ClickHouse/src/Storages/MergeTree/MergeTreeIndexReader.cpp
2024-03-18 15:57:58 +00:00

90 lines
2.6 KiB
C++

#include <Storages/MergeTree/MergeTreeIndexReader.h>
#include <Interpreters/Context.h>
#include <Storages/MergeTree/LoadedMergeTreeDataPartInfoForReader.h>
namespace
{
using namespace DB;
std::unique_ptr<MergeTreeReaderStream> makeIndexReader(
const std::string & extension,
MergeTreeIndexPtr index,
MergeTreeData::DataPartPtr part,
size_t marks_count,
const MarkRanges & all_mark_ranges,
MarkCache * mark_cache,
UncompressedCache * uncompressed_cache,
MergeTreeReaderSettings settings)
{
auto context = part->storage.getContext();
auto * load_marks_threadpool = settings.read_settings.load_marks_asynchronously ? &context->getLoadMarksThreadpool() : nullptr;
auto marks_loader = std::make_shared<MergeTreeMarksLoader>(
std::make_shared<LoadedMergeTreeDataPartInfoForReader>(part, std::make_shared<AlterConversions>()),
mark_cache,
part->index_granularity_info.getMarksFilePath(index->getFileName()),
marks_count,
part->index_granularity_info,
settings.save_marks_in_cache,
settings.read_settings,
load_marks_threadpool,
/*num_columns_in_mark=*/ 1);
return std::make_unique<MergeTreeReaderStreamSingleColumn>(
part->getDataPartStoragePtr(),
index->getFileName(), extension, marks_count,
all_mark_ranges, std::move(settings), uncompressed_cache,
part->getFileSizeOrZero(index->getFileName() + extension), std::move(marks_loader),
ReadBufferFromFileBase::ProfileCallback{}, CLOCK_MONOTONIC_COARSE);
}
}
namespace DB
{
MergeTreeIndexReader::MergeTreeIndexReader(
MergeTreeIndexPtr index_,
MergeTreeData::DataPartPtr part_,
size_t marks_count_,
const MarkRanges & all_mark_ranges_,
MarkCache * mark_cache,
UncompressedCache * uncompressed_cache,
MergeTreeReaderSettings settings)
: index(index_)
{
auto index_format = index->getDeserializedFormat(part_->getDataPartStorage(), index->getFileName());
stream = makeIndexReader(
index_format.extension,
index_,
part_,
marks_count_,
all_mark_ranges_,
mark_cache,
uncompressed_cache,
std::move(settings));
version = index_format.version;
stream->adjustRightMark(getLastMark(all_mark_ranges_));
stream->seekToStart();
}
MergeTreeIndexReader::~MergeTreeIndexReader() = default;
void MergeTreeIndexReader::seek(size_t mark)
{
stream->seekToMark(mark);
}
void MergeTreeIndexReader::read(MergeTreeIndexGranulePtr & granule)
{
if (granule == nullptr)
granule = index->createIndexGranule();
granule->deserializeBinary(*stream->getDataBuffer(), version);
}
}