fd24ae9d05
Summary: as title Test Plan: ./db_test Reviewers: sdong, yhchiang, rven, igor Reviewed By: igor Subscribers: dhruba, leveldb Differential Revision: https://reviews.facebook.net/D28269
460 lines
17 KiB
C++
460 lines
17 KiB
C++
// Copyright (c) 2013, Facebook, Inc. All rights reserved.
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// This source code is licensed under the BSD-style license found in the
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// LICENSE file in the root directory of this source tree. An additional grant
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// of patent rights can be found in the PATENTS file in the same directory.
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//
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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file. See the AUTHORS file for names of contributors.
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#pragma once
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#include <unordered_map>
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#include <string>
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#include <vector>
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#include <atomic>
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#include "rocksdb/options.h"
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#include "rocksdb/db.h"
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#include "rocksdb/env.h"
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#include "db/memtable_list.h"
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#include "db/write_batch_internal.h"
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#include "db/write_controller.h"
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#include "db/table_cache.h"
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#include "util/thread_local.h"
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#include "db/flush_scheduler.h"
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#include "util/mutable_cf_options.h"
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namespace rocksdb {
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class Version;
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class VersionSet;
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class MemTable;
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class MemTableListVersion;
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class CompactionPicker;
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class Compaction;
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class InternalKey;
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class InternalStats;
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class ColumnFamilyData;
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class DBImpl;
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class LogBuffer;
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// ColumnFamilyHandleImpl is the class that clients use to access different
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// column families. It has non-trivial destructor, which gets called when client
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// is done using the column family
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class ColumnFamilyHandleImpl : public ColumnFamilyHandle {
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public:
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// create while holding the mutex
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ColumnFamilyHandleImpl(ColumnFamilyData* cfd, DBImpl* db, port::Mutex* mutex);
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// destroy without mutex
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virtual ~ColumnFamilyHandleImpl();
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virtual ColumnFamilyData* cfd() const { return cfd_; }
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virtual const Comparator* user_comparator() const;
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virtual uint32_t GetID() const;
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private:
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ColumnFamilyData* cfd_;
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DBImpl* db_;
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port::Mutex* mutex_;
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};
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// Does not ref-count ColumnFamilyData
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// We use this dummy ColumnFamilyHandleImpl because sometimes MemTableInserter
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// calls DBImpl methods. When this happens, MemTableInserter need access to
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// ColumnFamilyHandle (same as the client would need). In that case, we feed
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// MemTableInserter dummy ColumnFamilyHandle and enable it to call DBImpl
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// methods
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class ColumnFamilyHandleInternal : public ColumnFamilyHandleImpl {
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public:
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ColumnFamilyHandleInternal()
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: ColumnFamilyHandleImpl(nullptr, nullptr, nullptr) {}
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void SetCFD(ColumnFamilyData* cfd) { internal_cfd_ = cfd; }
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virtual ColumnFamilyData* cfd() const override { return internal_cfd_; }
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private:
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ColumnFamilyData* internal_cfd_;
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};
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// holds references to memtable, all immutable memtables and version
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struct SuperVersion {
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MemTable* mem;
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MemTableListVersion* imm;
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Version* current;
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MutableCFOptions mutable_cf_options;
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std::atomic<uint32_t> refs;
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// We need to_delete because during Cleanup(), imm->Unref() returns
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// all memtables that we need to free through this vector. We then
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// delete all those memtables outside of mutex, during destruction
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autovector<MemTable*> to_delete;
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// Version number of the current SuperVersion
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uint64_t version_number;
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port::Mutex* db_mutex;
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// should be called outside the mutex
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SuperVersion() = default;
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~SuperVersion();
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SuperVersion* Ref();
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bool Unref();
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// call these two methods with db mutex held
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// Cleanup unrefs mem, imm and current. Also, it stores all memtables
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// that needs to be deleted in to_delete vector. Unrefing those
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// objects needs to be done in the mutex
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void Cleanup();
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void Init(MemTable* new_mem, MemTableListVersion* new_imm,
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Version* new_current);
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// The value of dummy is not actually used. kSVInUse takes its address as a
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// mark in the thread local storage to indicate the SuperVersion is in use
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// by thread. This way, the value of kSVInUse is guaranteed to have no
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// conflict with SuperVersion object address and portable on different
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// platform.
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static int dummy;
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static void* const kSVInUse;
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static void* const kSVObsolete;
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};
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extern ColumnFamilyOptions SanitizeOptions(const InternalKeyComparator* icmp,
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const ColumnFamilyOptions& src);
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class ColumnFamilySet;
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// This class keeps all the data that a column family needs. It's mosly dumb and
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// used just to provide access to metadata.
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// Most methods require DB mutex held, unless otherwise noted
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class ColumnFamilyData {
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public:
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~ColumnFamilyData();
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// thread-safe
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uint32_t GetID() const { return id_; }
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// thread-safe
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const std::string& GetName() const { return name_; }
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void Ref() { ++refs_; }
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// will just decrease reference count to 0, but will not delete it. returns
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// true if the ref count was decreased to zero. in that case, it can be
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// deleted by the caller immediately, or later, by calling
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// FreeDeadColumnFamilies()
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bool Unref() {
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assert(refs_ > 0);
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return --refs_ == 0;
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}
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// This can only be called from single-threaded VersionSet::LogAndApply()
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// After dropping column family no other operation on that column family
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// will be executed. All the files and memory will be, however, kept around
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// until client drops the column family handle. That way, client can still
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// access data from dropped column family.
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// Column family can be dropped and still alive. In that state:
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// *) Column family is not included in the iteration.
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// *) Compaction and flush is not executed on the dropped column family.
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// *) Client can continue writing and reading from column family. However, all
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// writes stay in the current memtable.
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// When the dropped column family is unreferenced, then we:
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// *) delete all memory associated with that column family
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// *) delete all the files associated with that column family
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void SetDropped() {
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// can't drop default CF
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assert(id_ != 0);
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dropped_ = true;
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write_controller_token_.reset();
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}
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bool IsDropped() const { return dropped_; }
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// thread-safe
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int NumberLevels() const { return ioptions_.num_levels; }
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void SetLogNumber(uint64_t log_number) { log_number_ = log_number; }
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uint64_t GetLogNumber() const { return log_number_; }
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// thread-safe
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const Options* options() const { return &options_; }
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const EnvOptions* soptions() const;
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const ImmutableCFOptions* ioptions() const { return &ioptions_; }
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// REQUIRES: DB mutex held
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// This returns the MutableCFOptions used by current SuperVersion
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// You shoul use this API to reference MutableCFOptions most of the time.
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const MutableCFOptions* mutable_cf_options() const {
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return &(super_version_->mutable_cf_options);
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}
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// REQUIRES: DB mutex held
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// This returns the latest MutableCFOptions, which may be not in effect yet.
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const MutableCFOptions* GetLatestMutableCFOptions() const {
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return &mutable_cf_options_;
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}
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// REQUIRES: DB mutex held
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Status SetOptions(
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const std::unordered_map<std::string, std::string>& options_map);
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InternalStats* internal_stats() { return internal_stats_.get(); }
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MemTableList* imm() { return &imm_; }
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MemTable* mem() { return mem_; }
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Version* current() { return current_; }
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Version* dummy_versions() { return dummy_versions_; }
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void SetMemtable(MemTable* new_mem) { mem_ = new_mem; }
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void SetCurrent(Version* current);
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void CreateNewMemtable(const MutableCFOptions& mutable_cf_options);
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TableCache* table_cache() const { return table_cache_.get(); }
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// See documentation in compaction_picker.h
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// REQUIRES: DB mutex held
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Compaction* PickCompaction(const MutableCFOptions& mutable_options,
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LogBuffer* log_buffer);
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Compaction* CompactRange(
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const MutableCFOptions& mutable_cf_options,
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int input_level, int output_level, uint32_t output_path_id,
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const InternalKey* begin, const InternalKey* end,
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InternalKey** compaction_end);
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CompactionPicker* compaction_picker() { return compaction_picker_.get(); }
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// thread-safe
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const Comparator* user_comparator() const {
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return internal_comparator_.user_comparator();
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}
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// thread-safe
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const InternalKeyComparator& internal_comparator() const {
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return internal_comparator_;
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}
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SuperVersion* GetSuperVersion() { return super_version_; }
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// thread-safe
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// Return a already referenced SuperVersion to be used safely.
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SuperVersion* GetReferencedSuperVersion(port::Mutex* db_mutex);
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// thread-safe
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// Get SuperVersion stored in thread local storage. If it does not exist,
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// get a reference from a current SuperVersion.
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SuperVersion* GetThreadLocalSuperVersion(port::Mutex* db_mutex);
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// Try to return SuperVersion back to thread local storage. Retrun true on
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// success and false on failure. It fails when the thread local storage
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// contains anything other than SuperVersion::kSVInUse flag.
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bool ReturnThreadLocalSuperVersion(SuperVersion* sv);
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// thread-safe
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uint64_t GetSuperVersionNumber() const {
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return super_version_number_.load();
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}
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// will return a pointer to SuperVersion* if previous SuperVersion
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// if its reference count is zero and needs deletion or nullptr if not
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// As argument takes a pointer to allocated SuperVersion to enable
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// the clients to allocate SuperVersion outside of mutex.
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SuperVersion* InstallSuperVersion(SuperVersion* new_superversion,
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port::Mutex* db_mutex,
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const MutableCFOptions& mutable_cf_options);
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SuperVersion* InstallSuperVersion(SuperVersion* new_superversion,
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port::Mutex* db_mutex);
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void ResetThreadLocalSuperVersions();
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private:
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friend class ColumnFamilySet;
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ColumnFamilyData(uint32_t id, const std::string& name,
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Version* dummy_versions, Cache* table_cache,
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const ColumnFamilyOptions& options,
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const DBOptions* db_options, const EnvOptions& env_options,
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ColumnFamilySet* column_family_set);
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// Recalculate some small conditions, which are changed only during
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// compaction, adding new memtable and/or
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// recalculation of compaction score. These values are used in
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// DBImpl::MakeRoomForWrite function to decide, if it need to make
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// a write stall
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void RecalculateWriteStallConditions(
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const MutableCFOptions& mutable_cf_options);
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uint32_t id_;
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const std::string name_;
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Version* dummy_versions_; // Head of circular doubly-linked list of versions.
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Version* current_; // == dummy_versions->prev_
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int refs_; // outstanding references to ColumnFamilyData
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bool dropped_; // true if client dropped it
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const InternalKeyComparator internal_comparator_;
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const Options options_;
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const ImmutableCFOptions ioptions_;
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MutableCFOptions mutable_cf_options_;
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std::unique_ptr<TableCache> table_cache_;
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std::unique_ptr<InternalStats> internal_stats_;
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MemTable* mem_;
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MemTableList imm_;
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SuperVersion* super_version_;
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// An ordinal representing the current SuperVersion. Updated by
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// InstallSuperVersion(), i.e. incremented every time super_version_
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// changes.
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std::atomic<uint64_t> super_version_number_;
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// Thread's local copy of SuperVersion pointer
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// This needs to be destructed before mutex_
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std::unique_ptr<ThreadLocalPtr> local_sv_;
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// pointers for a circular linked list. we use it to support iterations
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// that can be concurrent with writes
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ColumnFamilyData* next_;
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ColumnFamilyData* prev_;
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// This is the earliest log file number that contains data from this
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// Column Family. All earlier log files must be ignored and not
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// recovered from
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uint64_t log_number_;
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// An object that keeps all the compaction stats
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// and picks the next compaction
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std::unique_ptr<CompactionPicker> compaction_picker_;
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ColumnFamilySet* column_family_set_;
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std::unique_ptr<WriteControllerToken> write_controller_token_;
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};
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// ColumnFamilySet has interesting thread-safety requirements
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// * CreateColumnFamily() or RemoveColumnFamily() -- need to protect by DB
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// mutex. Inside, column_family_data_ and column_families_ will be protected
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// by Lock() and Unlock(). CreateColumnFamily() should ONLY be called from
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// VersionSet::LogAndApply() in the normal runtime. It is also called
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// during Recovery and in DumpManifest(). RemoveColumnFamily() is called
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// from ColumnFamilyData destructor
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// * Iteration -- hold DB mutex, but you can release it in the body of
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// iteration. If you release DB mutex in body, reference the column
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// family before the mutex and unreference after you unlock, since the column
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// family might get dropped when the DB mutex is released
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// * GetDefault() -- thread safe
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// * GetColumnFamily() -- either inside of DB mutex or call Lock() <-> Unlock()
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// * GetNextColumnFamilyID(), GetMaxColumnFamily(), UpdateMaxColumnFamily(),
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// NumberOfColumnFamilies -- inside of DB mutex
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class ColumnFamilySet {
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public:
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// ColumnFamilySet supports iteration
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class iterator {
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public:
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explicit iterator(ColumnFamilyData* cfd)
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: current_(cfd) {}
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iterator& operator++() {
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// dummy is never dead or dropped, so this will never be infinite
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do {
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current_ = current_->next_;
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} while (current_->refs_ == 0 || current_->IsDropped());
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return *this;
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}
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bool operator!=(const iterator& other) {
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return this->current_ != other.current_;
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}
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ColumnFamilyData* operator*() { return current_; }
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private:
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ColumnFamilyData* current_;
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};
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ColumnFamilySet(const std::string& dbname, const DBOptions* db_options,
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const EnvOptions& env_options, Cache* table_cache,
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WriteController* write_controller);
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~ColumnFamilySet();
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ColumnFamilyData* GetDefault() const;
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// GetColumnFamily() calls return nullptr if column family is not found
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ColumnFamilyData* GetColumnFamily(uint32_t id) const;
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ColumnFamilyData* GetColumnFamily(const std::string& name) const;
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// this call will return the next available column family ID. it guarantees
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// that there is no column family with id greater than or equal to the
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// returned value in the current running instance or anytime in RocksDB
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// instance history.
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uint32_t GetNextColumnFamilyID();
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uint32_t GetMaxColumnFamily();
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void UpdateMaxColumnFamily(uint32_t new_max_column_family);
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size_t NumberOfColumnFamilies() const;
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ColumnFamilyData* CreateColumnFamily(const std::string& name, uint32_t id,
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Version* dummy_version,
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const ColumnFamilyOptions& options);
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iterator begin() { return iterator(dummy_cfd_->next_); }
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iterator end() { return iterator(dummy_cfd_); }
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void Lock();
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void Unlock();
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// REQUIRES: DB mutex held
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// Don't call while iterating over ColumnFamilySet
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void FreeDeadColumnFamilies();
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private:
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friend class ColumnFamilyData;
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// helper function that gets called from cfd destructor
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// REQUIRES: DB mutex held
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void RemoveColumnFamily(ColumnFamilyData* cfd);
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// column_families_ and column_family_data_ need to be protected:
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// * when mutating: 1. DB mutex locked first, 2. spinlock locked second
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// * when reading, either: 1. lock DB mutex, or 2. lock spinlock
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// (if both, respect the ordering to avoid deadlock!)
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std::unordered_map<std::string, uint32_t> column_families_;
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std::unordered_map<uint32_t, ColumnFamilyData*> column_family_data_;
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uint32_t max_column_family_;
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ColumnFamilyData* dummy_cfd_;
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// We don't hold the refcount here, since default column family always exists
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// We are also not responsible for cleaning up default_cfd_cache_. This is
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// just a cache that makes common case (accessing default column family)
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// faster
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ColumnFamilyData* default_cfd_cache_;
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const std::string db_name_;
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const DBOptions* const db_options_;
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const EnvOptions env_options_;
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Cache* table_cache_;
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WriteController* write_controller_;
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std::atomic_flag spin_lock_;
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};
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// We use ColumnFamilyMemTablesImpl to provide WriteBatch a way to access
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// memtables of different column families (specified by ID in the write batch)
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class ColumnFamilyMemTablesImpl : public ColumnFamilyMemTables {
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public:
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explicit ColumnFamilyMemTablesImpl(ColumnFamilySet* column_family_set,
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FlushScheduler* flush_scheduler)
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: column_family_set_(column_family_set),
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current_(nullptr),
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flush_scheduler_(flush_scheduler) {}
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// sets current_ to ColumnFamilyData with column_family_id
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// returns false if column family doesn't exist
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bool Seek(uint32_t column_family_id) override;
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// Returns log number of the selected column family
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uint64_t GetLogNumber() const override;
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// REQUIRES: Seek() called first
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virtual MemTable* GetMemTable() const override;
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// Returns options for selected column family
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// REQUIRES: Seek() called first
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virtual const Options* GetOptions() const override;
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// Returns column family handle for the selected column family
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virtual ColumnFamilyHandle* GetColumnFamilyHandle() override;
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virtual void CheckMemtableFull() override;
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private:
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ColumnFamilySet* column_family_set_;
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ColumnFamilyData* current_;
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FlushScheduler* flush_scheduler_;
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ColumnFamilyHandleInternal handle_;
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};
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extern uint32_t GetColumnFamilyID(ColumnFamilyHandle* column_family);
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extern const Comparator* GetColumnFamilyUserComparator(
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ColumnFamilyHandle* column_family);
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} // namespace rocksdb
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