ClickHouse/src/IO/AsyncReadCounters.h
2023-02-08 21:26:24 +01:00

32 lines
935 B
C++

#pragma once
#include <Core/Types.h>
#include <Columns/ColumnMap.h>
namespace DB
{
/// Metrics for asynchronous reading feature.
struct AsyncReadCounters
{
/// Count current and max number of tasks in a asynchronous read pool.
/// The tasks are requests to read the data.
size_t max_parallel_read_tasks = 0;
size_t current_parallel_read_tasks = 0;
/// Count current and max number of tasks in a reader prefetch read pool.
/// The tasks are calls to IMergeTreeReader::prefetch(), which does not do
/// any reading but creates a request for read. But as we need to wait for
/// marks to be loaded during this prefetch, we do it in a threadpool too.
size_t max_parallel_prefetch_tasks = 0;
size_t current_parallel_prefetch_tasks = 0;
size_t total_prefetch_tasks = 0;
mutable std::mutex mutex;
AsyncReadCounters() = default;
void dumpToMapColumn(IColumn * column) const;
};
}