ClickHouse/dbms/src/Processors/Executors/PipelineExecutor.cpp
2020-01-09 12:03:08 +03:00

783 lines
22 KiB
C++

#include <Processors/Executors/PipelineExecutor.h>
#include <unordered_map>
#include <queue>
#include <IO/WriteBufferFromString.h>
#include <Processors/printPipeline.h>
#include <Common/EventCounter.h>
#include <ext/scope_guard.h>
#include <Common/CurrentThread.h>
#include <Common/Stopwatch.h>
#include <Processors/ISource.h>
#include <Common/setThreadName.h>
#if !defined(__APPLE__) && !defined(__FreeBSD__)
#include <sched.h>
#endif
namespace DB
{
namespace ErrorCodes
{
extern const int TOO_MANY_ROWS_OR_BYTES;
extern const int QUOTA_EXPIRED;
extern const int QUERY_WAS_CANCELLED;
}
static bool checkCanAddAdditionalInfoToException(const DB::Exception & exception)
{
/// Don't add additional info to limits and quota exceptions, and in case of kill query (to pass tests).
return exception.code() != ErrorCodes::TOO_MANY_ROWS_OR_BYTES
&& exception.code() != ErrorCodes::QUOTA_EXPIRED
&& exception.code() != ErrorCodes::QUERY_WAS_CANCELLED;
}
PipelineExecutor::PipelineExecutor(Processors & processors_)
: processors(processors_)
, cancelled(false)
, finished(false)
, num_processing_executors(0)
, expand_pipeline_task(nullptr)
{
buildGraph();
}
bool PipelineExecutor::addEdges(UInt64 node)
{
auto throwUnknownProcessor = [](const IProcessor * proc, const IProcessor * parent, bool from_input_port)
{
String msg = "Processor " + proc->getName() + " was found as " + (from_input_port ? "input" : "output")
+ " for processor " + parent->getName() + ", but not found in list of processors.";
throw Exception(msg, ErrorCodes::LOGICAL_ERROR);
};
const IProcessor * cur = graph[node].processor;
auto add_edge = [&](auto & from_port, const IProcessor * to_proc, Edges & edges,
bool is_backward, UInt64 input_port_number, UInt64 output_port_number,
std::vector<void *> * update_list)
{
auto it = processors_map.find(to_proc);
if (it == processors_map.end())
throwUnknownProcessor(to_proc, cur, true);
UInt64 proc_num = it->second;
auto & edge = edges.emplace_back(proc_num, is_backward, input_port_number, output_port_number, update_list);
from_port.setUpdateInfo(&edge.update_info);
};
bool was_edge_added = false;
auto & inputs = processors[node]->getInputs();
auto from_input = graph[node].backEdges.size();
if (from_input < inputs.size())
{
was_edge_added = true;
for (auto it = std::next(inputs.begin(), from_input); it != inputs.end(); ++it, ++from_input)
{
const IProcessor * proc = &it->getOutputPort().getProcessor();
auto output_port_number = proc->getOutputPortNumber(&it->getOutputPort());
add_edge(*it, proc, graph[node].backEdges, true, from_input, output_port_number, &graph[node].post_updated_input_ports);
}
}
auto & outputs = processors[node]->getOutputs();
auto from_output = graph[node].directEdges.size();
if (from_output < outputs.size())
{
was_edge_added = true;
for (auto it = std::next(outputs.begin(), from_output); it != outputs.end(); ++it, ++from_output)
{
const IProcessor * proc = &it->getInputPort().getProcessor();
auto input_port_number = proc->getInputPortNumber(&it->getInputPort());
add_edge(*it, proc, graph[node].directEdges, false, input_port_number, from_output, &graph[node].post_updated_output_ports);
}
}
return was_edge_added;
}
void PipelineExecutor::buildGraph()
{
UInt64 num_processors = processors.size();
graph.reserve(num_processors);
for (UInt64 node = 0; node < num_processors; ++node)
{
IProcessor * proc = processors[node].get();
processors_map[proc] = node;
graph.emplace_back(proc, node);
}
for (UInt64 node = 0; node < num_processors; ++node)
addEdges(node);
}
void PipelineExecutor::addChildlessProcessorsToStack(Stack & stack)
{
UInt64 num_processors = processors.size();
for (UInt64 proc = 0; proc < num_processors; ++proc)
{
if (graph[proc].directEdges.empty())
{
stack.push(proc);
/// do not lock mutex, as this function is executedin single thread
graph[proc].status = ExecStatus::Preparing;
}
}
}
static void executeJob(IProcessor * processor)
{
try
{
processor->work();
}
catch (Exception & exception)
{
if (checkCanAddAdditionalInfoToException(exception))
exception.addMessage("While executing " + processor->getName() + " ("
+ toString(reinterpret_cast<std::uintptr_t>(processor)) + ") ");
throw;
}
}
void PipelineExecutor::addJob(ExecutionState * execution_state)
{
auto job = [execution_state]()
{
try
{
// Stopwatch watch;
executeJob(execution_state->processor);
// execution_state->execution_time_ns += watch.elapsed();
++execution_state->num_executed_jobs;
}
catch (...)
{
execution_state->exception = std::current_exception();
}
};
execution_state->job = std::move(job);
}
bool PipelineExecutor::expandPipeline(Stack & stack, UInt64 pid)
{
auto & cur_node = graph[pid];
Processors new_processors;
try
{
new_processors = cur_node.processor->expandPipeline();
}
catch (...)
{
cur_node.execution_state->exception = std::current_exception();
return false;
}
for (const auto & processor : new_processors)
{
if (processors_map.count(processor.get()))
throw Exception("Processor " + processor->getName() + " was already added to pipeline.",
ErrorCodes::LOGICAL_ERROR);
processors_map[processor.get()] = graph.size();
graph.emplace_back(processor.get(), graph.size());
}
{
std::lock_guard guard(processors_mutex);
processors.insert(processors.end(), new_processors.begin(), new_processors.end());
}
UInt64 num_processors = processors.size();
for (UInt64 node = 0; node < num_processors; ++node)
{
size_t num_direct_edges = graph[node].directEdges.size();
size_t num_back_edges = graph[node].backEdges.size();
if (addEdges(node))
{
std::lock_guard guard(graph[node].status_mutex);
for (; num_back_edges < graph[node].backEdges.size(); ++num_back_edges)
graph[node].updated_input_ports.emplace_back(num_back_edges);
for (; num_direct_edges < graph[node].directEdges.size(); ++num_direct_edges)
graph[node].updated_output_ports.emplace_back(num_direct_edges);
if (graph[node].status == ExecStatus::Idle)
{
graph[node].status = ExecStatus::Preparing;
stack.push(node);
}
}
}
return true;
}
bool PipelineExecutor::tryAddProcessorToStackIfUpdated(Edge & edge, Queue & queue, size_t thread_number)
{
/// In this method we have ownership on edge, but node can be concurrently accessed.
auto & node = graph[edge.to];
std::unique_lock lock(node.status_mutex);
ExecStatus status = node.status;
if (status == ExecStatus::Finished)
return true;
if (edge.backward)
node.updated_output_ports.push_back(edge.output_port_number);
else
node.updated_input_ports.push_back(edge.input_port_number);
if (status == ExecStatus::Idle)
{
node.status = ExecStatus::Preparing;
return prepareProcessor(edge.to, thread_number, queue, std::move(lock));
}
return true;
}
bool PipelineExecutor::prepareProcessor(UInt64 pid, size_t thread_number, Queue & queue, std::unique_lock<std::mutex> node_lock)
{
/// In this method we have ownership on node.
auto & node = graph[pid];
bool need_traverse = false;
bool need_expand_pipeline = false;
std::vector<Edge *> updated_back_edges;
std::vector<Edge *> updated_direct_edges;
{
/// Stopwatch watch;
std::unique_lock<std::mutex> lock(std::move(node_lock));
try
{
node.last_processor_status = node.processor->prepare(node.updated_input_ports, node.updated_output_ports);
}
catch (...)
{
node.execution_state->exception = std::current_exception();
return false;
}
/// node.execution_state->preparation_time_ns += watch.elapsed();
node.updated_input_ports.clear();
node.updated_output_ports.clear();
switch (node.last_processor_status)
{
case IProcessor::Status::NeedData:
case IProcessor::Status::PortFull:
{
need_traverse = true;
node.status = ExecStatus::Idle;
break;
}
case IProcessor::Status::Finished:
{
need_traverse = true;
node.status = ExecStatus::Finished;
break;
}
case IProcessor::Status::Ready:
{
node.status = ExecStatus::Executing;
queue.push(node.execution_state.get());
break;
}
case IProcessor::Status::Async:
{
throw Exception("Async is temporary not supported.", ErrorCodes::LOGICAL_ERROR);
// node.status = ExecStatus::Executing;
// addAsyncJob(pid);
// break;
}
case IProcessor::Status::Wait:
{
throw Exception("Wait is temporary not supported.", ErrorCodes::LOGICAL_ERROR);
}
case IProcessor::Status::ExpandPipeline:
{
need_expand_pipeline = true;
break;
}
}
if (need_traverse)
{
for (auto & edge_id : node.post_updated_input_ports)
{
auto edge = static_cast<Edge *>(edge_id);
updated_back_edges.emplace_back(edge);
edge->update_info.trigger();
}
for (auto & edge_id : node.post_updated_output_ports)
{
auto edge = static_cast<Edge *>(edge_id);
updated_direct_edges.emplace_back(edge);
edge->update_info.trigger();
}
node.post_updated_input_ports.clear();
node.post_updated_output_ports.clear();
}
}
if (need_traverse)
{
for (auto & edge : updated_direct_edges)
{
if (!tryAddProcessorToStackIfUpdated(*edge, queue, thread_number))
return false;
}
for (auto & edge : updated_back_edges)
{
if (!tryAddProcessorToStackIfUpdated(*edge, queue, thread_number))
return false;
}
}
if (need_expand_pipeline)
{
Stack stack;
executor_contexts[thread_number]->task_list.emplace_back(
node.execution_state.get(),
&stack
);
ExpandPipelineTask * desired = &executor_contexts[thread_number]->task_list.back();
ExpandPipelineTask * expected = nullptr;
while (!expand_pipeline_task.compare_exchange_strong(expected, desired))
{
if (!doExpandPipeline(expected, true))
return false;
expected = nullptr;
}
if (!doExpandPipeline(desired, true))
return false;
/// Add itself back to be prepared again.
stack.push(pid);
while (!stack.empty())
{
auto item = stack.top();
if (!prepareProcessor(item, thread_number, queue, std::unique_lock<std::mutex>(graph[item].status_mutex)))
return false;
stack.pop();
}
}
return true;
}
bool PipelineExecutor::doExpandPipeline(ExpandPipelineTask * task, bool processing)
{
std::unique_lock lock(task->mutex);
if (processing)
++task->num_waiting_processing_threads;
task->condvar.wait(lock, [&]()
{
return task->num_waiting_processing_threads >= num_processing_executors || expand_pipeline_task != task;
});
bool result = true;
/// After condvar.wait() task may point to trash. Can change it only if it is still in expand_pipeline_task.
if (expand_pipeline_task == task)
{
result = expandPipeline(*task->stack, task->node_to_expand->processors_id);
expand_pipeline_task = nullptr;
lock.unlock();
task->condvar.notify_all();
}
return result;
}
void PipelineExecutor::cancel()
{
cancelled = true;
finish();
std::lock_guard guard(processors_mutex);
for (auto & processor : processors)
processor->cancel();
}
void PipelineExecutor::finish()
{
{
std::lock_guard lock(task_queue_mutex);
finished = true;
}
std::lock_guard guard(executor_contexts_mutex);
for (auto & context : executor_contexts)
{
{
std::lock_guard lock(context->mutex);
context->wake_flag = true;
}
context->condvar.notify_one();
}
}
void PipelineExecutor::execute(size_t num_threads)
{
try
{
executeImpl(num_threads);
/// Execution can be stopped because of exception. Check and rethrow if any.
for (auto & node : graph)
if (node.execution_state->exception)
std::rethrow_exception(node.execution_state->exception);
}
catch (Exception & exception)
{
if (checkCanAddAdditionalInfoToException(exception))
exception.addMessage("\nCurrent state:\n" + dumpPipeline());
throw;
}
if (cancelled)
return;
bool all_processors_finished = true;
for (auto & node : graph)
if (node.status != ExecStatus::Finished) /// Single thread, do not hold mutex
all_processors_finished = false;
if (!all_processors_finished)
throw Exception("Pipeline stuck. Current state:\n" + dumpPipeline(), ErrorCodes::LOGICAL_ERROR);
}
void PipelineExecutor::executeSingleThread(size_t thread_num, size_t num_threads)
{
#if !defined(__APPLE__) && !defined(__FreeBSD__)
/// Specify CPU core for thread if can.
/// It may reduce the number of context swithches.
/*
if (num_threads > 1)
{
cpu_set_t cpu_set;
CPU_ZERO(&cpu_set);
CPU_SET(thread_num, &cpu_set);
if (sched_setaffinity(0, sizeof(cpu_set_t), &cpu_set) == -1)
LOG_TRACE(log, "Cannot set affinity for thread " << num_threads);
}
*/
#endif
// UInt64 total_time_ns = 0;
// UInt64 execution_time_ns = 0;
// UInt64 processing_time_ns = 0;
// UInt64 wait_time_ns = 0;
// Stopwatch total_time_watch;
ExecutionState * state = nullptr;
auto prepare_processor = [&](UInt64 pid, Queue & queue)
{
if (!prepareProcessor(pid, thread_num, queue, std::unique_lock<std::mutex>(graph[pid].status_mutex)))
finish();
};
auto wake_up_executor = [&](size_t executor)
{
std::lock_guard guard(executor_contexts[executor]->mutex);
executor_contexts[executor]->wake_flag = true;
executor_contexts[executor]->condvar.notify_one();
};
while (!finished)
{
/// First, find any processor to execute.
/// Just travers graph and prepare any processor.
while (!finished)
{
{
std::unique_lock lock(task_queue_mutex);
if (!task_queue.empty())
{
state = task_queue.pop(thread_num);
if (!task_queue.empty() && !threads_queue.empty() /*&& task_queue.quota() > threads_queue.size()*/)
{
auto thread_to_wake = threads_queue.pop_any();
lock.unlock();
wake_up_executor(thread_to_wake);
}
break;
}
if (threads_queue.size() + 1 == num_threads)
{
lock.unlock();
finish();
break;
}
threads_queue.push(thread_num);
}
{
std::unique_lock lock(executor_contexts[thread_num]->mutex);
executor_contexts[thread_num]->condvar.wait(lock, [&]
{
return finished || executor_contexts[thread_num]->wake_flag;
});
executor_contexts[thread_num]->wake_flag = false;
}
}
if (finished)
break;
while (state)
{
if (finished)
break;
addJob(state);
{
// Stopwatch execution_time_watch;
state->job();
// execution_time_ns += execution_time_watch.elapsed();
}
if (state->exception)
finish();
if (finished)
break;
// Stopwatch processing_time_watch;
/// Try to execute neighbour processor.
{
Queue queue;
++num_processing_executors;
while (auto task = expand_pipeline_task.load())
doExpandPipeline(task, true);
/// Execute again if can.
prepare_processor(state->processors_id, queue);
state = nullptr;
/// Take local task from queue if has one.
if (!queue.empty())
{
state = queue.front();
queue.pop();
}
/// Push other tasks to global queue.
if (!queue.empty())
{
std::unique_lock lock(task_queue_mutex);
while (!queue.empty() && !finished)
{
task_queue.push(queue.front(), thread_num);
queue.pop();
}
if (!threads_queue.empty() /* && task_queue.quota() > threads_queue.size()*/)
{
auto thread_to_wake = threads_queue.pop_any();
lock.unlock();
wake_up_executor(thread_to_wake);
}
}
--num_processing_executors;
while (auto task = expand_pipeline_task.load())
doExpandPipeline(task, false);
}
// processing_time_ns += processing_time_watch.elapsed();
}
}
// total_time_ns = total_time_watch.elapsed();
// wait_time_ns = total_time_ns - execution_time_ns - processing_time_ns;
/*
LOG_TRACE(log, "Thread finished."
<< " Total time: " << (total_time_ns / 1e9) << " sec."
<< " Execution time: " << (execution_time_ns / 1e9) << " sec."
<< " Processing time: " << (processing_time_ns / 1e9) << " sec."
<< " Wait time: " << (wait_time_ns / 1e9) << "sec.");
*/
}
void PipelineExecutor::executeImpl(size_t num_threads)
{
Stack stack;
threads_queue.init(num_threads);
task_queue.init(num_threads);
{
std::lock_guard guard(executor_contexts_mutex);
executor_contexts.reserve(num_threads);
for (size_t i = 0; i < num_threads; ++i)
executor_contexts.emplace_back(std::make_unique<ExecutorContext>());
}
auto thread_group = CurrentThread::getGroup();
using ThreadsData = std::vector<ThreadFromGlobalPool>;
ThreadsData threads;
threads.reserve(num_threads);
bool finished_flag = false;
SCOPE_EXIT(
if (!finished_flag)
{
finish();
for (auto & thread : threads)
if (thread.joinable())
thread.join();
}
);
addChildlessProcessorsToStack(stack);
{
std::lock_guard lock(task_queue_mutex);
Queue queue;
size_t next_thread = 0;
while (!stack.empty())
{
UInt64 proc = stack.top();
stack.pop();
prepareProcessor(proc, 0, queue, std::unique_lock<std::mutex>(graph[proc].status_mutex));
while (!queue.empty())
{
task_queue.push(queue.front(), next_thread);
queue.pop();
++next_thread;
if (next_thread >= num_threads)
next_thread = 0;
}
}
}
if (num_threads > 1)
{
for (size_t i = 0; i < num_threads; ++i)
{
threads.emplace_back([this, thread_group, thread_num = i, num_threads]
{
/// ThreadStatus thread_status;
setThreadName("QueryPipelineEx");
if (thread_group)
CurrentThread::attachTo(thread_group);
SCOPE_EXIT(
if (thread_group)
CurrentThread::detachQueryIfNotDetached();
);
executeSingleThread(thread_num, num_threads);
});
}
for (auto & thread : threads)
if (thread.joinable())
thread.join();
}
else
executeSingleThread(0, num_threads);
finished_flag = true;
}
String PipelineExecutor::dumpPipeline() const
{
for (auto & node : graph)
{
if (node.execution_state)
node.processor->setDescription(
"(" + std::to_string(node.execution_state->num_executed_jobs) + " jobs, execution time: "
+ std::to_string(node.execution_state->execution_time_ns / 1e9) + " sec., preparation time: "
+ std::to_string(node.execution_state->preparation_time_ns / 1e9) + " sec.)");
}
std::vector<IProcessor::Status> statuses;
std::vector<IProcessor *> proc_list;
statuses.reserve(graph.size());
proc_list.reserve(graph.size());
for (auto & proc : graph)
{
proc_list.emplace_back(proc.processor);
statuses.emplace_back(proc.last_processor_status);
}
WriteBufferFromOwnString out;
printPipeline(processors, statuses, out);
out.finish();
return out.str();
}
}