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#pragma once
#include <memory>
#include <Common/CacheBase.h>
#include <Common/ProfileEvents.h>
#include <Common/SipHash.h>
#include <Common/HashTable/Hash.h>
#include <Interpreters/AggregationCommon.h>
#include <Formats/MarkInCompressedFile.h>
namespace ProfileEvents
{
extern const Event MarkCacheHits;
extern const Event MarkCacheMisses;
}
namespace DB
{
/// Estimate of number of bytes in cache for marks.
struct MarksWeightFunction
{
/// We spent additional bytes on key in hashmap, linked lists, shared pointers, etc ...
static constexpr size_t MARK_CACHE_OVERHEAD = 128;
size_t operator()(const MarksInCompressedFile & marks) const
{
return marks.approximateMemoryUsage() + MARK_CACHE_OVERHEAD;
}
};
/** Cache of 'marks' for StorageMergeTree.
* Marks is an index structure that addresses ranges in column file, corresponding to ranges of primary key.
*/
class MarkCache : public CacheBase<UInt128, MarksInCompressedFile, UInt128TrivialHash, MarksWeightFunction>
{
private:
using Base = CacheBase<UInt128, MarksInCompressedFile, UInt128TrivialHash, MarksWeightFunction>;
public:
MarkCache(const String & cache_policy, size_t max_size_in_bytes, double size_ratio)
: Base(cache_policy, max_size_in_bytes, 0, size_ratio) {}
/// Calculate key from path to file and offset.
static UInt128 hash(const String & path_to_file)
{
SipHash hash;
hash.update(path_to_file.data(), path_to_file.size() + 1);
return hash.get128();
}
template <typename LoadFunc>
MappedPtr getOrSet(const Key & key, LoadFunc && load)
{
auto result = Base::getOrSet(key, load);
if (result.second)
ProfileEvents::increment(ProfileEvents::MarkCacheMisses);
else
ProfileEvents::increment(ProfileEvents::MarkCacheHits);
return result.first;
}
};
using MarkCachePtr = std::shared_ptr<MarkCache>;
}
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