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#include <Processors/Executors/PushingAsyncPipelineExecutor.h>
#include <Processors/Executors/PipelineExecutor.h>
#include <Processors/ISource.h>
#include <QueryPipeline/QueryPipeline.h>
#include <QueryPipeline/ReadProgressCallback.h>
#include <Common/ThreadPool.h>
#include <Common/setThreadName.h>
#include <Common/scope_guard_safe.h>
#include <Common/CurrentThread.h>
#include <Poco/Event.h>
namespace DB
{
namespace ErrorCodes
{
extern const int LOGICAL_ERROR;
}
class PushingAsyncSource : public ISource
{
public:
explicit PushingAsyncSource(const Block & header)
: ISource(header)
{}
String getName() const override { return "PushingAsyncSource"; }
bool setData(Chunk chunk)
{
std::unique_lock lock(mutex);
condvar.wait(lock, [this] { return !has_data || is_finished; });
if (is_finished)
return false;
data.swap(chunk);
has_data = true;
condvar.notify_one();
return true;
}
void finish()
{
std::unique_lock lock(mutex);
is_finished = true;
condvar.notify_all();
}
protected:
Chunk generate() override
{
std::unique_lock lock(mutex);
condvar.wait(lock, [this] { return has_data || is_finished; });
Chunk res;
res.swap(data);
has_data = false;
condvar.notify_one();
return res;
}
private:
Chunk data;
bool has_data = false;
bool is_finished = false;
std::mutex mutex;
std::condition_variable condvar;
};
struct PushingAsyncPipelineExecutor::Data
{
PipelineExecutorPtr executor;
std::exception_ptr exception;
PushingAsyncSource * source = nullptr;
std::atomic_bool is_finished = false;
std::atomic_bool has_exception = false;
ThreadFromGlobalPool thread;
Poco::Event finish_event;
~Data()
{
if (thread.joinable())
thread.join();
}
void rethrowExceptionIfHas()
{
if (has_exception)
{
has_exception = false;
std::rethrow_exception(exception);
}
}
};
static void threadFunction(
PushingAsyncPipelineExecutor::Data & data, ThreadGroupPtr thread_group, size_t num_threads, bool concurrency_control)
{
SCOPE_EXIT_SAFE(
if (thread_group)
CurrentThread::detachFromGroupIfNotDetached();
);
setThreadName("QueryPushPipeEx");
try
{
if (thread_group)
CurrentThread::attachToGroup(thread_group);
data.executor->execute(num_threads, concurrency_control);
}
catch (...)
{
data.exception = std::current_exception();
data.has_exception = true;
/// Finish source in case of exception. Otherwise thread.join() may hung.
if (data.source)
data.source->finish();
}
data.is_finished = true;
data.finish_event.set();
}
PushingAsyncPipelineExecutor::PushingAsyncPipelineExecutor(QueryPipeline & pipeline_) : pipeline(pipeline_)
{
if (!pipeline.pushing())
throw Exception(ErrorCodes::LOGICAL_ERROR, "Pipeline for PushingPipelineExecutor must be pushing");
pushing_source = std::make_shared<PushingAsyncSource>(pipeline.input->getHeader());
connect(pushing_source->getPort(), *pipeline.input);
pipeline.processors->emplace_back(pushing_source);
}
PushingAsyncPipelineExecutor::~PushingAsyncPipelineExecutor()
{
/// It must be finalized explicitly. Otherwise we cancel it assuming it's due to an exception.
chassert(finished || std::uncaught_exceptions() || std::current_exception());
try
{
cancel();
}
catch (...)
{
tryLogCurrentException("PushingAsyncPipelineExecutor");
}
}
const Block & PushingAsyncPipelineExecutor::getHeader() const
{
return pushing_source->getPort().getHeader();
}
void PushingAsyncPipelineExecutor::start()
{
if (started)
return;
started = true;
data = std::make_unique<Data>();
data->executor = std::make_shared<PipelineExecutor>(pipeline.processors, pipeline.process_list_element);
data->executor->setReadProgressCallback(pipeline.getReadProgressCallback());
data->source = pushing_source.get();
auto func = [&, thread_group = CurrentThread::getGroup()]()
{
threadFunction(*data, thread_group, pipeline.getNumThreads(), pipeline.getConcurrencyControl());
};
data->thread = ThreadFromGlobalPool(std::move(func));
}
void PushingAsyncPipelineExecutor::push(Chunk chunk)
{
if (!started)
start();
bool is_pushed = pushing_source->setData(std::move(chunk));
data->rethrowExceptionIfHas();
if (!is_pushed)
throw Exception(ErrorCodes::LOGICAL_ERROR,
"Pipeline for PushingAsyncPipelineExecutor was finished before all data was inserted");
}
void PushingAsyncPipelineExecutor::push(Block block)
{
push(Chunk(block.getColumns(), block.rows()));
}
void PushingAsyncPipelineExecutor::finish()
{
if (finished)
return;
finished = true;
pushing_source->finish();
/// Join thread here to wait for possible exception.
if (data && data->thread.joinable())
data->thread.join();
/// Rethrow exception to not swallow it in destructor.
if (data)
data->rethrowExceptionIfHas();
}
void PushingAsyncPipelineExecutor::cancel()
{
/// Cancel execution if it wasn't finished.
if (data && !data->is_finished && data->executor)
data->executor->cancel();
finish();
}
}
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