Conflicts: Makefile db/db_impl.cc db/db_test.cc db/memtable_list.cc db/memtable_list.h table/block_based_table_reader.cc table/table_test.cc util/cache.cc util/coding.cc
623 lines
23 KiB
C++
623 lines
23 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 <atomic>
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#include <deque>
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#include <set>
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#include <utility>
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#include <vector>
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#include "db/dbformat.h"
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#include "db/log_writer.h"
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#include "db/snapshot.h"
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#include "db/version_edit.h"
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#include "memtable_list.h"
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#include "port/port.h"
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#include "rocksdb/db.h"
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#include "rocksdb/env.h"
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#include "rocksdb/memtablerep.h"
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#include "rocksdb/transaction_log.h"
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#include "util/autovector.h"
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#include "util/stats_logger.h"
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namespace rocksdb {
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class MemTable;
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class TableCache;
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class Version;
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class VersionEdit;
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class VersionSet;
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class DBImpl : public DB {
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public:
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DBImpl(const Options& options, const std::string& dbname);
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virtual ~DBImpl();
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// Implementations of the DB interface
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virtual Status Put(const WriteOptions&, const Slice& key, const Slice& value);
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virtual Status Merge(const WriteOptions&, const Slice& key,
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const Slice& value);
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virtual Status Delete(const WriteOptions&, const Slice& key);
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virtual Status Write(const WriteOptions& options, WriteBatch* updates);
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virtual Status Get(const ReadOptions& options,
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const Slice& key,
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std::string* value);
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virtual std::vector<Status> MultiGet(const ReadOptions& options,
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const std::vector<Slice>& keys,
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std::vector<std::string>* values);
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// Returns false if key doesn't exist in the database and true if it may.
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// If value_found is not passed in as null, then return the value if found in
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// memory. On return, if value was found, then value_found will be set to true
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// , otherwise false.
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virtual bool KeyMayExist(const ReadOptions& options,
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const Slice& key,
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std::string* value,
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bool* value_found = nullptr);
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virtual Iterator* NewIterator(const ReadOptions&);
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virtual const Snapshot* GetSnapshot();
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virtual void ReleaseSnapshot(const Snapshot* snapshot);
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virtual bool GetProperty(const Slice& property, std::string* value);
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virtual void GetApproximateSizes(const Range* range, int n, uint64_t* sizes);
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virtual Status CompactRange(const Slice* begin, const Slice* end,
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bool reduce_level = false, int target_level = -1);
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virtual int NumberLevels();
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virtual int MaxMemCompactionLevel();
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virtual int Level0StopWriteTrigger();
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virtual const std::string& GetName() const;
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virtual Env* GetEnv() const;
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virtual const Options& GetOptions() const;
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virtual Status Flush(const FlushOptions& options);
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virtual Status DisableFileDeletions();
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virtual Status EnableFileDeletions(bool force);
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// All the returned filenames start with "/"
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virtual Status GetLiveFiles(std::vector<std::string>&,
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uint64_t* manifest_file_size,
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bool flush_memtable = true);
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virtual Status GetSortedWalFiles(VectorLogPtr& files);
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virtual SequenceNumber GetLatestSequenceNumber() const;
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virtual Status GetUpdatesSince(SequenceNumber seq_number,
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unique_ptr<TransactionLogIterator>* iter);
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virtual Status DeleteFile(std::string name);
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virtual void GetLiveFilesMetaData(
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std::vector<LiveFileMetaData> *metadata);
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virtual Status GetDbIdentity(std::string& identity);
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Status RunManualCompaction(int input_level,
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int output_level,
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const Slice* begin,
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const Slice* end);
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// Extra methods (for testing) that are not in the public DB interface
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// Compact any files in the named level that overlap [*begin, *end]
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Status TEST_CompactRange(int level,
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const Slice* begin,
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const Slice* end);
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// Force current memtable contents to be flushed.
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Status TEST_FlushMemTable();
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// Wait for memtable compaction
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Status TEST_WaitForFlushMemTable();
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// Wait for any compaction
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Status TEST_WaitForCompact();
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// Return an internal iterator over the current state of the database.
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// The keys of this iterator are internal keys (see format.h).
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// The returned iterator should be deleted when no longer needed.
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Iterator* TEST_NewInternalIterator();
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// Return the maximum overlapping data (in bytes) at next level for any
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// file at a level >= 1.
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int64_t TEST_MaxNextLevelOverlappingBytes();
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// Simulate a db crash, no elegant closing of database.
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void TEST_Destroy_DBImpl();
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// Return the current manifest file no.
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uint64_t TEST_Current_Manifest_FileNo();
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// Trigger's a background call for testing.
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void TEST_PurgeObsoleteteWAL();
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// get total level0 file size. Only for testing.
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uint64_t TEST_GetLevel0TotalSize();
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void TEST_SetDefaultTimeToCheck(uint64_t default_interval_to_delete_obsolete_WAL)
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{
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default_interval_to_delete_obsolete_WAL_ = default_interval_to_delete_obsolete_WAL;
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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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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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// 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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// Returns true if this was the last reference and caller should
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// call Clenaup() and delete the object
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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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};
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// needed for CleanupIteratorState
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struct DeletionState {
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inline bool HaveSomethingToDelete() const {
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return candidate_files.size() ||
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sst_delete_files.size() ||
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log_delete_files.size();
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}
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// a list of all files that we'll consider deleting
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// (every once in a while this is filled up with all files
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// in the DB directory)
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std::vector<std::string> candidate_files;
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// the list of all live sst files that cannot be deleted
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std::vector<uint64_t> sst_live;
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// a list of sst files that we need to delete
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std::vector<FileMetaData*> sst_delete_files;
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// a list of log files that we need to delete
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std::vector<uint64_t> log_delete_files;
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// a list of memtables to be free
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autovector<MemTable*> memtables_to_free;
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SuperVersion* superversion_to_free; // if nullptr nothing to free
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SuperVersion* new_superversion; // if nullptr no new superversion
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// the current manifest_file_number, log_number and prev_log_number
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// that corresponds to the set of files in 'live'.
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uint64_t manifest_file_number, log_number, prev_log_number;
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explicit DeletionState(bool create_superversion = false) {
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manifest_file_number = 0;
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log_number = 0;
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prev_log_number = 0;
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superversion_to_free = nullptr;
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new_superversion =
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create_superversion ? new SuperVersion() : nullptr;
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}
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~DeletionState() {
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// free pending memtables
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for (auto m : memtables_to_free) {
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delete m;
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}
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// free superversion. if nullptr, this will be noop
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delete superversion_to_free;
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// if new_superversion was not used, it will be non-nullptr and needs
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// to be freed here
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delete new_superversion;
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}
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};
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// Returns the list of live files in 'live' and the list
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// of all files in the filesystem in 'candidate_files'.
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// If force == false and the last call was less than
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// options_.delete_obsolete_files_period_micros microseconds ago,
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// it will not fill up the deletion_state
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void FindObsoleteFiles(DeletionState& deletion_state,
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bool force,
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bool no_full_scan = false);
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// Diffs the files listed in filenames and those that do not
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// belong to live files are posibly removed. Also, removes all the
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// files in sst_delete_files and log_delete_files.
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// It is not necessary to hold the mutex when invoking this method.
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void PurgeObsoleteFiles(DeletionState& deletion_state);
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protected:
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Env* const env_;
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const std::string dbname_;
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unique_ptr<VersionSet> versions_;
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const InternalKeyComparator internal_comparator_;
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const Options options_; // options_.comparator == &internal_comparator_
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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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MemTable* GetMemTable() {
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return mem_;
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}
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Iterator* NewInternalIterator(const ReadOptions&,
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SequenceNumber* latest_snapshot);
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private:
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friend class DB;
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friend class TailingIterator;
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struct CompactionState;
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struct Writer;
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Status NewDB();
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// Recover the descriptor from persistent storage. May do a significant
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// amount of work to recover recently logged updates.
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Status Recover(bool read_only = false, bool error_if_log_file_exist = false);
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void MaybeIgnoreError(Status* s) const;
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const Status CreateArchivalDirectory();
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// Delete any unneeded files and stale in-memory entries.
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void DeleteObsoleteFiles();
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// Flush the in-memory write buffer to storage. Switches to a new
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// log-file/memtable and writes a new descriptor iff successful.
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Status FlushMemTableToOutputFile(bool* madeProgress,
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DeletionState& deletion_state);
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Status RecoverLogFile(uint64_t log_number, SequenceNumber* max_sequence,
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bool read_only);
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// The following two methods are used to flush a memtable to
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// storage. The first one is used atdatabase RecoveryTime (when the
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// database is opened) and is heavyweight because it holds the mutex
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// for the entire period. The second method WriteLevel0Table supports
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// concurrent flush memtables to storage.
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Status WriteLevel0TableForRecovery(MemTable* mem, VersionEdit* edit);
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Status WriteLevel0Table(autovector<MemTable*>& mems, VersionEdit* edit,
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uint64_t* filenumber);
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uint64_t SlowdownAmount(int n, double bottom, double top);
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// MakeRoomForWrite will return superversion_to_free through an arugment,
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// which the caller needs to delete. We do it because caller can delete
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// the superversion outside of mutex
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Status MakeRoomForWrite(bool force /* compact even if there is room? */,
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SuperVersion** superversion_to_free);
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void BuildBatchGroup(Writer** last_writer,
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autovector<WriteBatch*>* write_batch_group);
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// Force current memtable contents to be flushed.
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Status FlushMemTable(const FlushOptions& options);
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// Wait for memtable flushed
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Status WaitForFlushMemTable();
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void MaybeScheduleLogDBDeployStats();
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static void BGLogDBDeployStats(void* db);
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void LogDBDeployStats();
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void MaybeScheduleFlushOrCompaction();
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static void BGWorkCompaction(void* db);
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static void BGWorkFlush(void* db);
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void BackgroundCallCompaction();
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void BackgroundCallFlush();
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Status BackgroundCompaction(bool* madeProgress,DeletionState& deletion_state);
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Status BackgroundFlush(bool* madeProgress, DeletionState& deletion_state);
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void CleanupCompaction(CompactionState* compact, Status status);
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Status DoCompactionWork(CompactionState* compact,
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DeletionState& deletion_state);
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Status OpenCompactionOutputFile(CompactionState* compact);
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Status FinishCompactionOutputFile(CompactionState* compact, Iterator* input);
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Status InstallCompactionResults(CompactionState* compact);
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void AllocateCompactionOutputFileNumbers(CompactionState* compact);
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void ReleaseCompactionUnusedFileNumbers(CompactionState* compact);
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void PurgeObsoleteWALFiles();
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Status AppendSortedWalsOfType(const std::string& path,
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VectorLogPtr& log_files,
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WalFileType type);
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// Requires: all_logs should be sorted with earliest log file first
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// Retains all log files in all_logs which contain updates with seq no.
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// Greater Than or Equal to the requested SequenceNumber.
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Status RetainProbableWalFiles(VectorLogPtr& all_logs,
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const SequenceNumber target);
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// return true if
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bool CheckWalFileExistsAndEmpty(const WalFileType type,
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const uint64_t number);
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Status ReadFirstRecord(const WalFileType type, const uint64_t number,
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WriteBatch* const result);
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Status ReadFirstLine(const std::string& fname, WriteBatch* const batch);
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void PrintStatistics();
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// dump rocksdb.stats to LOG
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void MaybeDumpStats();
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// Return the minimum empty level that could hold the total data in the
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// input level. Return the input level, if such level could not be found.
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int FindMinimumEmptyLevelFitting(int level);
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// Move the files in the input level to the target level.
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// If target_level < 0, automatically calculate the minimum level that could
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// hold the data set.
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Status ReFitLevel(int level, int target_level = -1);
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// Returns the current SuperVersion number.
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uint64_t CurrentVersionNumber() const;
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// Returns a pair of iterators (mutable-only and immutable-only) used
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// internally by TailingIterator and stores CurrentVersionNumber() in
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// *superversion_number. These iterators are always up-to-date, i.e. can
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// be used to read new data.
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std::pair<Iterator*, Iterator*> GetTailingIteratorPair(
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const ReadOptions& options,
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uint64_t* superversion_number);
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// Constant after construction
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const InternalFilterPolicy internal_filter_policy_;
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bool owns_info_log_;
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// table_cache_ provides its own synchronization
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unique_ptr<TableCache> table_cache_;
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// Lock over the persistent DB state. Non-nullptr iff successfully acquired.
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FileLock* db_lock_;
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// State below is protected by mutex_
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port::Mutex mutex_;
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port::AtomicPointer shutting_down_;
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port::CondVar bg_cv_; // Signalled when background work finishes
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MemTableRepFactory* mem_rep_factory_;
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MemTable* mem_;
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MemTableList imm_; // Memtable that are not changing
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uint64_t logfile_number_;
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unique_ptr<log::Writer> log_;
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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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std::string host_name_;
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std::unique_ptr<Directory> db_directory_;
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// Queue of writers.
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std::deque<Writer*> writers_;
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WriteBatch tmp_batch_;
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SnapshotList snapshots_;
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// Set of table files to protect from deletion because they are
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// part of ongoing compactions.
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std::set<uint64_t> pending_outputs_;
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// count how many background compactions are running or have been scheduled
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int bg_compaction_scheduled_;
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// If non-zero, MaybeScheduleFlushOrCompaction() will only schedule manual
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// compactions (if manual_compaction_ is not null). This mechanism enables
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// manual compactions to wait until all other compactions are finished.
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int bg_manual_only_;
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// number of background memtable flush jobs, submitted to the HIGH pool
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int bg_flush_scheduled_;
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// Has a background stats log thread scheduled?
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bool bg_logstats_scheduled_;
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// Information for a manual compaction
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struct ManualCompaction {
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int input_level;
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int output_level;
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bool done;
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Status status;
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bool in_progress; // compaction request being processed?
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const InternalKey* begin; // nullptr means beginning of key range
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const InternalKey* end; // nullptr means end of key range
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InternalKey tmp_storage; // Used to keep track of compaction progress
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};
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ManualCompaction* manual_compaction_;
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// Have we encountered a background error in paranoid mode?
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Status bg_error_;
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std::unique_ptr<StatsLogger> logger_;
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int64_t volatile last_log_ts;
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// shall we disable deletion of obsolete files
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// if 0 the deletion is enabled.
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// if non-zero, files will not be getting deleted
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// This enables two different threads to call
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// EnableFileDeletions() and DisableFileDeletions()
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// without any synchronization
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int disable_delete_obsolete_files_;
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// last time when DeleteObsoleteFiles was invoked
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uint64_t delete_obsolete_files_last_run_;
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// last time when PurgeObsoleteWALFiles ran.
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uint64_t purge_wal_files_last_run_;
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// last time stats were dumped to LOG
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std::atomic<uint64_t> last_stats_dump_time_microsec_;
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// obsolete files will be deleted every this seconds if ttl deletion is
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// enabled and archive size_limit is disabled.
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uint64_t default_interval_to_delete_obsolete_WAL_;
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// These count the number of microseconds for which MakeRoomForWrite stalls.
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uint64_t stall_level0_slowdown_;
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uint64_t stall_memtable_compaction_;
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uint64_t stall_level0_num_files_;
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std::vector<uint64_t> stall_leveln_slowdown_;
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uint64_t stall_level0_slowdown_count_;
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uint64_t stall_memtable_compaction_count_;
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uint64_t stall_level0_num_files_count_;
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std::vector<uint64_t> stall_leveln_slowdown_count_;
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// Time at which this instance was started.
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const uint64_t started_at_;
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bool flush_on_destroy_; // Used when disableWAL is true.
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// Per level compaction stats. stats_[level] stores the stats for
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// compactions that produced data for the specified "level".
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struct CompactionStats {
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uint64_t micros;
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// Bytes read from level N during compaction between levels N and N+1
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int64_t bytes_readn;
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// Bytes read from level N+1 during compaction between levels N and N+1
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int64_t bytes_readnp1;
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// Total bytes written during compaction between levels N and N+1
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int64_t bytes_written;
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// Files read from level N during compaction between levels N and N+1
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int files_in_leveln;
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// Files read from level N+1 during compaction between levels N and N+1
|
|
int files_in_levelnp1;
|
|
|
|
// Files written during compaction between levels N and N+1
|
|
int files_out_levelnp1;
|
|
|
|
// Number of compactions done
|
|
int count;
|
|
|
|
CompactionStats() : micros(0), bytes_readn(0), bytes_readnp1(0),
|
|
bytes_written(0), files_in_leveln(0),
|
|
files_in_levelnp1(0), files_out_levelnp1(0),
|
|
count(0) { }
|
|
|
|
void Add(const CompactionStats& c) {
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|
this->micros += c.micros;
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|
this->bytes_readn += c.bytes_readn;
|
|
this->bytes_readnp1 += c.bytes_readnp1;
|
|
this->bytes_written += c.bytes_written;
|
|
this->files_in_leveln += c.files_in_leveln;
|
|
this->files_in_levelnp1 += c.files_in_levelnp1;
|
|
this->files_out_levelnp1 += c.files_out_levelnp1;
|
|
this->count += 1;
|
|
}
|
|
};
|
|
|
|
std::vector<CompactionStats> stats_;
|
|
|
|
// Used to compute per-interval statistics
|
|
struct StatsSnapshot {
|
|
uint64_t compaction_bytes_read_; // Bytes read by compaction
|
|
uint64_t compaction_bytes_written_; // Bytes written by compaction
|
|
uint64_t ingest_bytes_; // Bytes written by user
|
|
uint64_t wal_bytes_; // Bytes written to WAL
|
|
uint64_t wal_synced_; // Number of times WAL is synced
|
|
uint64_t write_with_wal_; // Number of writes that request WAL
|
|
// These count the number of writes processed by the calling thread or
|
|
// another thread.
|
|
uint64_t write_other_;
|
|
uint64_t write_self_;
|
|
double seconds_up_;
|
|
|
|
StatsSnapshot() : compaction_bytes_read_(0), compaction_bytes_written_(0),
|
|
ingest_bytes_(0), wal_bytes_(0), wal_synced_(0),
|
|
write_with_wal_(0), write_other_(0), write_self_(0),
|
|
seconds_up_(0) {}
|
|
};
|
|
|
|
// Counters from the previous time per-interval stats were computed
|
|
StatsSnapshot last_stats_;
|
|
|
|
static const int KEEP_LOG_FILE_NUM = 1000;
|
|
std::string db_absolute_path_;
|
|
|
|
// count of the number of contiguous delaying writes
|
|
int delayed_writes_;
|
|
|
|
// The options to access storage files
|
|
const EnvOptions storage_options_;
|
|
|
|
// A value of true temporarily disables scheduling of background work
|
|
bool bg_work_gate_closed_;
|
|
|
|
// Guard against multiple concurrent refitting
|
|
bool refitting_level_;
|
|
|
|
// No copying allowed
|
|
DBImpl(const DBImpl&);
|
|
void operator=(const DBImpl&);
|
|
|
|
// dump the delayed_writes_ to the log file and reset counter.
|
|
void DelayLoggingAndReset();
|
|
|
|
// Return the earliest snapshot where seqno is visible.
|
|
// Store the snapshot right before that, if any, in prev_snapshot
|
|
inline SequenceNumber findEarliestVisibleSnapshot(
|
|
SequenceNumber in,
|
|
std::vector<SequenceNumber>& snapshots,
|
|
SequenceNumber* prev_snapshot);
|
|
|
|
// will return a pointer to SuperVersion* if previous SuperVersion
|
|
// if its reference count is zero and needs deletion or nullptr if not
|
|
// As argument takes a pointer to allocated SuperVersion
|
|
// Foreground threads call this function directly (they don't carry
|
|
// deletion state and have to handle their own creation and deletion
|
|
// of SuperVersion)
|
|
SuperVersion* InstallSuperVersion(SuperVersion* new_superversion);
|
|
// Background threads call this function, which is just a wrapper around
|
|
// the InstallSuperVersion() function above. Background threads carry
|
|
// deletion_state which can have new_superversion already allocated.
|
|
void InstallSuperVersion(DeletionState& deletion_state);
|
|
|
|
// Function that Get and KeyMayExist call with no_io true or false
|
|
// Note: 'value_found' from KeyMayExist propagates here
|
|
Status GetImpl(const ReadOptions& options,
|
|
const Slice& key,
|
|
std::string* value,
|
|
bool* value_found = nullptr);
|
|
};
|
|
|
|
// Sanitize db options. The caller should delete result.info_log if
|
|
// it is not equal to src.info_log.
|
|
extern Options SanitizeOptions(const std::string& db,
|
|
const InternalKeyComparator* icmp,
|
|
const InternalFilterPolicy* ipolicy,
|
|
const Options& src);
|
|
|
|
|
|
// Determine compression type, based on user options, level of the output
|
|
// file and whether compression is disabled.
|
|
// If enable_compression is false, then compression is always disabled no
|
|
// matter what the values of the other two parameters are.
|
|
// Otherwise, the compression type is determined based on options and level.
|
|
CompressionType GetCompressionType(const Options& options, int level,
|
|
const bool enable_compression);
|
|
|
|
// Determine compression type for L0 file written by memtable flush.
|
|
CompressionType GetCompressionFlush(const Options& options);
|
|
|
|
} // namespace rocksdb
|