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rocksdb/db/table_cache.cc

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6.5 KiB

// Copyright (c) 2013, Facebook, Inc. All rights reserved.
// This source code is licensed under the BSD-style license found in the
// LICENSE file in the root directory of this source tree. An additional grant
// of patent rights can be found in the PATENTS file in the same directory.
//
// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#include "db/table_cache.h"
#include "db/filename.h"
#include "db/version_edit.h"
#include "rocksdb/statistics.h"
#include "table/table_reader.h"
#include "util/coding.h"
#include "util/stop_watch.h"
namespace rocksdb {
static void DeleteEntry(const Slice& key, void* value) {
TableReader* table_reader = reinterpret_cast<TableReader*>(value);
delete table_reader;
}
static void UnrefEntry(void* arg1, void* arg2) {
Cache* cache = reinterpret_cast<Cache*>(arg1);
Cache::Handle* h = reinterpret_cast<Cache::Handle*>(arg2);
cache->Release(h);
}
static Slice GetSliceForFileNumber(uint64_t* file_number) {
return Slice(reinterpret_cast<const char*>(file_number),
sizeof(*file_number));
}
TableCache::TableCache(const std::string& dbname,
const Options* options,
const EnvOptions& storage_options,
int entries)
: env_(options->env),
dbname_(dbname),
options_(options),
storage_options_(storage_options),
cache_(
NewLRUCache(entries, options->table_cache_numshardbits,
options->table_cache_remove_scan_count_limit)) {
}
TableCache::~TableCache() {
}
TableReader* TableCache::GetTableReaderFromHandle(Cache::Handle* handle) {
return reinterpret_cast<TableReader*>(cache_->Value(handle));
}
void TableCache::ReleaseHandle(Cache::Handle* handle) {
cache_->Release(handle);
}
Status TableCache::FindTable(const EnvOptions& toptions,
const InternalKeyComparator& internal_comparator,
uint64_t file_number, uint64_t file_size,
Cache::Handle** handle, bool* table_io,
const bool no_io) {
Status s;
Slice key = GetSliceForFileNumber(&file_number);
*handle = cache_->Lookup(key);
if (*handle == nullptr) {
if (no_io) { // Dont do IO and return a not-found status
return Status::Incomplete("Table not found in table_cache, no_io is set");
}
if (table_io != nullptr) {
*table_io = true; // we had to do IO from storage
}
std::string fname = TableFileName(dbname_, file_number);
unique_ptr<RandomAccessFile> file;
unique_ptr<TableReader> table_reader;
s = env_->NewRandomAccessFile(fname, &file, toptions);
RecordTick(options_->statistics.get(), NO_FILE_OPENS);
if (s.ok()) {
if (options_->advise_random_on_open) {
file->Hint(RandomAccessFile::RANDOM);
}
StopWatch sw(env_, options_->statistics.get(), TABLE_OPEN_IO_MICROS);
s = options_->table_factory->NewTableReader(
*options_, toptions, internal_comparator, std::move(file), file_size,
&table_reader);
}
if (!s.ok()) {
assert(table_reader == nullptr);
RecordTick(options_->statistics.get(), NO_FILE_ERRORS);
// We do not cache error results so that if the error is transient,
// or somebody repairs the file, we recover automatically.
} else {
assert(file.get() == nullptr);
*handle = cache_->Insert(key, table_reader.release(), 1, &DeleteEntry);
}
}
return s;
}
Iterator* TableCache::NewIterator(const ReadOptions& options,
const EnvOptions& toptions,
const InternalKeyComparator& icomparator,
const FileMetaData& file_meta,
TableReader** table_reader_ptr,
bool for_compaction) {
if (table_reader_ptr != nullptr) {
*table_reader_ptr = nullptr;
}
Cache::Handle* handle = file_meta.table_reader_handle;
Status s;
if (!handle) {
s = FindTable(toptions, icomparator, file_meta.number, file_meta.file_size,
&handle, nullptr, options.read_tier == kBlockCacheTier);
}
if (!s.ok()) {
return NewErrorIterator(s);
}
TableReader* table_reader = GetTableReaderFromHandle(handle);
Iterator* result = table_reader->NewIterator(options);
if (!file_meta.table_reader_handle) {
result->RegisterCleanup(&UnrefEntry, cache_.get(), handle);
}
if (table_reader_ptr != nullptr) {
*table_reader_ptr = table_reader;
}
if (for_compaction) {
table_reader->SetupForCompaction();
}
return result;
}
Status TableCache::Get(const ReadOptions& options,
const InternalKeyComparator& internal_comparator,
const FileMetaData& file_meta, const Slice& k, void* arg,
bool (*saver)(void*, const ParsedInternalKey&,
const Slice&, bool),
bool* table_io, void (*mark_key_may_exist)(void*)) {
Cache::Handle* handle = file_meta.table_reader_handle;
Status s;
if (!handle) {
s = FindTable(storage_options_, internal_comparator, file_meta.number,
file_meta.file_size, &handle, table_io,
options.read_tier == kBlockCacheTier);
}
if (s.ok()) {
TableReader* t = GetTableReaderFromHandle(handle);
s = t->Get(options, k, arg, saver, mark_key_may_exist);
if (!file_meta.table_reader_handle) {
ReleaseHandle(handle);
}
} else if (options.read_tier && s.IsIncomplete()) {
// Couldnt find Table in cache but treat as kFound if no_io set
(*mark_key_may_exist)(arg);
return Status::OK();
}
return s;
}
bool TableCache::PrefixMayMatch(const ReadOptions& options,
const InternalKeyComparator& icomparator,
uint64_t file_number, uint64_t file_size,
const Slice& internal_prefix, bool* table_io) {
Cache::Handle* handle = nullptr;
Status s = FindTable(storage_options_, icomparator, file_number, file_size,
&handle, table_io);
bool may_match = true;
if (s.ok()) {
TableReader* t = GetTableReaderFromHandle(handle);
may_match = t->PrefixMayMatch(internal_prefix);
ReleaseHandle(handle);
}
return may_match;
}
void TableCache::Evict(uint64_t file_number) {
cache_->Erase(GetSliceForFileNumber(&file_number));
}
} // namespace rocksdb