fix some thread safety issues

Author: arthurpassos

src/Storages/MergeTree/ExportList.cpp

@@ -46,15 +46,15 @@ ExportInfo ExportsListElement::getInfo() const
         res.destination_file_paths = destination_file_paths;
     }
 
-    res.rows_read = rows_read;
+    res.rows_read = rows_read.load(std::memory_order_relaxed);
     res.total_rows_to_read = total_rows_to_read;
     res.total_size_bytes_compressed = total_size_bytes_compressed;
     res.total_size_bytes_uncompressed = total_size_bytes_uncompressed;
-    res.bytes_read_uncompressed = bytes_read_uncompressed;
+    res.bytes_read_uncompressed = bytes_read_uncompressed.load(std::memory_order_relaxed);
     res.memory_usage = getMemoryUsage();
     res.peak_memory_usage = getPeakMemoryUsage();
     res.create_time = create_time;
-    res.elapsed = elapsed;
+    res.elapsed = watch.elapsedSeconds();
     return res;
 }
 

src/Storages/MergeTree/ExportList.h

@@ -42,14 +42,15 @@ struct ExportsListElement : private boost::noncopyable
     const StorageID destination_table_id;
     const UInt64 part_size;
     const String part_name;
+
+    /// see destination_file_paths_mutex
     std::vector<String> destination_file_paths;
-    UInt64 rows_read {0};
+    std::atomic<UInt64> rows_read {0};
     UInt64 total_rows_to_read {0};
     UInt64 total_size_bytes_compressed {0};
     UInt64 total_size_bytes_uncompressed {0};
-    UInt64 bytes_read_uncompressed {0};
+    std::atomic<UInt64> bytes_read_uncompressed {0};
     time_t create_time {0};
-    Float64 elapsed {0};
 
     Stopwatch watch;
     ThreadGroupPtr thread_group;

src/Storages/MergeTree/ExportPartTask.cpp

@@ -156,7 +156,6 @@ bool ExportPartTask::executeStep()
         {
             (*exports_list_entry)->bytes_read_uncompressed += progress.read_bytes;
             (*exports_list_entry)->rows_read += progress.read_rows;
-            (*exports_list_entry)->elapsed = (*exports_list_entry)->watch.elapsedSeconds();
         });
 
         pipeline = QueryPipelineBuilder::getPipeline(std::move(*builder));