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#include <Interpreters/Cache/LRUFileCachePriority.h>
#include <Interpreters/Cache/FileCache.h>
#include <Common/CurrentMetrics.h>
#include <Common/randomSeed.h>
#include <Common/logger_useful.h>
#include <pcg-random/pcg_random.hpp>
namespace CurrentMetrics
{
extern const Metric FilesystemCacheSize;
extern const Metric FilesystemCacheElements;
}
namespace DB
{
namespace ErrorCodes
{
extern const int LOGICAL_ERROR;
}
IFileCachePriority::Iterator LRUFileCachePriority::add(
KeyMetadataPtr key_metadata,
size_t offset,
size_t size,
const CacheGuard::Lock &)
{
const auto & key = key_metadata->key;
if (size == 0)
{
throw Exception(
ErrorCodes::LOGICAL_ERROR,
"Adding zero size entries to LRU queue is not allowed "
"(key: {}, offset: {})", key, offset);
}
#ifndef NDEBUG
for (const auto & entry : queue)
{
/// entry.size == 0 means entry was invalidated.
if (entry.size != 0 && entry.key == key && entry.offset == offset)
throw Exception(
ErrorCodes::LOGICAL_ERROR,
"Attempt to add duplicate queue entry to queue. "
"(Key: {}, offset: {}, size: {})",
entry.key, entry.offset, entry.size);
}
#endif
const auto & size_limit = getSizeLimit();
if (size_limit && current_size + size > size_limit)
{
throw Exception(
ErrorCodes::LOGICAL_ERROR,
"Not enough space to add {}:{} with size {}: current size: {}/{}",
key, offset, size, current_size, size_limit);
}
auto iter = queue.insert(queue.end(), Entry(key, offset, size, key_metadata));
updateSize(size);
updateElementsCount(1);
LOG_TEST(
log, "Added entry into LRU queue, key: {}, offset: {}, size: {}",
key, offset, size);
return std::make_shared<LRUFileCacheIterator>(this, iter);
}
void LRUFileCachePriority::removeAll(const CacheGuard::Lock &)
{
LOG_TEST(log, "Removed all entries from LRU queue");
updateSize(-current_size);
updateElementsCount(-current_elements_num);
queue.clear();
}
void LRUFileCachePriority::pop(const CacheGuard::Lock &)
{
remove(queue.begin());
}
LRUFileCachePriority::LRUQueueIterator LRUFileCachePriority::remove(LRUQueueIterator it)
{
/// If size is 0, entry is invalidated, current_elements_num was already updated.
if (it->size)
{
updateSize(-it->size);
updateElementsCount(-1);
}
LOG_TEST(
log, "Removed entry from LRU queue, key: {}, offset: {}, size: {}",
it->key, it->offset, it->size);
return queue.erase(it);
}
void LRUFileCachePriority::updateSize(int64_t size)
{
current_size += size;
CurrentMetrics::add(CurrentMetrics::FilesystemCacheSize, size);
}
void LRUFileCachePriority::updateElementsCount(int64_t num)
{
current_elements_num += num;
CurrentMetrics::add(CurrentMetrics::FilesystemCacheElements, num);
}
LRUFileCachePriority::LRUFileCacheIterator::LRUFileCacheIterator(
LRUFileCachePriority * cache_priority_,
LRUFileCachePriority::LRUQueueIterator queue_iter_)
: cache_priority(cache_priority_)
, queue_iter(queue_iter_)
{
}
void LRUFileCachePriority::iterate(IterateFunc && func, const CacheGuard::Lock &)
{
for (auto it = queue.begin(); it != queue.end();)
{
auto locked_key = it->key_metadata->tryLock();
if (!locked_key || it->size == 0)
{
it = remove(it);
continue;
}
auto metadata = locked_key->tryGetByOffset(it->offset);
if (!metadata)
{
it = remove(it);
continue;
}
if (metadata->size() != it->size)
{
throw Exception(
ErrorCodes::LOGICAL_ERROR,
"Mismatch of file segment size in file segment metadata "
"and priority queue: {} != {} ({})",
it->size, metadata->size(), metadata->file_segment->getInfoForLog());
}
auto result = func(*locked_key, metadata);
switch (result)
{
case IterationResult::BREAK:
{
return;
}
case IterationResult::CONTINUE:
{
++it;
break;
}
case IterationResult::REMOVE_AND_CONTINUE:
{
it = remove(it);
break;
}
}
}
}
void LRUFileCachePriority::LRUFileCacheIterator::remove(const CacheGuard::Lock &)
{
checkUsable();
cache_priority->remove(queue_iter);
queue_iter = LRUQueueIterator{};
}
void LRUFileCachePriority::LRUFileCacheIterator::invalidate()
{
checkUsable();
LOG_TEST(
cache_priority->log,
"Invalidating entry in LRU queue. Key: {}, offset: {}, previous size: {}",
queue_iter->key, queue_iter->offset, queue_iter->size);
cache_priority->updateSize(-queue_iter->size);
cache_priority->updateElementsCount(-1);
queue_iter->size = 0;
}
void LRUFileCachePriority::LRUFileCacheIterator::updateSize(int64_t size)
{
checkUsable();
LOG_TEST(
cache_priority->log,
"Update size with {} in LRU queue for key: {}, offset: {}, previous size: {}",
size, queue_iter->key, queue_iter->offset, queue_iter->size);
cache_priority->updateSize(size);
queue_iter->size += size;
}
size_t LRUFileCachePriority::LRUFileCacheIterator::use(const CacheGuard::Lock &)
{
checkUsable();
cache_priority->queue.splice(cache_priority->queue.end(), cache_priority->queue, queue_iter);
return ++queue_iter->hits;
}
void LRUFileCachePriority::LRUFileCacheIterator::checkUsable() const
{
if (queue_iter == LRUQueueIterator{})
throw Exception(ErrorCodes::LOGICAL_ERROR, "Attempt to use invalid iterator");
}
void LRUFileCachePriority::shuffle(const CacheGuard::Lock &)
{
std::vector<LRUQueueIterator> its;
its.reserve(queue.size());
for (auto it = queue.begin(); it != queue.end(); ++it)
its.push_back(it);
pcg64 generator(randomSeed());
std::shuffle(its.begin(), its.end(), generator);
for (auto & it : its)
queue.splice(queue.end(), queue, it);
}
}
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