Fix #839 and improve the code quality (#1470)

* Fix #839 and improve the code quality
Signed-off-by: NJinHai-CN <hai.jin@zilliz.com>

* Fix compiling error and building threads number
Signed-off-by: NJinHai-CN <hai.jin@zilliz.com>

.codacy.yaml

@@ -2,3 +2,6 @@ exclude_paths:
   - 'core/src/index/thirdparty/**'
   - 'sdk/build-support/**'
   - 'core/build-support/**'
+  - 'core/src/grpc/gen-milvus/**'
+  - 'core/src/grpc/gen-status/**'
+  - 'sdk/grpc-gen/**'

ci/scripts/build.sh

@@ -144,7 +144,7 @@ if [[ ${RUN_CPPLINT} == "ON" ]]; then
 fi
 
 # compile and build
-make -j8 || exit 1
+make -j6 || exit 1
 
 if [[ ${PRIVILEGES} == "ON" ]];then
     sudo make install || exit 1

core/src/db/DBImpl.cpp

@@ -432,8 +432,12 @@ DBImpl::DropPartition(const std::string& partition_name) {
         return SHUTDOWN_ERROR;
     }
 
-    auto status = mem_mgr_->EraseMemVector(partition_name);  // not allow insert
-    status = meta_ptr_->DropPartition(partition_name);       // soft delete table
+    mem_mgr_->EraseMemVector(partition_name);                // not allow insert
+    auto status = meta_ptr_->DropPartition(partition_name);  // soft delete table
+    if (!status.ok()) {
+        ENGINE_LOG_ERROR << status.message();
+        return status;
+    }
 
     // scheduler will determine when to delete table files
     auto nres = scheduler::ResMgrInst::GetInstance()->GetNumOfComputeResource();

core/src/db/DBImpl.h

@@ -74,7 +74,7 @@ class DBImpl : public DB {
     PreloadTable(const std::string& table_id) override;
 
     Status
-    UpdateTableFlag(const std::string& table_id, int64_t flag);
+    UpdateTableFlag(const std::string& table_id, int64_t flag) override;
 
     Status
     GetTableRowCount(const std::string& table_id, uint64_t& row_count) override;

core/src/db/meta/MySQLConnectionPool.h

@@ -24,8 +24,8 @@ namespace meta {
 class MySQLConnectionPool : public mysqlpp::ConnectionPool {
  public:
     // The object's only constructor
-    MySQLConnectionPool(std::string dbName, std::string userName, std::string passWord, std::string serverIp,
-                        int port = 0, int maxPoolSize = 8)
+    MySQLConnectionPool(const std::string& dbName, const std::string& userName, const std::string& passWord,
+                        const std::string& serverIp, int port = 0, int maxPoolSize = 8)
         : db_(dbName),
           user_(userName),
           password_(passWord),

core/src/db/wal/WalManager.cpp

@@ -341,7 +341,7 @@ WalManager::DeleteById(const std::string& table_id, const IDNumbers& vector_ids)
 }
 
 uint64_t
-WalManager::Flush(const std::string table_id) {
+WalManager::Flush(const std::string& table_id) {
     std::lock_guard<std::mutex> lck(mutex_);
     // At most one flush requirement is waiting at any time.
     // Otherwise, flush_info_ should be modified to a list.

core/src/db/wal/WalManager.h

@@ -107,7 +107,7 @@ class WalManager {
      *         else, return 0
      */
     uint64_t
-    Flush(const std::string table_id = "");
+    Flush(const std::string& table_id = "");
 
     void
     RemoveOldFiles(uint64_t flushed_lsn);