Merge branch 'branch-0.3.1' into 'branch-0.3.1'

MS-234 Some case cause background merge thread stop

See merge request megasearch/milvus!221

Former-commit-id: b58d96af019405602c2b7e25ccb989ff847694f2

cpp/CHANGELOG.md

@@ -17,6 +17,7 @@ Please mark all change in change log and use the ticket from JIRA.
 - MS-232 - Add MySQLMetaImpl::UpdateTableFilesToIndex and set maximum_memory to default if config value = 0
 - MS-233 - Remove mem manager log
 - MS-230 - Change parameter name: Maximum_memory to insert_buffer_size
+- MS-234 - Some case cause background merge thread stop
 
 ## Improvement
 - MS-156 - Add unittest for merge result functions

cpp/src/db/DBImpl.cpp

@@ -236,7 +236,6 @@ void DBImpl::BackgroundTimerTask() {
     Status status;
     server::SystemInfo::GetInstance().Init();
     while (true) {
-        if (!bg_error_.ok()) break;
         if (shutting_down_.load(std::memory_order_acquire)){
             for(auto& iter : compact_thread_results_) {
                 iter.wait();
@@ -395,8 +394,7 @@ void DBImpl::BackgroundCompaction(std::set<std::string> table_ids) {
     for (auto& table_id : table_ids) {
         status = BackgroundMergeFiles(table_id);
         if (!status.ok()) {
-            ENGINE_LOG_ERROR << "BGERROR found during merge files: " << status.ToString();
-            bg_error_ = status;
+            ENGINE_LOG_ERROR << "Merge files for table " << table_id << " failed: " << status.ToString();
             return;
         }
     }
@@ -540,8 +538,7 @@ void DBImpl::BackgroundBuildIndex() {
     for (auto& file : to_index_files) {
         status = BuildIndex(file);
         if (!status.ok()) {
-            ENGINE_LOG_ERROR << "BGERROR found during build index: " << status.ToString();
-            bg_error_ = status;
+            ENGINE_LOG_ERROR << "Building index for " << file.id_ << " failed: " << status.ToString();
             return;
         }
 

cpp/src/db/DBImpl.h

@@ -118,10 +118,8 @@ class DBImpl : public DB {
     BuildIndex(const meta::TableFileSchema &);
 
  private:
-
     const Options options_;
 
-    Status bg_error_;
     std::atomic<bool> shutting_down_;
 
     std::thread bg_timer_thread_;