rocksdb/db/blob/blob_file_cache.cc

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// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
// This source code is licensed under both the GPLv2 (found in the
// COPYING file in the root directory) and Apache 2.0 License
// (found in the LICENSE.Apache file in the root directory).
#include "db/blob/blob_file_cache.h"
#include <cassert>
#include <memory>
#include "db/blob/blob_file_reader.h"
#include "options/cf_options.h"
#include "rocksdb/cache.h"
#include "rocksdb/slice.h"
#include "test_util/sync_point.h"
#include "util/hash.h"
namespace ROCKSDB_NAMESPACE {
BlobFileCache::BlobFileCache(Cache* cache,
const ImmutableCFOptions* immutable_cf_options,
const FileOptions* file_options,
uint32_t column_family_id,
HistogramImpl* blob_file_read_hist)
: cache_(cache),
mutex_(kNumberOfMutexStripes, GetSliceNPHash64),
immutable_cf_options_(immutable_cf_options),
file_options_(file_options),
column_family_id_(column_family_id),
blob_file_read_hist_(blob_file_read_hist) {
assert(cache_);
assert(immutable_cf_options_);
assert(file_options_);
}
Status BlobFileCache::GetBlobFileReader(
uint64_t blob_file_number,
CacheHandleGuard<BlobFileReader>* blob_file_reader) {
assert(blob_file_reader);
assert(blob_file_reader->IsEmpty());
const Slice key = GetSlice(&blob_file_number);
assert(cache_);
Cache::Handle* handle = cache_->Lookup(key);
if (handle) {
*blob_file_reader = CacheHandleGuard<BlobFileReader>(cache_, handle);
return Status::OK();
}
TEST_SYNC_POINT("BlobFileCache::GetBlobFileReader:DoubleCheck");
// Check again while holding mutex
MutexLock lock(mutex_.get(key));
handle = cache_->Lookup(key);
if (handle) {
*blob_file_reader = CacheHandleGuard<BlobFileReader>(cache_, handle);
return Status::OK();
}
assert(immutable_cf_options_);
Statistics* const statistics = immutable_cf_options_->statistics;
RecordTick(statistics, NO_FILE_OPENS);
std::unique_ptr<BlobFileReader> reader;
{
assert(file_options_);
const Status s = BlobFileReader::Create(
*immutable_cf_options_, *file_options_, column_family_id_,
blob_file_read_hist_, blob_file_number, &reader);
if (!s.ok()) {
RecordTick(statistics, NO_FILE_ERRORS);
return s;
}
}
{
constexpr size_t charge = 1;
const Status s = cache_->Insert(key, reader.get(), charge,
&DeleteCacheEntry<BlobFileReader>, &handle);
if (!s.ok()) {
RecordTick(statistics, NO_FILE_ERRORS);
return s;
}
}
reader.release();
*blob_file_reader = CacheHandleGuard<BlobFileReader>(cache_, handle);
return Status::OK();
}
} // namespace ROCKSDB_NAMESPACE