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rocksdb/db/db_impl/db_impl.h

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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).
//
// 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.
#pragma once
#include <atomic>
#include <deque>
#include <functional>
#include <limits>
#include <list>
#include <map>
#include <set>
#include <string>
#include <utility>
#include <vector>
#include "db/column_family.h"
#include "db/compaction/compaction_iterator.h"
#include "db/compaction/compaction_job.h"
#include "db/dbformat.h"
#include "db/error_handler.h"
#include "db/event_helpers.h"
#include "db/external_sst_file_ingestion_job.h"
#include "db/flush_job.h"
#include "db/flush_scheduler.h"
#include "db/import_column_family_job.h"
#include "db/internal_stats.h"
#include "db/log_writer.h"
#include "db/logs_with_prep_tracker.h"
#include "db/memtable_list.h"
#include "db/pre_release_callback.h"
#include "db/range_del_aggregator.h"
#include "db/read_callback.h"
#include "db/snapshot_checker.h"
#include "db/snapshot_impl.h"
#include "db/trim_history_scheduler.h"
#include "db/version_edit.h"
#include "db/wal_manager.h"
#include "db/write_controller.h"
#include "db/write_thread.h"
#include "logging/event_logger.h"
#include "monitoring/instrumented_mutex.h"
#include "options/db_options.h"
#include "port/port.h"
#include "rocksdb/db.h"
#include "rocksdb/env.h"
#include "rocksdb/memtablerep.h"
#include "rocksdb/status.h"
#ifndef ROCKSDB_LITE
#include "rocksdb/trace_reader_writer.h"
#endif // ROCKSDB_LITE
#include "rocksdb/transaction_log.h"
#ifndef ROCKSDB_LITE
#include "rocksdb/utilities/replayer.h"
#endif // ROCKSDB_LITE
#include "rocksdb/write_buffer_manager.h"
#include "table/merging_iterator.h"
#include "table/scoped_arena_iterator.h"
#include "util/autovector.h"
#include "util/hash.h"
#include "util/repeatable_thread.h"
#include "util/stop_watch.h"
#include "util/thread_local.h"
namespace ROCKSDB_NAMESPACE {
class Arena;
class ArenaWrappedDBIter;
class InMemoryStatsHistoryIterator;
class MemTable;
class PersistentStatsHistoryIterator;
class PeriodicWorkScheduler;
#ifndef NDEBUG
class PeriodicWorkTestScheduler;
#endif // !NDEBUG
class TableCache;
class TaskLimiterToken;
class Version;
class VersionEdit;
class VersionSet;
class WriteCallback;
struct JobContext;
struct ExternalSstFileInfo;
struct MemTableInfo;
// Class to maintain directories for all database paths other than main one.
class Directories {
public:
IOStatus SetDirectories(FileSystem* fs, const std::string& dbname,
const std::string& wal_dir,
const std::vector<DbPath>& data_paths);
FSDirectory* GetDataDir(size_t path_id) const {
assert(path_id < data_dirs_.size());
FSDirectory* ret_dir = data_dirs_[path_id].get();
if (ret_dir == nullptr) {
// Should use db_dir_
return db_dir_.get();
}
return ret_dir;
}
FSDirectory* GetWalDir() {
if (wal_dir_) {
return wal_dir_.get();
}
return db_dir_.get();
}
FSDirectory* GetDbDir() { return db_dir_.get(); }
private:
std::unique_ptr<FSDirectory> db_dir_;
std::vector<std::unique_ptr<FSDirectory>> data_dirs_;
std::unique_ptr<FSDirectory> wal_dir_;
};
// While DB is the public interface of RocksDB, and DBImpl is the actual
// class implementing it. It's the entrance of the core RocksdB engine.
// All other DB implementations, e.g. TransactionDB, BlobDB, etc, wrap a
// DBImpl internally.
// Other than functions implementing the DB interface, some public
// functions are there for other internal components to call. For
// example, TransactionDB directly calls DBImpl::WriteImpl() and
// BlobDB directly calls DBImpl::GetImpl(). Some other functions
// are for sub-components to call. For example, ColumnFamilyHandleImpl
// calls DBImpl::FindObsoleteFiles().
//
// Since it's a very large class, the definition of the functions is
// divided in several db_impl_*.cc files, besides db_impl.cc.
class DBImpl : public DB {
public:
DBImpl(const DBOptions& options, const std::string& dbname,
const bool seq_per_batch = false, const bool batch_per_txn = true,
bool read_only = false);
// No copying allowed
DBImpl(const DBImpl&) = delete;
void operator=(const DBImpl&) = delete;
virtual ~DBImpl();
// ---- Implementations of the DB interface ----
using DB::Resume;
virtual Status Resume() override;
using DB::Put;
virtual Status Put(const WriteOptions& options,
ColumnFamilyHandle* column_family, const Slice& key,
const Slice& value) override;
using DB::Merge;
virtual Status Merge(const WriteOptions& options,
ColumnFamilyHandle* column_family, const Slice& key,
const Slice& value) override;
using DB::Delete;
virtual Status Delete(const WriteOptions& options,
ColumnFamilyHandle* column_family,
const Slice& key) override;
using DB::SingleDelete;
virtual Status SingleDelete(const WriteOptions& options,
ColumnFamilyHandle* column_family,
const Slice& key) override;
using DB::Write;
virtual Status Write(const WriteOptions& options,
WriteBatch* updates) override;
using DB::Get;
virtual Status Get(const ReadOptions& options,
ColumnFamilyHandle* column_family, const Slice& key,
PinnableSlice* value) override;
virtual Status Get(const ReadOptions& options,
ColumnFamilyHandle* column_family, const Slice& key,
PinnableSlice* value, std::string* timestamp) override;
using DB::GetMergeOperands;
Status GetMergeOperands(const ReadOptions& options,
ColumnFamilyHandle* column_family, const Slice& key,
PinnableSlice* merge_operands,
GetMergeOperandsOptions* get_merge_operands_options,
int* number_of_operands) override {
GetImplOptions get_impl_options;
get_impl_options.column_family = column_family;
get_impl_options.merge_operands = merge_operands;
get_impl_options.get_merge_operands_options = get_merge_operands_options;
get_impl_options.number_of_operands = number_of_operands;
get_impl_options.get_value = false;
return GetImpl(options, key, get_impl_options);
}
using DB::MultiGet;
virtual std::vector<Status> MultiGet(
const ReadOptions& options,
const std::vector<ColumnFamilyHandle*>& column_family,
const std::vector<Slice>& keys,
std::vector<std::string>* values) override;
virtual std::vector<Status> MultiGet(
const ReadOptions& options,
const std::vector<ColumnFamilyHandle*>& column_family,
const std::vector<Slice>& keys, std::vector<std::string>* values,
std::vector<std::string>* timestamps) override;
// This MultiGet is a batched version, which may be faster than calling Get
// multiple times, especially if the keys have some spatial locality that
// enables them to be queried in the same SST files/set of files. The larger
// the batch size, the more scope for batching and performance improvement
// The values and statuses parameters are arrays with number of elements
// equal to keys.size(). This allows the storage for those to be alloacted
// by the caller on the stack for small batches
virtual void MultiGet(const ReadOptions& options,
ColumnFamilyHandle* column_family,
const size_t num_keys, const Slice* keys,
PinnableSlice* values, Status* statuses,
const bool sorted_input = false) override;
virtual void MultiGet(const ReadOptions& options,
ColumnFamilyHandle* column_family,
const size_t num_keys, const Slice* keys,
PinnableSlice* values, std::string* timestamps,
Status* statuses,
const bool sorted_input = false) override;
virtual void MultiGet(const ReadOptions& options, const size_t num_keys,
ColumnFamilyHandle** column_families, const Slice* keys,
PinnableSlice* values, Status* statuses,
const bool sorted_input = false) override;
virtual void MultiGet(const ReadOptions& options, const size_t num_keys,
ColumnFamilyHandle** column_families, const Slice* keys,
PinnableSlice* values, std::string* timestamps,
Status* statuses,
const bool sorted_input = false) override;
virtual void MultiGetWithCallback(
const ReadOptions& options, ColumnFamilyHandle* column_family,
ReadCallback* callback,
autovector<KeyContext*, MultiGetContext::MAX_BATCH_SIZE>* sorted_keys);
virtual Status CreateColumnFamily(const ColumnFamilyOptions& cf_options,
const std::string& column_family,
ColumnFamilyHandle** handle) override;
virtual Status CreateColumnFamilies(
const ColumnFamilyOptions& cf_options,
const std::vector<std::string>& column_family_names,
std::vector<ColumnFamilyHandle*>* handles) override;
virtual Status CreateColumnFamilies(
const std::vector<ColumnFamilyDescriptor>& column_families,
std::vector<ColumnFamilyHandle*>* handles) override;
virtual Status DropColumnFamily(ColumnFamilyHandle* column_family) override;
virtual Status DropColumnFamilies(
const std::vector<ColumnFamilyHandle*>& column_families) override;
// Returns false if key doesn't exist in the database and true if it may.
// If value_found is not passed in as null, then return the value if found in
// memory. On return, if value was found, then value_found will be set to true
// , otherwise false.
using DB::KeyMayExist;
virtual bool KeyMayExist(const ReadOptions& options,
ColumnFamilyHandle* column_family, const Slice& key,
std::string* value, std::string* timestamp,
bool* value_found = nullptr) override;
using DB::NewIterator;
virtual Iterator* NewIterator(const ReadOptions& options,
ColumnFamilyHandle* column_family) override;
virtual Status NewIterators(
const ReadOptions& options,
const std::vector<ColumnFamilyHandle*>& column_families,
std::vector<Iterator*>* iterators) override;
virtual const Snapshot* GetSnapshot() override;
virtual void ReleaseSnapshot(const Snapshot* snapshot) override;
using DB::GetProperty;
virtual bool GetProperty(ColumnFamilyHandle* column_family,
const Slice& property, std::string* value) override;
using DB::GetMapProperty;
virtual bool GetMapProperty(
ColumnFamilyHandle* column_family, const Slice& property,
std::map<std::string, std::string>* value) override;
using DB::GetIntProperty;
virtual bool GetIntProperty(ColumnFamilyHandle* column_family,
const Slice& property, uint64_t* value) override;
using DB::GetAggregatedIntProperty;
virtual bool GetAggregatedIntProperty(const Slice& property,
uint64_t* aggregated_value) override;
using DB::GetApproximateSizes;
virtual Status GetApproximateSizes(const SizeApproximationOptions& options,
ColumnFamilyHandle* column_family,
const Range* range, int n,
uint64_t* sizes) override;
using DB::GetApproximateMemTableStats;
virtual void GetApproximateMemTableStats(ColumnFamilyHandle* column_family,
const Range& range,
uint64_t* const count,
uint64_t* const size) override;
using DB::CompactRange;
virtual Status CompactRange(const CompactRangeOptions& options,
ColumnFamilyHandle* column_family,
const Slice* begin, const Slice* end) override;
using DB::CompactFiles;
virtual Status CompactFiles(
const CompactionOptions& compact_options,
ColumnFamilyHandle* column_family,
const std::vector<std::string>& input_file_names, const int output_level,
const int output_path_id = -1,
std::vector<std::string>* const output_file_names = nullptr,
CompactionJobInfo* compaction_job_info = nullptr) override;
virtual Status PauseBackgroundWork() override;
virtual Status ContinueBackgroundWork() override;
virtual Status EnableAutoCompaction(
const std::vector<ColumnFamilyHandle*>& column_family_handles) override;
virtual void EnableManualCompaction() override;
virtual void DisableManualCompaction() override;
using DB::SetOptions;
Status SetOptions(
ColumnFamilyHandle* column_family,
const std::unordered_map<std::string, std::string>& options_map) override;
virtual Status SetDBOptions(
const std::unordered_map<std::string, std::string>& options_map) override;
using DB::NumberLevels;
virtual int NumberLevels(ColumnFamilyHandle* column_family) override;
using DB::MaxMemCompactionLevel;
virtual int MaxMemCompactionLevel(ColumnFamilyHandle* column_family) override;
using DB::Level0StopWriteTrigger;
virtual int Level0StopWriteTrigger(
ColumnFamilyHandle* column_family) override;
virtual const std::string& GetName() const override;
virtual Env* GetEnv() const override;
virtual FileSystem* GetFileSystem() const override;
using DB::GetOptions;
virtual Options GetOptions(ColumnFamilyHandle* column_family) const override;
using DB::GetDBOptions;
virtual DBOptions GetDBOptions() const override;
using DB::Flush;
virtual Status Flush(const FlushOptions& options,
ColumnFamilyHandle* column_family) override;
virtual Status Flush(
const FlushOptions& options,
const std::vector<ColumnFamilyHandle*>& column_families) override;
virtual Status FlushWAL(bool sync) override;
bool TEST_WALBufferIsEmpty(bool lock = true);
virtual Status SyncWAL() override;
virtual Status LockWAL() override;
virtual Status UnlockWAL() override;
virtual SequenceNumber GetLatestSequenceNumber() const override;
virtual bool SetPreserveDeletesSequenceNumber(SequenceNumber seqnum) override;
virtual Status GetDbIdentity(std::string& identity) const override;
virtual Status GetDbIdentityFromIdentityFile(std::string* identity) const;
virtual Status GetDbSessionId(std::string& session_id) const override;
ColumnFamilyHandle* DefaultColumnFamily() const override;
ColumnFamilyHandle* PersistentStatsColumnFamily() const;
virtual Status Close() override;
virtual Status DisableFileDeletions() override;
virtual Status EnableFileDeletions(bool force) override;
virtual bool IsFileDeletionsEnabled() const;
Status GetStatsHistory(
uint64_t start_time, uint64_t end_time,
std::unique_ptr<StatsHistoryIterator>* stats_iterator) override;
#ifndef ROCKSDB_LITE
using DB::ResetStats;
virtual Status ResetStats() override;
// All the returned filenames start with "/"
virtual Status GetLiveFiles(std::vector<std::string>&,
uint64_t* manifest_file_size,
bool flush_memtable = true) override;
virtual Status GetSortedWalFiles(VectorLogPtr& files) override;
virtual Status GetCurrentWalFile(
std::unique_ptr<LogFile>* current_log_file) override;
virtual Status GetCreationTimeOfOldestFile(
uint64_t* creation_time) override;
virtual Status GetUpdatesSince(
SequenceNumber seq_number, std::unique_ptr<TransactionLogIterator>* iter,
const TransactionLogIterator::ReadOptions& read_options =
TransactionLogIterator::ReadOptions()) override;
virtual Status DeleteFile(std::string name) override;
Status DeleteFilesInRanges(ColumnFamilyHandle* column_family,
const RangePtr* ranges, size_t n,
bool include_end = true);
virtual void GetLiveFilesMetaData(
std::vector<LiveFileMetaData>* metadata) override;
virtual Status GetLiveFilesChecksumInfo(
FileChecksumList* checksum_list) override;
// Obtains the meta data of the specified column family of the DB.
// TODO(yhchiang): output parameter is placed in the end in this codebase.
virtual void GetColumnFamilyMetaData(ColumnFamilyHandle* column_family,
ColumnFamilyMetaData* metadata) override;
void GetAllColumnFamilyMetaData(
std::vector<ColumnFamilyMetaData>* metadata) override;
Status SuggestCompactRange(ColumnFamilyHandle* column_family,
const Slice* begin, const Slice* end) override;
Status PromoteL0(ColumnFamilyHandle* column_family,
int target_level) override;
using DB::IngestExternalFile;
virtual Status IngestExternalFile(
ColumnFamilyHandle* column_family,
const std::vector<std::string>& external_files,
const IngestExternalFileOptions& ingestion_options) override;
using DB::IngestExternalFiles;
virtual Status IngestExternalFiles(
const std::vector<IngestExternalFileArg>& args) override;
using DB::CreateColumnFamilyWithImport;
virtual Status CreateColumnFamilyWithImport(
const ColumnFamilyOptions& options, const std::string& column_family_name,
const ImportColumnFamilyOptions& import_options,
const ExportImportFilesMetaData& metadata,
ColumnFamilyHandle** handle) override;
using DB::VerifyFileChecksums;
Status VerifyFileChecksums(const ReadOptions& read_options) override;
using DB::VerifyChecksum;
virtual Status VerifyChecksum(const ReadOptions& /*read_options*/) override;
// Verify the checksums of files in db. Currently only tables are checked.
//
// read_options: controls file I/O behavior, e.g. read ahead size while
// reading all the live table files.
//
// use_file_checksum: if false, verify the block checksums of all live table
// in db. Otherwise, obtain the file checksums and compare
// with the MANIFEST. Currently, file checksums are
// recomputed by reading all table files.
//
// Returns: OK if there is no file whose file or block checksum mismatches.
Status VerifyChecksumInternal(const ReadOptions& read_options,
bool use_file_checksum);
Status VerifyFullFileChecksum(const std::string& file_checksum_expected,
const std::string& func_name_expected,
const std::string& fpath,
const ReadOptions& read_options);
using DB::StartTrace;
virtual Status StartTrace(
const TraceOptions& options,
std::unique_ptr<TraceWriter>&& trace_writer) override;
using DB::EndTrace;
virtual Status EndTrace() override;
using DB::NewDefaultReplayer;
virtual Status NewDefaultReplayer(
const std::vector<ColumnFamilyHandle*>& handles,
std::unique_ptr<TraceReader>&& reader,
std::unique_ptr<Replayer>* replayer) override;
using DB::StartBlockCacheTrace;
Status StartBlockCacheTrace(
const TraceOptions& options,
std::unique_ptr<TraceWriter>&& trace_writer) override;
using DB::EndBlockCacheTrace;
Status EndBlockCacheTrace() override;
using DB::StartIOTrace;
Status StartIOTrace(const TraceOptions& options,
std::unique_ptr<TraceWriter>&& trace_writer) override;
using DB::EndIOTrace;
Status EndIOTrace() override;
using DB::GetPropertiesOfAllTables;
virtual Status GetPropertiesOfAllTables(
ColumnFamilyHandle* column_family,
TablePropertiesCollection* props) override;
virtual Status GetPropertiesOfTablesInRange(
ColumnFamilyHandle* column_family, const Range* range, std::size_t n,
TablePropertiesCollection* props) override;
#endif // ROCKSDB_LITE
// ---- End of implementations of the DB interface ----
SystemClock* GetSystemClock() const;
struct GetImplOptions {
ColumnFamilyHandle* column_family = nullptr;
PinnableSlice* value = nullptr;
std::string* timestamp = nullptr;
bool* value_found = nullptr;
ReadCallback* callback = nullptr;
bool* is_blob_index = nullptr;
// If true return value associated with key via value pointer else return
// all merge operands for key via merge_operands pointer
bool get_value = true;
// Pointer to an array of size
// get_merge_operands_options.expected_max_number_of_operands allocated by
// user
PinnableSlice* merge_operands = nullptr;
GetMergeOperandsOptions* get_merge_operands_options = nullptr;
int* number_of_operands = nullptr;
};
// Function that Get and KeyMayExist call with no_io true or false
// Note: 'value_found' from KeyMayExist propagates here
// This function is also called by GetMergeOperands
// If get_impl_options.get_value = true get value associated with
// get_impl_options.key via get_impl_options.value
// If get_impl_options.get_value = false get merge operands associated with
// get_impl_options.key via get_impl_options.merge_operands
Status GetImpl(const ReadOptions& options, const Slice& key,
GetImplOptions& get_impl_options);
// If `snapshot` == kMaxSequenceNumber, set a recent one inside the file.
ArenaWrappedDBIter* NewIteratorImpl(const ReadOptions& options,
ColumnFamilyData* cfd,
SequenceNumber snapshot,
ReadCallback* read_callback,
bool expose_blob_index = false,
bool allow_refresh = true);
virtual SequenceNumber GetLastPublishedSequence() const {
if (last_seq_same_as_publish_seq_) {
return versions_->LastSequence();
} else {
return versions_->LastPublishedSequence();
}
}
// REQUIRES: joined the main write queue if two_write_queues is disabled, and
// the second write queue otherwise.
virtual void SetLastPublishedSequence(SequenceNumber seq);
// Returns LastSequence in last_seq_same_as_publish_seq_
// mode and LastAllocatedSequence otherwise. This is useful when visiblility
// depends also on data written to the WAL but not to the memtable.
SequenceNumber TEST_GetLastVisibleSequence() const;
#ifndef ROCKSDB_LITE
// Similar to Write() but will call the callback once on the single write
// thread to determine whether it is safe to perform the write.
virtual Status WriteWithCallback(const WriteOptions& write_options,
WriteBatch* my_batch,
WriteCallback* callback);
// Returns the sequence number that is guaranteed to be smaller than or equal
// to the sequence number of any key that could be inserted into the current
// memtables. It can then be assumed that any write with a larger(or equal)
// sequence number will be present in this memtable or a later memtable.
//
// If the earliest sequence number could not be determined,
// kMaxSequenceNumber will be returned.
//
// If include_history=true, will also search Memtables in MemTableList
// History.
SequenceNumber GetEarliestMemTableSequenceNumber(SuperVersion* sv,
bool include_history);
// For a given key, check to see if there are any records for this key
// in the memtables, including memtable history. If cache_only is false,
// SST files will also be checked.
//
// If a key is found, *found_record_for_key will be set to true and
// *seq will be set to the stored sequence number for the latest
// operation on this key or kMaxSequenceNumber if unknown.
// If no key is found, *found_record_for_key will be set to false.
//
// Note: If cache_only=false, it is possible for *seq to be set to 0 if
// the sequence number has been cleared from the record. If the caller is
// holding an active db snapshot, we know the missing sequence must be less
// than the snapshot's sequence number (sequence numbers are only cleared
// when there are no earlier active snapshots).
//
// If NotFound is returned and found_record_for_key is set to false, then no
// record for this key was found. If the caller is holding an active db
// snapshot, we know that no key could have existing after this snapshot
// (since we do not compact keys that have an earlier snapshot).
//
// Only records newer than or at `lower_bound_seq` are guaranteed to be
// returned. Memtables and files may not be checked if it only contains data
// older than `lower_bound_seq`.
//
// Returns OK or NotFound on success,
// other status on unexpected error.
// TODO(andrewkr): this API need to be aware of range deletion operations
Status GetLatestSequenceForKey(SuperVersion* sv, const Slice& key,
bool cache_only,
SequenceNumber lower_bound_seq,
SequenceNumber* seq,
bool* found_record_for_key,
bool* is_blob_index = nullptr);
Status TraceIteratorSeek(const uint32_t& cf_id, const Slice& key,
const Slice& lower_bound, const Slice upper_bound);
Status TraceIteratorSeekForPrev(const uint32_t& cf_id, const Slice& key,
const Slice& lower_bound,
const Slice upper_bound);
#endif // ROCKSDB_LITE
// Similar to GetSnapshot(), but also lets the db know that this snapshot
// will be used for transaction write-conflict checking. The DB can then
// make sure not to compact any keys that would prevent a write-conflict from
// being detected.
const Snapshot* GetSnapshotForWriteConflictBoundary();
// checks if all live files exist on file system and that their file sizes
// match to our in-memory records
virtual Status CheckConsistency();
// max_file_num_to_ignore allows bottom level compaction to filter out newly
// compacted SST files. Setting max_file_num_to_ignore to kMaxUint64 will
// disable the filtering
Status RunManualCompaction(ColumnFamilyData* cfd, int input_level,
int output_level,
const CompactRangeOptions& compact_range_options,
const Slice* begin, const Slice* end,
bool exclusive, bool disallow_trivial_move,
uint64_t max_file_num_to_ignore);
// Return an internal iterator over the current state of the database.
// The keys of this iterator are internal keys (see format.h).
// The returned iterator should be deleted when no longer needed.
// If allow_unprepared_value is true, the returned iterator may defer reading
// the value and so will require PrepareValue() to be called before value();
// allow_unprepared_value = false is convenient when this optimization is not
// useful, e.g. when reading the whole column family.
// @param read_options Must outlive the returned iterator.
InternalIterator* NewInternalIterator(
const ReadOptions& read_options, Arena* arena,
RangeDelAggregator* range_del_agg, SequenceNumber sequence,
ColumnFamilyHandle* column_family = nullptr,
bool allow_unprepared_value = false);
LogsWithPrepTracker* logs_with_prep_tracker() {
return &logs_with_prep_tracker_;
}
struct BGJobLimits {
int max_flushes;
int max_compactions;
};
// Returns maximum background flushes and compactions allowed to be scheduled
BGJobLimits GetBGJobLimits() const;
// Need a static version that can be called during SanitizeOptions().
static BGJobLimits GetBGJobLimits(int max_background_flushes,
int max_background_compactions,
int max_background_jobs,
bool parallelize_compactions);
// move logs pending closing from job_context to the DB queue and
// schedule a purge
void ScheduleBgLogWriterClose(JobContext* job_context);
uint64_t MinLogNumberToKeep();
// Returns the lower bound file number for SSTs that won't be deleted, even if
// they're obsolete. This lower bound is used internally to prevent newly
// created flush/compaction output files from being deleted before they're
// installed. This technique avoids the need for tracking the exact numbers of
// files pending creation, although it prevents more files than necessary from
// being deleted.
uint64_t MinObsoleteSstNumberToKeep();
// Returns the list of live files in 'live' and the list
// of all files in the filesystem in 'candidate_files'.
// If force == false and the last call was less than
// db_options_.delete_obsolete_files_period_micros microseconds ago,
// it will not fill up the job_context
void FindObsoleteFiles(JobContext* job_context, bool force,
bool no_full_scan = false);
// Diffs the files listed in filenames and those that do not
// belong to live files are possibly removed. Also, removes all the
// files in sst_delete_files and log_delete_files.
// It is not necessary to hold the mutex when invoking this method.
// If FindObsoleteFiles() was run, we need to also run
// PurgeObsoleteFiles(), even if disable_delete_obsolete_files_ is true
void PurgeObsoleteFiles(JobContext& background_contet,
bool schedule_only = false);
// Schedule a background job to actually delete obsolete files.
void SchedulePurge();
const SnapshotList& snapshots() const { return snapshots_; }
// load list of snapshots to `snap_vector` that is no newer than `max_seq`
// in ascending order.
// `oldest_write_conflict_snapshot` is filled with the oldest snapshot
// which satisfies SnapshotImpl.is_write_conflict_boundary_ = true.
void LoadSnapshots(std::vector<SequenceNumber>* snap_vector,
SequenceNumber* oldest_write_conflict_snapshot,
const SequenceNumber& max_seq) const {
InstrumentedMutexLock l(mutex());
snapshots().GetAll(snap_vector, oldest_write_conflict_snapshot, max_seq);
}
const ImmutableDBOptions& immutable_db_options() const {
return immutable_db_options_;
}
// Cancel all background jobs, including flush, compaction, background
// purging, stats dumping threads, etc. If `wait` = true, wait for the
// running jobs to abort or finish before returning. Otherwise, only
// sends the signals.
void CancelAllBackgroundWork(bool wait);
// Find Super version and reference it. Based on options, it might return
// the thread local cached one.
// Call ReturnAndCleanupSuperVersion() when it is no longer needed.
SuperVersion* GetAndRefSuperVersion(ColumnFamilyData* cfd);
// Similar to the previous function but looks up based on a column family id.
// nullptr will be returned if this column family no longer exists.
// REQUIRED: this function should only be called on the write thread or if the
// mutex is held.
SuperVersion* GetAndRefSuperVersion(uint32_t column_family_id);
// Un-reference the super version and clean it up if it is the last reference.
void CleanupSuperVersion(SuperVersion* sv);
// Un-reference the super version and return it to thread local cache if
// needed. If it is the last reference of the super version. Clean it up
// after un-referencing it.
void ReturnAndCleanupSuperVersion(ColumnFamilyData* cfd, SuperVersion* sv);
// Similar to the previous function but looks up based on a column family id.
// nullptr will be returned if this column family no longer exists.
// REQUIRED: this function should only be called on the write thread.
void ReturnAndCleanupSuperVersion(uint32_t colun_family_id, SuperVersion* sv);
// REQUIRED: this function should only be called on the write thread or if the
// mutex is held. Return value only valid until next call to this function or
// mutex is released.
ColumnFamilyHandle* GetColumnFamilyHandle(uint32_t column_family_id);
// Same as above, should called without mutex held and not on write thread.
std::unique_ptr<ColumnFamilyHandle> GetColumnFamilyHandleUnlocked(
uint32_t column_family_id);
// Returns the number of currently running flushes.
// REQUIREMENT: mutex_ must be held when calling this function.
int num_running_flushes() {
mutex_.AssertHeld();
return num_running_flushes_;
}
// Returns the number of currently running compactions.
// REQUIREMENT: mutex_ must be held when calling this function.
int num_running_compactions() {
mutex_.AssertHeld();
return num_running_compactions_;
}
const WriteController& write_controller() { return write_controller_; }
// @param read_options Must outlive the returned iterator.
InternalIterator* NewInternalIterator(const ReadOptions& read_options,
ColumnFamilyData* cfd,
SuperVersion* super_version,
Arena* arena,
RangeDelAggregator* range_del_agg,
SequenceNumber sequence,
bool allow_unprepared_value);
// hollow transactions shell used for recovery.
// these will then be passed to TransactionDB so that
// locks can be reacquired before writing can resume.
struct RecoveredTransaction {
std::string name_;
bool unprepared_;
struct BatchInfo {
uint64_t log_number_;
// TODO(lth): For unprepared, the memory usage here can be big for
// unprepared transactions. This is only useful for rollbacks, and we
// can in theory just keep keyset for that.
WriteBatch* batch_;
// Number of sub-batches. A new sub-batch is created if txn attempts to
// insert a duplicate key,seq to memtable. This is currently used in
// WritePreparedTxn/WriteUnpreparedTxn.
size_t batch_cnt_;
};
// This maps the seq of the first key in the batch to BatchInfo, which
// contains WriteBatch and other information relevant to the batch.
//
// For WriteUnprepared, batches_ can have size greater than 1, but for
// other write policies, it must be of size 1.
std::map<SequenceNumber, BatchInfo> batches_;
explicit RecoveredTransaction(const uint64_t log, const std::string& name,
WriteBatch* batch, SequenceNumber seq,
size_t batch_cnt, bool unprepared)
: name_(name), unprepared_(unprepared) {
batches_[seq] = {log, batch, batch_cnt};
}
~RecoveredTransaction() {
for (auto& it : batches_) {
delete it.second.batch_;
}
}
void AddBatch(SequenceNumber seq, uint64_t log_number, WriteBatch* batch,
size_t batch_cnt, bool unprepared) {
assert(batches_.count(seq) == 0);
batches_[seq] = {log_number, batch, batch_cnt};
// Prior state must be unprepared, since the prepare batch must be the
// last batch.
assert(unprepared_);
unprepared_ = unprepared;
}
};
bool allow_2pc() const { return immutable_db_options_.allow_2pc; }
std::unordered_map<std::string, RecoveredTransaction*>
recovered_transactions() {
return recovered_transactions_;
}
RecoveredTransaction* GetRecoveredTransaction(const std::string& name) {
auto it = recovered_transactions_.find(name);
if (it == recovered_transactions_.end()) {
return nullptr;
} else {
return it->second;
}
}
void InsertRecoveredTransaction(const uint64_t log, const std::string& name,
WriteBatch* batch, SequenceNumber seq,
size_t batch_cnt, bool unprepared_batch) {
// For WriteUnpreparedTxn, InsertRecoveredTransaction is called multiple
// times for every unprepared batch encountered during recovery.
//
// If the transaction is prepared, then the last call to
// InsertRecoveredTransaction will have unprepared_batch = false.
auto rtxn = recovered_transactions_.find(name);
if (rtxn == recovered_transactions_.end()) {
recovered_transactions_[name] = new RecoveredTransaction(
log, name, batch, seq, batch_cnt, unprepared_batch);
} else {
rtxn->second->AddBatch(seq, log, batch, batch_cnt, unprepared_batch);
}
logs_with_prep_tracker_.MarkLogAsContainingPrepSection(log);
}
void DeleteRecoveredTransaction(const std::string& name) {
auto it = recovered_transactions_.find(name);
assert(it != recovered_transactions_.end());
auto* trx = it->second;
recovered_transactions_.erase(it);
for (const auto& info : trx->batches_) {
logs_with_prep_tracker_.MarkLogAsHavingPrepSectionFlushed(
info.second.log_number_);
}
delete trx;
}
void DeleteAllRecoveredTransactions() {
for (auto it = recovered_transactions_.begin();
it != recovered_transactions_.end(); ++it) {
delete it->second;
}
recovered_transactions_.clear();
}
void AddToLogsToFreeQueue(log::Writer* log_writer) {
logs_to_free_queue_.push_back(log_writer);
}
void AddSuperVersionsToFreeQueue(SuperVersion* sv) {
superversions_to_free_queue_.push_back(sv);
}
void SetSnapshotChecker(SnapshotChecker* snapshot_checker);
// Fill JobContext with snapshot information needed by flush and compaction.
void GetSnapshotContext(JobContext* job_context,
std::vector<SequenceNumber>* snapshot_seqs,
SequenceNumber* earliest_write_conflict_snapshot,
SnapshotChecker** snapshot_checker);
// Not thread-safe.
void SetRecoverableStatePreReleaseCallback(PreReleaseCallback* callback);
InstrumentedMutex* mutex() const { return &mutex_; }
// Initialize a brand new DB. The DB directory is expected to be empty before
// calling it. Push new manifest file name into `new_filenames`.
Status NewDB(std::vector<std::string>* new_filenames);
// This is to be used only by internal rocksdb classes.
static Status Open(const DBOptions& db_options, const std::string& name,
const std::vector<ColumnFamilyDescriptor>& column_families,
std::vector<ColumnFamilyHandle*>* handles, DB** dbptr,
const bool seq_per_batch, const bool batch_per_txn);
static IOStatus CreateAndNewDirectory(
FileSystem* fs, const std::string& dirname,
std::unique_ptr<FSDirectory>* directory);
// find stats map from stats_history_ with smallest timestamp in
// the range of [start_time, end_time)
bool FindStatsByTime(uint64_t start_time, uint64_t end_time,
uint64_t* new_time,
std::map<std::string, uint64_t>* stats_map);
// Print information of all tombstones of all iterators to the std::string
// This is only used by ldb. The output might be capped. Tombstones
// printed out are not guaranteed to be in any order.
Status TablesRangeTombstoneSummary(ColumnFamilyHandle* column_family,
int max_entries_to_print,
std::string* out_str);
#ifndef NDEBUG
// Compact any files in the named level that overlap [*begin, *end]
Status TEST_CompactRange(int level, const Slice* begin, const Slice* end,
ColumnFamilyHandle* column_family = nullptr,
bool disallow_trivial_move = false);
Status TEST_SwitchWAL();
bool TEST_UnableToReleaseOldestLog() { return unable_to_release_oldest_log_; }
bool TEST_IsLogGettingFlushed() {
return alive_log_files_.begin()->getting_flushed;
}
Status TEST_SwitchMemtable(ColumnFamilyData* cfd = nullptr);
// Force current memtable contents to be flushed.
Status TEST_FlushMemTable(bool wait = true, bool allow_write_stall = false,
ColumnFamilyHandle* cfh = nullptr);
Status TEST_FlushMemTable(ColumnFamilyData* cfd,
const FlushOptions& flush_opts);
// Flush (multiple) ColumnFamilyData without using ColumnFamilyHandle. This
// is because in certain cases, we can flush column families, wait for the
// flush to complete, but delete the column family handle before the wait
// finishes. For example in CompactRange.
Status TEST_AtomicFlushMemTables(const autovector<ColumnFamilyData*>& cfds,
const FlushOptions& flush_opts);
// Wait for memtable compaction
Status TEST_WaitForFlushMemTable(ColumnFamilyHandle* column_family = nullptr);
// Wait for any compaction
// We add a bool parameter to wait for unscheduledCompactions_ == 0, but this
// is only for the special test of CancelledCompactions
Status TEST_WaitForCompact(bool waitUnscheduled = false);
// Get the background error status
Status TEST_GetBGError();
// Return the maximum overlapping data (in bytes) at next level for any
// file at a level >= 1.
uint64_t TEST_MaxNextLevelOverlappingBytes(
ColumnFamilyHandle* column_family = nullptr);
// Return the current manifest file no.
uint64_t TEST_Current_Manifest_FileNo();
// Returns the number that'll be assigned to the next file that's created.
uint64_t TEST_Current_Next_FileNo();
// get total level0 file size. Only for testing.
uint64_t TEST_GetLevel0TotalSize();
void TEST_GetFilesMetaData(
ColumnFamilyHandle* column_family,
std::vector<std::vector<FileMetaData>>* metadata,
std::vector<std::shared_ptr<BlobFileMetaData>>* blob_metadata = nullptr);
void TEST_LockMutex();
void TEST_UnlockMutex();
// REQUIRES: mutex locked
void* TEST_BeginWrite();
// REQUIRES: mutex locked
// pass the pointer that you got from TEST_BeginWrite()
void TEST_EndWrite(void* w);
uint64_t TEST_MaxTotalInMemoryState() const {
return max_total_in_memory_state_;
}
size_t TEST_LogsToFreeSize();
uint64_t TEST_LogfileNumber();
uint64_t TEST_total_log_size() const { return total_log_size_; }
// Returns column family name to ImmutableCFOptions map.
Status TEST_GetAllImmutableCFOptions(
std::unordered_map<std::string, const ImmutableCFOptions*>* iopts_map);
// Return the lastest MutableCFOptions of a column family
Status TEST_GetLatestMutableCFOptions(ColumnFamilyHandle* column_family,
MutableCFOptions* mutable_cf_options);
Cache* TEST_table_cache() { return table_cache_.get(); }
WriteController& TEST_write_controler() { return write_controller_; }
uint64_t TEST_FindMinLogContainingOutstandingPrep();
uint64_t TEST_FindMinPrepLogReferencedByMemTable();
size_t TEST_PreparedSectionCompletedSize();
size_t TEST_LogsWithPrepSize();
int TEST_BGCompactionsAllowed() const;
int TEST_BGFlushesAllowed() const;
size_t TEST_GetWalPreallocateBlockSize(uint64_t write_buffer_size) const;
void TEST_WaitForStatsDumpRun(std::function<void()> callback) const;
size_t TEST_EstimateInMemoryStatsHistorySize() const;
VersionSet* TEST_GetVersionSet() const { return versions_.get(); }
uint64_t TEST_GetCurrentLogNumber() const {
InstrumentedMutexLock l(mutex());
assert(!logs_.empty());
return logs_.back().number;
}
const std::unordered_set<uint64_t>& TEST_GetFilesGrabbedForPurge() const {
return files_grabbed_for_purge_;
}
#ifndef ROCKSDB_LITE
PeriodicWorkTestScheduler* TEST_GetPeriodicWorkScheduler() const;
#endif // !ROCKSDB_LITE
#endif // NDEBUG
// persist stats to column family "_persistent_stats"
void PersistStats();
// dump rocksdb.stats to LOG
void DumpStats();
// flush LOG out of application buffer
void FlushInfoLog();
// Interface to block and signal the DB in case of stalling writes by
// WriteBufferManager. Each DBImpl object contains ptr to WBMStallInterface.
// When DB needs to be blocked or signalled by WriteBufferManager,
// state_ is changed accordingly.
class WBMStallInterface : public StallInterface {
public:
enum State {
BLOCKED = 0,
RUNNING,
};
WBMStallInterface() : state_cv_(&state_mutex_) {
MutexLock lock(&state_mutex_);
state_ = State::RUNNING;
}
void SetState(State state) {
MutexLock lock(&state_mutex_);
state_ = state;
}
// Change the state_ to State::BLOCKED and wait until its state is
// changed by WriteBufferManager. When stall is cleared, Signal() is
// called to change the state and unblock the DB.
void Block() override {
MutexLock lock(&state_mutex_);
while (state_ == State::BLOCKED) {
TEST_SYNC_POINT("WBMStallInterface::BlockDB");
state_cv_.Wait();
}
}
// Called from WriteBufferManager. This function changes the state_
// to State::RUNNING indicating the stall is cleared and DB can proceed.
void Signal() override {
MutexLock lock(&state_mutex_);
state_ = State::RUNNING;
state_cv_.Signal();
}
private:
// Conditional variable and mutex to block and
// signal the DB during stalling process.
port::Mutex state_mutex_;
port::CondVar state_cv_;
// state represting whether DB is running or blocked because of stall by
// WriteBufferManager.
State state_;
};
static std::string GenerateDbSessionId(Env* env);
protected:
const std::string dbname_;
std::string db_id_;
// db_session_id_ is an identifier that gets reset
// every time the DB is opened
std::string db_session_id_;
std::unique_ptr<VersionSet> versions_;
// Flag to check whether we allocated and own the info log file
bool own_info_log_;
const DBOptions initial_db_options_;
Env* const env_;
std::shared_ptr<IOTracer> io_tracer_;
const ImmutableDBOptions immutable_db_options_;
FileSystemPtr fs_;
MutableDBOptions mutable_db_options_;
Statistics* stats_;
std::unordered_map<std::string, RecoveredTransaction*>
recovered_transactions_;
std::unique_ptr<Tracer> tracer_;
InstrumentedMutex trace_mutex_;
BlockCacheTracer block_cache_tracer_;
// State below is protected by mutex_
// With two_write_queues enabled, some of the variables that accessed during
// WriteToWAL need different synchronization: log_empty_, alive_log_files_,
// logs_, logfile_number_. Refer to the definition of each variable below for
// more description.
mutable InstrumentedMutex mutex_;
ColumnFamilyHandleImpl* default_cf_handle_;
InternalStats* default_cf_internal_stats_;
// table_cache_ provides its own synchronization
std::shared_ptr<Cache> table_cache_;
ErrorHandler error_handler_;
// Unified interface for logging events
EventLogger event_logger_;
// only used for dynamically adjusting max_total_wal_size. it is a sum of
// [write_buffer_size * max_write_buffer_number] over all column families
uint64_t max_total_in_memory_state_;
// If true, we have only one (default) column family. We use this to optimize
// some code-paths
bool single_column_family_mode_;
// The options to access storage files
const FileOptions file_options_;
// Additonal options for compaction and flush
FileOptions file_options_for_compaction_;
std::unique_ptr<ColumnFamilyMemTablesImpl> column_family_memtables_;
// Increase the sequence number after writing each batch, whether memtable is
// disabled for that or not. Otherwise the sequence number is increased after
// writing each key into memtable. This implies that when disable_memtable is
// set, the seq is not increased at all.
//
// Default: false
const bool seq_per_batch_;
// This determines during recovery whether we expect one writebatch per
// recovered transaction, or potentially multiple writebatches per
// transaction. For WriteUnprepared, this is set to false, since multiple
// batches can exist per transaction.
//
// Default: true
const bool batch_per_txn_;
// Each flush or compaction gets its own job id. this counter makes sure
// they're unique
std::atomic<int> next_job_id_;
std::atomic<bool> shutting_down_;
// Except in DB::Open(), WriteOptionsFile can only be called when:
// Persist options to options file.
// If need_mutex_lock = false, the method will lock DB mutex.
// If need_enter_write_thread = false, the method will enter write thread.
Status WriteOptionsFile(bool need_mutex_lock, bool need_enter_write_thread);
Status CompactRangeInternal(const CompactRangeOptions& options,
ColumnFamilyHandle* column_family,
const Slice* begin, const Slice* end);
// The following two functions can only be called when:
// 1. WriteThread::Writer::EnterUnbatched() is used.
// 2. db_mutex is NOT held
Status RenameTempFileToOptionsFile(const std::string& file_name);
Status DeleteObsoleteOptionsFiles();
void NotifyOnFlushBegin(ColumnFamilyData* cfd, FileMetaData* file_meta,
const MutableCFOptions& mutable_cf_options,
int job_id);
void NotifyOnFlushCompleted(
ColumnFamilyData* cfd, const MutableCFOptions& mutable_cf_options,
std::list<std::unique_ptr<FlushJobInfo>>* flush_jobs_info);
void NotifyOnCompactionBegin(ColumnFamilyData* cfd, Compaction* c,
const Status& st,
const CompactionJobStats& job_stats, int job_id);
void NotifyOnCompactionCompleted(ColumnFamilyData* cfd, Compaction* c,
const Status& st,
const CompactionJobStats& job_stats,
int job_id);
void NotifyOnMemTableSealed(ColumnFamilyData* cfd,
const MemTableInfo& mem_table_info);
#ifndef ROCKSDB_LITE
void NotifyOnExternalFileIngested(
ColumnFamilyData* cfd, const ExternalSstFileIngestionJob& ingestion_job);
#endif // !ROCKSDB_LITE
void NewThreadStatusCfInfo(ColumnFamilyData* cfd) const;
void EraseThreadStatusCfInfo(ColumnFamilyData* cfd) const;
void EraseThreadStatusDbInfo() const;
// If disable_memtable is set the application logic must guarantee that the
// batch will still be skipped from memtable during the recovery. An excption
// to this is seq_per_batch_ mode, in which since each batch already takes one
// seq, it is ok for the batch to write to memtable during recovery as long as
// it only takes one sequence number: i.e., no duplicate keys.
// In WriteCommitted it is guarnateed since disable_memtable is used for
// prepare batch which will be written to memtable later during the commit,
// and in WritePrepared it is guaranteed since it will be used only for WAL
// markers which will never be written to memtable. If the commit marker is
// accompanied with CommitTimeWriteBatch that is not written to memtable as
// long as it has no duplicate keys, it does not violate the one-seq-per-batch
// policy.
// batch_cnt is expected to be non-zero in seq_per_batch mode and
// indicates the number of sub-patches. A sub-patch is a subset of the write
// batch that does not have duplicate keys.
Status WriteImpl(const WriteOptions& options, WriteBatch* updates,
WriteCallback* callback = nullptr,
uint64_t* log_used = nullptr, uint64_t log_ref = 0,
bool disable_memtable = false, uint64_t* seq_used = nullptr,
size_t batch_cnt = 0,
PreReleaseCallback* pre_release_callback = nullptr);
Status PipelinedWriteImpl(const WriteOptions& options, WriteBatch* updates,
WriteCallback* callback = nullptr,
uint64_t* log_used = nullptr, uint64_t log_ref = 0,
bool disable_memtable = false,
uint64_t* seq_used = nullptr);
// Write only to memtables without joining any write queue
Status UnorderedWriteMemtable(const WriteOptions& write_options,
WriteBatch* my_batch, WriteCallback* callback,
uint64_t log_ref, SequenceNumber seq,
const size_t sub_batch_cnt);
// Whether the batch requires to be assigned with an order
enum AssignOrder : bool { kDontAssignOrder, kDoAssignOrder };
// Whether it requires publishing last sequence or not
enum PublishLastSeq : bool { kDontPublishLastSeq, kDoPublishLastSeq };
// Join the write_thread to write the batch only to the WAL. It is the
// responsibility of the caller to also write the write batch to the memtable
// if it required.
//
// sub_batch_cnt is expected to be non-zero when assign_order = kDoAssignOrder
// indicating the number of sub-batches in my_batch. A sub-patch is a subset
// of the write batch that does not have duplicate keys. When seq_per_batch is
// not set, each key is a separate sub_batch. Otherwise each duplicate key
// marks start of a new sub-batch.
Status WriteImplWALOnly(
WriteThread* write_thread, const WriteOptions& options,
WriteBatch* updates, WriteCallback* callback, uint64_t* log_used,
const uint64_t log_ref, uint64_t* seq_used, const size_t sub_batch_cnt,
PreReleaseCallback* pre_release_callback, const AssignOrder assign_order,
const PublishLastSeq publish_last_seq, const bool disable_memtable);
// write cached_recoverable_state_ to memtable if it is not empty
// The writer must be the leader in write_thread_ and holding mutex_
Status WriteRecoverableState();
// Actual implementation of Close()
Status CloseImpl();
// Recover the descriptor from persistent storage. May do a significant
// amount of work to recover recently logged updates. Any changes to
// be made to the descriptor are added to *edit.
// recovered_seq is set to less than kMaxSequenceNumber if the log's tail is
// skipped.
virtual Status Recover(
const std::vector<ColumnFamilyDescriptor>& column_families,
bool read_only = false, bool error_if_wal_file_exists = false,
bool error_if_data_exists_in_wals = false,
uint64_t* recovered_seq = nullptr);
virtual bool OwnTablesAndLogs() const { return true; }
// Set DB identity file, and write DB ID to manifest if necessary.
Status SetDBId(bool read_only);
// REQUIRES: db mutex held when calling this function, but the db mutex can
// be released and re-acquired. Db mutex will be held when the function
// returns.
// After recovery, there may be SST files in db/cf paths that are
// not referenced in the MANIFEST (e.g.
// 1. It's best effort recovery;
// 2. The VersionEdits referencing the SST files are appended to
// MANIFEST, DB crashes when syncing the MANIFEST, the VersionEdits are
// still not synced to MANIFEST during recovery.)
// We delete these SST files. In the
// meantime, we find out the largest file number present in the paths, and
// bump up the version set's next_file_number_ to be 1 + largest_file_number.
Status DeleteUnreferencedSstFiles();
// SetDbSessionId() should be called in the constuctor DBImpl()
// to ensure that db_session_id_ gets updated every time the DB is opened
void SetDbSessionId();
private:
friend class DB;
friend class ErrorHandler;
friend class InternalStats;
friend class PessimisticTransaction;
friend class TransactionBaseImpl;
friend class WriteCommittedTxn;
friend class WritePreparedTxn;
friend class WritePreparedTxnDB;
friend class WriteBatchWithIndex;
friend class WriteUnpreparedTxnDB;
friend class WriteUnpreparedTxn;
#ifndef ROCKSDB_LITE
friend class ForwardIterator;
#endif
friend struct SuperVersion;
friend class CompactedDBImpl;
friend class DBTest_ConcurrentFlushWAL_Test;
friend class DBTest_MixedSlowdownOptionsStop_Test;
friend class DBCompactionTest_CompactBottomLevelFilesWithDeletions_Test;
friend class DBCompactionTest_CompactionDuringShutdown_Test;
friend class StatsHistoryTest_PersistentStatsCreateColumnFamilies_Test;
#ifndef NDEBUG
friend class DBTest2_ReadCallbackTest_Test;
friend class WriteCallbackPTest_WriteWithCallbackTest_Test;
friend class XFTransactionWriteHandler;
friend class DBBlobIndexTest;
friend class WriteUnpreparedTransactionTest_RecoveryTest_Test;
#endif
struct CompactionState;
struct PrepickedCompaction;
struct PurgeFileInfo;
struct WriteContext {
SuperVersionContext superversion_context;
autovector<MemTable*> memtables_to_free_;
explicit WriteContext(bool create_superversion = false)
: superversion_context(create_superversion) {}
~WriteContext() {
superversion_context.Clean();
for (auto& m : memtables_to_free_) {
delete m;
}
}
};
struct LogFileNumberSize {
explicit LogFileNumberSize(uint64_t _number) : number(_number) {}
LogFileNumberSize() {}
void AddSize(uint64_t new_size) { size += new_size; }
uint64_t number;
uint64_t size = 0;
bool getting_flushed = false;
};
struct LogWriterNumber {
// pass ownership of _writer
LogWriterNumber(uint64_t _number, log::Writer* _writer)
: number(_number), writer(_writer) {}
log::Writer* ReleaseWriter() {
auto* w = writer;
writer = nullptr;
return w;
}
Status ClearWriter() {
Status s = writer->WriteBuffer();
delete writer;
writer = nullptr;
return s;
}
uint64_t number;
// Visual Studio doesn't support deque's member to be noncopyable because
// of a std::unique_ptr as a member.
log::Writer* writer; // own
// true for some prefix of logs_
bool getting_synced = false;
};
// PurgeFileInfo is a structure to hold information of files to be deleted in
// purge_files_
struct PurgeFileInfo {
std::string fname;
std::string dir_to_sync;
FileType type;
uint64_t number;
int job_id;
PurgeFileInfo(std::string fn, std::string d, FileType t, uint64_t num,
int jid)
: fname(fn), dir_to_sync(d), type(t), number(num), job_id(jid) {}
};
// Argument required by background flush thread.
struct BGFlushArg {
BGFlushArg()
: cfd_(nullptr), max_memtable_id_(0), superversion_context_(nullptr) {}
BGFlushArg(ColumnFamilyData* cfd, uint64_t max_memtable_id,
SuperVersionContext* superversion_context)
: cfd_(cfd),
max_memtable_id_(max_memtable_id),
superversion_context_(superversion_context) {}
// Column family to flush.
ColumnFamilyData* cfd_;
// Maximum ID of memtable to flush. In this column family, memtables with
// IDs smaller than this value must be flushed before this flush completes.
uint64_t max_memtable_id_;
// Pointer to a SuperVersionContext object. After flush completes, RocksDB
// installs a new superversion for the column family. This operation
// requires a SuperVersionContext object (currently embedded in JobContext).
SuperVersionContext* superversion_context_;
};
// Argument passed to flush thread.
struct FlushThreadArg {
DBImpl* db_;
Env::Priority thread_pri_;
};
// Information for a manual compaction
struct ManualCompactionState {
ColumnFamilyData* cfd;
int input_level;
int output_level;
uint32_t output_path_id;
Status status;
bool done;
bool in_progress; // compaction request being processed?
bool incomplete; // only part of requested range compacted
bool exclusive; // current behavior of only one manual
bool disallow_trivial_move; // Force actual compaction to run
const InternalKey* begin; // nullptr means beginning of key range
const InternalKey* end; // nullptr means end of key range
InternalKey* manual_end; // how far we are compacting
InternalKey tmp_storage; // Used to keep track of compaction progress
InternalKey tmp_storage1; // Used to keep track of compaction progress
std::atomic<bool>* canceled; // Compaction canceled by the user?
};
struct PrepickedCompaction {
// background compaction takes ownership of `compaction`.
Compaction* compaction;
// caller retains ownership of `manual_compaction_state` as it is reused
// across background compactions.
ManualCompactionState* manual_compaction_state; // nullptr if non-manual
// task limiter token is requested during compaction picking.
std::unique_ptr<TaskLimiterToken> task_token;
};
struct CompactionArg {
// caller retains ownership of `db`.
DBImpl* db;
// background compaction takes ownership of `prepicked_compaction`.
PrepickedCompaction* prepicked_compaction;
Env::Priority compaction_pri_;
};
// Initialize the built-in column family for persistent stats. Depending on
// whether on-disk persistent stats have been enabled before, it may either
// create a new column family and column family handle or just a column family
// handle.
// Required: DB mutex held
Status InitPersistStatsColumnFamily();
// Persistent Stats column family has two format version key which are used
// for compatibility check. Write format version if it's created for the
// first time, read format version and check compatibility if recovering
// from disk. This function requires DB mutex held at entrance but may
// release and re-acquire DB mutex in the process.
// Required: DB mutex held
Status PersistentStatsProcessFormatVersion();
Status ResumeImpl(DBRecoverContext context);
void MaybeIgnoreError(Status* s) const;
const Status CreateArchivalDirectory();
Status CreateColumnFamilyImpl(const ColumnFamilyOptions& cf_options,
const std::string& cf_name,
ColumnFamilyHandle** handle);
Status DropColumnFamilyImpl(ColumnFamilyHandle* column_family);
// Delete any unneeded files and stale in-memory entries.
void DeleteObsoleteFiles();
// Delete obsolete files and log status and information of file deletion
void DeleteObsoleteFileImpl(int job_id, const std::string& fname,
const std::string& path_to_sync, FileType type,
uint64_t number);
// Background process needs to call
// auto x = CaptureCurrentFileNumberInPendingOutputs()
// auto file_num = versions_->NewFileNumber();
// <do something>
// ReleaseFileNumberFromPendingOutputs(x)
// This will protect any file with number `file_num` or greater from being
// deleted while <do something> is running.
// -----------
// This function will capture current file number and append it to
// pending_outputs_. This will prevent any background process to delete any
// file created after this point.
std::list<uint64_t>::iterator CaptureCurrentFileNumberInPendingOutputs();
// This function should be called with the result of
// CaptureCurrentFileNumberInPendingOutputs(). It then marks that any file
// created between the calls CaptureCurrentFileNumberInPendingOutputs() and
// ReleaseFileNumberFromPendingOutputs() can now be deleted (if it's not live
// and blocked by any other pending_outputs_ calls)
void ReleaseFileNumberFromPendingOutputs(
std::unique_ptr<std::list<uint64_t>::iterator>& v);
IOStatus SyncClosedLogs(JobContext* job_context);
// Flush the in-memory write buffer to storage. Switches to a new
// log-file/memtable and writes a new descriptor iff successful. Then
// installs a new super version for the column family.
Status FlushMemTableToOutputFile(
ColumnFamilyData* cfd, const MutableCFOptions& mutable_cf_options,
bool* madeProgress, JobContext* job_context,
SuperVersionContext* superversion_context,
std::vector<SequenceNumber>& snapshot_seqs,
SequenceNumber earliest_write_conflict_snapshot,
SnapshotChecker* snapshot_checker, LogBuffer* log_buffer,
Env::Priority thread_pri);
// Flush the memtables of (multiple) column families to multiple files on
// persistent storage.
Status FlushMemTablesToOutputFiles(
const autovector<BGFlushArg>& bg_flush_args, bool* made_progress,
JobContext* job_context, LogBuffer* log_buffer, Env::Priority thread_pri);
Status AtomicFlushMemTablesToOutputFiles(
const autovector<BGFlushArg>& bg_flush_args, bool* made_progress,
JobContext* job_context, LogBuffer* log_buffer, Env::Priority thread_pri);
// REQUIRES: log_numbers are sorted in ascending order
// corrupted_log_found is set to true if we recover from a corrupted log file.
Status RecoverLogFiles(const std::vector<uint64_t>& log_numbers,
SequenceNumber* next_sequence, bool read_only,
bool* corrupted_log_found);
// The following two methods are used to flush a memtable to
// storage. The first one is used at database RecoveryTime (when the
// database is opened) and is heavyweight because it holds the mutex
// for the entire period. The second method WriteLevel0Table supports
// concurrent flush memtables to storage.
Status WriteLevel0TableForRecovery(int job_id, ColumnFamilyData* cfd,
MemTable* mem, VersionEdit* edit);
// Get the size of a log file and, if truncate is true, truncate the
// log file to its actual size, thereby freeing preallocated space.
// Return success even if truncate fails
Status GetLogSizeAndMaybeTruncate(uint64_t wal_number, bool truncate,
LogFileNumberSize* log);
// Restore alive_log_files_ and total_log_size_ after recovery.
// It needs to run only when there's no flush during recovery
// (e.g. avoid_flush_during_recovery=true). May also trigger flush
// in case total_log_size > max_total_wal_size.
Status RestoreAliveLogFiles(const std::vector<uint64_t>& log_numbers);
// num_bytes: for slowdown case, delay time is calculated based on
// `num_bytes` going through.
Status DelayWrite(uint64_t num_bytes, const WriteOptions& write_options);
// Begin stalling of writes when memory usage increases beyond a certain
// threshold.
void WriteBufferManagerStallWrites();
Status ThrottleLowPriWritesIfNeeded(const WriteOptions& write_options,
WriteBatch* my_batch);
// REQUIRES: mutex locked and in write thread.
Status ScheduleFlushes(WriteContext* context);
void MaybeFlushStatsCF(autovector<ColumnFamilyData*>* cfds);
Status TrimMemtableHistory(WriteContext* context);
Status SwitchMemtable(ColumnFamilyData* cfd, WriteContext* context);
void SelectColumnFamiliesForAtomicFlush(autovector<ColumnFamilyData*>* cfds);
// Force current memtable contents to be flushed.
Status FlushMemTable(ColumnFamilyData* cfd, const FlushOptions& options,
FlushReason flush_reason, bool writes_stopped = false);
Status AtomicFlushMemTables(
const autovector<ColumnFamilyData*>& column_family_datas,
const FlushOptions& options, FlushReason flush_reason,
bool writes_stopped = false);
// Wait until flushing this column family won't stall writes
Status WaitUntilFlushWouldNotStallWrites(ColumnFamilyData* cfd,
bool* flush_needed);
// Wait for memtable flushed.
// If flush_memtable_id is non-null, wait until the memtable with the ID
// gets flush. Otherwise, wait until the column family don't have any
// memtable pending flush.
// resuming_from_bg_err indicates whether the caller is attempting to resume
// from background error.
Status WaitForFlushMemTable(ColumnFamilyData* cfd,
const uint64_t* flush_memtable_id = nullptr,
bool resuming_from_bg_err = false) {
return WaitForFlushMemTables({cfd}, {flush_memtable_id},
resuming_from_bg_err);
}
// Wait for memtables to be flushed for multiple column families.
Status WaitForFlushMemTables(
const autovector<ColumnFamilyData*>& cfds,
const autovector<const uint64_t*>& flush_memtable_ids,
bool resuming_from_bg_err);
inline void WaitForPendingWrites() {
mutex_.AssertHeld();
TEST_SYNC_POINT("DBImpl::WaitForPendingWrites:BeforeBlock");
// In case of pipelined write is enabled, wait for all pending memtable
// writers.
if (immutable_db_options_.enable_pipelined_write) {
// Memtable writers may call DB::Get in case max_successive_merges > 0,
// which may lock mutex. Unlocking mutex here to avoid deadlock.
mutex_.Unlock();
write_thread_.WaitForMemTableWriters();
mutex_.Lock();
}
if (!immutable_db_options_.unordered_write) {
// Then the writes are finished before the next write group starts
return;
}
// Wait for the ones who already wrote to the WAL to finish their
// memtable write.
if (pending_memtable_writes_.load() != 0) {
std::unique_lock<std::mutex> guard(switch_mutex_);
switch_cv_.wait(guard,
[&] { return pending_memtable_writes_.load() == 0; });
}
}
// REQUIRES: mutex locked and in write thread.
void AssignAtomicFlushSeq(const autovector<ColumnFamilyData*>& cfds);
// REQUIRES: mutex locked and in write thread.
Status SwitchWAL(WriteContext* write_context);
// REQUIRES: mutex locked and in write thread.
Status HandleWriteBufferManagerFlush(WriteContext* write_context);
// REQUIRES: mutex locked
Status PreprocessWrite(const WriteOptions& write_options, bool* need_log_sync,
WriteContext* write_context);
WriteBatch* MergeBatch(const WriteThread::WriteGroup& write_group,
WriteBatch* tmp_batch, size_t* write_with_wal,
WriteBatch** to_be_cached_state);
IOStatus WriteToWAL(const WriteBatch& merged_batch, log::Writer* log_writer,
uint64_t* log_used, uint64_t* log_size);
IOStatus WriteToWAL(const WriteThread::WriteGroup& write_group,
log::Writer* log_writer, uint64_t* log_used,
bool need_log_sync, bool need_log_dir_sync,
SequenceNumber sequence);
IOStatus ConcurrentWriteToWAL(const WriteThread::WriteGroup& write_group,
uint64_t* log_used,
SequenceNumber* last_sequence, size_t seq_inc);
// Used by WriteImpl to update bg_error_ if paranoid check is enabled.
// Caller must hold mutex_.
void WriteStatusCheckOnLocked(const Status& status);
// Used by WriteImpl to update bg_error_ if paranoid check is enabled.
void WriteStatusCheck(const Status& status);
// Used by WriteImpl to update bg_error_ when IO error happens, e.g., write
// WAL, sync WAL fails, if paranoid check is enabled.
void IOStatusCheck(const IOStatus& status);
// Used by WriteImpl to update bg_error_ in case of memtable insert error.
void MemTableInsertStatusCheck(const Status& memtable_insert_status);
#ifndef ROCKSDB_LITE
Status CompactFilesImpl(const CompactionOptions& compact_options,
ColumnFamilyData* cfd, Version* version,
const std::vector<std::string>& input_file_names,
std::vector<std::string>* const output_file_names,
const int output_level, int output_path_id,
JobContext* job_context, LogBuffer* log_buffer,
CompactionJobInfo* compaction_job_info);
// Wait for current IngestExternalFile() calls to finish.
// REQUIRES: mutex_ held
void WaitForIngestFile();
#else
// IngestExternalFile is not supported in ROCKSDB_LITE so this function
// will be no-op
void WaitForIngestFile() {}
#endif // ROCKSDB_LITE
ColumnFamilyData* GetColumnFamilyDataByName(const std::string& cf_name);
void MaybeScheduleFlushOrCompaction();
// A flush request specifies the column families to flush as well as the
// largest memtable id to persist for each column family. Once all the
// memtables whose IDs are smaller than or equal to this per-column-family
// specified value, this flush request is considered to have completed its
// work of flushing this column family. After completing the work for all
// column families in this request, this flush is considered complete.
typedef std::vector<std::pair<ColumnFamilyData*, uint64_t>> FlushRequest;
void GenerateFlushRequest(const autovector<ColumnFamilyData*>& cfds,
FlushRequest* req);
void SchedulePendingFlush(const FlushRequest& req, FlushReason flush_reason);
void SchedulePendingCompaction(ColumnFamilyData* cfd);
void SchedulePendingPurge(std::string fname, std::string dir_to_sync,
FileType type, uint64_t number, int job_id);
static void BGWorkCompaction(void* arg);
// Runs a pre-chosen universal compaction involving bottom level in a
// separate, bottom-pri thread pool.
static void BGWorkBottomCompaction(void* arg);
static void BGWorkFlush(void* arg);
static void BGWorkPurge(void* arg);
static void UnscheduleCompactionCallback(void* arg);
static void UnscheduleFlushCallback(void* arg);
void BackgroundCallCompaction(PrepickedCompaction* prepicked_compaction,
Env::Priority thread_pri);
void BackgroundCallFlush(Env::Priority thread_pri);
void BackgroundCallPurge();
Status BackgroundCompaction(bool* madeProgress, JobContext* job_context,
LogBuffer* log_buffer,
PrepickedCompaction* prepicked_compaction,
Env::Priority thread_pri);
Status BackgroundFlush(bool* madeProgress, JobContext* job_context,
LogBuffer* log_buffer, FlushReason* reason,
Env::Priority thread_pri);
bool EnoughRoomForCompaction(ColumnFamilyData* cfd,
const std::vector<CompactionInputFiles>& inputs,
bool* sfm_bookkeeping, LogBuffer* log_buffer);
// Request compaction tasks token from compaction thread limiter.
// It always succeeds if force = true or limiter is disable.
bool RequestCompactionToken(ColumnFamilyData* cfd, bool force,
std::unique_ptr<TaskLimiterToken>* token,
LogBuffer* log_buffer);
// Schedule background tasks
void StartPeriodicWorkScheduler();
void PrintStatistics();
size_t EstimateInMemoryStatsHistorySize() const;
// Return the minimum empty level that could hold the total data in the
// input level. Return the input level, if such level could not be found.
int FindMinimumEmptyLevelFitting(ColumnFamilyData* cfd,
const MutableCFOptions& mutable_cf_options,
int level);
// Move the files in the input level to the target level.
// If target_level < 0, automatically calculate the minimum level that could
// hold the data set.
Status ReFitLevel(ColumnFamilyData* cfd, int level, int target_level = -1);
// helper functions for adding and removing from flush & compaction queues
void AddToCompactionQueue(ColumnFamilyData* cfd);
ColumnFamilyData* PopFirstFromCompactionQueue();
FlushRequest PopFirstFromFlushQueue();
// Pick the first unthrottled compaction with task token from queue.
ColumnFamilyData* PickCompactionFromQueue(
std::unique_ptr<TaskLimiterToken>* token, LogBuffer* log_buffer);
// helper function to call after some of the logs_ were synced
Status MarkLogsSynced(uint64_t up_to, bool synced_dir);
// WALs with log number up to up_to are not synced successfully.
void MarkLogsNotSynced(uint64_t up_to);
SnapshotImpl* GetSnapshotImpl(bool is_write_conflict_boundary,
bool lock = true);
uint64_t GetMaxTotalWalSize() const;
FSDirectory* GetDataDir(ColumnFamilyData* cfd, size_t path_id) const;
Status CloseHelper();
void WaitForBackgroundWork();
// Background threads call this function, which is just a wrapper around
// the InstallSuperVersion() function. Background threads carry
// sv_context which can have new_superversion already
// allocated.
// All ColumnFamily state changes go through this function. Here we analyze
// the new state and we schedule background work if we detect that the new
// state needs flush or compaction.
void InstallSuperVersionAndScheduleWork(
ColumnFamilyData* cfd, SuperVersionContext* sv_context,
const MutableCFOptions& mutable_cf_options);
bool GetIntPropertyInternal(ColumnFamilyData* cfd,
const DBPropertyInfo& property_info,
bool is_locked, uint64_t* value);
bool GetPropertyHandleOptionsStatistics(std::string* value);
bool HasPendingManualCompaction();
bool HasExclusiveManualCompaction();
void AddManualCompaction(ManualCompactionState* m);
void RemoveManualCompaction(ManualCompactionState* m);
bool ShouldntRunManualCompaction(ManualCompactionState* m);
bool HaveManualCompaction(ColumnFamilyData* cfd);
bool MCOverlap(ManualCompactionState* m, ManualCompactionState* m1);
#ifndef ROCKSDB_LITE
void BuildCompactionJobInfo(const ColumnFamilyData* cfd, Compaction* c,
const Status& st,
const CompactionJobStats& compaction_job_stats,
const int job_id, const Version* current,
CompactionJobInfo* compaction_job_info) const;
// Reserve the next 'num' file numbers for to-be-ingested external SST files,
// and return the current file_number in 'next_file_number'.
// Write a version edit to the MANIFEST.
Status ReserveFileNumbersBeforeIngestion(
ColumnFamilyData* cfd, uint64_t num,
std::unique_ptr<std::list<uint64_t>::iterator>& pending_output_elem,
uint64_t* next_file_number);
#endif //! ROCKSDB_LITE
bool ShouldPurge(uint64_t file_number) const;
void MarkAsGrabbedForPurge(uint64_t file_number);
size_t GetWalPreallocateBlockSize(uint64_t write_buffer_size) const;
Env::WriteLifeTimeHint CalculateWALWriteHint() { return Env::WLTH_SHORT; }
IOStatus CreateWAL(uint64_t log_file_num, uint64_t recycle_log_number,
size_t preallocate_block_size, log::Writer** new_log);
// Validate self-consistency of DB options
static Status ValidateOptions(const DBOptions& db_options);
// Validate self-consistency of DB options and its consistency with cf options
static Status ValidateOptions(
const DBOptions& db_options,
const std::vector<ColumnFamilyDescriptor>& column_families);
// Utility function to do some debug validation and sort the given vector
// of MultiGet keys
void PrepareMultiGetKeys(
const size_t num_keys, bool sorted,
autovector<KeyContext*, MultiGetContext::MAX_BATCH_SIZE>* key_ptrs);
// A structure to hold the information required to process MultiGet of keys
// belonging to one column family. For a multi column family MultiGet, there
// will be a container of these objects.
struct MultiGetColumnFamilyData {
ColumnFamilyHandle* cf;
ColumnFamilyData* cfd;
// For the batched MultiGet which relies on sorted keys, start specifies
// the index of first key belonging to this column family in the sorted
// list.
size_t start;
// For the batched MultiGet case, num_keys specifies the number of keys
// belonging to this column family in the sorted list
size_t num_keys;
// SuperVersion for the column family obtained in a manner that ensures a
// consistent view across all column families in the DB
SuperVersion* super_version;
MultiGetColumnFamilyData(ColumnFamilyHandle* column_family,
SuperVersion* sv)
: cf(column_family),
cfd(static_cast<ColumnFamilyHandleImpl*>(cf)->cfd()),
start(0),
num_keys(0),
super_version(sv) {}
MultiGetColumnFamilyData(ColumnFamilyHandle* column_family, size_t first,
size_t count, SuperVersion* sv)
: cf(column_family),
cfd(static_cast<ColumnFamilyHandleImpl*>(cf)->cfd()),
start(first),
num_keys(count),
super_version(sv) {}
MultiGetColumnFamilyData() = default;
};
// A common function to obtain a consistent snapshot, which can be implicit
// if the user doesn't specify a snapshot in read_options, across
// multiple column families for MultiGet. It will attempt to get an implicit
// snapshot without acquiring the db_mutes, but will give up after a few
// tries and acquire the mutex if a memtable flush happens. The template
// allows both the batched and non-batched MultiGet to call this with
// either an std::unordered_map or autovector of column families.
//
// If callback is non-null, the callback is refreshed with the snapshot
// sequence number
//
// A return value of true indicates that the SuperVersions were obtained
// from the ColumnFamilyData, whereas false indicates they are thread
// local
template <class T>
bool MultiCFSnapshot(
const ReadOptions& read_options, ReadCallback* callback,
std::function<MultiGetColumnFamilyData*(typename T::iterator&)>&
iter_deref_func,
T* cf_list, SequenceNumber* snapshot);
// The actual implementation of the batching MultiGet. The caller is expected
// to have acquired the SuperVersion and pass in a snapshot sequence number
// in order to construct the LookupKeys. The start_key and num_keys specify
// the range of keys in the sorted_keys vector for a single column family.
Status MultiGetImpl(
const ReadOptions& read_options, size_t start_key, size_t num_keys,
autovector<KeyContext*, MultiGetContext::MAX_BATCH_SIZE>* sorted_keys,
SuperVersion* sv, SequenceNumber snap_seqnum, ReadCallback* callback);
Status DisableFileDeletionsWithLock();
Status IncreaseFullHistoryTsLow(ColumnFamilyData* cfd, std::string ts_low);
// Lock over the persistent DB state. Non-nullptr iff successfully acquired.
FileLock* db_lock_;
// In addition to mutex_, log_write_mutex_ protected writes to stats_history_
InstrumentedMutex stats_history_mutex_;
// In addition to mutex_, log_write_mutex_ protected writes to logs_ and
// logfile_number_. With two_write_queues it also protects alive_log_files_,
// and log_empty_. Refer to the definition of each variable below for more
// details.
// Note: to avoid dealock, if needed to acquire both log_write_mutex_ and
// mutex_, the order should be first mutex_ and then log_write_mutex_.
InstrumentedMutex log_write_mutex_;
// If zero, manual compactions are allowed to proceed. If non-zero, manual
// compactions may still be running, but will quickly fail with
// `Status::Incomplete`. The value indicates how many threads have paused
// manual compactions. It is accessed in read mode outside the DB mutex in
// compaction code paths.
std::atomic<int> manual_compaction_paused_;
// This condition variable is signaled on these conditions:
// * whenever bg_compaction_scheduled_ goes down to 0
// * if AnyManualCompaction, whenever a compaction finishes, even if it hasn't
// made any progress
// * whenever a compaction made any progress
// * whenever bg_flush_scheduled_ or bg_purge_scheduled_ value decreases
// (i.e. whenever a flush is done, even if it didn't make any progress)
// * whenever there is an error in background purge, flush or compaction
// * whenever num_running_ingest_file_ goes to 0.
// * whenever pending_purge_obsolete_files_ goes to 0.
// * whenever disable_delete_obsolete_files_ goes to 0.
// * whenever SetOptions successfully updates options.
// * whenever a column family is dropped.
InstrumentedCondVar bg_cv_;
// Writes are protected by locking both mutex_ and log_write_mutex_, and reads
// must be under either mutex_ or log_write_mutex_. Since after ::Open,
// logfile_number_ is currently updated only in write_thread_, it can be read
// from the same write_thread_ without any locks.
uint64_t logfile_number_;
std::deque<uint64_t>
log_recycle_files_; // a list of log files that we can recycle
bool log_dir_synced_;
// Without two_write_queues, read and writes to log_empty_ are protected by
// mutex_. Since it is currently updated/read only in write_thread_, it can be
// accessed from the same write_thread_ without any locks. With
// two_write_queues writes, where it can be updated in different threads,
// read and writes are protected by log_write_mutex_ instead. This is to avoid
// expesnive mutex_ lock during WAL write, which update log_empty_.
bool log_empty_;
ColumnFamilyHandleImpl* persist_stats_cf_handle_;
bool persistent_stats_cfd_exists_ = true;
// Without two_write_queues, read and writes to alive_log_files_ are
// protected by mutex_. However since back() is never popped, and push_back()
// is done only from write_thread_, the same thread can access the item
// reffered by back() without mutex_. With two_write_queues_, writes
// are protected by locking both mutex_ and log_write_mutex_, and reads must
// be under either mutex_ or log_write_mutex_.
std::deque<LogFileNumberSize> alive_log_files_;
// Log files that aren't fully synced, and the current log file.
// Synchronization:
// - push_back() is done from write_thread_ with locked mutex_ and
// log_write_mutex_
// - pop_front() is done from any thread with locked mutex_ and
// log_write_mutex_
// - reads are done with either locked mutex_ or log_write_mutex_
// - back() and items with getting_synced=true are not popped,
// - The same thread that sets getting_synced=true will reset it.
// - it follows that the object referred by back() can be safely read from
// the write_thread_ without using mutex
// - it follows that the items with getting_synced=true can be safely read
// from the same thread that has set getting_synced=true
std::deque<LogWriterNumber> logs_;
// Signaled when getting_synced becomes false for some of the logs_.
InstrumentedCondVar log_sync_cv_;
// This is the app-level state that is written to the WAL but will be used
// only during recovery. Using this feature enables not writing the state to
// memtable on normal writes and hence improving the throughput. Each new
// write of the state will replace the previous state entirely even if the
// keys in the two consecuitive states do not overlap.
// It is protected by log_write_mutex_ when two_write_queues_ is enabled.
// Otherwise only the heaad of write_thread_ can access it.
WriteBatch cached_recoverable_state_;
std::atomic<bool> cached_recoverable_state_empty_ = {true};
std::atomic<uint64_t> total_log_size_;
// If this is non-empty, we need to delete these log files in background
// threads. Protected by db mutex.
autovector<log::Writer*> logs_to_free_;
bool is_snapshot_supported_;
std::map<uint64_t, std::map<std::string, uint64_t>> stats_history_;
std::map<std::string, uint64_t> stats_slice_;
bool stats_slice_initialized_ = false;
Directories directories_;
WriteBufferManager* write_buffer_manager_;
WriteThread write_thread_;
WriteBatch tmp_batch_;
// The write thread when the writers have no memtable write. This will be used
// in 2PC to batch the prepares separately from the serial commit.
WriteThread nonmem_write_thread_;
WriteController write_controller_;
// Size of the last batch group. In slowdown mode, next write needs to
// sleep if it uses up the quota.
// Note: This is to protect memtable and compaction. If the batch only writes
// to the WAL its size need not to be included in this.
uint64_t last_batch_group_size_;
FlushScheduler flush_scheduler_;
TrimHistoryScheduler trim_history_scheduler_;
SnapshotList snapshots_;
// For each background job, pending_outputs_ keeps the current file number at
// the time that background job started.
// FindObsoleteFiles()/PurgeObsoleteFiles() never deletes any file that has
// number bigger than any of the file number in pending_outputs_. Since file
// numbers grow monotonically, this also means that pending_outputs_ is always
// sorted. After a background job is done executing, its file number is
// deleted from pending_outputs_, which allows PurgeObsoleteFiles() to clean
// it up.
// State is protected with db mutex.
std::list<uint64_t> pending_outputs_;
// flush_queue_ and compaction_queue_ hold column families that we need to
// flush and compact, respectively.
// A column family is inserted into flush_queue_ when it satisfies condition
// cfd->imm()->IsFlushPending()
// A column family is inserted into compaction_queue_ when it satisfied
// condition cfd->NeedsCompaction()
// Column families in this list are all Ref()-erenced
// TODO(icanadi) Provide some kind of ReferencedColumnFamily class that will
// do RAII on ColumnFamilyData
// Column families are in this queue when they need to be flushed or
// compacted. Consumers of these queues are flush and compaction threads. When
// column family is put on this queue, we increase unscheduled_flushes_ and
// unscheduled_compactions_. When these variables are bigger than zero, that
// means we need to schedule background threads for flush and compaction.
// Once the background threads are scheduled, we decrease unscheduled_flushes_
// and unscheduled_compactions_. That way we keep track of number of
// compaction and flush threads we need to schedule. This scheduling is done
// in MaybeScheduleFlushOrCompaction()
// invariant(column family present in flush_queue_ <==>
// ColumnFamilyData::pending_flush_ == true)
std::deque<FlushRequest> flush_queue_;
// invariant(column family present in compaction_queue_ <==>
// ColumnFamilyData::pending_compaction_ == true)
std::deque<ColumnFamilyData*> compaction_queue_;
// A map to store file numbers and filenames of the files to be purged
std::unordered_map<uint64_t, PurgeFileInfo> purge_files_;
// A vector to store the file numbers that have been assigned to certain
// JobContext. Current implementation tracks table and blob files only.
std::unordered_set<uint64_t> files_grabbed_for_purge_;
// A queue to store log writers to close
std::deque<log::Writer*> logs_to_free_queue_;
std::deque<SuperVersion*> superversions_to_free_queue_;
int unscheduled_flushes_;
int unscheduled_compactions_;
// count how many background compactions are running or have been scheduled in
// the BOTTOM pool
int bg_bottom_compaction_scheduled_;
// count how many background compactions are running or have been scheduled
int bg_compaction_scheduled_;
// stores the number of compactions are currently running
int num_running_compactions_;
// number of background memtable flush jobs, submitted to the HIGH pool
int bg_flush_scheduled_;
// stores the number of flushes are currently running
int num_running_flushes_;
// number of background obsolete file purge jobs, submitted to the HIGH pool
int bg_purge_scheduled_;
std::deque<ManualCompactionState*> manual_compaction_dequeue_;
// shall we disable deletion of obsolete files
// if 0 the deletion is enabled.
// if non-zero, files will not be getting deleted
// This enables two different threads to call
// EnableFileDeletions() and DisableFileDeletions()
// without any synchronization
int disable_delete_obsolete_files_;
// Number of times FindObsoleteFiles has found deletable files and the
// corresponding call to PurgeObsoleteFiles has not yet finished.
int pending_purge_obsolete_files_;
// last time when DeleteObsoleteFiles with full scan was executed. Originally
// initialized with startup time.
uint64_t delete_obsolete_files_last_run_;
// last time stats were dumped to LOG
std::atomic<uint64_t> last_stats_dump_time_microsec_;
// The thread that wants to switch memtable, can wait on this cv until the
// pending writes to memtable finishes.
std::condition_variable switch_cv_;
// The mutex used by switch_cv_. mutex_ should be acquired beforehand.
std::mutex switch_mutex_;
// Number of threads intending to write to memtable
std::atomic<size_t> pending_memtable_writes_ = {};
// A flag indicating whether the current rocksdb database has any
// data that is not yet persisted into either WAL or SST file.
// Used when disableWAL is true.
std::atomic<bool> has_unpersisted_data_;
// if an attempt was made to flush all column families that
// the oldest log depends on but uncommitted data in the oldest
// log prevents the log from being released.
// We must attempt to free the dependent memtables again
// at a later time after the transaction in the oldest
// log is fully commited.
bool unable_to_release_oldest_log_;
static const int KEEP_LOG_FILE_NUM = 1000;
// MSVC version 1800 still does not have constexpr for ::max()
static const uint64_t kNoTimeOut = port::kMaxUint64;
std::string db_absolute_path_;
// Number of running IngestExternalFile() or CreateColumnFamilyWithImport()
// calls.
// REQUIRES: mutex held
int num_running_ingest_file_;
#ifndef ROCKSDB_LITE
WalManager wal_manager_;
#endif // ROCKSDB_LITE
// A value of > 0 temporarily disables scheduling of background work
int bg_work_paused_;
// A value of > 0 temporarily disables scheduling of background compaction
int bg_compaction_paused_;
// Guard against multiple concurrent refitting
bool refitting_level_;
// Indicate DB was opened successfully
bool opened_successfully_;
// The min threshold to triggere bottommost compaction for removing
// garbages, among all column families.
SequenceNumber bottommost_files_mark_threshold_ = kMaxSequenceNumber;
LogsWithPrepTracker logs_with_prep_tracker_;
// Callback for compaction to check if a key is visible to a snapshot.
// REQUIRES: mutex held
std::unique_ptr<SnapshotChecker> snapshot_checker_;
// Callback for when the cached_recoverable_state_ is written to memtable
// Only to be set during initialization
std::unique_ptr<PreReleaseCallback> recoverable_state_pre_release_callback_;
#ifndef ROCKSDB_LITE
// Scheduler to run DumpStats(), PersistStats(), and FlushInfoLog().
// Currently, it always use a global instance from
// PeriodicWorkScheduler::Default(). Only in unittest, it can be overrided by
// PeriodicWorkTestScheduler.
PeriodicWorkScheduler* periodic_work_scheduler_;
#endif
// When set, we use a separate queue for writes that don't write to memtable.
// In 2PC these are the writes at Prepare phase.
const bool two_write_queues_;
const bool manual_wal_flush_;
// LastSequence also indicates last published sequence visibile to the
// readers. Otherwise LastPublishedSequence should be used.
const bool last_seq_same_as_publish_seq_;
// It indicates that a customized gc algorithm must be used for
// flush/compaction and if it is not provided vis SnapshotChecker, we should
// disable gc to be safe.
const bool use_custom_gc_;
// Flag to indicate that the DB instance shutdown has been initiated. This
// different from shutting_down_ atomic in that it is set at the beginning
// of shutdown sequence, specifically in order to prevent any background
// error recovery from going on in parallel. The latter, shutting_down_,
// is set a little later during the shutdown after scheduling memtable
// flushes
std::atomic<bool> shutdown_initiated_;
// Flag to indicate whether sst_file_manager object was allocated in
// DB::Open() or passed to us
bool own_sfm_;
// Clients must periodically call SetPreserveDeletesSequenceNumber()
// to advance this seqnum. Default value is 0 which means ALL deletes are
// preserved. Note that this has no effect if DBOptions.preserve_deletes
// is set to false.
std::atomic<SequenceNumber> preserve_deletes_seqnum_;
const bool preserve_deletes_;
// Flag to check whether Close() has been called on this DB
bool closed_;
// Conditional variable to coordinate installation of atomic flush results.
// With atomic flush, each bg thread installs the result of flushing multiple
// column families, and different threads can flush different column
// families. It's difficult to rely on one thread to perform batch
// installation for all threads. This is different from the non-atomic flush
// case.
// atomic_flush_install_cv_ makes sure that threads install atomic flush
// results sequentially. Flush results of memtables with lower IDs get
// installed to MANIFEST first.
InstrumentedCondVar atomic_flush_install_cv_;
bool wal_in_db_path_;
BlobFileCompletionCallback blob_callback_;
// Pointer to WriteBufferManager stalling interface.
std::unique_ptr<StallInterface> wbm_stall_;
};
extern Options SanitizeOptions(const std::string& db, const Options& src,
bool read_only = false);
extern DBOptions SanitizeOptions(const std::string& db, const DBOptions& src,
bool read_only = false);
extern CompressionType GetCompressionFlush(
const ImmutableCFOptions& ioptions,
const MutableCFOptions& mutable_cf_options);
// Return the earliest log file to keep after the memtable flush is
// finalized.
// `cfd_to_flush` is the column family whose memtable (specified in
// `memtables_to_flush`) will be flushed and thus will not depend on any WAL
// file.
// The function is only applicable to 2pc mode.
extern uint64_t PrecomputeMinLogNumberToKeep2PC(
VersionSet* vset, const ColumnFamilyData& cfd_to_flush,
const autovector<VersionEdit*>& edit_list,
const autovector<MemTable*>& memtables_to_flush,
LogsWithPrepTracker* prep_tracker);
// For atomic flush.
extern uint64_t PrecomputeMinLogNumberToKeep2PC(
VersionSet* vset, const autovector<ColumnFamilyData*>& cfds_to_flush,
const autovector<autovector<VersionEdit*>>& edit_lists,
const autovector<const autovector<MemTable*>*>& memtables_to_flush,
LogsWithPrepTracker* prep_tracker);
// In non-2PC mode, WALs with log number < the returned number can be
// deleted after the cfd_to_flush column family is flushed successfully.
extern uint64_t PrecomputeMinLogNumberToKeepNon2PC(
VersionSet* vset, const ColumnFamilyData& cfd_to_flush,
const autovector<VersionEdit*>& edit_list);
// For atomic flush.
extern uint64_t PrecomputeMinLogNumberToKeepNon2PC(
VersionSet* vset, const autovector<ColumnFamilyData*>& cfds_to_flush,
const autovector<autovector<VersionEdit*>>& edit_lists);
// `cfd_to_flush` is the column family whose memtable will be flushed and thus
// will not depend on any WAL file. nullptr means no memtable is being flushed.
// The function is only applicable to 2pc mode.
extern uint64_t FindMinPrepLogReferencedByMemTable(
VersionSet* vset, const ColumnFamilyData* cfd_to_flush,
const autovector<MemTable*>& memtables_to_flush);
// For atomic flush.
extern uint64_t FindMinPrepLogReferencedByMemTable(
VersionSet* vset, const autovector<ColumnFamilyData*>& cfds_to_flush,
const autovector<const autovector<MemTable*>*>& memtables_to_flush);
// Fix user-supplied options to be reasonable
template <class T, class V>
static void ClipToRange(T* ptr, V minvalue, V maxvalue) {
if (static_cast<V>(*ptr) > maxvalue) *ptr = maxvalue;
if (static_cast<V>(*ptr) < minvalue) *ptr = minvalue;
}
} // namespace ROCKSDB_NAMESPACE