cpp2::ErrorCode getSchemas(GraphSpaceID spaceId);
 
+  void sleepIfScannedSomeRecord(size_t& countToSleep);
+
  protected:
   GraphSpaceID spaceId_;
 
@@ -65,6 +67,8 @@ class StatsTask : public AdminTask {
 
   // The number of subtasks equals to the number of parts in request
   size_t subTaskSize_{0};
+
+  static constexpr size_t kRecordsToSleep{1000};
 };
 
 }  // namespace storage