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https://github.com/ClickHouse/ClickHouse.git
synced 2024-12-15 19:02:04 +00:00
1076 lines
34 KiB
C++
1076 lines
34 KiB
C++
#include "FileCache.h"
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#include <Common/randomSeed.h>
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#include <Common/SipHash.h>
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#include <Common/hex.h>
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#include <Common/FileCacheSettings.h>
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#include <IO/ReadHelpers.h>
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#include <IO/WriteBufferFromFile.h>
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#include <IO/ReadSettings.h>
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#include <IO/WriteBufferFromString.h>
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#include <IO/Operators.h>
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#include <pcg-random/pcg_random.hpp>
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#include <filesystem>
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namespace fs = std::filesystem;
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namespace DB
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{
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namespace ErrorCodes
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{
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extern const int REMOTE_FS_OBJECT_CACHE_ERROR;
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extern const int LOGICAL_ERROR;
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}
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namespace
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{
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String keyToStr(const IFileCache::Key & key)
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{
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return getHexUIntLowercase(key);
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}
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}
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IFileCache::IFileCache(
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const String & cache_base_path_,
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const FileCacheSettings & cache_settings_)
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: cache_base_path(cache_base_path_)
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, max_size(cache_settings_.max_size)
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, max_element_size(cache_settings_.max_elements)
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, max_file_segment_size(cache_settings_.max_file_segment_size)
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{
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}
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IFileCache::Key IFileCache::hash(const String & path)
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{
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return sipHash128(path.data(), path.size());
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}
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String IFileCache::getPathInLocalCache(const Key & key, size_t offset)
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{
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auto key_str = keyToStr(key);
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return fs::path(cache_base_path) / key_str.substr(0, 3) / key_str / std::to_string(offset);
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}
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String IFileCache::getPathInLocalCache(const Key & key)
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{
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auto key_str = keyToStr(key);
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return fs::path(cache_base_path) / key_str.substr(0, 3) / key_str;
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}
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bool IFileCache::isReadOnly()
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{
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return !CurrentThread::isInitialized()
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|| !CurrentThread::get().getQueryContext()
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|| CurrentThread::getQueryId().size == 0;
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}
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void IFileCache::assertInitialized() const
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{
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if (!is_initialized)
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throw Exception(ErrorCodes::REMOTE_FS_OBJECT_CACHE_ERROR, "Cache not initialized");
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}
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LRUFileCache::LRUFileCache(const String & cache_base_path_, const FileCacheSettings & cache_settings_)
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: IFileCache(cache_base_path_, cache_settings_)
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, max_stash_element_size(cache_settings_.max_elements)
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, enable_cache_hits_threshold(cache_settings_.enable_cache_hits_threshold)
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, log(&Poco::Logger::get("LRUFileCache"))
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{
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}
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void LRUFileCache::initialize()
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{
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std::lock_guard cache_lock(mutex);
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if (!is_initialized)
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{
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if (fs::exists(cache_base_path))
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loadCacheInfoIntoMemory(cache_lock);
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else
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fs::create_directories(cache_base_path);
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is_initialized = true;
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}
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}
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void LRUFileCache::useCell(
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const FileSegmentCell & cell, FileSegments & result, std::lock_guard<std::mutex> & cache_lock)
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{
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auto file_segment = cell.file_segment;
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if (file_segment->isDownloaded()
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&& fs::file_size(getPathInLocalCache(file_segment->key(), file_segment->offset())) == 0)
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throw Exception(ErrorCodes::LOGICAL_ERROR,
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"Cannot have zero size downloaded file segments. Current file segment: {}",
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file_segment->range().toString());
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result.push_back(cell.file_segment);
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/**
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* A cell receives a queue iterator on first successful space reservation attempt
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* (space is reserved incrementally on each read buffer nextImpl() call).
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*/
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if (cell.queue_iterator)
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{
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/// Move to the end of the queue. The iterator remains valid.
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queue.moveToEnd(*cell.queue_iterator, cache_lock);
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}
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}
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LRUFileCache::FileSegmentCell * LRUFileCache::getCell(
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const Key & key, size_t offset, std::lock_guard<std::mutex> & /* cache_lock */)
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{
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auto it = files.find(key);
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if (it == files.end())
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return nullptr;
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auto & offsets = it->second;
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auto cell_it = offsets.find(offset);
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if (cell_it == offsets.end())
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return nullptr;
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return &cell_it->second;
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}
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FileSegments LRUFileCache::getImpl(
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const Key & key, const FileSegment::Range & range, std::lock_guard<std::mutex> & cache_lock)
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{
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/// Given range = [left, right] and non-overlapping ordered set of file segments,
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/// find list [segment1, ..., segmentN] of segments which intersect with given range.
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auto it = files.find(key);
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if (it == files.end())
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return {};
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const auto & file_segments = it->second;
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if (file_segments.empty())
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{
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auto key_path = getPathInLocalCache(key);
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files.erase(key);
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if (fs::exists(key_path))
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fs::remove(key_path);
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return {};
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}
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FileSegments result;
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auto segment_it = file_segments.lower_bound(range.left);
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if (segment_it == file_segments.end())
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{
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/// N - last cached segment for given file key, segment{N}.offset < range.left:
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/// segment{N} segment{N}
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/// [________ [_______]
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/// [__________] OR [________]
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/// ^ ^
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/// range.left range.left
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const auto & cell = file_segments.rbegin()->second;
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if (cell.file_segment->range().right < range.left)
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return {};
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useCell(cell, result, cache_lock);
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}
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else /// segment_it <-- segmment{k}
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{
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if (segment_it != file_segments.begin())
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{
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const auto & prev_cell = std::prev(segment_it)->second;
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const auto & prev_cell_range = prev_cell.file_segment->range();
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if (range.left <= prev_cell_range.right)
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{
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/// segment{k-1} segment{k}
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/// [________] [_____
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/// [___________
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/// ^
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/// range.left
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useCell(prev_cell, result, cache_lock);
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}
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}
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/// segment{k} ... segment{k-1} segment{k} segment{k}
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/// [______ [______] [____ [________
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/// [_________ OR [________ OR [______] ^
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/// ^ ^ ^ segment{k}.offset
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/// range.left range.left range.right
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while (segment_it != file_segments.end())
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{
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const auto & cell = segment_it->second;
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if (range.right < cell.file_segment->range().left)
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break;
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useCell(cell, result, cache_lock);
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++segment_it;
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}
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}
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return result;
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}
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FileSegments LRUFileCache::splitRangeIntoCells(
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const Key & key, size_t offset, size_t size, FileSegment::State state, std::lock_guard<std::mutex> & cache_lock)
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{
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assert(size > 0);
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auto current_pos = offset;
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auto end_pos_non_included = offset + size;
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size_t current_cell_size;
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size_t remaining_size = size;
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FileSegments file_segments;
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while (current_pos < end_pos_non_included)
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{
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current_cell_size = std::min(remaining_size, max_file_segment_size);
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remaining_size -= current_cell_size;
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auto * cell = addCell(key, current_pos, current_cell_size, state, cache_lock);
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if (cell)
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file_segments.push_back(cell->file_segment);
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assert(cell);
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current_pos += current_cell_size;
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}
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assert(file_segments.empty() || offset + size - 1 == file_segments.back()->range().right);
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return file_segments;
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}
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void LRUFileCache::fillHolesWithEmptyFileSegments(
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FileSegments & file_segments,
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const Key & key,
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const FileSegment::Range & range,
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bool fill_with_detached_file_segments,
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std::lock_guard<std::mutex> & cache_lock)
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{
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/// There are segments [segment1, ..., segmentN]
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/// (non-overlapping, non-empty, ascending-ordered) which (maybe partially)
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/// intersect with given range.
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/// It can have holes:
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/// [____________________] -- requested range
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/// [____] [_] [_________] -- intersecting cache [segment1, ..., segmentN]
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///
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/// For each such hole create a cell with file segment state EMPTY.
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auto it = file_segments.begin();
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auto segment_range = (*it)->range();
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size_t current_pos;
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if (segment_range.left < range.left)
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{
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/// [_______ -- requested range
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/// [_______
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/// ^
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/// segment1
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current_pos = segment_range.right + 1;
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++it;
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}
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else
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current_pos = range.left;
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while (current_pos <= range.right && it != file_segments.end())
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{
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segment_range = (*it)->range();
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if (current_pos == segment_range.left)
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{
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current_pos = segment_range.right + 1;
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++it;
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continue;
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}
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assert(current_pos < segment_range.left);
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auto hole_size = segment_range.left - current_pos;
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if (fill_with_detached_file_segments)
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{
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auto file_segment = std::make_shared<FileSegment>(current_pos, hole_size, key, this, FileSegment::State::EMPTY);
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{
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std::lock_guard segment_lock(file_segment->mutex);
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file_segment->markAsDetached(segment_lock);
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}
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file_segments.insert(it, file_segment);
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}
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else
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{
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file_segments.splice(it, splitRangeIntoCells(key, current_pos, hole_size, FileSegment::State::EMPTY, cache_lock));
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}
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current_pos = segment_range.right + 1;
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++it;
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}
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if (current_pos <= range.right)
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{
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/// ________] -- requested range
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/// _____]
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/// ^
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/// segmentN
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auto hole_size = range.right - current_pos + 1;
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if (fill_with_detached_file_segments)
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{
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auto file_segment = std::make_shared<FileSegment>(current_pos, hole_size, key, this, FileSegment::State::EMPTY);
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{
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std::lock_guard segment_lock(file_segment->mutex);
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file_segment->markAsDetached(segment_lock);
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}
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file_segments.insert(file_segments.end(), file_segment);
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}
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else
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{
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file_segments.splice(
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file_segments.end(), splitRangeIntoCells(key, current_pos, hole_size, FileSegment::State::EMPTY, cache_lock));
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}
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}
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}
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FileSegmentsHolder LRUFileCache::getOrSet(const Key & key, size_t offset, size_t size)
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{
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assertInitialized();
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FileSegment::Range range(offset, offset + size - 1);
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std::lock_guard cache_lock(mutex);
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#ifndef NDEBUG
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assertCacheCorrectness(key, cache_lock);
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#endif
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/// Get all segments which intersect with the given range.
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auto file_segments = getImpl(key, range, cache_lock);
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if (file_segments.empty())
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{
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file_segments = splitRangeIntoCells(key, offset, size, FileSegment::State::EMPTY, cache_lock);
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}
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else
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{
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fillHolesWithEmptyFileSegments(file_segments, key, range, false, cache_lock);
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}
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assert(!file_segments.empty());
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return FileSegmentsHolder(std::move(file_segments));
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}
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FileSegmentsHolder LRUFileCache::get(const Key & key, size_t offset, size_t size)
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{
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assertInitialized();
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FileSegment::Range range(offset, offset + size - 1);
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std::lock_guard cache_lock(mutex);
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#ifndef NDEBUG
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assertCacheCorrectness(key, cache_lock);
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#endif
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/// Get all segments which intersect with the given range.
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auto file_segments = getImpl(key, range, cache_lock);
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if (file_segments.empty())
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{
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auto file_segment = std::make_shared<FileSegment>(offset, size, key, this, FileSegment::State::EMPTY);
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{
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std::lock_guard segment_lock(file_segment->mutex);
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file_segment->markAsDetached(segment_lock);
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}
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file_segments = { file_segment };
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}
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else
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{
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fillHolesWithEmptyFileSegments(file_segments, key, range, true, cache_lock);
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}
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return FileSegmentsHolder(std::move(file_segments));
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}
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LRUFileCache::FileSegmentCell * LRUFileCache::addCell(
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const Key & key, size_t offset, size_t size, FileSegment::State state,
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std::lock_guard<std::mutex> & cache_lock)
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{
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/// Create a file segment cell and put it in `files` map by [key][offset].
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if (!size)
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return nullptr; /// Empty files are not cached.
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if (files[key].contains(offset))
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throw Exception(
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ErrorCodes::LOGICAL_ERROR,
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"Cache already exists for key: `{}`, offset: {}, size: {}.\nCurrent cache structure: {}",
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keyToStr(key), offset, size, dumpStructureUnlocked(key, cache_lock));
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auto skip_or_download = [&]() -> FileSegmentPtr
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{
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if (state == FileSegment::State::EMPTY && enable_cache_hits_threshold)
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{
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auto record = records.find({key, offset});
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if (record == records.end())
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{
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auto queue_iter = stash_queue.add(key, offset, 0, cache_lock);
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records.insert({{key, offset}, queue_iter});
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if (stash_queue.getElementsNum(cache_lock) > max_stash_element_size)
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{
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auto remove_queue_iter = stash_queue.begin();
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records.erase({remove_queue_iter->key, remove_queue_iter->offset});
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stash_queue.remove(remove_queue_iter, cache_lock);
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}
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/// For segments that do not reach the download threshold, we do not download them, but directly read them
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return std::make_shared<FileSegment>(offset, size, key, this, FileSegment::State::SKIP_CACHE);
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}
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else
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{
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auto queue_iter = record->second;
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queue_iter->hits++;
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stash_queue.moveToEnd(queue_iter, cache_lock);
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state = queue_iter->hits >= enable_cache_hits_threshold ? FileSegment::State::EMPTY : FileSegment::State::SKIP_CACHE;
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return std::make_shared<FileSegment>(offset, size, key, this, state);
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}
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}
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else
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return std::make_shared<FileSegment>(offset, size, key, this, state);
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};
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FileSegmentCell cell(skip_or_download(), this, cache_lock);
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auto & offsets = files[key];
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if (offsets.empty())
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{
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auto key_path = getPathInLocalCache(key);
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if (!fs::exists(key_path))
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fs::create_directories(key_path);
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}
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auto [it, inserted] = offsets.insert({offset, std::move(cell)});
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if (!inserted)
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throw Exception(
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ErrorCodes::LOGICAL_ERROR,
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"Failed to insert into cache key: `{}`, offset: {}, size: {}",
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keyToStr(key), offset, size);
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return &(it->second);
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}
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FileSegmentsHolder LRUFileCache::setDownloading(const Key & key, size_t offset, size_t size)
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{
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std::lock_guard cache_lock(mutex);
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#ifndef NDEBUG
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assertCacheCorrectness(key, cache_lock);
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#endif
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auto * cell = getCell(key, offset, cache_lock);
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if (cell)
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throw Exception(
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ErrorCodes::REMOTE_FS_OBJECT_CACHE_ERROR,
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"Cache cell already exists for key `{}` and offset {}",
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keyToStr(key), offset);
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auto file_segments = splitRangeIntoCells(key, offset, size, FileSegment::State::DOWNLOADING, cache_lock);
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return FileSegmentsHolder(std::move(file_segments));
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}
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bool LRUFileCache::tryReserve(
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const Key & key, size_t offset, size_t size, std::lock_guard<std::mutex> & cache_lock)
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{
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auto removed_size = 0;
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size_t queue_size = queue.getElementsNum(cache_lock);
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assert(queue_size <= max_element_size);
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/// Since space reservation is incremental, cache cell already exists if it's state is EMPTY.
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/// And it cache cell does not exist on startup -- as we first check for space and then add a cell.
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auto * cell_for_reserve = getCell(key, offset, cache_lock);
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/// A cell acquires a LRUQueue iterator on first successful space reservation attempt.
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/// cell_for_reserve can be nullptr here when we call tryReserve() from loadCacheInfoIntoMemory().
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if (!cell_for_reserve || !cell_for_reserve->queue_iterator)
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queue_size += 1;
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auto is_overflow = [&]
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{
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/// max_size == 0 means unlimited cache size, max_element_size means unlimited number of cache elements.
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return (max_size != 0 && queue.getTotalWeight(cache_lock) + size - removed_size > max_size)
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|| (max_element_size != 0 && queue_size > max_element_size);
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};
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std::vector<FileSegmentCell *> to_evict;
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std::vector<FileSegmentCell *> trash;
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for (const auto & [entry_key, entry_offset, entry_size, _] : queue)
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{
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if (!is_overflow())
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break;
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auto * cell = getCell(entry_key, entry_offset, cache_lock);
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if (!cell)
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throw Exception(
|
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ErrorCodes::REMOTE_FS_OBJECT_CACHE_ERROR,
|
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"Cache became inconsistent. Key: {}, offset: {}",
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keyToStr(key), offset);
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size_t cell_size = cell->size();
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assert(entry_size == cell_size);
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|
/// It is guaranteed that cell is not removed from cache as long as
|
|
/// pointer to corresponding file segment is hold by any other thread.
|
|
|
|
if (cell->releasable())
|
|
{
|
|
auto & file_segment = cell->file_segment;
|
|
|
|
std::lock_guard segment_lock(file_segment->mutex);
|
|
|
|
switch (file_segment->download_state)
|
|
{
|
|
case FileSegment::State::DOWNLOADED:
|
|
{
|
|
/// Cell will actually be removed only if
|
|
/// we managed to reserve enough space.
|
|
|
|
to_evict.push_back(cell);
|
|
break;
|
|
}
|
|
default:
|
|
{
|
|
trash.push_back(cell);
|
|
break;
|
|
}
|
|
}
|
|
|
|
removed_size += cell_size;
|
|
--queue_size;
|
|
}
|
|
}
|
|
|
|
|
|
/// This case is very unlikely, can happen in case of exception from
|
|
/// file_segment->complete(), which would be a logical error.
|
|
assert(trash.empty());
|
|
for (auto & cell : trash)
|
|
{
|
|
auto file_segment = cell->file_segment;
|
|
if (file_segment)
|
|
{
|
|
std::lock_guard segment_lock(file_segment->mutex);
|
|
remove(file_segment->key(), file_segment->offset(), cache_lock, segment_lock);
|
|
}
|
|
}
|
|
|
|
if (is_overflow())
|
|
return false;
|
|
|
|
/// cache cell is nullptr on server startup because we first check for space and then add a cell.
|
|
if (cell_for_reserve)
|
|
{
|
|
/// queue_iteratir is std::nullopt here if no space has been reserved yet, a cache cell
|
|
/// acquires queue iterator on first successful space reservation attempt.
|
|
/// If queue iterator already exists, we need to update the size after each space reservation.
|
|
auto queue_iterator = cell_for_reserve->queue_iterator;
|
|
if (queue_iterator)
|
|
queue.incrementSize(*queue_iterator, size, cache_lock);
|
|
else
|
|
cell_for_reserve->queue_iterator = queue.add(key, offset, size, cache_lock);
|
|
}
|
|
|
|
for (auto & cell : to_evict)
|
|
{
|
|
auto file_segment = cell->file_segment;
|
|
if (file_segment)
|
|
{
|
|
std::lock_guard<std::mutex> segment_lock(file_segment->mutex);
|
|
remove(file_segment->key(), file_segment->offset(), cache_lock, segment_lock);
|
|
}
|
|
}
|
|
|
|
if (queue.getTotalWeight(cache_lock) > (1ull << 63))
|
|
throw Exception(ErrorCodes::LOGICAL_ERROR, "Cache became inconsistent. There must be a bug");
|
|
|
|
return true;
|
|
}
|
|
|
|
void LRUFileCache::remove(const Key & key)
|
|
{
|
|
assertInitialized();
|
|
|
|
std::lock_guard cache_lock(mutex);
|
|
|
|
auto it = files.find(key);
|
|
if (it == files.end())
|
|
return;
|
|
|
|
auto & offsets = it->second;
|
|
|
|
std::vector<FileSegmentCell *> to_remove;
|
|
to_remove.reserve(offsets.size());
|
|
|
|
for (auto & [offset, cell] : offsets)
|
|
to_remove.push_back(&cell);
|
|
|
|
for (auto & cell : to_remove)
|
|
{
|
|
if (!cell->releasable())
|
|
throw Exception(
|
|
ErrorCodes::LOGICAL_ERROR,
|
|
"Cannot remove file from cache because someone reads from it. File segment info: {}",
|
|
cell->file_segment->getInfoForLog());
|
|
|
|
auto file_segment = cell->file_segment;
|
|
if (file_segment)
|
|
{
|
|
std::lock_guard<std::mutex> segment_lock(file_segment->mutex);
|
|
remove(file_segment->key(), file_segment->offset(), cache_lock, segment_lock);
|
|
}
|
|
}
|
|
|
|
auto key_path = getPathInLocalCache(key);
|
|
|
|
files.erase(key);
|
|
|
|
if (fs::exists(key_path))
|
|
fs::remove(key_path);
|
|
|
|
#ifndef NDEBUG
|
|
assertCacheCorrectness(cache_lock);
|
|
#endif
|
|
}
|
|
|
|
void LRUFileCache::remove()
|
|
{
|
|
/// Try remove all cached files by cache_base_path.
|
|
/// Only releasable file segments are evicted.
|
|
|
|
std::lock_guard cache_lock(mutex);
|
|
|
|
std::vector<FileSegment *> to_remove;
|
|
for (auto it = queue.begin(); it != queue.end();)
|
|
{
|
|
const auto & [key, offset, size, _] = *it++;
|
|
auto * cell = getCell(key, offset, cache_lock);
|
|
if (!cell)
|
|
throw Exception(
|
|
ErrorCodes::LOGICAL_ERROR,
|
|
"Cache is in inconsistent state: LRU queue contains entries with no cache cell");
|
|
|
|
if (cell->releasable())
|
|
{
|
|
auto file_segment = cell->file_segment;
|
|
if (file_segment)
|
|
{
|
|
std::lock_guard segment_lock(file_segment->mutex);
|
|
file_segment->detach(cache_lock, segment_lock);
|
|
remove(file_segment->key(), file_segment->offset(), cache_lock, segment_lock);
|
|
}
|
|
}
|
|
}
|
|
|
|
/// Remove all access information.
|
|
records.clear();
|
|
stash_queue.removeAll(cache_lock);
|
|
}
|
|
|
|
void LRUFileCache::remove(
|
|
Key key, size_t offset,
|
|
std::lock_guard<std::mutex> & cache_lock, std::lock_guard<std::mutex> & /* segment_lock */)
|
|
{
|
|
LOG_TEST(log, "Remove. Key: {}, offset: {}", keyToStr(key), offset);
|
|
|
|
auto * cell = getCell(key, offset, cache_lock);
|
|
if (!cell)
|
|
throw Exception(ErrorCodes::LOGICAL_ERROR, "No cache cell for key: {}, offset: {}", keyToStr(key), offset);
|
|
|
|
if (cell->queue_iterator)
|
|
{
|
|
queue.remove(*cell->queue_iterator, cache_lock);
|
|
}
|
|
|
|
auto & offsets = files[key];
|
|
offsets.erase(offset);
|
|
|
|
auto cache_file_path = getPathInLocalCache(key, offset);
|
|
if (fs::exists(cache_file_path))
|
|
{
|
|
try
|
|
{
|
|
fs::remove(cache_file_path);
|
|
|
|
if (is_initialized && offsets.empty())
|
|
{
|
|
auto key_path = getPathInLocalCache(key);
|
|
|
|
files.erase(key);
|
|
|
|
if (fs::exists(key_path))
|
|
fs::remove(key_path);
|
|
}
|
|
}
|
|
catch (...)
|
|
{
|
|
throw Exception(ErrorCodes::REMOTE_FS_OBJECT_CACHE_ERROR,
|
|
"Removal of cached file failed. Key: {}, offset: {}, path: {}, error: {}",
|
|
keyToStr(key), offset, cache_file_path, getCurrentExceptionMessage(false));
|
|
}
|
|
}
|
|
}
|
|
|
|
void LRUFileCache::loadCacheInfoIntoMemory(std::lock_guard<std::mutex> & cache_lock)
|
|
{
|
|
Key key;
|
|
UInt64 offset = 0;
|
|
size_t size = 0;
|
|
std::vector<std::pair<LRUQueue::Iterator, std::weak_ptr<FileSegment>>> queue_entries;
|
|
|
|
/// cache_base_path / key_prefix / key / offset
|
|
|
|
fs::directory_iterator key_prefix_it{cache_base_path};
|
|
for (; key_prefix_it != fs::directory_iterator(); ++key_prefix_it)
|
|
{
|
|
fs::directory_iterator key_it{key_prefix_it->path()};
|
|
for (; key_it != fs::directory_iterator(); ++key_it)
|
|
{
|
|
key = unhexUInt<UInt128>(key_it->path().filename().string().data());
|
|
|
|
fs::directory_iterator offset_it{key_it->path()};
|
|
for (; offset_it != fs::directory_iterator(); ++offset_it)
|
|
{
|
|
bool parsed = tryParse<UInt64>(offset, offset_it->path().filename());
|
|
if (!parsed)
|
|
{
|
|
LOG_WARNING(log, "Unexpected file: ", offset_it->path().string());
|
|
continue; /// Or just remove? Some unexpected file.
|
|
}
|
|
|
|
size = offset_it->file_size();
|
|
if (!size)
|
|
{
|
|
fs::remove(offset_it->path());
|
|
continue;
|
|
}
|
|
|
|
if (tryReserve(key, offset, size, cache_lock))
|
|
{
|
|
auto * cell = addCell(key, offset, size, FileSegment::State::DOWNLOADED, cache_lock);
|
|
if (cell)
|
|
queue_entries.emplace_back(*cell->queue_iterator, cell->file_segment);
|
|
}
|
|
else
|
|
{
|
|
LOG_WARNING(log,
|
|
"Cache capacity changed (max size: {}, available: {}), cached file `{}` does not fit in cache anymore (size: {})",
|
|
max_size, getAvailableCacheSizeUnlocked(cache_lock), key_it->path().string(), size);
|
|
fs::remove(offset_it->path());
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/// Shuffle cells to have random order in LRUQueue as at startup all cells have the same priority.
|
|
pcg64 generator(randomSeed());
|
|
std::shuffle(queue_entries.begin(), queue_entries.end(), generator);
|
|
for (const auto & [it, file_segment] : queue_entries)
|
|
{
|
|
/// Cell cache size changed and, for example, 1st file segment fits into cache
|
|
/// and 2nd file segment will fit only if first was evicted, then first will be removed and
|
|
/// cell is nullptr here.
|
|
if (file_segment.expired())
|
|
continue;
|
|
|
|
queue.moveToEnd(it, cache_lock);
|
|
}
|
|
#ifndef NDEBUG
|
|
assertCacheCorrectness(cache_lock);
|
|
#endif
|
|
}
|
|
|
|
void LRUFileCache::reduceSizeToDownloaded(
|
|
const Key & key, size_t offset,
|
|
std::lock_guard<std::mutex> & cache_lock, std::lock_guard<std::mutex> & /* segment_lock */)
|
|
{
|
|
/**
|
|
* In case file was partially downloaded and it's download cannot be continued
|
|
* because of no space left in cache, we need to be able to cut cell's size to downloaded_size.
|
|
*/
|
|
|
|
auto * cell = getCell(key, offset, cache_lock);
|
|
|
|
if (!cell)
|
|
{
|
|
throw Exception(
|
|
ErrorCodes::LOGICAL_ERROR,
|
|
"No cell found for key: {}, offset: {}",
|
|
keyToStr(key), offset);
|
|
}
|
|
|
|
const auto & file_segment = cell->file_segment;
|
|
|
|
size_t downloaded_size = file_segment->downloaded_size;
|
|
if (downloaded_size == file_segment->range().size())
|
|
{
|
|
throw Exception(
|
|
ErrorCodes::LOGICAL_ERROR,
|
|
"Nothing to reduce, file segment fully downloaded, key: {}, offset: {}",
|
|
keyToStr(key), offset);
|
|
}
|
|
|
|
cell->file_segment = std::make_shared<FileSegment>(offset, downloaded_size, key, this, FileSegment::State::DOWNLOADED);
|
|
}
|
|
|
|
bool LRUFileCache::isLastFileSegmentHolder(
|
|
const Key & key, size_t offset,
|
|
std::lock_guard<std::mutex> & cache_lock, std::lock_guard<std::mutex> & /* segment_lock */)
|
|
{
|
|
auto * cell = getCell(key, offset, cache_lock);
|
|
|
|
if (!cell)
|
|
throw Exception(ErrorCodes::LOGICAL_ERROR, "No cell found for key: {}, offset: {}", keyToStr(key), offset);
|
|
|
|
/// The caller of this method is last file segment holder if use count is 2 (the second pointer is cache itself)
|
|
return cell->file_segment.use_count() == 2;
|
|
}
|
|
|
|
FileSegments LRUFileCache::getSnapshot() const
|
|
{
|
|
std::lock_guard cache_lock(mutex);
|
|
|
|
FileSegments file_segments;
|
|
|
|
for (const auto & [key, cells_by_offset] : files)
|
|
{
|
|
for (const auto & [offset, cell] : cells_by_offset)
|
|
file_segments.push_back(FileSegment::getSnapshot(cell.file_segment, cache_lock));
|
|
}
|
|
|
|
return file_segments;
|
|
}
|
|
|
|
std::vector<String> LRUFileCache::tryGetCachePaths(const Key & key)
|
|
{
|
|
std::lock_guard cache_lock(mutex);
|
|
|
|
std::vector<String> cache_paths;
|
|
|
|
const auto & cells_by_offset = files[key];
|
|
|
|
for (const auto & [offset, cell] : cells_by_offset)
|
|
{
|
|
if (cell.file_segment->state() == FileSegment::State::DOWNLOADED)
|
|
cache_paths.push_back(getPathInLocalCache(key, offset));
|
|
}
|
|
|
|
return cache_paths;
|
|
}
|
|
|
|
size_t LRUFileCache::getUsedCacheSize() const
|
|
{
|
|
std::lock_guard cache_lock(mutex);
|
|
return getUsedCacheSizeUnlocked(cache_lock);
|
|
}
|
|
|
|
size_t LRUFileCache::getUsedCacheSizeUnlocked(std::lock_guard<std::mutex> & cache_lock) const
|
|
{
|
|
return queue.getTotalWeight(cache_lock);
|
|
}
|
|
|
|
size_t LRUFileCache::getAvailableCacheSize() const
|
|
{
|
|
std::lock_guard cache_lock(mutex);
|
|
return getAvailableCacheSizeUnlocked(cache_lock);
|
|
}
|
|
|
|
size_t LRUFileCache::getAvailableCacheSizeUnlocked(std::lock_guard<std::mutex> & cache_lock) const
|
|
{
|
|
return max_size - getUsedCacheSizeUnlocked(cache_lock);
|
|
}
|
|
|
|
size_t LRUFileCache::getFileSegmentsNum() const
|
|
{
|
|
std::lock_guard cache_lock(mutex);
|
|
return getFileSegmentsNumUnlocked(cache_lock);
|
|
}
|
|
|
|
size_t LRUFileCache::getFileSegmentsNumUnlocked(std::lock_guard<std::mutex> & cache_lock) const
|
|
{
|
|
return queue.getElementsNum(cache_lock);
|
|
}
|
|
|
|
LRUFileCache::FileSegmentCell::FileSegmentCell(
|
|
FileSegmentPtr file_segment_,
|
|
LRUFileCache * cache,
|
|
std::lock_guard<std::mutex> & cache_lock)
|
|
: file_segment(file_segment_)
|
|
{
|
|
/**
|
|
* Cell can be created with either DOWNLOADED or EMPTY file segment's state.
|
|
* File segment acquires DOWNLOADING state and creates LRUQueue iterator on first
|
|
* successful getOrSetDownaloder call.
|
|
*/
|
|
|
|
switch (file_segment->download_state)
|
|
{
|
|
case FileSegment::State::DOWNLOADED:
|
|
{
|
|
queue_iterator = cache->queue.add(file_segment->key(), file_segment->offset(), file_segment->range().size(), cache_lock);
|
|
break;
|
|
}
|
|
case FileSegment::State::SKIP_CACHE:
|
|
case FileSegment::State::EMPTY:
|
|
case FileSegment::State::DOWNLOADING:
|
|
{
|
|
break;
|
|
}
|
|
default:
|
|
throw Exception(ErrorCodes::REMOTE_FS_OBJECT_CACHE_ERROR,
|
|
"Can create cell with either EMPTY, DOWNLOADED, DOWNLOADING state, got: {}",
|
|
FileSegment::stateToString(file_segment->download_state));
|
|
}
|
|
}
|
|
|
|
LRUFileCache::LRUQueue::Iterator LRUFileCache::LRUQueue::add(
|
|
const IFileCache::Key & key, size_t offset, size_t size, std::lock_guard<std::mutex> & /* cache_lock */)
|
|
{
|
|
#ifndef NDEBUG
|
|
for (const auto & [entry_key, entry_offset, entry_size, entry_hits] : queue)
|
|
{
|
|
if (entry_key == key && entry_offset == offset)
|
|
throw Exception(
|
|
ErrorCodes::LOGICAL_ERROR,
|
|
"Attempt to add duplicate queue entry to queue. (Key: {}, offset: {}, size: {})",
|
|
keyToStr(key), offset, size);
|
|
}
|
|
#endif
|
|
|
|
cache_size += size;
|
|
return queue.insert(queue.end(), FileKeyAndOffset(key, offset, size));
|
|
}
|
|
|
|
void LRUFileCache::LRUQueue::remove(Iterator queue_it, std::lock_guard<std::mutex> & /* cache_lock */)
|
|
{
|
|
cache_size -= queue_it->size;
|
|
queue.erase(queue_it);
|
|
}
|
|
|
|
void LRUFileCache::LRUQueue::removeAll(std::lock_guard<std::mutex> & /* cache_lock */)
|
|
{
|
|
queue.clear();
|
|
cache_size = 0;
|
|
}
|
|
|
|
void LRUFileCache::LRUQueue::moveToEnd(Iterator queue_it, std::lock_guard<std::mutex> & /* cache_lock */)
|
|
{
|
|
queue.splice(queue.end(), queue, queue_it);
|
|
}
|
|
|
|
void LRUFileCache::LRUQueue::incrementSize(Iterator queue_it, size_t size_increment, std::lock_guard<std::mutex> & /* cache_lock */)
|
|
{
|
|
cache_size += size_increment;
|
|
queue_it->size += size_increment;
|
|
}
|
|
|
|
bool LRUFileCache::LRUQueue::contains(
|
|
const IFileCache::Key & key, size_t offset, std::lock_guard<std::mutex> & /* cache_lock */) const
|
|
{
|
|
/// This method is used for assertions in debug mode.
|
|
/// So we do not care about complexity here.
|
|
for (const auto & [entry_key, entry_offset, size, _] : queue)
|
|
{
|
|
if (key == entry_key && offset == entry_offset)
|
|
return true;
|
|
}
|
|
return false;
|
|
}
|
|
|
|
void LRUFileCache::LRUQueue::assertCorrectness(LRUFileCache * cache, std::lock_guard<std::mutex> & cache_lock)
|
|
{
|
|
[[maybe_unused]] size_t total_size = 0;
|
|
for (auto it = queue.begin(); it != queue.end();)
|
|
{
|
|
auto & [key, offset, size, _] = *it++;
|
|
|
|
auto * cell = cache->getCell(key, offset, cache_lock);
|
|
if (!cell)
|
|
{
|
|
throw Exception(
|
|
ErrorCodes::LOGICAL_ERROR,
|
|
"Cache is in inconsistent state: LRU queue contains entries with no cache cell (assertCorrectness())");
|
|
}
|
|
|
|
assert(cell->size() == size);
|
|
total_size += size;
|
|
}
|
|
|
|
assert(total_size == cache_size);
|
|
assert(cache_size <= cache->max_size);
|
|
assert(queue.size() <= cache->max_element_size);
|
|
}
|
|
|
|
String LRUFileCache::LRUQueue::toString(std::lock_guard<std::mutex> & /* cache_lock */) const
|
|
{
|
|
String result;
|
|
for (const auto & [key, offset, size, _] : queue)
|
|
{
|
|
if (!result.empty())
|
|
result += ", ";
|
|
result += fmt::format("{}: [{}, {}]", keyToStr(key), offset, offset + size - 1);
|
|
}
|
|
return result;
|
|
}
|
|
|
|
String LRUFileCache::dumpStructure(const Key & key)
|
|
{
|
|
std::lock_guard cache_lock(mutex);
|
|
return dumpStructureUnlocked(key, cache_lock);
|
|
}
|
|
|
|
String LRUFileCache::dumpStructureUnlocked(const Key & key, std::lock_guard<std::mutex> & cache_lock)
|
|
{
|
|
WriteBufferFromOwnString result;
|
|
const auto & cells_by_offset = files[key];
|
|
|
|
for (const auto & [offset, cell] : cells_by_offset)
|
|
result << cell.file_segment->getInfoForLog() << "\n";
|
|
|
|
result << "\n\nQueue: " << queue.toString(cache_lock);
|
|
return result.str();
|
|
}
|
|
|
|
void LRUFileCache::assertCacheCellsCorrectness(
|
|
const FileSegmentsByOffset & cells_by_offset, [[maybe_unused]] std::lock_guard<std::mutex> & cache_lock)
|
|
{
|
|
for (const auto & [_, cell] : cells_by_offset)
|
|
{
|
|
const auto & file_segment = cell.file_segment;
|
|
file_segment->assertCorrectness();
|
|
|
|
if (file_segment->reserved_size != 0)
|
|
{
|
|
assert(cell.queue_iterator);
|
|
/// FIXME: this is too slow, need to make it O(1)
|
|
/// assert(queue.contains(file_segment->key(), file_segment->offset(), cache_lock));
|
|
}
|
|
}
|
|
}
|
|
|
|
void LRUFileCache::assertCacheCorrectness(const Key & key, std::lock_guard<std::mutex> & cache_lock)
|
|
{
|
|
assertCacheCellsCorrectness(files[key], cache_lock);
|
|
queue.assertCorrectness(this, cache_lock);
|
|
}
|
|
|
|
void LRUFileCache::assertCacheCorrectness(std::lock_guard<std::mutex> & cache_lock)
|
|
{
|
|
for (const auto & [key, cells_by_offset] : files)
|
|
assertCacheCellsCorrectness(files[key], cache_lock);
|
|
queue.assertCorrectness(this, cache_lock);
|
|
}
|
|
|
|
}
|