save max threads as well

Author: arthurpassos

src/Storages/MergeTree/MergeTreeData.cpp

@@ -6246,7 +6246,8 @@ void MergeTreeData::exportPartToTable(const PartitionCommand & command, ContextP
             part,
             query_context->getSettingsRef()[Setting::export_merge_tree_part_overwrite_file_if_exists],
             query_context->getSettingsRef()[Setting::output_format_parallel_formatting],
-            query_context->getSettingsRef()[Setting::output_format_parquet_parallel_encoding]);
+            query_context->getSettingsRef()[Setting::output_format_parquet_parallel_encoding],
+            query_context->getSettingsRef()[Setting::max_threads]);
 
         std::lock_guard lock(export_manifests_mutex);
 
@@ -6295,6 +6296,7 @@ void MergeTreeData::exportPartToTableImpl(
         auto context_copy = Context::createCopy(local_context);
         context_copy->setSetting("output_format_parallel_formatting", manifest.parallel_formatting);
         context_copy->setSetting("output_format_parquet_parallel_encoding", manifest.parallel_formatting_parquet);
+        context_copy->setSetting("max_threads", manifest.max_threads);
 
         sink = destination_storage->import(
             manifest.data_part->name + "_" + manifest.data_part->checksums.getTotalChecksumHex(),

src/Storages/MergeTree/MergeTreeExportManifest.h

@@ -14,12 +14,14 @@ struct MergeTreeExportManifest
         const DataPartPtr & data_part_,
         bool overwrite_file_if_exists_,
         bool parallel_formatting_,
-        bool parallel_formatting_parquet_)
+        bool parallel_formatting_parquet_,
+        std::size_t max_threads_)
         : destination_storage_id(destination_storage_id_),
           data_part(data_part_),
           overwrite_file_if_exists(overwrite_file_if_exists_),
           parallel_formatting(parallel_formatting_),
           parallel_formatting_parquet(parallel_formatting_parquet_),
+          max_threads(max_threads_),
           create_time(time(nullptr)) {}
 
     StorageID destination_storage_id;
@@ -28,6 +30,7 @@ struct MergeTreeExportManifest
     bool parallel_formatting;
     /// parquet has a different setting for parallel formatting
     bool parallel_formatting_parquet;
+    std::size_t max_threads;
 
     time_t create_time;
     mutable bool in_progress = false;