Merge pull request #272 from ludv1x/METR-23783

Consecutive optimization for vertical merge algorithm

dbms/include/DB/DataStreams/ColumnGathererStream.h

@@ -58,7 +58,7 @@ class ColumnGathererStream : public IProfilingBlockInputStream
 {
 public:
 	ColumnGathererStream(const BlockInputStreams & source_streams, const String & column_name_,
-						 const MergedRowSources & pos_to_source_idx_, size_t block_size_ = DEFAULT_BLOCK_SIZE);
+						 const MergedRowSources & row_source_, size_t block_size_ = DEFAULT_MERGE_BLOCK_SIZE);
 
 	String getName() const override { return "ColumnGatherer"; }
 
@@ -66,11 +66,13 @@ public:
 
 	Block readImpl() override;
 
+	void readSuffixImpl() override;
+
 private:
 
 	String name;
 	ColumnWithTypeAndName column;
-	const MergedRowSources & pos_to_source_idx;
+	const MergedRowSources & row_source;
 
 	/// Cache required fileds
 	struct Source
@@ -95,7 +97,7 @@ private:
 
 	std::vector<Source> sources;
 
-	size_t pos_global = 0;
+	size_t pos_global_start = 0;
 	size_t block_size;
 
 	Logger * log = &Logger::get("ColumnGathererStream");

dbms/include/DB/DataStreams/MergingSortedBlockInputStream.h

@@ -52,44 +52,21 @@ inline void intrusive_ptr_release(detail::SharedBlock * ptr)
 }
 
 
-/** Соединяет несколько сортированных потоков в один.
+/** Merges several sorted streams into one sorted stream.
   */
 class MergingSortedBlockInputStream : public IProfilingBlockInputStream
 {
 public:
-	/// limit - if isn't 0, then we can produce only first limit rows in sorted order.
-	/// out_row_sources - if isn't nullptr, then at the end of execution it should contain part numbers of each readed row (and needed flag)
-	MergingSortedBlockInputStream(BlockInputStreams & inputs_, const SortDescription & description_,
-								  size_t max_block_size_, size_t limit_ = 0, MergedRowSources * out_row_sources_ = nullptr)
-		: description(description_), max_block_size(max_block_size_), limit(limit_),
-		source_blocks(inputs_.size()), cursors(inputs_.size()), out_row_sources(out_row_sources_)
-	{
-		children.insert(children.end(), inputs_.begin(), inputs_.end());
-	}
+	/** limit - if isn't 0, then we can produce only first limit rows in sorted order.
+	  * out_row_sources - if isn't nullptr, then at the end of execution it should contain part numbers of each readed row (and needed flag)
+	  * quiet - don't log profiling info
+	  */
+	MergingSortedBlockInputStream(BlockInputStreams & inputs_, const SortDescription & description_, size_t max_block_size_,
+								  size_t limit_ = 0, MergedRowSources * out_row_sources_ = nullptr, bool quiet_ = false);
 
 	String getName() const override { return "MergingSorted"; }
 
-	String getID() const override
-	{
-		std::stringstream res;
-		res << "MergingSorted(";
-
-		Strings children_ids(children.size());
-		for (size_t i = 0; i < children.size(); ++i)
-			children_ids[i] = children[i]->getID();
-
-		/// Порядок не имеет значения.
-		std::sort(children_ids.begin(), children_ids.end());
-
-		for (size_t i = 0; i < children_ids.size(); ++i)
-			res << (i == 0 ? "" : ", ") << children_ids[i];
-
-		for (size_t i = 0; i < description.size(); ++i)
-			res << ", " << description[i].getID();
-
-		res << ")";
-		return res.str();
-	}
+	String getID() const override;
 
 protected:
 	struct RowRef
@@ -144,6 +121,7 @@ protected:
 
 	bool first = true;
 	bool has_collation = false;
+	bool quiet = false;
 
 	/// May be smaller or equal to max_block_size. To do 'reserve' for columns.
 	size_t expected_block_size = 0;

dbms/src/DataStreams/ColumnGathererStream.cpp

@@ -1,4 +1,5 @@
 #include <DB/DataStreams/ColumnGathererStream.h>
+#include <iomanip>
 
 namespace DB
 {
@@ -13,8 +14,8 @@ namespace ErrorCodes
 }
 
 ColumnGathererStream::ColumnGathererStream(const BlockInputStreams & source_streams, const String & column_name_,
-										   const MergedRowSources & pos_to_source_idx_, size_t block_size_)
-: name(column_name_), pos_to_source_idx(pos_to_source_idx_), block_size(block_size_)
+										   const MergedRowSources & row_source_, size_t block_size_)
+: name(column_name_), row_source(row_source_), block_size(block_size_)
 {
 	if (source_streams.empty())
 		throw Exception("There are no streams to gather", ErrorCodes::EMPTY_DATA_PASSED);
@@ -63,19 +64,20 @@ Block ColumnGathererStream::readImpl()
 	if (children.size() == 1)
 		return children[0]->read();
 
-	if (pos_global >= pos_to_source_idx.size())
+	if (pos_global_start >= row_source.size())
 		return Block();
 
 	Block block_res{column.cloneEmpty()};
 	IColumn & column_res = *block_res.unsafeGetByPosition(0).column;
 
-	size_t pos_finish = std::min(pos_global + block_size, pos_to_source_idx.size());
-	column_res.reserve(pos_finish - pos_global);
+	size_t pos_global_finish = std::min(pos_global_start + block_size, row_source.size());
+	size_t curr_block_size = pos_global_finish - pos_global_start;
+	column_res.reserve(curr_block_size);
 
-	for (size_t pos = pos_global; pos < pos_finish; ++pos)
+	for (size_t pos_global = pos_global_start; pos_global < pos_global_finish;)
 	{
-		auto source_id = pos_to_source_idx[pos].getSourceNum();
-		bool skip = pos_to_source_idx[pos].getSkipFlag();
+		auto source_id = row_source[pos_global].getSourceNum();
+		bool skip = row_source[pos_global].getSkipFlag();
 		Source & source = sources[source_id];
 
 		if (source.pos >= source.size) /// Fetch new block
@@ -98,14 +100,44 @@ Block ColumnGathererStream::readImpl()
 			}
 		}
 
+		/// Consecutive optimization. TODO: precompute lens
+		size_t len = 1;
+		size_t max_len = std::min(pos_global_finish - pos_global, source.size - source.pos); // interval should be in the same block
+		for (; len < max_len && row_source[pos_global].getData() == row_source[pos_global + len].getData(); ++len);
+
 		if (!skip)
-			column_res.insertFrom(*source.column, source.pos); //TODO: vectorize
-		++source.pos;
+		{
+			if (column_res.size() == 0 && source.pos == 0 && curr_block_size == len && source.size == len)
+			{
+				// Whole block could be produced via copying pointer from current block
+				block_res.unsafeGetByPosition(0).column = source.block.getByName(name).column;
+			}
+			else
+			{
+				column_res.insertRangeFrom(*source.column, source.pos, len);
+			}
 		}
 
-	pos_global = pos_finish;
+		source.pos += len;
+		pos_global += len;
+	}
+
+	pos_global_start = pos_global_finish;
 
 	return block_res;
 }
 
+
+void ColumnGathererStream::readSuffixImpl()
+{
+	const BlockStreamProfileInfo & profile_info = getProfileInfo();
+	double seconds = profile_info.total_stopwatch.elapsedSeconds();
+	LOG_DEBUG(log, std::fixed << std::setprecision(2)
+		<< "Gathred column " << column.name << " " << column.type->getName()
+		<< " (" << static_cast<double>(profile_info.bytes) / profile_info.rows << " bytes/elem.)"
+		<< " in " << seconds << " sec., "
+		<< profile_info.rows / seconds << " rows/sec., "
+		<< profile_info.bytes / 1000000.0 / seconds << " MiB/sec.");
+}
+
 }

dbms/src/DataStreams/MergingSortedBlockInputStream.cpp

@@ -15,6 +15,36 @@ namespace ErrorCodes
 }
 
 
+MergingSortedBlockInputStream::MergingSortedBlockInputStream(BlockInputStreams & inputs_, const SortDescription & description_,
+	size_t max_block_size_, size_t limit_, MergedRowSources * out_row_sources_, bool quiet_)
+	: description(description_), max_block_size(max_block_size_), limit(limit_), quiet(quiet_),
+	source_blocks(inputs_.size()), cursors(inputs_.size()), out_row_sources(out_row_sources_)
+{
+	children.insert(children.end(), inputs_.begin(), inputs_.end());
+}
+
+String MergingSortedBlockInputStream::getID() const
+{
+	std::stringstream res;
+	res << "MergingSorted(";
+
+	Strings children_ids(children.size());
+	for (size_t i = 0; i < children.size(); ++i)
+		children_ids[i] = children[i]->getID();
+
+	/// Порядок не имеет значения.
+	std::sort(children_ids.begin(), children_ids.end());
+
+	for (size_t i = 0; i < children_ids.size(); ++i)
+		res << (i == 0 ? "" : ", ") << children_ids[i];
+
+	for (size_t i = 0; i < description.size(); ++i)
+		res << ", " << description[i].getID();
+
+	res << ")";
+	return res.str();
+}
+
 void MergingSortedBlockInputStream::init(Block & merged_block, ColumnPlainPtrs & merged_columns)
 {
 	/// Читаем первые блоки, инициализируем очередь.
@@ -312,13 +342,16 @@ void MergingSortedBlockInputStream::fetchNextBlock(const TSortCursor & current,
 
 void MergingSortedBlockInputStream::readSuffixImpl()
 {
+ 	if (quiet)
+ 		return;
+
 	const BlockStreamProfileInfo & profile_info = getProfileInfo();
 	double seconds = profile_info.total_stopwatch.elapsedSeconds();
 	LOG_DEBUG(log, std::fixed << std::setprecision(2)
 		<< "Merge sorted " << profile_info.blocks << " blocks, " << profile_info.rows << " rows"
 		<< " in " << seconds << " sec., "
 		<< profile_info.rows / seconds << " rows/sec., "
-		<< profile_info.bytes / 1000000.0 / seconds << " MiB/sec.");
+		<< profile_info.bytes / 1000000.0 / seconds << " MB/sec.");
 }
 
 }

dbms/src/Storages/MergeTree/MergeTreeDataMerger.cpp

@@ -25,6 +25,7 @@
 
 #include <cmath>
 #include <numeric>
+#include <iomanip>
 
 
 namespace ProfileEvents
@@ -557,7 +558,7 @@ MergeTreeData::MutableDataPartPtr MergeTreeDataMerger::mergePartsToTemporaryPart
 	{
 		case MergeTreeData::MergingParams::Ordinary:
 			merged_stream = std::make_unique<MergingSortedBlockInputStream>(
-				src_streams, sort_desc, DEFAULT_MERGE_BLOCK_SIZE, 0, merged_rows_sources_ptr);
+				src_streams, sort_desc, DEFAULT_MERGE_BLOCK_SIZE, 0, merged_rows_sources_ptr, true);
 			break;
 
 		case MergeTreeData::MergingParams::Collapsing:
@@ -618,19 +619,25 @@ MergeTreeData::MutableDataPartPtr MergeTreeDataMerger::mergePartsToTemporaryPart
 		merge_entry->rows_written = merged_stream->getProfileInfo().rows;
 		merge_entry->bytes_written_uncompressed = merged_stream->getProfileInfo().bytes;
 
-		/// This update is unactual for VERTICAL algorithm sicne it requires more accurate per-column updates
 		/// Reservation updates is not performed yet, during the merge it may lead to higher free space requirements
-		if (disk_reservation && merge_alg == MergeAlgorithm::Horizontal)
+		if (disk_reservation)
 		{
-			Float64 relative_rows_written = std::min(1., 1. * rows_written / sum_input_rows_upper_bound);
-			disk_reservation->update(static_cast<size_t>((1. - relative_rows_written) * initial_reservation));
+			/// The same progress from merge_entry could be used for both algorithms (it should be more accurate)
+			/// But now we are using inaccurate row-based estimation in Horizontal case for backward compability
+			Float64 progress = (merge_alg == MergeAlgorithm::Horizontal)
+				? std::min(1., 1. * rows_written / sum_input_rows_upper_bound)
+				: std::min(1., merge_entry->progress);
+
+			disk_reservation->update(static_cast<size_t>((1. - progress) * initial_reservation));
 		}
 	}
+	merged_stream->readSuffix();
+	merged_stream.reset();
 
 	if (isCancelled())
 		throw Exception("Cancelled merging parts", ErrorCodes::ABORTED);
 
-	MergeTreeData::DataPart::Checksums checksums_ordinary_columns;
+	MergeTreeData::DataPart::Checksums checksums_gathered_columns;
 
 	/// Gather ordinary columns
 	if (merge_alg == MergeAlgorithm::Vertical)
@@ -649,18 +656,15 @@ MergeTreeData::MutableDataPartPtr MergeTreeDataMerger::mergePartsToTemporaryPart
 			const String & column_name = it_name_and_type->name;
 			const DataTypePtr & column_type = it_name_and_type->type;
 			const String offset_column_name = DataTypeNested::extractNestedTableName(column_name);
-			Names column_name_(1, column_name);
-			NamesAndTypesList column_name_and_type_(1, *it_name_and_type);
+			Names column_name_{column_name};
+			NamesAndTypesList column_name_and_type_{*it_name_and_type};
 			Float64 progress_before = merge_entry->progress;
 			bool offset_written = offset_columns_written.count(offset_column_name);
 
-			LOG_TRACE(log, "Gathering column " << column_name <<  " " << column_type->getName());
-
 			for (size_t part_num = 0; part_num < parts.size(); ++part_num)
 			{
 				String part_path = data.getFullPath() + parts[part_num]->name + '/';
 
-				/// TODO: test perfomance with more accurate settings
 				auto column_part_stream = std::make_shared<MergeTreeBlockInputStream>(
 					part_path, DEFAULT_MERGE_BLOCK_SIZE, column_name_, data, parts[part_num],
 					MarkRanges(1, MarkRange(0, parts[part_num]->size)), false, nullptr, "", true, aio_threshold, DBMS_DEFAULT_BUFFER_SIZE,
@@ -672,16 +676,17 @@ MergeTreeData::MutableDataPartPtr MergeTreeDataMerger::mergePartsToTemporaryPart
 				column_part_streams[part_num] = std::move(column_part_stream);
 			}
 
-			ColumnGathererStream column_gathered_stream(column_part_streams, column_name, merged_rows_sources, DEFAULT_BLOCK_SIZE);
-			MergedColumnOnlyOutputStream column_to(data, new_part_tmp_path, true, compression_method, offset_written);
+			/// Block size should match with block size of column_part_stream to enable fast gathering via copying of column pointer
+			ColumnGathererStream column_gathered_stream(column_part_streams, column_name, merged_rows_sources, DEFAULT_MERGE_BLOCK_SIZE);
+			MergedColumnOnlyOutputStream column_to(data, new_part_tmp_path, false, compression_method, offset_written);
 
 			column_to.writePrefix();
 			while ((block = column_gathered_stream.read()))
 			{
 				column_to.write(block);
 			}
-			/// NOTE: nested column contains duplicates checksums (and files)
-			checksums_ordinary_columns.add(column_to.writeSuffixAndGetChecksums());
+			column_gathered_stream.readSuffix();
+			checksums_gathered_columns.add(column_to.writeSuffixAndGetChecksums());
 
 			if (typeid_cast<const DataTypeArray *>(column_type.get()))
 				offset_columns_written.emplace(offset_column_name);
@@ -695,12 +700,23 @@ MergeTreeData::MutableDataPartPtr MergeTreeDataMerger::mergePartsToTemporaryPart
 		}
 	}
 
-	merged_stream->readSuffix();
+	/// Print overall profiling info. NOTE: it may duplicates previous messages
+	{
+		double elapsed_seconds = merge_entry->watch.elapsedSeconds();
+		LOG_DEBUG(log, std::fixed << std::setprecision(2)
+			<< "Merge sorted " << merge_entry->rows_read << " rows"
+			<< ", containing " << all_column_names.size() << " columns"
+			<< " (" << merging_column_names.size() << " merged, " << gathering_column_names.size() << " gathered)"
+			<< " in " << elapsed_seconds << " sec., "
+			<< merge_entry->rows_read / elapsed_seconds << " rows/sec., "
+			<< merge_entry->bytes_read_uncompressed / 1000000.0 / elapsed_seconds << " MB/sec.");
+	}
+
 	new_data_part->columns = all_columns;
 	if (merge_alg != MergeAlgorithm::Vertical)
 		new_data_part->checksums = to.writeSuffixAndGetChecksums();
 	else
-		new_data_part->checksums = to.writeSuffixAndGetChecksums(all_columns, &checksums_ordinary_columns);
+		new_data_part->checksums = to.writeSuffixAndGetChecksums(all_columns, &checksums_gathered_columns);
 	new_data_part->index.swap(to.getIndex());
 
 	/// Для удобства, даже CollapsingSortedBlockInputStream не может выдать ноль строк.