ClickHouse/src/Interpreters/SortedBlocksWriter.cpp
2022-08-24 16:15:54 +00:00

347 lines
10 KiB
C++

#include <Core/SortCursor.h>
#include <Interpreters/SortedBlocksWriter.h>
#include <QueryPipeline/QueryPipelineBuilder.h>
#include <Processors/Executors/PullingPipelineExecutor.h>
#include <Processors/Sources/SourceFromSingleChunk.h>
#include <Processors/Merges/MergingSortedTransform.h>
#include <Processors/Sources/TemporaryFileLazySource.h>
#include <Formats/TemporaryFileStream.h>
#include <Disks/IVolume.h>
#include <Disks/TemporaryFileOnDisk.h>
namespace ProfileEvents
{
extern const Event ExternalJoinWritePart;
extern const Event ExternalJoinMerge;
extern const Event ExternalJoinCompressedBytes;
extern const Event ExternalJoinUncompressedBytes;
extern const Event ExternalProcessingCompressedBytesTotal;
extern const Event ExternalProcessingUncompressedBytesTotal;
}
namespace CurrentMetrics
{
extern const Metric TemporaryFilesForJoin;
}
namespace DB
{
namespace
{
TemporaryFileOnDiskHolder flushToFile(const DiskPtr & disk, const Block & header, QueryPipelineBuilder pipeline, const String & codec)
{
auto tmp_file = std::make_unique<TemporaryFileOnDisk>(disk, CurrentMetrics::TemporaryFilesForJoin);
auto write_stat = TemporaryFileStream::write(tmp_file->getPath(), header, std::move(pipeline), codec);
ProfileEvents::increment(ProfileEvents::ExternalProcessingCompressedBytesTotal, write_stat.compressed_bytes);
ProfileEvents::increment(ProfileEvents::ExternalProcessingUncompressedBytesTotal, write_stat.uncompressed_bytes);
ProfileEvents::increment(ProfileEvents::ExternalJoinCompressedBytes, write_stat.compressed_bytes);
ProfileEvents::increment(ProfileEvents::ExternalJoinUncompressedBytes, write_stat.uncompressed_bytes);
ProfileEvents::increment(ProfileEvents::ExternalJoinWritePart);
return tmp_file;
}
SortedBlocksWriter::SortedFiles flushToManyFiles(const DiskPtr & disk, const Block & header, QueryPipelineBuilder builder,
const String & codec, std::function<void(const Block &)> callback = [](const Block &){})
{
std::vector<TemporaryFileOnDiskHolder> files;
auto pipeline = QueryPipelineBuilder::getPipeline(std::move(builder));
PullingPipelineExecutor executor(pipeline);
Block block;
while (executor.pull(block))
{
if (!block.rows())
continue;
callback(block);
QueryPipelineBuilder one_block_pipeline;
Chunk chunk(block.getColumns(), block.rows());
one_block_pipeline.init(Pipe(std::make_shared<SourceFromSingleChunk>(block.cloneEmpty(), std::move(chunk))));
auto tmp_file = flushToFile(disk, header, std::move(one_block_pipeline), codec);
files.emplace_back(std::move(tmp_file));
}
return files;
}
}
void SortedBlocksWriter::insert(Block && block)
{
bool can_insert_more = false;
bool has_data_to_flush = false;
BlocksList current_blocks;
size_t row_count = 0;
size_t bytes = 0;
size_t flush_no = 0;
{
std::lock_guard lock{insert_mutex};
/// insert bock into BlocksList undef lock
inserted_blocks.insert(std::move(block));
size_t total_row_count = inserted_blocks.row_count + row_count_in_flush;
size_t total_bytes = inserted_blocks.bytes + bytes_in_flush;
can_insert_more = size_limits.softCheck(total_row_count, total_bytes);
has_data_to_flush = !size_limits.softCheck(inserted_blocks.row_count * num_streams, inserted_blocks.bytes * num_streams);
if (has_data_to_flush)
{
++flush_inflight;
current_blocks.swap(inserted_blocks.blocks);
row_count_in_flush = total_row_count;
bytes_in_flush = total_bytes;
row_count = inserted_blocks.row_count;
bytes = inserted_blocks.bytes;
inserted_blocks.clear();
}
else if (can_insert_more)
flush_no = flush_number;
}
if (has_data_to_flush)
{
/// flush new blocks without lock
auto flushed = flush(current_blocks);
current_blocks.clear();
std::lock_guard lock{insert_mutex};
sorted_files.emplace_back(std::move(flushed));
row_count_in_flush -= row_count;
bytes_in_flush -= bytes;
/// notify another insert (flush_number) and merge (flush_inflight)
++flush_number;
--flush_inflight;
flush_condvar.notify_all();
}
else if (!can_insert_more)
{
/// wakeup insert blocked by out of limit
std::unique_lock lock{insert_mutex};
flush_condvar.wait(lock, [&]{ return flush_no < flush_number; });
}
}
SortedBlocksWriter::TmpFilePtr SortedBlocksWriter::flush(const BlocksList & blocks) const
{
Pipes pipes;
pipes.reserve(blocks.size());
for (const auto & block : blocks)
if (auto num_rows = block.rows())
pipes.emplace_back(std::make_shared<SourceFromSingleChunk>(block.cloneEmpty(), Chunk(block.getColumns(), num_rows)));
if (pipes.empty())
return {};
QueryPipelineBuilder pipeline;
pipeline.init(Pipe::unitePipes(std::move(pipes)));
if (pipeline.getNumStreams() > 1)
{
auto transform = std::make_shared<MergingSortedTransform>(
pipeline.getHeader(),
pipeline.getNumStreams(),
sort_description,
rows_in_block,
SortingQueueStrategy::Default);
pipeline.addTransform(std::move(transform));
}
return flushToFile(volume->getDisk(), sample_block, std::move(pipeline), codec);
}
SortedBlocksWriter::PremergedFiles SortedBlocksWriter::premerge()
{
SortedFiles files;
BlocksList blocks;
/// wait other flushes if any
{
std::unique_lock lock{insert_mutex};
files.swap(sorted_files);
blocks.swap(inserted_blocks.blocks);
inserted_blocks.clear();
flush_condvar.wait(lock, [&]{ return !flush_inflight; });
}
/// flush not flushed
if (!blocks.empty())
files.emplace_back(flush(blocks));
Pipes pipes;
pipes.reserve(num_files_for_merge);
/// Merge by parts to save memory. It's possible to exchange disk I/O and memory by num_files_for_merge.
{
SortedFiles new_files;
new_files.reserve(files.size() / num_files_for_merge + 1);
while (files.size() > num_files_for_merge)
{
for (const auto & file : files)
{
pipes.emplace_back(streamFromFile(file));
if (pipes.size() == num_files_for_merge || &file == &files.back())
{
QueryPipelineBuilder pipeline;
pipeline.init(Pipe::unitePipes(std::move(pipes)));
pipes = Pipes();
if (pipeline.getNumStreams() > 1)
{
auto transform = std::make_shared<MergingSortedTransform>(
pipeline.getHeader(),
pipeline.getNumStreams(),
sort_description,
rows_in_block,
SortingQueueStrategy::Default);
pipeline.addTransform(std::move(transform));
}
new_files.emplace_back(flushToFile(volume->getDisk(), sample_block, std::move(pipeline), codec));
}
}
files.clear();
files.swap(new_files);
}
for (const auto & file : files)
pipes.emplace_back(streamFromFile(file));
}
return PremergedFiles{std::move(files), Pipe::unitePipes(std::move(pipes))};
}
SortedBlocksWriter::SortedFiles SortedBlocksWriter::finishMerge(std::function<void(const Block &)> callback)
{
PremergedFiles files = premerge();
QueryPipelineBuilder pipeline;
pipeline.init(std::move(files.pipe));
if (pipeline.getNumStreams() > 1)
{
ProfileEvents::increment(ProfileEvents::ExternalJoinMerge);
auto transform = std::make_shared<MergingSortedTransform>(
pipeline.getHeader(),
pipeline.getNumStreams(),
sort_description,
rows_in_block,
SortingQueueStrategy::Default);
pipeline.addTransform(std::move(transform));
}
return flushToManyFiles(volume->getDisk(), sample_block, std::move(pipeline), codec, callback);
}
Pipe SortedBlocksWriter::streamFromFile(const TmpFilePtr & file) const
{
return Pipe(std::make_shared<TemporaryFileLazySource>(file->path(), materializeBlock(sample_block)));
}
Block SortedBlocksBuffer::exchange(Block && block)
{
static constexpr const float reserve_coef = 1.2;
Blocks out_blocks;
Block empty_out = block.cloneEmpty();
{
std::lock_guard lock(mutex);
if (block)
{
current_bytes += block.bytes();
buffer.emplace_back(std::move(block));
/// Saved. Return empty block with same structure.
if (current_bytes < max_bytes)
return empty_out;
}
/// Not saved. Return buffered.
out_blocks.swap(buffer);
buffer.reserve(out_blocks.size() * reserve_coef);
current_bytes = 0;
}
if (size_t size = out_blocks.size())
{
if (size == 1)
return out_blocks[0];
return mergeBlocks(std::move(out_blocks));
}
return {};
}
Block SortedBlocksBuffer::mergeBlocks(Blocks && blocks) const
{
size_t num_rows = 0;
{ /// Merge sort blocks
Pipes pipes;
pipes.reserve(blocks.size());
for (auto & block : blocks)
{
num_rows += block.rows();
Chunk chunk(block.getColumns(), block.rows());
pipes.emplace_back(std::make_shared<SourceFromSingleChunk>(block.cloneEmpty(), std::move(chunk)));
}
Blocks tmp_blocks;
QueryPipelineBuilder builder;
builder.init(Pipe::unitePipes(std::move(pipes)));
if (builder.getNumStreams() > 1)
{
auto transform = std::make_shared<MergingSortedTransform>(
builder.getHeader(),
builder.getNumStreams(),
sort_description,
num_rows,
SortingQueueStrategy::Default);
builder.addTransform(std::move(transform));
}
auto pipeline = QueryPipelineBuilder::getPipeline(std::move(builder));
PullingPipelineExecutor executor(pipeline);
Block block;
while (executor.pull(block))
tmp_blocks.emplace_back(block);
blocks.swap(tmp_blocks);
}
if (blocks.size() == 1)
return blocks[0];
return concatenateBlocks(blocks);
}
}