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#include <Interpreters/Cache/WriteBufferToFileSegment.h>
#include <Interpreters/Cache/FileSegment.h>
#include <Interpreters/Cache/FileCache.h>
#include <IO/SwapHelper.h>
#include <IO/ReadBufferFromFile.h>
#include <base/scope_guard.h>
#include <Common/logger_useful.h>
namespace DB
{
namespace ErrorCodes
{
extern const int LOGICAL_ERROR;
extern const int NOT_ENOUGH_SPACE;
}
WriteBufferToFileSegment::WriteBufferToFileSegment(FileSegment * file_segment_)
: WriteBufferFromFileDecorator(std::make_unique<WriteBufferFromFile>(file_segment_->getPathInLocalCache()))
, file_segment(file_segment_)
{
}
WriteBufferToFileSegment::WriteBufferToFileSegment(FileSegmentsHolderPtr segment_holder_)
: WriteBufferFromFileDecorator(
segment_holder_->size() == 1
? std::make_unique<WriteBufferFromFile>(segment_holder_->front().getPathInLocalCache())
: throw Exception(ErrorCodes::LOGICAL_ERROR, "WriteBufferToFileSegment can be created only from single segment"))
, file_segment(&segment_holder_->front())
, segment_holder(std::move(segment_holder_))
{
}
/// If it throws an exception, the file segment will be incomplete, so you should not use it in the future.
void WriteBufferToFileSegment::nextImpl()
{
auto downloader [[maybe_unused]] = file_segment->getOrSetDownloader();
chassert(downloader == FileSegment::getCallerId());
SCOPE_EXIT({
file_segment->completePartAndResetDownloader();
});
size_t bytes_to_write = offset();
FileCacheReserveStat reserve_stat;
/// In case of an error, we don't need to finalize the file segment
/// because it will be deleted soon and completed in the holder's destructor.
bool ok = file_segment->reserve(bytes_to_write, &reserve_stat);
if (!ok)
{
String reserve_stat_msg;
for (const auto & [kind, stat] : reserve_stat.stat_by_kind)
reserve_stat_msg += fmt::format("{} hold {}, can release {}; ",
toString(kind), ReadableSize(stat.non_releasable_size), ReadableSize(stat.releasable_size));
throw Exception(ErrorCodes::NOT_ENOUGH_SPACE, "Failed to reserve {} bytes for {}: {}(segment info: {})",
bytes_to_write,
file_segment->getKind() == FileSegmentKind::Temporary ? "temporary file" : "the file in cache",
reserve_stat_msg,
file_segment->getInfoForLog()
);
}
try
{
SwapHelper swap(*this, *impl);
/// Write data to the underlying buffer.
impl->next();
}
catch (...)
{
LOG_WARNING(&Poco::Logger::get("WriteBufferToFileSegment"), "Failed to write to the underlying buffer ({})", file_segment->getInfoForLog());
throw;
}
file_segment->setDownloadedSize(bytes_to_write);
}
std::shared_ptr<ReadBuffer> WriteBufferToFileSegment::getReadBufferImpl()
{
finalize();
return std::make_shared<ReadBufferFromFile>(file_segment->getPathInLocalCache());
}
WriteBufferToFileSegment::~WriteBufferToFileSegment()
{
/// To be sure that file exists before destructor of segment_holder is called
WriteBufferFromFileDecorator::finalize();
}
}
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