diff --git a/.clang-format b/.clang-format
index 1e124f7be8..73dc2aeb8f 100644
--- a/.clang-format
+++ b/.clang-format
@@ -23,3 +23,5 @@ AccessModifierOffset: -3
 AlwaysBreakAfterReturnType: All
 AllowShortBlocksOnASingleLine: false
 AllowShortFunctionsOnASingleLine: false
+AllowShortIfStatementsOnASingleLine: false
+AlignTrailingComments: true
diff --git a/cpp/src/config/YamlConfigMgr.h b/cpp/src/config/YamlConfigMgr.h
index 9697ce3cae..743276b504 100644
--- a/cpp/src/config/YamlConfigMgr.h
+++ b/cpp/src/config/YamlConfigMgr.h
@@ -47,7 +47,7 @@ class YamlConfigMgr : public ConfigMgr {
     SetConfigValue(const YAML::Node& node, const std::string& key, ConfigNode& config);
 
     bool
-    SetChildConfig(const YAML::Node& node, const std::string& name, ConfigNode& config);
+    SetChildConfig(const YAML::Node& node, const std::string& child_name, ConfigNode& config);
 
     bool
     SetSequence(const YAML::Node& node, const std::string& child_name, ConfigNode& config);
diff --git a/cpp/src/core/knowhere/knowhere/common/Config.h b/cpp/src/core/knowhere/knowhere/common/Config.h
index 208641d666..cfee35c35b 100644
--- a/cpp/src/core/knowhere/knowhere/common/Config.h
+++ b/cpp/src/core/knowhere/knowhere/common/Config.h
@@ -46,12 +46,14 @@ struct Cfg {
         const int64_t &k,
         const int64_t &gpu_id,
         METRICTYPE type)
-        : d(dim), k(k), gpu_id(gpu_id), metric_type(type) {}
+        : metric_type(type), k(k), gpu_id(gpu_id), d(dim) {}
 
     Cfg() = default;
 
     virtual bool
-    CheckValid(){};
+    CheckValid(){
+        return true;
+    };
 };
 using Config = std::shared_ptr<Cfg>;
 
diff --git a/cpp/src/core/knowhere/knowhere/common/Dataset.h b/cpp/src/core/knowhere/knowhere/common/Dataset.h
index c2d74a59e5..91fb165811 100644
--- a/cpp/src/core/knowhere/knowhere/common/Dataset.h
+++ b/cpp/src/core/knowhere/knowhere/common/Dataset.h
@@ -127,10 +127,10 @@ class Dataset {
     //}
 
  private:
-    SchemaPtr array_schema_;
-    SchemaPtr tensor_schema_;
     std::vector<ArrayPtr> array_;
+    SchemaPtr array_schema_;
     std::vector<TensorPtr> tensor_;
+    SchemaPtr tensor_schema_;
     //Config meta_;
 };
 
diff --git a/cpp/src/core/knowhere/knowhere/index/vector_index/helpers/IndexParameter.cpp b/cpp/src/core/knowhere/knowhere/index/vector_index/helpers/IndexParameter.cpp
index 503f0c2f67..9999444368 100644
--- a/cpp/src/core/knowhere/knowhere/index/vector_index/helpers/IndexParameter.cpp
+++ b/cpp/src/core/knowhere/knowhere/index/vector_index/helpers/IndexParameter.cpp
@@ -25,9 +25,14 @@ namespace zilliz {
 namespace knowhere {
 
 faiss::MetricType GetMetricType(METRICTYPE &type) {
-    if (type == METRICTYPE::L2) return faiss::METRIC_L2;
-    if (type == METRICTYPE::IP) return faiss::METRIC_INNER_PRODUCT;
-    if (type == METRICTYPE::INVALID) KNOWHERE_THROW_MSG("Metric type is invalid");
+    if (type == METRICTYPE::L2) {
+        return faiss::METRIC_L2;
+    }
+    if (type == METRICTYPE::IP) {
+        return faiss::METRIC_INNER_PRODUCT;
+    }
+
+    KNOWHERE_THROW_MSG("Metric type is invalid");
 }
 
 
diff --git a/cpp/src/core/knowhere/knowhere/index/vector_index/helpers/IndexParameter.h b/cpp/src/core/knowhere/knowhere/index/vector_index/helpers/IndexParameter.h
index 521754e2e3..cd873ed251 100644
--- a/cpp/src/core/knowhere/knowhere/index/vector_index/helpers/IndexParameter.h
+++ b/cpp/src/core/knowhere/knowhere/index/vector_index/helpers/IndexParameter.h
@@ -52,12 +52,15 @@ struct IVFCfg : public Cfg {
            const int64_t &nlist,
            const int64_t &nprobe,
            METRICTYPE type)
-        : nlist(nlist), nprobe(nprobe), Cfg(dim, k, gpu_id, type) {}
+        : Cfg(dim, k, gpu_id, type), nlist(nlist), nprobe(nprobe) {
+    }
 
     IVFCfg() = default;
 
     bool
-    CheckValid() override {};
+    CheckValid() override {
+        return true;
+    };
 };
 using IVFConfig = std::shared_ptr<IVFCfg>;
 
@@ -72,12 +75,15 @@ struct IVFSQCfg : public IVFCfg {
              const int64_t &nprobe,
              const int64_t &nbits,
              METRICTYPE type)
-        : nbits(nbits), IVFCfg(dim, k, gpu_id, nlist, nprobe, type) {}
+        : IVFCfg(dim, k, gpu_id, nlist, nprobe, type), nbits(nbits) {
+    }
 
     IVFSQCfg() = default;
 
     bool
-    CheckValid() override {};
+    CheckValid() override {
+        return true;
+    };
 };
 using IVFSQConfig = std::shared_ptr<IVFSQCfg>;
 
@@ -98,12 +104,15 @@ struct IVFPQCfg : public IVFCfg {
              const int64_t &nbits,
              const int64_t &m,
              METRICTYPE type)
-        : nbits(nbits), m(m), IVFCfg(dim, k, gpu_id, nlist, nprobe, type) {}
+        : IVFCfg(dim, k, gpu_id, nlist, nprobe, type), m(m), nbits(nbits) {
+    }
 
     IVFPQCfg() = default;
 
     bool
-    CheckValid() override {};
+    CheckValid() override {
+        return true;
+    };
 };
 using IVFPQConfig = std::shared_ptr<IVFPQCfg>;
 
@@ -123,13 +132,17 @@ struct NSGCfg : public IVFCfg {
            const int64_t &out_degree,
            const int64_t &candidate_size,
            METRICTYPE type)
-        : knng(knng), search_length(search_length), out_degree(out_degree), candidate_pool_size(candidate_size),
-          IVFCfg(dim, k, gpu_id, nlist, nprobe, type) {}
+        : IVFCfg(dim, k, gpu_id, nlist, nprobe, type),
+          knng(knng), search_length(search_length),
+          out_degree(out_degree), candidate_pool_size(candidate_size) {
+    }
 
     NSGCfg() = default;
 
     bool
-    CheckValid() override {};
+    CheckValid() override {
+        return true;
+    };
 };
 using NSGConfig = std::shared_ptr<NSGCfg>;
 
diff --git a/cpp/src/core/knowhere/knowhere/index/vector_index/nsg/NSG.cpp b/cpp/src/core/knowhere/knowhere/index/vector_index/nsg/NSG.cpp
index 0f3bb639c2..fcf77625db 100644
--- a/cpp/src/core/knowhere/knowhere/index/vector_index/nsg/NSG.cpp
+++ b/cpp/src/core/knowhere/knowhere/index/vector_index/nsg/NSG.cpp
@@ -81,7 +81,7 @@ void NsgIndex::Build_with_ids(size_t nb, const float *data, const long *ids, con
     //>> Debug code
     ///
     int total_degree = 0;
-    for (int i = 0; i < ntotal; ++i) {
+    for (size_t i = 0; i < ntotal; ++i) {
         total_degree += nsg[i].size();
     }
 
@@ -172,7 +172,7 @@ void NsgIndex::GetNeighbors(const float *query,
         for (size_t i = 0; i < init_ids.size(); ++i) {
             node_t id = init_ids[i];
 
-            if (id >= ntotal) {
+            if (id >= static_cast<node_t>(ntotal)) {
                 KNOWHERE_THROW_MSG("Build Index Error, id > ntotal");
                 continue;
             }
@@ -262,7 +262,7 @@ void NsgIndex::GetNeighbors(const float *query, std::vector<Neighbor> &resset, s
         for (size_t i = 0; i < init_ids.size(); ++i) {
             node_t id = init_ids[i];
 
-            if (id >= ntotal) {
+            if (id >= static_cast<node_t>(ntotal)) {
                 KNOWHERE_THROW_MSG("Build Index Error, id > ntotal");
                 continue;
             }
@@ -350,7 +350,7 @@ void NsgIndex::GetNeighbors(const float *query,
             node_t id = init_ids[i];
 
             //assert(id < ntotal);
-            if (id >= ntotal) {
+            if (id >= static_cast<node_t>(ntotal)) {
                 KNOWHERE_THROW_MSG("Build Index Error, id > ntotal");
                 continue;
             }
@@ -461,7 +461,7 @@ void NsgIndex::Link() {
     //}
     /////
 
-    for (int i = 0; i < ntotal; ++i) {
+    for (size_t i = 0; i < ntotal; ++i) {
         nsg[i].shrink_to_fit();
     }
 }
@@ -483,7 +483,9 @@ void NsgIndex::SyncPrune(size_t n,
     unsigned cursor = 0;
     std::sort(pool.begin(), pool.end());
     std::vector<Neighbor> result;
-    if (pool[cursor].id == n) cursor++;
+    if (pool[cursor].id == static_cast<node_t>(n)) {
+        cursor++;
+    }
     result.push_back(pool[cursor]); // init result with nearest neighbor
 
     SelectEdge(cursor, pool, result, true);
@@ -518,7 +520,7 @@ void NsgIndex::InterInsert(unsigned n, std::vector<std::mutex> &mutex_vec, float
         int duplicate = false;
         {
             LockGuard lk(mutex_vec[current_neighbor]);
-            for (int j = 0; j < out_degree; ++j) {
+            for (size_t j = 0; j < out_degree; ++j) {
                 if (nsn_dist_pool[j] == -1) break;
 
                 // 保证至少有一条边能连回来
@@ -551,14 +553,14 @@ void NsgIndex::InterInsert(unsigned n, std::vector<std::mutex> &mutex_vec, float
 
             {
                 LockGuard lk(mutex_vec[current_neighbor]);
-                for (int j = 0; j < result.size(); ++j) {
+                for (size_t j = 0; j < result.size(); ++j) {
                     nsn_id_pool[j] = result[j].id;
                     nsn_dist_pool[j] = result[j].distance;
                 }
             }
         } else {
             LockGuard lk(mutex_vec[current_neighbor]);
-            for (int j = 0; j < out_degree; ++j) {
+            for (size_t j = 0; j < out_degree; ++j) {
                 if (nsn_dist_pool[j] == -1) {
                     nsn_id_pool.push_back(current_as_neighbor.id);
                     nsn_dist_pool[j] = current_as_neighbor.distance;
@@ -605,9 +607,11 @@ void NsgIndex::CheckConnectivity() {
     boost::dynamic_bitset<> has_linked{ntotal, 0};
     int64_t linked_count = 0;
 
-    while (linked_count < ntotal) {
+    while (linked_count < static_cast<int64_t>(ntotal)) {
         DFS(root, has_linked, linked_count);
-        if (linked_count >= ntotal) break;
+        if (linked_count >= static_cast<int64_t>(ntotal)) {
+            break;
+        }
         FindUnconnectedNode(has_linked, root);
     }
 }
@@ -697,7 +701,7 @@ void NsgIndex::Search(const float *query,
     } else{
         //#pragma omp parallel for schedule(dynamic, 50)
         #pragma omp parallel for
-        for (int i = 0; i < nq; ++i) {
+        for (unsigned int i = 0; i < nq; ++i) {
             // TODO(linxj): when to use openmp
             auto single_query = query + i * dim;
             GetNeighbors(single_query, resset[i], nsg, &params);
@@ -705,8 +709,8 @@ void NsgIndex::Search(const float *query,
     }
     rc.ElapseFromBegin("cost");
 
-    for (int i = 0; i < nq; ++i) {
-        for (int j = 0; j < k; ++j) {
+    for (unsigned int i = 0; i < nq; ++i) {
+        for (unsigned int j = 0; j < k; ++j) {
             //ids[i * k + j] = resset[i][j].id;
 
             // Fix(linxj): bug, reset[i][j] out of range
diff --git a/cpp/src/core/knowhere/knowhere/index/vector_index/nsg/NSGHelper.cpp b/cpp/src/core/knowhere/knowhere/index/vector_index/nsg/NSGHelper.cpp
index eb87f97f3e..77cf0e9464 100644
--- a/cpp/src/core/knowhere/knowhere/index/vector_index/nsg/NSGHelper.cpp
+++ b/cpp/src/core/knowhere/knowhere/index/vector_index/nsg/NSGHelper.cpp
@@ -29,7 +29,7 @@ namespace algo {
 // TODO: impl search && insert && return insert pos. why not just find and swap?
 int InsertIntoPool(Neighbor *addr, unsigned K, Neighbor nn) {
     //>> Fix: Add assert
-    for (int i = 0; i < K; ++i) {
+    for (unsigned int i = 0; i < K; ++i) {
         assert(addr[i].id != nn.id);
     }
 
diff --git a/cpp/src/core/test/utils.cpp b/cpp/src/core/test/utils.cpp
index 4e240f5f74..df9410bd6c 100644
--- a/cpp/src/core/test/utils.cpp
+++ b/cpp/src/core/test/utils.cpp
@@ -38,8 +38,8 @@ void DataGen::Generate(const int &dim, const int &nb, const int &nq) {
     this->dim = dim;
 
     GenAll(dim, nb, xb, ids, nq, xq);
-    assert(xb.size() == dim * nb);
-    assert(xq.size() == dim * nq);
+    assert(xb.size() == (size_t)dim * nb);
+    assert(xq.size() == (size_t)dim * nq);
 
     base_dataset = generate_dataset(nb, dim, xb.data(), ids.data());
     query_dataset = generate_query_dataset(nq, dim, xq.data());
@@ -47,7 +47,7 @@ void DataGen::Generate(const int &dim, const int &nb, const int &nq) {
 }
 zilliz::knowhere::DatasetPtr DataGen::GenQuery(const int &nq) {
     xq.resize(nq * dim);
-    for (size_t i = 0; i < nq * dim; ++i) {
+    for (int i = 0; i < nq * dim; ++i) {
         xq[i] = xb[i];
     }
     return generate_query_dataset(nq, dim, xq.data());
@@ -72,7 +72,7 @@ void GenAll(const int64_t &dim,
             const int64_t &nq,
             float *xq) {
     GenBase(dim, nb, xb, ids);
-    for (size_t i = 0; i < nq * dim; ++i) {
+    for (int64_t i = 0; i < nq * dim; ++i) {
         xq[i] = xb[i];
     }
 }
diff --git a/cpp/src/db/DBImpl.cpp b/cpp/src/db/DBImpl.cpp
index 2780d0f763..2e6955a81d 100644
--- a/cpp/src/db/DBImpl.cpp
+++ b/cpp/src/db/DBImpl.cpp
@@ -638,7 +638,8 @@ DBImpl::MergeFiles(const std::string& table_id, const meta::DateT& date, const m
         ENGINE_LOG_DEBUG << "Merging file " << file_schema.file_id_;
         index_size = index->Size();
 
-        if (index_size >= file_schema.index_file_size_) break;
+        if (index_size >= file_schema.index_file_size_)
+            break;
     }
 
     // step 3: serialize to disk
diff --git a/cpp/src/db/Options.h b/cpp/src/db/Options.h
index df3b1fc0c5..d51a30f2b4 100644
--- a/cpp/src/db/Options.h
+++ b/cpp/src/db/Options.h
@@ -53,9 +53,9 @@ struct ArchiveConf {
 
  private:
     void
-    ParseCritirias(const std::string& type);
+    ParseCritirias(const std::string& criterias);
     void
-    ParseType(const std::string& criterias);
+    ParseType(const std::string& type);
 
     std::string type_;
     CriteriaT criterias_;
diff --git a/cpp/src/db/Utils.cpp b/cpp/src/db/Utils.cpp
index 84e099b579..2055ff391c 100644
--- a/cpp/src/db/Utils.cpp
+++ b/cpp/src/db/Utils.cpp
@@ -143,14 +143,14 @@ GetTableFilePath(const DBMetaOptions& options, meta::TableFileSchema& table_file
     if (boost::filesystem::exists(file_path)) {
         table_file.location_ = file_path;
         return Status::OK();
-    } else {
-        for (auto& path : options.slave_paths_) {
-            parent_path = ConstructParentFolder(path, table_file);
-            file_path = parent_path + "/" + table_file.file_id_;
-            if (boost::filesystem::exists(file_path)) {
-                table_file.location_ = file_path;
-                return Status::OK();
-            }
+    }
+
+    for (auto& path : options.slave_paths_) {
+        parent_path = ConstructParentFolder(path, table_file);
+        file_path = parent_path + "/" + table_file.file_id_;
+        if (boost::filesystem::exists(file_path)) {
+            table_file.location_ = file_path;
+            return Status::OK();
         }
     }
 
diff --git a/cpp/src/db/engine/ExecutionEngineImpl.cpp b/cpp/src/db/engine/ExecutionEngineImpl.cpp
index e8f9ba395d..52b4992dab 100644
--- a/cpp/src/db/engine/ExecutionEngineImpl.cpp
+++ b/cpp/src/db/engine/ExecutionEngineImpl.cpp
@@ -342,7 +342,8 @@ Status
 ExecutionEngineImpl::Init() {
     server::Config& config = server::Config::GetInstance();
     Status s = config.GetDBConfigBuildIndexGPU(gpu_num_);
-    if (!s.ok()) return s;
+    if (!s.ok())
+        return s;
 
     return Status::OK();
 }
diff --git a/cpp/src/main.cpp b/cpp/src/main.cpp
index bced85af6d..5d808a7e4c 100644
--- a/cpp/src/main.cpp
+++ b/cpp/src/main.cpp
@@ -39,12 +39,12 @@ main(int argc, char* argv[]) {
     std::cout << std::endl << "Welcome to use Milvus by Zilliz!" << std::endl;
     std::cout << "Milvus " << BUILD_TYPE << " version: v" << MILVUS_VERSION << " built at " << BUILD_TIME << std::endl;
 
-    static struct option long_options[] = {{"conf_file", required_argument, 0, 'c'},
-                                           {"log_conf_file", required_argument, 0, 'l'},
-                                           {"help", no_argument, 0, 'h'},
-                                           {"daemon", no_argument, 0, 'd'},
-                                           {"pid_file", required_argument, 0, 'p'},
-                                           {NULL, 0, 0, 0}};
+    static struct option long_options[] = {{"conf_file", required_argument, nullptr, 'c'},
+                                           {"log_conf_file", required_argument, nullptr, 'l'},
+                                           {"help", no_argument, nullptr, 'h'},
+                                           {"daemon", no_argument, nullptr, 'd'},
+                                           {"pid_file", required_argument, nullptr, 'p'},
+                                           {nullptr, 0, nullptr, 0}};
 
     int option_index = 0;
     int64_t start_daemonized = 0;
diff --git a/cpp/src/metrics/PrometheusMetrics.cpp b/cpp/src/metrics/PrometheusMetrics.cpp
index dd6410b46a..72b26eb63d 100644
--- a/cpp/src/metrics/PrometheusMetrics.cpp
+++ b/cpp/src/metrics/PrometheusMetrics.cpp
@@ -33,13 +33,20 @@ PrometheusMetrics::Init() {
     try {
         Config& config = Config::GetInstance();
         Status s = config.GetMetricConfigEnableMonitor(startup_);
-        if (!s.ok()) return s.code();
-        if (!startup_) return SERVER_SUCCESS;
+        if (!s.ok()) {
+            return s.code();
+        }
+        if (!startup_) {
+            return SERVER_SUCCESS;
+        }
 
         // Following should be read from config file.
         std::string bind_address;
         s = config.GetMetricConfigPrometheusPort(bind_address);
-        if (!s.ok()) return s.code();
+        if (!s.ok()) {
+            return s.code();
+        }
+
         const std::string uri = std::string("/tmp/metrics");
         const std::size_t num_threads = 2;
 
@@ -58,21 +65,30 @@ PrometheusMetrics::Init() {
 
 void
 PrometheusMetrics::CPUUsagePercentSet() {
-    if (!startup_) return;
+    if (!startup_) {
+        return;
+    }
+
     double usage_percent = server::SystemInfo::GetInstance().CPUPercent();
     CPU_usage_percent_.Set(usage_percent);
 }
 
 void
 PrometheusMetrics::RAMUsagePercentSet() {
-    if (!startup_) return;
+    if (!startup_) {
+        return;
+    }
+
     double usage_percent = server::SystemInfo::GetInstance().MemoryPercent();
     RAM_usage_percent_.Set(usage_percent);
 }
 
 void
 PrometheusMetrics::GPUPercentGaugeSet() {
-    if (!startup_) return;
+    if (!startup_) {
+        return;
+    }
+
     int numDevice = server::SystemInfo::GetInstance().num_device();
     std::vector<uint64_t> used_total = server::SystemInfo::GetInstance().GPUMemoryTotal();
     std::vector<uint64_t> used_memory = server::SystemInfo::GetInstance().GPUMemoryUsed();
@@ -86,7 +102,10 @@ PrometheusMetrics::GPUPercentGaugeSet() {
 
 void
 PrometheusMetrics::GPUMemoryUsageGaugeSet() {
-    if (!startup_) return;
+    if (!startup_) {
+        return;
+    }
+
     std::vector<uint64_t> values = server::SystemInfo::GetInstance().GPUMemoryUsed();
     constexpr uint64_t MtoB = 1024 * 1024;
     int numDevice = server::SystemInfo::GetInstance().num_device();
@@ -100,7 +119,9 @@ PrometheusMetrics::GPUMemoryUsageGaugeSet() {
 void
 PrometheusMetrics::AddVectorsPerSecondGaugeSet(int num_vector, int dim, double time) {
     // MB/s
-    if (!startup_) return;
+    if (!startup_) {
+        return;
+    }
 
     int64_t MtoB = 1024 * 1024;
     int64_t size = num_vector * dim * 4;
@@ -109,7 +130,10 @@ PrometheusMetrics::AddVectorsPerSecondGaugeSet(int num_vector, int dim, double t
 
 void
 PrometheusMetrics::QueryIndexTypePerSecondSet(std::string type, double value) {
-    if (!startup_) return;
+    if (!startup_) {
+        return;
+    }
+
     if (type == "IVF") {
         query_index_IVF_type_per_second_gauge_.Set(value);
     } else if (type == "IDMap") {
@@ -119,19 +143,27 @@ PrometheusMetrics::QueryIndexTypePerSecondSet(std::string type, double value) {
 
 void
 PrometheusMetrics::ConnectionGaugeIncrement() {
-    if (!startup_) return;
+    if (!startup_) {
+        return;
+    }
+
     connection_gauge_.Increment();
 }
 
 void
 PrometheusMetrics::ConnectionGaugeDecrement() {
-    if (!startup_) return;
+    if (!startup_) {
+        return;
+    }
+
     connection_gauge_.Decrement();
 }
 
 void
 PrometheusMetrics::OctetsSet() {
-    if (!startup_) return;
+    if (!startup_) {
+        return;
+    }
 
     // get old stats and reset them
     uint64_t old_inoctets = SystemInfo::GetInstance().get_inoctets();
@@ -147,14 +179,19 @@ PrometheusMetrics::OctetsSet() {
     auto now_time = std::chrono::system_clock::now();
     auto total_microsecond = METRICS_MICROSECONDS(old_time, now_time);
     auto total_second = total_microsecond * micro_to_second;
-    if (total_second == 0) return;
+    if (total_second == 0) {
+        return;
+    }
+
     inoctets_gauge_.Set((in_and_out_octets.first - old_inoctets) / total_second);
     outoctets_gauge_.Set((in_and_out_octets.second - old_outoctets) / total_second);
 }
 
 void
 PrometheusMetrics::CPUCoreUsagePercentSet() {
-    if (!startup_) return;
+    if (!startup_) {
+        return;
+    }
 
     std::vector<double> cpu_core_percent = server::SystemInfo::GetInstance().CPUCorePercent();
 
@@ -166,7 +203,9 @@ PrometheusMetrics::CPUCoreUsagePercentSet() {
 
 void
 PrometheusMetrics::GPUTemperature() {
-    if (!startup_) return;
+    if (!startup_) {
+        return;
+    }
 
     std::vector<uint64_t> GPU_temperatures = server::SystemInfo::GetInstance().GPUTemperature();
 
@@ -178,7 +217,9 @@ PrometheusMetrics::GPUTemperature() {
 
 void
 PrometheusMetrics::CPUTemperature() {
-    if (!startup_) return;
+    if (!startup_) {
+        return;
+    }
 
     std::vector<float> CPU_temperatures = server::SystemInfo::GetInstance().CPUTemperature();
 
diff --git a/cpp/src/metrics/SystemInfo.cpp b/cpp/src/metrics/SystemInfo.cpp
index 68c1182726..4647b1435b 100644
--- a/cpp/src/metrics/SystemInfo.cpp
+++ b/cpp/src/metrics/SystemInfo.cpp
@@ -31,7 +31,8 @@ namespace server {
 
 void
 SystemInfo::Init() {
-    if (initialized_) return;
+    if (initialized_)
+        return;
 
     initialized_ = true;
 
@@ -45,7 +46,8 @@ SystemInfo::Init() {
     file = fopen("/proc/cpuinfo", "r");
     num_processors_ = 0;
     while (fgets(line, 128, file) != NULL) {
-        if (strncmp(line, "processor", 9) == 0) num_processors_++;
+        if (strncmp(line, "processor", 9) == 0)
+            num_processors_++;
         if (strncmp(line, "physical", 8) == 0) {
             num_physical_processors_ = ParseLine(line);
         }
@@ -116,7 +118,8 @@ SystemInfo::GetProcessUsedMemory() {
 
 double
 SystemInfo::MemoryPercent() {
-    if (!initialized_) Init();
+    if (!initialized_)
+        Init();
     return (double)(GetProcessUsedMemory() * 100) / (double)total_ram_;
 }
 
@@ -171,7 +174,8 @@ SystemInfo::getTotalCpuTime(std::vector<uint64_t>& work_time_array) {
 
 double
 SystemInfo::CPUPercent() {
-    if (!initialized_) Init();
+    if (!initialized_)
+        Init();
     struct tms time_sample;
     clock_t now;
     double percent;
@@ -195,7 +199,8 @@ SystemInfo::CPUPercent() {
 std::vector<uint64_t>
 SystemInfo::GPUMemoryTotal() {
     // get GPU usage percent
-    if (!initialized_) Init();
+    if (!initialized_)
+        Init();
     std::vector<uint64_t> result;
     nvmlMemory_t nvmlMemory;
     for (int i = 0; i < num_device_; ++i) {
@@ -209,7 +214,8 @@ SystemInfo::GPUMemoryTotal() {
 
 std::vector<uint64_t>
 SystemInfo::GPUTemperature() {
-    if (!initialized_) Init();
+    if (!initialized_)
+        Init();
     std::vector<uint64_t> result;
     for (int i = 0; i < num_device_; i++) {
         nvmlDevice_t device;
@@ -241,7 +247,8 @@ SystemInfo::CPUTemperature() {
 std::vector<uint64_t>
 SystemInfo::GPUMemoryUsed() {
     // get GPU memory used
-    if (!initialized_) Init();
+    if (!initialized_)
+        Init();
 
     std::vector<uint64_t> result;
     nvmlMemory_t nvmlMemory;
diff --git a/cpp/src/scheduler/ResourceMgr.h b/cpp/src/scheduler/ResourceMgr.h
index b6720a2054..05393041bf 100644
--- a/cpp/src/scheduler/ResourceMgr.h
+++ b/cpp/src/scheduler/ResourceMgr.h
@@ -48,7 +48,7 @@ class ResourceMgr {
     Add(ResourcePtr&& resource);
 
     bool
-    Connect(const std::string& res1, const std::string& res2, Connection& connection);
+    Connect(const std::string& name1, const std::string& name2, Connection& connection);
 
     void
     Clear();
diff --git a/cpp/src/scheduler/action/PushTaskToNeighbour.cpp b/cpp/src/scheduler/action/PushTaskToNeighbour.cpp
index c7514b1e2d..4cafffa365 100644
--- a/cpp/src/scheduler/action/PushTaskToNeighbour.cpp
+++ b/cpp/src/scheduler/action/PushTaskToNeighbour.cpp
@@ -30,7 +30,8 @@ get_neighbours(const ResourcePtr& self) {
     std::vector<ResourcePtr> neighbours;
     for (auto& neighbour_node : self->GetNeighbours()) {
         auto node = neighbour_node.neighbour_node.lock();
-        if (not node) continue;
+        if (not node)
+            continue;
 
         auto resource = std::static_pointer_cast<Resource>(node);
         //        if (not resource->HasExecutor()) continue;
@@ -45,7 +46,8 @@ get_neighbours_with_connetion(const ResourcePtr& self) {
     std::vector<std::pair<ResourcePtr, Connection>> neighbours;
     for (auto& neighbour_node : self->GetNeighbours()) {
         auto node = neighbour_node.neighbour_node.lock();
-        if (not node) continue;
+        if (not node)
+            continue;
 
         auto resource = std::static_pointer_cast<Resource>(node);
         //        if (not resource->HasExecutor()) continue;
diff --git a/cpp/src/scheduler/resource/Resource.cpp b/cpp/src/scheduler/resource/Resource.cpp
index 8273d69d33..48208a07a5 100644
--- a/cpp/src/scheduler/resource/Resource.cpp
+++ b/cpp/src/scheduler/resource/Resource.cpp
@@ -92,7 +92,8 @@ uint64_t
 Resource::NumOfTaskToExec() {
     uint64_t count = 0;
     for (auto& task : task_table_) {
-        if (task->state == TaskTableItemState::LOADED) ++count;
+        if (task->state == TaskTableItemState::LOADED)
+            ++count;
     }
     return count;
 }
@@ -102,7 +103,8 @@ Resource::pick_task_load() {
     auto indexes = task_table_.PickToLoad(10);
     for (auto index : indexes) {
         // try to set one task loading, then return
-        if (task_table_.Load(index)) return task_table_.Get(index);
+        if (task_table_.Load(index))
+            return task_table_.Get(index);
         // else try next
     }
     return nullptr;
@@ -113,7 +115,8 @@ Resource::pick_task_execute() {
     auto indexes = task_table_.PickToExecute(3);
     for (auto index : indexes) {
         // try to set one task executing, then return
-        if (task_table_.Execute(index)) return task_table_.Get(index);
+        if (task_table_.Execute(index))
+            return task_table_.Get(index);
         // else try next
     }
     return nullptr;
diff --git a/cpp/src/scheduler/task/DeleteTask.h b/cpp/src/scheduler/task/DeleteTask.h
index 65e8724940..473fee2681 100644
--- a/cpp/src/scheduler/task/DeleteTask.h
+++ b/cpp/src/scheduler/task/DeleteTask.h
@@ -26,7 +26,7 @@ namespace scheduler {
 
 class XDeleteTask : public Task {
  public:
-    explicit XDeleteTask(const scheduler::DeleteJobPtr& job);
+    explicit XDeleteTask(const scheduler::DeleteJobPtr& delete_job);
 
     void
     Load(LoadType type, uint8_t device_id) override;
diff --git a/cpp/src/sdk/grpc/ClientProxy.cpp b/cpp/src/sdk/grpc/ClientProxy.cpp
index 8ebd577e3a..db4f717eaa 100644
--- a/cpp/src/sdk/grpc/ClientProxy.cpp
+++ b/cpp/src/sdk/grpc/ClientProxy.cpp
@@ -31,9 +31,8 @@ UriCheck(const std::string& uri) {
     size_t index = uri.find_first_of(':', 0);
     if (index == std::string::npos) {
         return false;
-    } else {
-        return true;
     }
+    return true;
 }
 
 Status
@@ -45,11 +44,11 @@ ClientProxy::Connect(const ConnectParam& param) {
         connected_ = true;
         client_ptr_ = std::make_shared<GrpcClient>(channel_);
         return Status::OK();
-    } else {
-        std::string reason = "connect failed!";
-        connected_ = false;
-        return Status(StatusCode::NotConnected, reason);
     }
+
+    std::string reason = "connect failed!";
+    connected_ = false;
+    return Status(StatusCode::NotConnected, reason);
 }
 
 Status
@@ -134,7 +133,7 @@ ClientProxy::CreateIndex(const IndexParam& index_param) {
         // TODO: add index params
         ::milvus::grpc::IndexParam grpc_index_param;
         grpc_index_param.set_table_name(index_param.table_name);
-        grpc_index_param.mutable_index()->set_index_type((int32_t)index_param.index_type);
+        grpc_index_param.mutable_index()->set_index_type(static_cast<int32_t>(index_param.index_type));
         grpc_index_param.mutable_index()->set_nlist(index_param.nlist);
         return client_ptr_->CreateIndex(grpc_index_param);
     } catch (std::exception& ex) {
diff --git a/cpp/src/sdk/include/Status.h b/cpp/src/sdk/include/Status.h
index e9b267c5f7..a81116b31d 100644
--- a/cpp/src/sdk/include/Status.h
+++ b/cpp/src/sdk/include/Status.h
@@ -85,7 +85,7 @@ class Status {
     MoveFrom(Status& s);
 
  private:
-    const char* state_ = nullptr;
+    char* state_ = nullptr;
 };  // Status
 
 }  // namespace milvus
diff --git a/cpp/src/sdk/interface/Status.cpp b/cpp/src/sdk/interface/Status.cpp
index cd46c8c245..a5e89556f2 100644
--- a/cpp/src/sdk/interface/Status.cpp
+++ b/cpp/src/sdk/interface/Status.cpp
@@ -28,7 +28,7 @@ Status::Status(StatusCode code, const std::string& msg) {
     // 4 bytes store message length
     // the left bytes store message string
     const uint32_t length = (uint32_t)msg.size();
-    char* result = new char[length + sizeof(length) + CODE_WIDTH];
+    auto result = new char[length + sizeof(length) + CODE_WIDTH];
     memcpy(result, &code, CODE_WIDTH);
     memcpy(result + CODE_WIDTH, &length, sizeof(length));
     memcpy(result + sizeof(length) + CODE_WIDTH, msg.data(), length);
@@ -75,7 +75,7 @@ Status::CopyFrom(const Status& s) {
     memcpy(&length, s.state_ + CODE_WIDTH, sizeof(length));
     int buff_len = length + sizeof(length) + CODE_WIDTH;
     state_ = new char[buff_len];
-    memcpy((void*)state_, (void*)s.state_, buff_len);
+    memcpy(state_, s.state_, buff_len);
 }
 
 void
diff --git a/cpp/src/server/Config.cpp b/cpp/src/server/Config.cpp
index 788f792feb..76ac246c24 100644
--- a/cpp/src/server/Config.cpp
+++ b/cpp/src/server/Config.cpp
@@ -77,100 +77,146 @@ Config::ValidateConfig() {
     /* server config */
     std::string server_addr;
     s = GetServerConfigAddress(server_addr);
-    if (!s.ok()) return s;
+    if (!s.ok()) {
+        return s;
+    }
 
     std::string server_port;
     s = GetServerConfigPort(server_port);
-    if (!s.ok()) return s;
+    if (!s.ok()) {
+        return s;
+    }
 
     std::string server_mode;
     s = GetServerConfigDeployMode(server_mode);
-    if (!s.ok()) return s;
+    if (!s.ok()) {
+        return s;
+    }
 
     std::string server_time_zone;
     s = GetServerConfigTimeZone(server_time_zone);
-    if (!s.ok()) return s;
+    if (!s.ok()) {
+        return s;
+    }
 
     /* db config */
     std::string db_primary_path;
     s = GetDBConfigPrimaryPath(db_primary_path);
-    if (!s.ok()) return s;
+    if (!s.ok()) {
+        return s;
+    }
 
     std::string db_secondary_path;
     s = GetDBConfigSecondaryPath(db_secondary_path);
-    if (!s.ok()) return s;
+    if (!s.ok()) {
+        return s;
+    }
 
     std::string db_backend_url;
     s = GetDBConfigBackendUrl(db_backend_url);
-    if (!s.ok()) return s;
+    if (!s.ok()) {
+        return s;
+    }
 
     int32_t db_archive_disk_threshold;
     s = GetDBConfigArchiveDiskThreshold(db_archive_disk_threshold);
-    if (!s.ok()) return s;
+    if (!s.ok()) {
+        return s;
+    }
 
     int32_t db_archive_days_threshold;
     s = GetDBConfigArchiveDaysThreshold(db_archive_days_threshold);
-    if (!s.ok()) return s;
+    if (!s.ok()) {
+        return s;
+    }
 
     int32_t db_insert_buffer_size;
     s = GetDBConfigInsertBufferSize(db_insert_buffer_size);
-    if (!s.ok()) return s;
+    if (!s.ok()) {
+        return s;
+    }
 
     int32_t db_build_index_gpu;
     s = GetDBConfigBuildIndexGPU(db_build_index_gpu);
-    if (!s.ok()) return s;
+    if (!s.ok()) {
+        return s;
+    }
 
     /* metric config */
     bool metric_enable_monitor;
     s = GetMetricConfigEnableMonitor(metric_enable_monitor);
-    if (!s.ok()) return s;
+    if (!s.ok()) {
+        return s;
+    }
 
     std::string metric_collector;
     s = GetMetricConfigCollector(metric_collector);
-    if (!s.ok()) return s;
+    if (!s.ok()) {
+        return s;
+    }
 
     std::string metric_prometheus_port;
     s = GetMetricConfigPrometheusPort(metric_prometheus_port);
-    if (!s.ok()) return s;
+    if (!s.ok()) {
+        return s;
+    }
 
     /* cache config */
     int32_t cache_cpu_cache_capacity;
     s = GetCacheConfigCpuCacheCapacity(cache_cpu_cache_capacity);
-    if (!s.ok()) return s;
+    if (!s.ok()) {
+        return s;
+    }
 
     float cache_cpu_cache_threshold;
     s = GetCacheConfigCpuCacheThreshold(cache_cpu_cache_threshold);
-    if (!s.ok()) return s;
+    if (!s.ok()) {
+        return s;
+    }
 
     int32_t cache_gpu_cache_capacity;
     s = GetCacheConfigGpuCacheCapacity(cache_gpu_cache_capacity);
-    if (!s.ok()) return s;
+    if (!s.ok()) {
+        return s;
+    }
 
     float cache_gpu_cache_threshold;
     s = GetCacheConfigGpuCacheThreshold(cache_gpu_cache_threshold);
-    if (!s.ok()) return s;
+    if (!s.ok()) {
+        return s;
+    }
 
     bool cache_insert_data;
     s = GetCacheConfigCacheInsertData(cache_insert_data);
-    if (!s.ok()) return s;
+    if (!s.ok()) {
+        return s;
+    }
 
     /* engine config */
     int32_t engine_use_blas_threshold;
     s = GetEngineConfigUseBlasThreshold(engine_use_blas_threshold);
-    if (!s.ok()) return s;
+    if (!s.ok()) {
+        return s;
+    }
 
     int32_t engine_omp_thread_num;
     s = GetEngineConfigOmpThreadNum(engine_omp_thread_num);
-    if (!s.ok()) return s;
+    if (!s.ok()) {
+        return s;
+    }
 
     /* resource config */
     std::string resource_mode;
     s = GetResourceConfigMode(resource_mode);
-    if (!s.ok()) return s;
+    if (!s.ok()) {
+        return s;
+    }
 
     std::vector<std::string> resource_pool;
     s = GetResourceConfigPool(resource_pool);
-    if (!s.ok()) return s;
+    if (!s.ok()) {
+        return s;
+    }
 
     return Status::OK();
 }
@@ -181,75 +227,119 @@ Config::ResetDefaultConfig() {
 
     /* server config */
     s = SetServerConfigAddress(CONFIG_SERVER_ADDRESS_DEFAULT);
-    if (!s.ok()) return s;
+    if (!s.ok()) {
+        return s;
+    }
 
     s = SetServerConfigPort(CONFIG_SERVER_PORT_DEFAULT);
-    if (!s.ok()) return s;
+    if (!s.ok()) {
+        return s;
+    }
 
     s = SetServerConfigDeployMode(CONFIG_SERVER_DEPLOY_MODE_DEFAULT);
-    if (!s.ok()) return s;
+    if (!s.ok()) {
+        return s;
+    }
 
     s = SetServerConfigTimeZone(CONFIG_SERVER_TIME_ZONE_DEFAULT);
-    if (!s.ok()) return s;
+    if (!s.ok()) {
+        return s;
+    }
 
     /* db config */
     s = SetDBConfigPrimaryPath(CONFIG_DB_PRIMARY_PATH_DEFAULT);
-    if (!s.ok()) return s;
+    if (!s.ok()) {
+        return s;
+    }
 
     s = SetDBConfigSecondaryPath(CONFIG_DB_SECONDARY_PATH_DEFAULT);
-    if (!s.ok()) return s;
+    if (!s.ok()) {
+        return s;
+    }
 
     s = SetDBConfigBackendUrl(CONFIG_DB_BACKEND_URL_DEFAULT);
-    if (!s.ok()) return s;
+    if (!s.ok()) {
+        return s;
+    }
 
     s = SetDBConfigArchiveDiskThreshold(CONFIG_DB_ARCHIVE_DISK_THRESHOLD_DEFAULT);
-    if (!s.ok()) return s;
+    if (!s.ok()) {
+        return s;
+    }
 
     s = SetDBConfigArchiveDaysThreshold(CONFIG_DB_ARCHIVE_DAYS_THRESHOLD_DEFAULT);
-    if (!s.ok()) return s;
+    if (!s.ok()) {
+        return s;
+    }
 
     s = SetDBConfigInsertBufferSize(CONFIG_DB_INSERT_BUFFER_SIZE_DEFAULT);
-    if (!s.ok()) return s;
+    if (!s.ok()) {
+        return s;
+    }
 
     s = SetDBConfigBuildIndexGPU(CONFIG_DB_BUILD_INDEX_GPU_DEFAULT);
-    if (!s.ok()) return s;
+    if (!s.ok()) {
+        return s;
+    }
 
     /* metric config */
     s = SetMetricConfigEnableMonitor(CONFIG_METRIC_ENABLE_MONITOR_DEFAULT);
-    if (!s.ok()) return s;
+    if (!s.ok()) {
+        return s;
+    }
 
     s = SetMetricConfigCollector(CONFIG_METRIC_COLLECTOR_DEFAULT);
-    if (!s.ok()) return s;
+    if (!s.ok()) {
+        return s;
+    }
 
     s = SetMetricConfigPrometheusPort(CONFIG_METRIC_PROMETHEUS_PORT_DEFAULT);
-    if (!s.ok()) return s;
+    if (!s.ok()) {
+        return s;
+    }
 
     /* cache config */
     s = SetCacheConfigCpuCacheCapacity(CONFIG_CACHE_CPU_CACHE_CAPACITY_DEFAULT);
-    if (!s.ok()) return s;
+    if (!s.ok()) {
+        return s;
+    }
 
     s = SetCacheConfigCpuCacheThreshold(CONFIG_CACHE_CPU_CACHE_THRESHOLD_DEFAULT);
-    if (!s.ok()) return s;
+    if (!s.ok()) {
+        return s;
+    }
 
     s = SetCacheConfigGpuCacheCapacity(CONFIG_CACHE_GPU_CACHE_CAPACITY_DEFAULT);
-    if (!s.ok()) return s;
+    if (!s.ok()) {
+        return s;
+    }
 
     s = SetCacheConfigGpuCacheThreshold(CONFIG_CACHE_GPU_CACHE_THRESHOLD_DEFAULT);
-    if (!s.ok()) return s;
+    if (!s.ok()) {
+        return s;
+    }
 
     s = SetCacheConfigCacheInsertData(CONFIG_CACHE_CACHE_INSERT_DATA_DEFAULT);
-    if (!s.ok()) return s;
+    if (!s.ok()) {
+        return s;
+    }
 
     /* engine config */
     s = SetEngineConfigUseBlasThreshold(CONFIG_ENGINE_USE_BLAS_THRESHOLD_DEFAULT);
-    if (!s.ok()) return s;
+    if (!s.ok()) {
+        return s;
+    }
 
     s = SetEngineConfigOmpThreadNum(CONFIG_ENGINE_OMP_THREAD_NUM_DEFAULT);
-    if (!s.ok()) return s;
+    if (!s.ok()) {
+        return s;
+    }
 
     /* resource config */
     s = SetResourceConfigMode(CONFIG_RESOURCE_MODE_DEFAULT);
-    if (!s.ok()) return s;
+    if (!s.ok()) {
+        return s;
+    }
 
     return Status::OK();
 }
@@ -423,13 +513,16 @@ Config::CheckCacheConfigCpuCacheCapacity(const std::string& value) {
         CommonUtil::GetSystemMemInfo(total_mem, free_mem);
         if (cpu_cache_capacity >= total_mem) {
             return Status(SERVER_INVALID_ARGUMENT, "Cache config cpu_cache_capacity exceed system memory: " + value);
-        } else if (cpu_cache_capacity > (double)total_mem * 0.9) {
+        } else if (cpu_cache_capacity > static_cast<double>(total_mem * 0.9)) {
             std::cerr << "Warning: cpu_cache_capacity value is too big" << std::endl;
         }
 
         int32_t buffer_value;
         Status s = GetDBConfigInsertBufferSize(buffer_value);
-        if (!s.ok()) return s;
+        if (!s.ok()) {
+            return s;
+        }
+
         int64_t insert_buffer_size = buffer_value * GB;
         if (insert_buffer_size + cpu_cache_capacity >= total_mem) {
             return Status(SERVER_INVALID_ARGUMENT, "Sum of cpu_cache_capacity and buffer_size exceed system memory");
@@ -459,7 +552,10 @@ Config::CheckCacheConfigGpuCacheCapacity(const std::string& value) {
         uint64_t gpu_cache_capacity = std::stoi(value) * GB;
         int gpu_index;
         Status s = GetDBConfigBuildIndexGPU(gpu_index);
-        if (!s.ok()) return s;
+        if (!s.ok()) {
+            return s;
+        }
+
         size_t gpu_memory;
         if (!ValidationUtil::GetGpuMemory(gpu_index, gpu_memory).ok()) {
             return Status(SERVER_UNEXPECTED_ERROR,
@@ -507,12 +603,13 @@ Status
 Config::CheckEngineConfigOmpThreadNum(const std::string& value) {
     if (!ValidationUtil::ValidateStringIsNumber(value).ok()) {
         return Status(SERVER_INVALID_ARGUMENT, "Invalid engine config omp_thread_num: " + value);
-    } else {
-        int32_t omp_thread = std::stoi(value);
-        uint32_t sys_thread_cnt = 8;
-        if (omp_thread > CommonUtil::GetSystemAvailableThreads(sys_thread_cnt)) {
-            return Status(SERVER_INVALID_ARGUMENT, "Invalid engine config omp_thread_num: " + value);
-        }
+    }
+
+    int32_t omp_thread = std::stoi(value);
+    uint32_t sys_thread_cnt = 8;
+    CommonUtil::GetSystemAvailableThreads(sys_thread_cnt);
+    if (omp_thread > static_cast<int32_t>(sys_thread_cnt)) {
+        return Status(SERVER_INVALID_ARGUMENT, "Invalid engine config omp_thread_num: " + value);
     }
     return Status::OK();
 }
@@ -548,9 +645,8 @@ Config::GetConfigValueInMem(const std::string& parent_key, const std::string& ch
         config_map_[parent_key].find(child_key) != config_map_[parent_key].end()) {
         value = config_map_[parent_key][child_key];
         return Status::OK();
-    } else {
-        return Status(SERVER_UNEXPECTED_ERROR, "key not exist");
     }
+    return Status(SERVER_UNEXPECTED_ERROR, "key not exist");
 }
 
 void
@@ -849,7 +945,10 @@ Status
 Config::GetDBConfigArchiveDiskThreshold(int32_t& value) {
     std::string str = GetDBConfigStrArchiveDiskThreshold();
     Status s = CheckDBConfigArchiveDiskThreshold(str);
-    if (!s.ok()) return s;
+    if (!s.ok()) {
+        return s;
+    }
+
     value = std::stoi(str);
     return Status::OK();
 }
@@ -858,7 +957,10 @@ Status
 Config::GetDBConfigArchiveDaysThreshold(int32_t& value) {
     std::string str = GetDBConfigStrArchiveDaysThreshold();
     Status s = CheckDBConfigArchiveDaysThreshold(str);
-    if (!s.ok()) return s;
+    if (!s.ok()) {
+        return s;
+    }
+
     value = std::stoi(str);
     return Status::OK();
 }
@@ -867,7 +969,10 @@ Status
 Config::GetDBConfigInsertBufferSize(int32_t& value) {
     std::string str = GetDBConfigStrInsertBufferSize();
     Status s = CheckDBConfigInsertBufferSize(str);
-    if (!s.ok()) return s;
+    if (!s.ok()) {
+        return s;
+    }
+
     value = std::stoi(str);
     return Status::OK();
 }
@@ -876,7 +981,10 @@ Status
 Config::GetDBConfigBuildIndexGPU(int32_t& value) {
     std::string str = GetDBConfigStrBuildIndexGPU();
     Status s = CheckDBConfigBuildIndexGPU(str);
-    if (!s.ok()) return s;
+    if (!s.ok()) {
+        return s;
+    }
+
     value = std::stoi(str);
     return Status::OK();
 }
@@ -885,7 +993,10 @@ Status
 Config::GetMetricConfigEnableMonitor(bool& value) {
     std::string str = GetMetricConfigStrEnableMonitor();
     Status s = CheckMetricConfigEnableMonitor(str);
-    if (!s.ok()) return s;
+    if (!s.ok()) {
+        return s;
+    }
+
     std::transform(str.begin(), str.end(), str.begin(), ::tolower);
     value = (str == "true" || str == "on" || str == "yes" || str == "1");
     return Status::OK();
@@ -907,7 +1018,10 @@ Status
 Config::GetCacheConfigCpuCacheCapacity(int32_t& value) {
     std::string str = GetCacheConfigStrCpuCacheCapacity();
     Status s = CheckCacheConfigCpuCacheCapacity(str);
-    if (!s.ok()) return s;
+    if (!s.ok()) {
+        return s;
+    }
+
     value = std::stoi(str);
     return Status::OK();
 }
@@ -916,7 +1030,10 @@ Status
 Config::GetCacheConfigCpuCacheThreshold(float& value) {
     std::string str = GetCacheConfigStrCpuCacheThreshold();
     Status s = CheckCacheConfigCpuCacheThreshold(str);
-    if (!s.ok()) return s;
+    if (!s.ok()) {
+        return s;
+    }
+
     value = std::stof(str);
     return Status::OK();
 }
@@ -925,7 +1042,10 @@ Status
 Config::GetCacheConfigGpuCacheCapacity(int32_t& value) {
     std::string str = GetCacheConfigStrGpuCacheCapacity();
     Status s = CheckCacheConfigGpuCacheCapacity(str);
-    if (!s.ok()) return s;
+    if (!s.ok()) {
+        return s;
+    }
+
     value = std::stoi(str);
     return Status::OK();
 }
@@ -934,7 +1054,10 @@ Status
 Config::GetCacheConfigGpuCacheThreshold(float& value) {
     std::string str = GetCacheConfigStrGpuCacheThreshold();
     Status s = CheckCacheConfigGpuCacheThreshold(str);
-    if (!s.ok()) return s;
+    if (!s.ok()) {
+        return s;
+    }
+
     value = std::stof(str);
     return Status::OK();
 }
@@ -943,7 +1066,10 @@ Status
 Config::GetCacheConfigCacheInsertData(bool& value) {
     std::string str = GetCacheConfigStrCacheInsertData();
     Status s = CheckCacheConfigCacheInsertData(str);
-    if (!s.ok()) return s;
+    if (!s.ok()) {
+        return s;
+    }
+
     std::transform(str.begin(), str.end(), str.begin(), ::tolower);
     value = (str == "true" || str == "on" || str == "yes" || str == "1");
     return Status::OK();
@@ -953,7 +1079,10 @@ Status
 Config::GetEngineConfigUseBlasThreshold(int32_t& value) {
     std::string str = GetEngineConfigStrUseBlasThreshold();
     Status s = CheckEngineConfigUseBlasThreshold(str);
-    if (!s.ok()) return s;
+    if (!s.ok()) {
+        return s;
+    }
+
     value = std::stoi(str);
     return Status::OK();
 }
@@ -962,7 +1091,10 @@ Status
 Config::GetEngineConfigOmpThreadNum(int32_t& value) {
     std::string str = GetEngineConfigStrOmpThreadNum();
     Status s = CheckEngineConfigOmpThreadNum(str);
-    if (!s.ok()) return s;
+    if (!s.ok()) {
+        return s;
+    }
+
     value = std::stoi(str);
     return Status::OK();
 }
@@ -985,7 +1117,10 @@ Config::GetResourceConfigPool(std::vector<std::string>& value) {
 Status
 Config::SetServerConfigAddress(const std::string& value) {
     Status s = CheckServerConfigAddress(value);
-    if (!s.ok()) return s;
+    if (!s.ok()) {
+        return s;
+    }
+
     SetConfigValueInMem(CONFIG_SERVER, CONFIG_SERVER_ADDRESS, value);
     return Status::OK();
 }
@@ -993,7 +1128,10 @@ Config::SetServerConfigAddress(const std::string& value) {
 Status
 Config::SetServerConfigPort(const std::string& value) {
     Status s = CheckServerConfigPort(value);
-    if (!s.ok()) return s;
+    if (!s.ok()) {
+        return s;
+    }
+
     SetConfigValueInMem(CONFIG_SERVER, CONFIG_SERVER_PORT, value);
     return Status::OK();
 }
@@ -1001,7 +1139,10 @@ Config::SetServerConfigPort(const std::string& value) {
 Status
 Config::SetServerConfigDeployMode(const std::string& value) {
     Status s = CheckServerConfigDeployMode(value);
-    if (!s.ok()) return s;
+    if (!s.ok()) {
+        return s;
+    }
+
     SetConfigValueInMem(CONFIG_SERVER, CONFIG_SERVER_DEPLOY_MODE, value);
     return Status::OK();
 }
@@ -1009,7 +1150,10 @@ Config::SetServerConfigDeployMode(const std::string& value) {
 Status
 Config::SetServerConfigTimeZone(const std::string& value) {
     Status s = CheckServerConfigTimeZone(value);
-    if (!s.ok()) return s;
+    if (!s.ok()) {
+        return s;
+    }
+
     SetConfigValueInMem(CONFIG_SERVER, CONFIG_SERVER_TIME_ZONE, value);
     return Status::OK();
 }
@@ -1018,7 +1162,10 @@ Config::SetServerConfigTimeZone(const std::string& value) {
 Status
 Config::SetDBConfigPrimaryPath(const std::string& value) {
     Status s = CheckDBConfigPrimaryPath(value);
-    if (!s.ok()) return s;
+    if (!s.ok()) {
+        return s;
+    }
+
     SetConfigValueInMem(CONFIG_DB, CONFIG_DB_PRIMARY_PATH, value);
     return Status::OK();
 }
@@ -1026,7 +1173,10 @@ Config::SetDBConfigPrimaryPath(const std::string& value) {
 Status
 Config::SetDBConfigSecondaryPath(const std::string& value) {
     Status s = CheckDBConfigSecondaryPath(value);
-    if (!s.ok()) return s;
+    if (!s.ok()) {
+        return s;
+    }
+
     SetConfigValueInMem(CONFIG_DB, CONFIG_DB_SECONDARY_PATH, value);
     return Status::OK();
 }
@@ -1034,7 +1184,10 @@ Config::SetDBConfigSecondaryPath(const std::string& value) {
 Status
 Config::SetDBConfigBackendUrl(const std::string& value) {
     Status s = CheckDBConfigBackendUrl(value);
-    if (!s.ok()) return s;
+    if (!s.ok()) {
+        return s;
+    }
+
     SetConfigValueInMem(CONFIG_DB, CONFIG_DB_BACKEND_URL, value);
     return Status::OK();
 }
@@ -1042,7 +1195,10 @@ Config::SetDBConfigBackendUrl(const std::string& value) {
 Status
 Config::SetDBConfigArchiveDiskThreshold(const std::string& value) {
     Status s = CheckDBConfigArchiveDiskThreshold(value);
-    if (!s.ok()) return s;
+    if (!s.ok()) {
+        return s;
+    }
+
     SetConfigValueInMem(CONFIG_DB, CONFIG_DB_ARCHIVE_DISK_THRESHOLD, value);
     return Status::OK();
 }
@@ -1050,7 +1206,10 @@ Config::SetDBConfigArchiveDiskThreshold(const std::string& value) {
 Status
 Config::SetDBConfigArchiveDaysThreshold(const std::string& value) {
     Status s = CheckDBConfigArchiveDaysThreshold(value);
-    if (!s.ok()) return s;
+    if (!s.ok()) {
+        return s;
+    }
+
     SetConfigValueInMem(CONFIG_DB, CONFIG_DB_ARCHIVE_DAYS_THRESHOLD, value);
     return Status::OK();
 }
@@ -1058,7 +1217,10 @@ Config::SetDBConfigArchiveDaysThreshold(const std::string& value) {
 Status
 Config::SetDBConfigInsertBufferSize(const std::string& value) {
     Status s = CheckDBConfigInsertBufferSize(value);
-    if (!s.ok()) return s;
+    if (!s.ok()) {
+        return s;
+    }
+
     SetConfigValueInMem(CONFIG_DB, CONFIG_DB_INSERT_BUFFER_SIZE, value);
     return Status::OK();
 }
@@ -1066,7 +1228,10 @@ Config::SetDBConfigInsertBufferSize(const std::string& value) {
 Status
 Config::SetDBConfigBuildIndexGPU(const std::string& value) {
     Status s = CheckDBConfigBuildIndexGPU(value);
-    if (!s.ok()) return s;
+    if (!s.ok()) {
+        return s;
+    }
+
     SetConfigValueInMem(CONFIG_DB, CONFIG_DB_BUILD_INDEX_GPU, value);
     return Status::OK();
 }
@@ -1075,7 +1240,10 @@ Config::SetDBConfigBuildIndexGPU(const std::string& value) {
 Status
 Config::SetMetricConfigEnableMonitor(const std::string& value) {
     Status s = CheckMetricConfigEnableMonitor(value);
-    if (!s.ok()) return s;
+    if (!s.ok()) {
+        return s;
+    }
+
     SetConfigValueInMem(CONFIG_DB, CONFIG_METRIC_ENABLE_MONITOR, value);
     return Status::OK();
 }
@@ -1083,7 +1251,10 @@ Config::SetMetricConfigEnableMonitor(const std::string& value) {
 Status
 Config::SetMetricConfigCollector(const std::string& value) {
     Status s = CheckMetricConfigCollector(value);
-    if (!s.ok()) return s;
+    if (!s.ok()) {
+        return s;
+    }
+
     SetConfigValueInMem(CONFIG_DB, CONFIG_METRIC_COLLECTOR, value);
     return Status::OK();
 }
@@ -1091,7 +1262,10 @@ Config::SetMetricConfigCollector(const std::string& value) {
 Status
 Config::SetMetricConfigPrometheusPort(const std::string& value) {
     Status s = CheckMetricConfigPrometheusPort(value);
-    if (!s.ok()) return s;
+    if (!s.ok()) {
+        return s;
+    }
+
     SetConfigValueInMem(CONFIG_DB, CONFIG_METRIC_PROMETHEUS_PORT, value);
     return Status::OK();
 }
@@ -1100,7 +1274,10 @@ Config::SetMetricConfigPrometheusPort(const std::string& value) {
 Status
 Config::SetCacheConfigCpuCacheCapacity(const std::string& value) {
     Status s = CheckCacheConfigCpuCacheCapacity(value);
-    if (!s.ok()) return s;
+    if (!s.ok()) {
+        return s;
+    }
+
     SetConfigValueInMem(CONFIG_DB, CONFIG_CACHE_CPU_CACHE_CAPACITY, value);
     return Status::OK();
 }
@@ -1108,7 +1285,10 @@ Config::SetCacheConfigCpuCacheCapacity(const std::string& value) {
 Status
 Config::SetCacheConfigCpuCacheThreshold(const std::string& value) {
     Status s = CheckCacheConfigCpuCacheThreshold(value);
-    if (!s.ok()) return s;
+    if (!s.ok()) {
+        return s;
+    }
+
     SetConfigValueInMem(CONFIG_DB, CONFIG_CACHE_CPU_CACHE_THRESHOLD, value);
     return Status::OK();
 }
@@ -1116,7 +1296,10 @@ Config::SetCacheConfigCpuCacheThreshold(const std::string& value) {
 Status
 Config::SetCacheConfigGpuCacheCapacity(const std::string& value) {
     Status s = CheckCacheConfigGpuCacheCapacity(value);
-    if (!s.ok()) return s;
+    if (!s.ok()) {
+        return s;
+    }
+
     SetConfigValueInMem(CONFIG_DB, CONFIG_CACHE_GPU_CACHE_CAPACITY, value);
     return Status::OK();
 }
@@ -1124,7 +1307,10 @@ Config::SetCacheConfigGpuCacheCapacity(const std::string& value) {
 Status
 Config::SetCacheConfigGpuCacheThreshold(const std::string& value) {
     Status s = CheckCacheConfigGpuCacheThreshold(value);
-    if (!s.ok()) return s;
+    if (!s.ok()) {
+        return s;
+    }
+
     SetConfigValueInMem(CONFIG_DB, CONFIG_CACHE_GPU_CACHE_THRESHOLD, value);
     return Status::OK();
 }
@@ -1132,7 +1318,10 @@ Config::SetCacheConfigGpuCacheThreshold(const std::string& value) {
 Status
 Config::SetCacheConfigCacheInsertData(const std::string& value) {
     Status s = CheckCacheConfigCacheInsertData(value);
-    if (!s.ok()) return s;
+    if (!s.ok()) {
+        return s;
+    }
+
     SetConfigValueInMem(CONFIG_DB, CONFIG_CACHE_CACHE_INSERT_DATA, value);
     return Status::OK();
 }
@@ -1141,7 +1330,10 @@ Config::SetCacheConfigCacheInsertData(const std::string& value) {
 Status
 Config::SetEngineConfigUseBlasThreshold(const std::string& value) {
     Status s = CheckEngineConfigUseBlasThreshold(value);
-    if (!s.ok()) return s;
+    if (!s.ok()) {
+        return s;
+    }
+
     SetConfigValueInMem(CONFIG_DB, CONFIG_ENGINE_USE_BLAS_THRESHOLD, value);
     return Status::OK();
 }
@@ -1149,7 +1341,10 @@ Config::SetEngineConfigUseBlasThreshold(const std::string& value) {
 Status
 Config::SetEngineConfigOmpThreadNum(const std::string& value) {
     Status s = CheckEngineConfigOmpThreadNum(value);
-    if (!s.ok()) return s;
+    if (!s.ok()) {
+        return s;
+    }
+
     SetConfigValueInMem(CONFIG_DB, CONFIG_ENGINE_OMP_THREAD_NUM, value);
     return Status::OK();
 }
@@ -1158,7 +1353,10 @@ Config::SetEngineConfigOmpThreadNum(const std::string& value) {
 Status
 Config::SetResourceConfigMode(const std::string& value) {
     Status s = CheckResourceConfigMode(value);
-    if (!s.ok()) return s;
+    if (!s.ok()) {
+        return s;
+    }
+
     SetConfigValueInMem(CONFIG_DB, CONFIG_RESOURCE_MODE, value);
     return Status::OK();
 }
diff --git a/cpp/src/server/DBWrapper.cpp b/cpp/src/server/DBWrapper.cpp
index c0e02f24e4..713714cadc 100644
--- a/cpp/src/server/DBWrapper.cpp
+++ b/cpp/src/server/DBWrapper.cpp
@@ -30,9 +30,6 @@ namespace zilliz {
 namespace milvus {
 namespace server {
 
-DBWrapper::DBWrapper() {
-}
-
 Status
 DBWrapper::StartService() {
     Config& config = Config::GetInstance();
@@ -41,27 +38,37 @@ DBWrapper::StartService() {
     engine::DBOptions opt;
 
     s = config.GetDBConfigBackendUrl(opt.meta_.backend_uri_);
-    if (!s.ok()) return s;
+    if (!s.ok()) {
+        return s;
+    }
 
     std::string path;
     s = config.GetDBConfigPrimaryPath(path);
-    if (!s.ok()) return s;
+    if (!s.ok()) {
+        return s;
+    }
 
     opt.meta_.path_ = path + "/db";
 
     std::string db_slave_path;
     s = config.GetDBConfigSecondaryPath(db_slave_path);
-    if (!s.ok()) return s;
+    if (!s.ok()) {
+        return s;
+    }
 
     StringHelpFunctions::SplitStringByDelimeter(db_slave_path, ";", opt.meta_.slave_paths_);
 
     // cache config
     s = config.GetCacheConfigCacheInsertData(opt.insert_cache_immediately_);
-    if (!s.ok()) return s;
+    if (!s.ok()) {
+        return s;
+    }
 
     std::string mode;
     s = config.GetServerConfigDeployMode(mode);
-    if (!s.ok()) return s;
+    if (!s.ok()) {
+        return s;
+    }
 
     if (mode == "single") {
         opt.mode_ = engine::DBOptions::MODE::SINGLE;
@@ -78,14 +85,17 @@ DBWrapper::StartService() {
     // engine config
     int32_t omp_thread;
     s = config.GetEngineConfigOmpThreadNum(omp_thread);
-    if (!s.ok()) return s;
+    if (!s.ok()) {
+        return s;
+    }
+
     if (omp_thread > 0) {
         omp_set_num_threads(omp_thread);
         SERVER_LOG_DEBUG << "Specify openmp thread number: " << omp_thread;
     } else {
         uint32_t sys_thread_cnt = 8;
         if (CommonUtil::GetSystemAvailableThreads(sys_thread_cnt)) {
-            omp_thread = (int32_t)ceil(sys_thread_cnt * 0.5);
+            omp_thread = static_cast<int32_t>(ceil(sys_thread_cnt * 0.5));
             omp_set_num_threads(omp_thread);
         }
     }
@@ -93,20 +103,29 @@ DBWrapper::StartService() {
     // init faiss global variable
     int32_t use_blas_threshold;
     s = config.GetEngineConfigUseBlasThreshold(use_blas_threshold);
-    if (!s.ok()) return s;
+    if (!s.ok()) {
+        return s;
+    }
+
     faiss::distance_compute_blas_threshold = use_blas_threshold;
 
     // set archive config
     engine::ArchiveConf::CriteriaT criterial;
     int32_t disk, days;
     s = config.GetDBConfigArchiveDiskThreshold(disk);
-    if (!s.ok()) return s;
+    if (!s.ok()) {
+        return s;
+    }
+
     if (disk > 0) {
         criterial[engine::ARCHIVE_CONF_DISK] = disk;
     }
 
     s = config.GetDBConfigArchiveDaysThreshold(days);
-    if (!s.ok()) return s;
+    if (!s.ok()) {
+        return s;
+    }
+
     if (days > 0) {
         criterial[engine::ARCHIVE_CONF_DAYS] = days;
     }
diff --git a/cpp/src/server/DBWrapper.h b/cpp/src/server/DBWrapper.h
index 5a035e44bc..6adc68dcb3 100644
--- a/cpp/src/server/DBWrapper.h
+++ b/cpp/src/server/DBWrapper.h
@@ -28,7 +28,7 @@ namespace server {
 
 class DBWrapper {
  private:
-    DBWrapper();
+    DBWrapper() = default;
     ~DBWrapper() = default;
 
  public:
diff --git a/cpp/src/server/Server.cpp b/cpp/src/server/Server.cpp
index b86f386acc..2e06cccf8a 100644
--- a/cpp/src/server/Server.cpp
+++ b/cpp/src/server/Server.cpp
@@ -146,7 +146,7 @@ Server::Daemonize() {
 
 void
 Server::Start() {
-    if (daemonized_) {
+    if (daemonized_ != 0) {
         Daemonize();
     }
 
diff --git a/cpp/src/server/grpc_impl/GrpcRequestHandler.h b/cpp/src/server/grpc_impl/GrpcRequestHandler.h
index 73f05572de..66ec126371 100644
--- a/cpp/src/server/grpc_impl/GrpcRequestHandler.h
+++ b/cpp/src/server/grpc_impl/GrpcRequestHandler.h
@@ -227,7 +227,7 @@ class GrpcRequestHandler final : public ::milvus::grpc::MilvusService::Service {
      */
     ::grpc::Status
     ShowTables(::grpc::ServerContext* context, const ::milvus::grpc::Command* request,
-               ::milvus::grpc::TableNameList* table_name_list) override;
+               ::milvus::grpc::TableNameList* response) override;
 
     /**
      * @brief Give the server status
diff --git a/cpp/src/server/grpc_impl/GrpcRequestScheduler.cpp b/cpp/src/server/grpc_impl/GrpcRequestScheduler.cpp
index fc302414c2..9135cd6f6c 100644
--- a/cpp/src/server/grpc_impl/GrpcRequestScheduler.cpp
+++ b/cpp/src/server/grpc_impl/GrpcRequestScheduler.cpp
@@ -163,7 +163,8 @@ GrpcRequestScheduler::Stop() {
     }
 
     for (auto iter : execute_threads_) {
-        if (iter == nullptr) continue;
+        if (iter == nullptr)
+            continue;
 
         iter->join();
     }
diff --git a/cpp/src/server/grpc_impl/GrpcRequestScheduler.h b/cpp/src/server/grpc_impl/GrpcRequestScheduler.h
index b5a87c0bfa..d38f4c67ac 100644
--- a/cpp/src/server/grpc_impl/GrpcRequestScheduler.h
+++ b/cpp/src/server/grpc_impl/GrpcRequestScheduler.h
@@ -69,7 +69,7 @@ class GrpcBaseTask {
     OnExecute() = 0;
 
     Status
-    SetStatus(ErrorCode error_code, const std::string& msg);
+    SetStatus(ErrorCode error_code, const std::string& error_msg);
 
  protected:
     mutable std::mutex finish_mtx_;
diff --git a/cpp/src/server/grpc_impl/GrpcRequestTask.cpp b/cpp/src/server/grpc_impl/GrpcRequestTask.cpp
index 7ced2e69c1..a76552b65b 100644
--- a/cpp/src/server/grpc_impl/GrpcRequestTask.cpp
+++ b/cpp/src/server/grpc_impl/GrpcRequestTask.cpp
@@ -159,7 +159,7 @@ CreateTableTask::OnExecute() {
         // step 2: construct table schema
         engine::meta::TableSchema table_info;
         table_info.table_id_ = schema_->table_name();
-        table_info.dimension_ = (uint16_t)schema_->dimension();
+        table_info.dimension_ = static_cast<uint16_t>(schema_->dimension());
         table_info.index_file_size_ = schema_->index_file_size();
         table_info.metric_type_ = schema_->metric_type();
 
@@ -446,13 +446,13 @@ InsertTask::OnExecute() {
         // all user provide id, or all internal id
         bool user_provide_ids = !insert_param_->row_id_array().empty();
         // user already provided id before, all insert action require user id
-        if ((table_info.flag_ & engine::meta::FLAG_MASK_HAS_USERID) && !user_provide_ids) {
+        if ((table_info.flag_ & engine::meta::FLAG_MASK_HAS_USERID) != 0 && !user_provide_ids) {
             return Status(SERVER_ILLEGAL_VECTOR_ID,
                           "Table vector ids are user defined, please provide id for this batch");
         }
 
         // user didn't provided id before, no need to provide user id
-        if ((table_info.flag_ & engine::meta::FLAG_MASK_NO_USERID) && user_provide_ids) {
+        if ((table_info.flag_ & engine::meta::FLAG_MASK_NO_USERID) != 0 && user_provide_ids) {
             return Status(SERVER_ILLEGAL_VECTOR_ID,
                           "Table vector ids are auto generated, no need to provide id for this batch");
         }
@@ -487,12 +487,12 @@ InsertTask::OnExecute() {
         rc.ElapseFromBegin("prepare vectors data");
 
         // step 5: insert vectors
-        auto vec_count = (uint64_t)insert_param_->row_record_array_size();
+        auto vec_count = static_cast<uint64_t>(insert_param_->row_record_array_size());
         std::vector<int64_t> vec_ids(insert_param_->row_id_array_size(), 0);
         if (!insert_param_->row_id_array().empty()) {
             const int64_t* src_data = insert_param_->row_id_array().data();
             int64_t* target_data = vec_ids.data();
-            memcpy(target_data, src_data, (size_t)(sizeof(int64_t) * insert_param_->row_id_array_size()));
+            memcpy(target_data, src_data, static_cast<size_t>(sizeof(int64_t) * insert_param_->row_id_array_size()));
         }
 
         status = DBWrapper::DB()->InsertVectors(insert_param_->table_name(), vec_count, vec_f.data(), vec_ids);
@@ -710,7 +710,7 @@ CountTableTask::OnExecute() {
             return status;
         }
 
-        row_count_ = (int64_t)row_count;
+        row_count_ = static_cast<int64_t>(row_count);
 
         rc.ElapseFromBegin("total cost");
     } catch (std::exception& ex) {
diff --git a/cpp/src/server/grpc_impl/GrpcRequestTask.h b/cpp/src/server/grpc_impl/GrpcRequestTask.h
index f0e77ea791..af5ed2bc80 100644
--- a/cpp/src/server/grpc_impl/GrpcRequestTask.h
+++ b/cpp/src/server/grpc_impl/GrpcRequestTask.h
@@ -41,7 +41,7 @@ class CreateTableTask : public GrpcBaseTask {
     Create(const ::milvus::grpc::TableSchema* schema);
 
  protected:
-    explicit CreateTableTask(const ::milvus::grpc::TableSchema* request);
+    explicit CreateTableTask(const ::milvus::grpc::TableSchema* schema);
 
     Status
     OnExecute() override;
@@ -57,7 +57,7 @@ class HasTableTask : public GrpcBaseTask {
     Create(const std::string& table_name, bool& has_table);
 
  protected:
-    HasTableTask(const std::string& request, bool& has_table);
+    HasTableTask(const std::string& table_name, bool& has_table);
 
     Status
     OnExecute() override;
@@ -104,10 +104,10 @@ class DropTableTask : public GrpcBaseTask {
 class CreateIndexTask : public GrpcBaseTask {
  public:
     static BaseTaskPtr
-    Create(const ::milvus::grpc::IndexParam* index_Param);
+    Create(const ::milvus::grpc::IndexParam* index_param);
 
  protected:
-    explicit CreateIndexTask(const ::milvus::grpc::IndexParam* index_Param);
+    explicit CreateIndexTask(const ::milvus::grpc::IndexParam* index_param);
 
     Status
     OnExecute() override;
@@ -136,10 +136,10 @@ class ShowTablesTask : public GrpcBaseTask {
 class InsertTask : public GrpcBaseTask {
  public:
     static BaseTaskPtr
-    Create(const ::milvus::grpc::InsertParam* insert_Param, ::milvus::grpc::VectorIds* record_ids_);
+    Create(const ::milvus::grpc::InsertParam* insert_param, ::milvus::grpc::VectorIds* record_ids);
 
  protected:
-    InsertTask(const ::milvus::grpc::InsertParam* insert_Param, ::milvus::grpc::VectorIds* record_ids_);
+    InsertTask(const ::milvus::grpc::InsertParam* insert_param, ::milvus::grpc::VectorIds* record_ids);
 
     Status
     OnExecute() override;
diff --git a/cpp/src/utils/CommonUtil.cpp b/cpp/src/utils/CommonUtil.cpp
index 760c54c4a7..14ed34481f 100644
--- a/cpp/src/utils/CommonUtil.cpp
+++ b/cpp/src/utils/CommonUtil.cpp
@@ -59,7 +59,9 @@ CommonUtil::GetSystemAvailableThreads(uint32_t& thread_count) {
     // threadCnt = std::thread::hardware_concurrency();
     thread_count = sysconf(_SC_NPROCESSORS_CONF);
     thread_count *= THREAD_MULTIPLY_CPU;
-    if (thread_count == 0) thread_count = 8;
+    if (thread_count == 0) {
+        thread_count = 8;
+    }
 
     return true;
 }
@@ -162,9 +164,9 @@ CommonUtil::GetFileSize(const std::string& path) {
     struct stat file_info;
     if (stat(path.c_str(), &file_info) < 0) {
         return 0;
-    } else {
-        return (uint64_t)file_info.st_size;
     }
+
+    return static_cast<uint64_t>(file_info.st_size);
 }
 
 std::string
diff --git a/cpp/src/utils/Status.cpp b/cpp/src/utils/Status.cpp
index 3f807a8a51..95132d3a2a 100644
--- a/cpp/src/utils/Status.cpp
+++ b/cpp/src/utils/Status.cpp
@@ -29,7 +29,7 @@ Status::Status(StatusCode code, const std::string& msg) {
     // 4 bytes store message length
     // the left bytes store message string
     const uint32_t length = (uint32_t)msg.size();
-    char* result = new char[length + sizeof(length) + CODE_WIDTH];
+    auto result = new char[length + sizeof(length) + CODE_WIDTH];
     std::memcpy(result, &code, CODE_WIDTH);
     std::memcpy(result + CODE_WIDTH, &length, sizeof(length));
     memcpy(result + sizeof(length) + CODE_WIDTH, msg.data(), length);
@@ -76,7 +76,7 @@ Status::CopyFrom(const Status& s) {
     memcpy(&length, s.state_ + CODE_WIDTH, sizeof(length));
     int buff_len = length + sizeof(length) + CODE_WIDTH;
     state_ = new char[buff_len];
-    memcpy((void*)state_, (void*)s.state_, buff_len);
+    memcpy(state_, s.state_, buff_len);
 }
 
 void
diff --git a/cpp/src/utils/Status.h b/cpp/src/utils/Status.h
index 4450a4c0e7..cb6c134781 100644
--- a/cpp/src/utils/Status.h
+++ b/cpp/src/utils/Status.h
@@ -71,7 +71,7 @@ class Status {
     MoveFrom(Status& s);
 
  private:
-    const char* state_ = nullptr;
+    char* state_ = nullptr;
 };  // Status
 
 }  // namespace milvus
diff --git a/cpp/src/utils/ThreadPool.h b/cpp/src/utils/ThreadPool.h
index 24c4d20ad5..db4c9d11ad 100644
--- a/cpp/src/utils/ThreadPool.h
+++ b/cpp/src/utils/ThreadPool.h
@@ -70,7 +70,8 @@ inline ThreadPool::ThreadPool(size_t threads, size_t queue_size) : max_queue_siz
                 {
                     std::unique_lock<std::mutex> lock(this->queue_mutex_);
                     this->condition_.wait(lock, [this] { return this->stop || !this->tasks_.empty(); });
-                    if (this->stop && this->tasks_.empty()) return;
+                    if (this->stop && this->tasks_.empty())
+                        return;
                     task = std::move(this->tasks_.front());
                     this->tasks_.pop();
                 }
@@ -95,7 +96,8 @@ ThreadPool::enqueue(F&& f, Args&&... args) -> std::future<typename std::result_o
         std::unique_lock<std::mutex> lock(queue_mutex_);
         this->condition_.wait(lock, [this] { return this->tasks_.size() < max_queue_size_; });
         // don't allow enqueueing after stopping the pool
-        if (stop) throw std::runtime_error("enqueue on stopped ThreadPool");
+        if (stop)
+            throw std::runtime_error("enqueue on stopped ThreadPool");
 
         tasks_.emplace([task]() { (*task)(); });
     }
diff --git a/cpp/src/utils/TimeRecorder.cpp b/cpp/src/utils/TimeRecorder.cpp
index 64a0c70fc9..cffcbc98ef 100644
--- a/cpp/src/utils/TimeRecorder.cpp
+++ b/cpp/src/utils/TimeRecorder.cpp
@@ -39,7 +39,8 @@ TimeRecorder::GetTimeSpanStr(double span) {
 void
 TimeRecorder::PrintTimeRecord(const std::string& msg, double span) {
     std::string str_log;
-    if (!header_.empty()) str_log += header_ + ": ";
+    if (!header_.empty())
+        str_log += header_ + ": ";
     str_log += msg;
     str_log += " (";
     str_log += TimeRecorder::GetTimeSpanStr(span);
diff --git a/cpp/src/utils/ValidationUtil.cpp b/cpp/src/utils/ValidationUtil.cpp
index 7047e65d30..a39427ef15 100644
--- a/cpp/src/utils/ValidationUtil.cpp
+++ b/cpp/src/utils/ValidationUtil.cpp
@@ -83,8 +83,8 @@ ValidationUtil::ValidateTableDimension(int64_t dimension) {
 
 Status
 ValidationUtil::ValidateTableIndexType(int32_t index_type) {
-    int engine_type = (int)engine::EngineType(index_type);
-    if (engine_type <= 0 || engine_type > (int)engine::EngineType::MAX_VALUE) {
+    int engine_type = static_cast<int>(engine::EngineType(index_type));
+    if (engine_type <= 0 || engine_type > static_cast<int>(engine::EngineType::MAX_VALUE)) {
         std::string msg = "Invalid index type: " + std::to_string(index_type);
         SERVER_LOG_ERROR << msg;
         return Status(SERVER_INVALID_INDEX_TYPE, msg);
@@ -117,7 +117,8 @@ ValidationUtil::ValidateTableIndexFileSize(int64_t index_file_size) {
 
 Status
 ValidationUtil::ValidateTableIndexMetricType(int32_t metric_type) {
-    if (metric_type != (int32_t)engine::MetricType::L2 && metric_type != (int32_t)engine::MetricType::IP) {
+    if (metric_type != static_cast<int32_t>(engine::MetricType::L2) &&
+        metric_type != static_cast<int32_t>(engine::MetricType::IP)) {
         std::string msg = "Invalid metric type: " + std::to_string(metric_type);
         SERVER_LOG_ERROR << msg;
         return Status(SERVER_INVALID_INDEX_METRIC_TYPE, msg);
@@ -151,7 +152,7 @@ Status
 ValidationUtil::ValidateGpuIndex(uint32_t gpu_index) {
     int num_devices = 0;
     auto cuda_err = cudaGetDeviceCount(&num_devices);
-    if (cuda_err) {
+    if (cuda_err != cudaSuccess) {
         std::string msg = "Failed to get gpu card number, cuda error:" + std::to_string(cuda_err);
         SERVER_LOG_ERROR << msg;
         return Status(SERVER_UNEXPECTED_ERROR, msg);
@@ -222,9 +223,8 @@ ValidationUtil::ValidateStringIsBool(const std::string& str) {
     if (s == "true" || s == "on" || s == "yes" || s == "1" || s == "false" || s == "off" || s == "no" || s == "0" ||
         s.empty()) {
         return Status::OK();
-    } else {
-        return Status(SERVER_INVALID_ARGUMENT, "Invalid boolean: " + str);
     }
+    return Status(SERVER_INVALID_ARGUMENT, "Invalid boolean: " + str);
 }
 
 Status