#pragma once #include #include 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; }; }