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rocksdb/db/db_impl/db_impl.h
Jay Huh 58a98bded9 MultiCFIterator Refactor - CoalescingIterator & AttributeGroupIterator (#12480) 
Summary:
There are a couple of reasons to modify the current implementation of the MultiCfIterator, which implements the generic `Iterator` interface.
- The default behavior of `value()`/`columns()` returning data from different Column Families for different keys can be prone to errors, even though there might be valid use cases where users do not care about the origin of the value/columns.
- The `attribute_groups()` API, which is not yet implemented, will not be useful for a single-CF iterator.

In this PR, we are implementing the following changes:
- `IteratorBase` introduced, which includes all basic iterator functions except `value()` and `columns()`.
- `Iterator`, which now inherits from `IteratorBase`, includes `value()` and `columns()`.
- New public interface `AttributeGroupIterator` inherits from `IteratorBase` and additionally includes `attribute_groups()` (to be implemented).
- Renamed former `MultiCfIterator` to `CoalescingIterator` which inherits from `Iterator`
- Existing MultiCfIteratorTest has been split into two - `CoalescingIteratorTest` and `AttributeGroupIteratorTest`.
- Moved AttributeGroup related code from `wide_columns.h` to a new file, `attribute_groups.h`.

Some Implementation Details
- `MultiCfIteratorImpl` takes two functions - `populate_func` and `reset_func` and use them to populate `value_` and `columns_` in CoalescingIterator and `attribute_groups_` in AttributeGroupIterator. In CoalescingIterator, populate_func is `Coalesce()`, in AttributeGroupIterator populate_func is `AddToAttributeGroups()`. `reset_func` clears populated value_, columns_ and attribute_groups_ accordingly.
- `Coalesce()` merge sorts columns from multiple CFs when a key exists in more than on CFs. column that appears in later CF overwrites the prior ones.

For example, if CF1 has `"key_1" ==> {"col_1": "foo",  "col_2", "baz"}` and CF2 has `"key_1" ==> {"col_2": "quux", "col_3", "bla"}`, and when the iterator is at `key_1`, `columns()` will return `{"col_1": "foo", "col_2", "quux", "col_3", "bla"}`

In this example, `value()` will be empty, because none of them have values for `kDefaultColumnName`

Pull Request resolved: https://github.com/facebook/rocksdb/pull/12480

Test Plan:
## Unit Test
```
./multi_cf_iterator_test
```

## Performance Test

To make sure this change does not impact existing `Iterator` performance

**Build**
```
$> make -j64 release
```
**Setup**
```
$> TEST_TMPDIR=/dev/shm/db_bench ./db_bench -benchmarks="filluniquerandom" -key_size=32 -value_size=512 -num=1000000 -compression_type=none
```
**Run**
```
TEST_TMPDIR=/dev/shm/db_bench ./db_bench -use_existing_db=1 -benchmarks="newiterator,seekrandom" -cache_size=10485760000
```

**Before the change**
```
DB path: [/dev/shm/db_bench/dbbench]
newiterator  :       0.519 micros/op 1927904 ops/sec 0.519 seconds 1000000 operations;
DB path: [/dev/shm/db_bench/dbbench]
seekrandom   :       5.302 micros/op 188589 ops/sec 5.303 seconds 1000000 operations; (0 of 1000000 found)
```
**After the change**
```
DB path: [/dev/shm/db_bench/dbbench]
newiterator  :       0.497 micros/op 2011012 ops/sec 0.497 seconds 1000000 operations;
DB path: [/dev/shm/db_bench/dbbench]
seekrandom   :       5.252 micros/op 190405 ops/sec 5.252 seconds 1000000 operations; (0 of 1000000 found)
```

Reviewed By: ltamasi

Differential Revision: D55353909

Pulled By: jaykorean

fbshipit-source-id: 8d7786ffee09e022261ce34aa60e8633685e1946
2024-04-11 11:34:04 -07:00

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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 <unordered_map>
#include <utility>
#include <vector>
#include "db/column_family.h"
#include "db/compaction/compaction_iterator.h"
#include "db/compaction/compaction_job.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/periodic_task_scheduler.h"
#include "db/post_memtable_callback.h"
#include "db/pre_release_callback.h"
#include "db/range_del_aggregator.h"
#include "db/read_callback.h"
#include "db/seqno_to_time_mapping.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/attribute_groups.h"
#include "rocksdb/db.h"
#include "rocksdb/env.h"
#include "rocksdb/memtablerep.h"
#include "rocksdb/status.h"
#include "rocksdb/trace_reader_writer.h"
#include "rocksdb/transaction_log.h"
#include "rocksdb/utilities/replayer.h"
#include "rocksdb/write_buffer_manager.h"
#include "table/merging_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 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(); }
IOStatus Close(const IOOptions& options, IODebugContext* dbg) {
// close all directories for all database paths
IOStatus s = IOStatus::OK();
// The default implementation for Close() in Directory/FSDirectory class
// "NotSupported" status, the upper level interface should be able to
// handle this error so that Close() does not fail after upgrading when
// run on FileSystems that have not implemented `Directory::Close()` or
// `FSDirectory::Close()` yet
if (db_dir_) {
IOStatus temp_s = db_dir_->Close(options, dbg);
if (!temp_s.ok() && !temp_s.IsNotSupported() && s.ok()) {
s = std::move(temp_s);
}
}
// Attempt to close everything even if one fails
s.PermitUncheckedError();
if (wal_dir_) {
IOStatus temp_s = wal_dir_->Close(options, dbg);
if (!temp_s.ok() && !temp_s.IsNotSupported() && s.ok()) {
s = std::move(temp_s);
}
}
s.PermitUncheckedError();
for (auto& data_dir_ptr : data_dirs_) {
if (data_dir_ptr) {
IOStatus temp_s = data_dir_ptr->Close(options, dbg);
if (!temp_s.ok() && !temp_s.IsNotSupported() && s.ok()) {
s = std::move(temp_s);
}
}
}
// Ready for caller
s.MustCheck();
return s;
}
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;
Status Resume() override;
using DB::Put;
Status Put(const WriteOptions& options, ColumnFamilyHandle* column_family,
const Slice& key, const Slice& value) override;
Status Put(const WriteOptions& options, ColumnFamilyHandle* column_family,
const Slice& key, const Slice& ts, const Slice& value) override;
using DB::PutEntity;
Status PutEntity(const WriteOptions& options,
ColumnFamilyHandle* column_family, const Slice& key,
const WideColumns& columns) override;
Status PutEntity(const WriteOptions& options, const Slice& key,
const AttributeGroups& attribute_groups) override;
using DB::Merge;
Status Merge(const WriteOptions& options, ColumnFamilyHandle* column_family,
const Slice& key, const Slice& value) override;
Status Merge(const WriteOptions& options, ColumnFamilyHandle* column_family,
const Slice& key, const Slice& ts, const Slice& value) override;
using DB::Delete;
Status Delete(const WriteOptions& options, ColumnFamilyHandle* column_family,
const Slice& key) override;
Status Delete(const WriteOptions& options, ColumnFamilyHandle* column_family,
const Slice& key, const Slice& ts) override;
using DB::SingleDelete;
Status SingleDelete(const WriteOptions& options,
ColumnFamilyHandle* column_family,
const Slice& key) override;
Status SingleDelete(const WriteOptions& options,
ColumnFamilyHandle* column_family, const Slice& key,
const Slice& ts) override;
using DB::DeleteRange;
Status DeleteRange(const WriteOptions& options,
ColumnFamilyHandle* column_family, const Slice& begin_key,
const Slice& end_key) override;
Status DeleteRange(const WriteOptions& options,
ColumnFamilyHandle* column_family, const Slice& begin_key,
const Slice& end_key, const Slice& ts) override;
using DB::Write;
Status Write(const WriteOptions& options, WriteBatch* updates) override;
using DB::Get;
Status Get(const ReadOptions& _read_options,
ColumnFamilyHandle* column_family, const Slice& key,
PinnableSlice* value, std::string* timestamp) override;
using DB::GetEntity;
Status GetEntity(const ReadOptions& options,
ColumnFamilyHandle* column_family, const Slice& key,
PinnableWideColumns* columns) override;
Status GetEntity(const ReadOptions& options, const Slice& key,
PinnableAttributeGroups* result) 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;
// 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
void MultiGet(const ReadOptions& _read_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;
void MultiGetWithCallback(
const ReadOptions& _read_options, ColumnFamilyHandle* column_family,
ReadCallback* callback,
autovector<KeyContext*, MultiGetContext::MAX_BATCH_SIZE>* sorted_keys);
using DB::MultiGetEntity;
void MultiGetEntity(const ReadOptions& options,
ColumnFamilyHandle* column_family, size_t num_keys,
const Slice* keys, PinnableWideColumns* results,
Status* statuses, bool sorted_input) override;
void MultiGetEntity(const ReadOptions& options, size_t num_keys,
ColumnFamilyHandle** column_families, const Slice* keys,
PinnableWideColumns* results, Status* statuses,
bool sorted_input) override;
void MultiGetEntity(const ReadOptions& options, size_t num_keys,
const Slice* keys,
PinnableAttributeGroups* results) override;
Status CreateColumnFamily(const ColumnFamilyOptions& cf_options,
const std::string& column_family,
ColumnFamilyHandle** handle) override {
// TODO: plumb Env::IOActivity, Env::IOPriority
return CreateColumnFamily(ReadOptions(), WriteOptions(), cf_options,
column_family, handle);
}
virtual Status CreateColumnFamily(const ReadOptions& read_options,
const WriteOptions& write_options,
const ColumnFamilyOptions& cf_options,
const std::string& column_family,
ColumnFamilyHandle** handle);
Status CreateColumnFamilies(
const ColumnFamilyOptions& cf_options,
const std::vector<std::string>& column_family_names,
std::vector<ColumnFamilyHandle*>* handles) override {
// TODO: plumb Env::IOActivity, Env::IOPriority
return CreateColumnFamilies(ReadOptions(), WriteOptions(), cf_options,
column_family_names, handles);
}
virtual Status CreateColumnFamilies(
const ReadOptions& read_options, const WriteOptions& write_options,
const ColumnFamilyOptions& cf_options,
const std::vector<std::string>& column_family_names,
std::vector<ColumnFamilyHandle*>* handles);
Status CreateColumnFamilies(
const std::vector<ColumnFamilyDescriptor>& column_families,
std::vector<ColumnFamilyHandle*>* handles) override {
// TODO: plumb Env::IOActivity, Env::IOPriority
return CreateColumnFamilies(ReadOptions(), WriteOptions(), column_families,
handles);
}
virtual Status CreateColumnFamilies(
const ReadOptions& read_options, const WriteOptions& write_options,
const std::vector<ColumnFamilyDescriptor>& column_families,
std::vector<ColumnFamilyHandle*>* handles);
Status DropColumnFamily(ColumnFamilyHandle* column_family) override;
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;
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;
Iterator* NewIterator(const ReadOptions& _read_options,
ColumnFamilyHandle* column_family) override;
Status NewIterators(const ReadOptions& _read_options,
const std::vector<ColumnFamilyHandle*>& column_families,
std::vector<Iterator*>* iterators) override;
const Snapshot* GetSnapshot() override;
void ReleaseSnapshot(const Snapshot* snapshot) override;
// UNDER CONSTRUCTION - DO NOT USE
std::unique_ptr<Iterator> NewCoalescingIterator(
const ReadOptions& options,
const std::vector<ColumnFamilyHandle*>& column_families) override;
// UNDER CONSTRUCTION - DO NOT USE
std::unique_ptr<AttributeGroupIterator> NewAttributeGroupIterator(
const ReadOptions& options,
const std::vector<ColumnFamilyHandle*>& column_families) override;
// Create a timestamped snapshot. This snapshot can be shared by multiple
// readers. If any of them uses it for write conflict checking, then
// is_write_conflict_boundary is true. For simplicity, set it to true by
// default.
std::pair<Status, std::shared_ptr<const Snapshot>> CreateTimestampedSnapshot(
SequenceNumber snapshot_seq, uint64_t ts);
std::shared_ptr<const SnapshotImpl> GetTimestampedSnapshot(uint64_t ts) const;
void ReleaseTimestampedSnapshotsOlderThan(
uint64_t ts, size_t* remaining_total_ss = nullptr);
Status GetTimestampedSnapshots(uint64_t ts_lb, uint64_t ts_ub,
std::vector<std::shared_ptr<const Snapshot>>&
timestamped_snapshots) const;
using DB::GetProperty;
bool GetProperty(ColumnFamilyHandle* column_family, const Slice& property,
std::string* value) override;
using DB::GetMapProperty;
bool GetMapProperty(ColumnFamilyHandle* column_family, const Slice& property,
std::map<std::string, std::string>* value) override;
using DB::GetIntProperty;
bool GetIntProperty(ColumnFamilyHandle* column_family, const Slice& property,
uint64_t* value) override;
using DB::GetAggregatedIntProperty;
bool GetAggregatedIntProperty(const Slice& property,
uint64_t* aggregated_value) override;
using DB::GetApproximateSizes;
Status GetApproximateSizes(const SizeApproximationOptions& options,
ColumnFamilyHandle* column_family,
const Range* range, int n,
uint64_t* sizes) override;
using DB::GetApproximateMemTableStats;
void GetApproximateMemTableStats(ColumnFamilyHandle* column_family,
const Range& range, uint64_t* const count,
uint64_t* const size) override;
using DB::CompactRange;
Status CompactRange(const CompactRangeOptions& options,
ColumnFamilyHandle* column_family, const Slice* begin,
const Slice* end) override;
using DB::CompactFiles;
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;
Status PauseBackgroundWork() override;
Status ContinueBackgroundWork() override;
Status EnableAutoCompaction(
const std::vector<ColumnFamilyHandle*>& column_family_handles) override;
void EnableManualCompaction() override;
void DisableManualCompaction() override;
using DB::SetOptions;
Status SetOptions(
ColumnFamilyHandle* column_family,
const std::unordered_map<std::string, std::string>& options_map) override;
Status SetDBOptions(
const std::unordered_map<std::string, std::string>& options_map) override;
using DB::NumberLevels;
int NumberLevels(ColumnFamilyHandle* column_family) override;
using DB::MaxMemCompactionLevel;
int MaxMemCompactionLevel(ColumnFamilyHandle* column_family) override;
using DB::Level0StopWriteTrigger;
int Level0StopWriteTrigger(ColumnFamilyHandle* column_family) override;
const std::string& GetName() const override;
Env* GetEnv() const override;
FileSystem* GetFileSystem() const override;
using DB::GetOptions;
Options GetOptions(ColumnFamilyHandle* column_family) const override;
using DB::GetDBOptions;
DBOptions GetDBOptions() const override;
using DB::Flush;
Status Flush(const FlushOptions& options,
ColumnFamilyHandle* column_family) override;
Status Flush(
const FlushOptions& options,
const std::vector<ColumnFamilyHandle*>& column_families) override;
Status FlushWAL(bool sync) override {
// TODO: plumb Env::IOActivity, Env::IOPriority
return FlushWAL(WriteOptions(), sync);
}
virtual Status FlushWAL(const WriteOptions& write_options, bool sync);
bool WALBufferIsEmpty();
Status SyncWAL() override;
Status LockWAL() override;
Status UnlockWAL() override;
SequenceNumber GetLatestSequenceNumber() const override;
// IncreaseFullHistoryTsLow(ColumnFamilyHandle*, std::string) will acquire
// and release db_mutex
Status IncreaseFullHistoryTsLow(ColumnFamilyHandle* column_family,
std::string ts_low) override;
// GetFullHistoryTsLow(ColumnFamilyHandle*, std::string*) will acquire and
// release db_mutex
Status GetFullHistoryTsLow(ColumnFamilyHandle* column_family,
std::string* ts_low) override;
Status GetDbIdentity(std::string& identity) const override;
virtual Status GetDbIdentityFromIdentityFile(std::string* identity) const;
Status GetDbSessionId(std::string& session_id) const override;
ColumnFamilyHandle* DefaultColumnFamily() const override;
ColumnFamilyHandle* PersistentStatsColumnFamily() const;
Status Close() override;
Status DisableFileDeletions() override;
Status EnableFileDeletions() override;
virtual bool IsFileDeletionsEnabled() const;
Status GetStatsHistory(
uint64_t start_time, uint64_t end_time,
std::unique_ptr<StatsHistoryIterator>* stats_iterator) override;
using DB::ResetStats;
Status ResetStats() override;
// All the returned filenames start with "/"
Status GetLiveFiles(std::vector<std::string>&, uint64_t* manifest_file_size,
bool flush_memtable = true) override;
Status GetSortedWalFiles(VectorLogPtr& files) override;
Status GetCurrentWalFile(std::unique_ptr<LogFile>* current_log_file) override;
Status GetCreationTimeOfOldestFile(uint64_t* creation_time) override;
Status GetUpdatesSince(
SequenceNumber seq_number, std::unique_ptr<TransactionLogIterator>* iter,
const TransactionLogIterator::ReadOptions& read_options =
TransactionLogIterator::ReadOptions()) override;
Status DeleteFile(std::string name) override;
Status DeleteFilesInRanges(ColumnFamilyHandle* column_family,
const RangePtr* ranges, size_t n,
bool include_end = true);
void GetLiveFilesMetaData(std::vector<LiveFileMetaData>* metadata) override;
Status GetLiveFilesChecksumInfo(FileChecksumList* checksum_list) override;
Status GetLiveFilesStorageInfo(
const LiveFilesStorageInfoOptions& opts,
std::vector<LiveFileStorageInfo>* files) 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.
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;
Status IngestExternalFile(
ColumnFamilyHandle* column_family,
const std::vector<std::string>& external_files,
const IngestExternalFileOptions& ingestion_options) override;
using DB::IngestExternalFiles;
Status IngestExternalFiles(
const std::vector<IngestExternalFileArg>& args) override;
using DB::CreateColumnFamilyWithImport;
Status CreateColumnFamilyWithImport(
const ColumnFamilyOptions& options, const std::string& column_family_name,
const ImportColumnFamilyOptions& import_options,
const std::vector<const ExportImportFilesMetaData*>& metadatas,
ColumnFamilyHandle** handle) override;
using DB::ClipColumnFamily;
Status ClipColumnFamily(ColumnFamilyHandle* column_family,
const Slice& begin_key,
const Slice& end_key) override;
using DB::VerifyFileChecksums;
Status VerifyFileChecksums(const ReadOptions& read_options) override;
using DB::VerifyChecksum;
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;
Status StartTrace(const TraceOptions& options,
std::unique_ptr<TraceWriter>&& trace_writer) override;
using DB::EndTrace;
Status EndTrace() override;
using DB::NewDefaultReplayer;
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& trace_options,
std::unique_ptr<TraceWriter>&& trace_writer) override;
Status StartBlockCacheTrace(
const BlockCacheTraceOptions& options,
std::unique_ptr<BlockCacheTraceWriter>&& 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;
Status GetPropertiesOfAllTables(ColumnFamilyHandle* column_family,
TablePropertiesCollection* props) override;
Status GetPropertiesOfTablesInRange(
ColumnFamilyHandle* column_family, const Range* range, std::size_t n,
TablePropertiesCollection* props) override;
// ---- End of implementations of the DB interface ----
SystemClock* GetSystemClock() const;
struct GetImplOptions {
ColumnFamilyHandle* column_family = nullptr;
PinnableSlice* value = nullptr;
PinnableWideColumns* columns = 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;
};
Status GetImpl(const ReadOptions& read_options,
ColumnFamilyHandle* column_family, const Slice& key,
PinnableSlice* value);
Status GetImpl(const ReadOptions& read_options,
ColumnFamilyHandle* column_family, const Slice& key,
PinnableSlice* value, std::string* timestamp);
// 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
virtual 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,
ColumnFamilyHandleImpl* cfh,
SuperVersion* sv, 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;
// 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.
//
// `key` should NOT have user-defined timestamp appended to user key even if
// timestamp is enabled.
//
// 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 user-defined
// timestamp is enabled for this column family and timestamp is not nullptr,
// then *timestamp will be set to the stored timestamp for the latest
// operation on this key.
// 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, std::string* timestamp,
bool* found_record_for_key,
bool* is_blob_index);
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);
// 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
// If `final_output_level` is not nullptr, it is set to manual compaction's
// output level if returned status is OK, and it may or may not be set to
// manual compaction's output level if returned status is not OK.
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,
const std::string& trim_ts,
int* final_output_level = nullptr);
// 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.
//
// read_options.ignore_range_deletions determines whether range tombstones are
// processed in the returned interator internally, i.e., whether range
// tombstone covered keys are in this iterator's output.
// @param read_options Must outlive the returned iterator.
InternalIterator* NewInternalIterator(
const ReadOptions& read_options, Arena* arena, SequenceNumber sequence,
ColumnFamilyHandle* column_family = nullptr,
bool allow_unprepared_value = false);
// Note: to support DB iterator refresh, memtable range tombstones in the
// underlying merging iterator needs to be refreshed. If db_iter is not
// nullptr, db_iter->SetMemtableRangetombstoneIter() is called with the
// memtable range tombstone iterator used by the underlying merging iterator.
// This range tombstone iterator can be refreshed later by db_iter.
// @param read_options Must outlive the returned iterator.
InternalIterator* NewInternalIterator(const ReadOptions& read_options,
ColumnFamilyData* cfd,
SuperVersion* super_version,
Arena* arena, SequenceNumber sequence,
bool allow_unprepared_value,
ArenaWrappedDBIter* db_iter = nullptr);
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();
uint64_t GetObsoleteSstFilesSize();
// 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_; }
// 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) {
mutex_.AssertHeld();
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);
VersionSet* GetVersionSet() const { return versions_.get(); }
Status WaitForCompact(
const WaitForCompactOptions& wait_for_compact_options) override;
#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*>& provided_candidate_cfds,
const FlushOptions& flush_opts);
// Wait for background threads to complete scheduled work.
Status TEST_WaitForBackgroundWork();
// Wait for memtable compaction
Status TEST_WaitForFlushMemTable(ColumnFamilyHandle* column_family = nullptr);
Status TEST_WaitForCompact();
Status TEST_WaitForCompact(
const WaitForCompactOptions& wait_for_compact_options);
// Wait for any background purge
Status TEST_WaitForPurge();
// 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();
InstrumentedMutex* TEST_Mutex() { return &mutex_; }
void TEST_SignalAllBgCv();
// 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_WaitForPeriodicTaskRun(std::function<void()> callback) const;
SeqnoToTimeMapping TEST_GetSeqnoToTimeMapping() const;
const autovector<uint64_t>& TEST_GetFilesToQuarantine() const;
size_t TEST_EstimateInMemoryStatsHistorySize() const;
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_;
}
const PeriodicTaskScheduler& TEST_GetPeriodicTaskScheduler() const;
static Status TEST_ValidateOptions(const DBOptions& db_options) {
return ValidateOptions(db_options);
}
#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();
// record current sequence number to time mapping. If
// populate_historical_seconds > 0 then pre-populate all the
// sequence numbers from [1, last] to map to [now minus
// populate_historical_seconds, now].
void RecordSeqnoToTimeMapping(uint64_t populate_historical_seconds);
// Everytime DB's seqno to time mapping changed (which already hold the db
// mutex), we install a new SuperVersion in each column family with a shared
// copy of the new mapping while holding the db mutex.
// This is done for all column families even though the column family does not
// explicitly enabled the
// `preclude_last_level_data_seconds` or `preserve_internal_time_seconds`
// features.
// This mapping supports iterators to fulfill the
// "rocksdb.iterator.write-time" iterator property for entries in memtables.
//
// Since this new SuperVersion doesn't involve an LSM tree shape change, we
// don't schedule work after installing this SuperVersion. It returns the used
// `SuperVersionContext` for clean up after release mutex.
void InstallSeqnoToTimeMappingInSV(
std::vector<SuperVersionContext>* sv_contexts);
// 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 void TEST_ResetDbSessionIdGen();
static std::string GenerateDbSessionId(Env* env);
bool seq_per_batch() const { return seq_per_batch_; }
protected:
const std::string dbname_;
// TODO(peterd): unify with VersionSet::db_id_
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_;
Status init_logger_creation_s_;
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_;
// constant false canceled flag, used when the compaction is not manual
const std::atomic<bool> kManualCompactionCanceledFalse_{false};
// 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.
//
// `mutex_` can be a hot lock in some workloads, so it deserves dedicated
// cachelines.
mutable CacheAlignedInstrumentedMutex 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
std::atomic<uint64_t> max_total_in_memory_state_;
// 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_;
// No new background jobs can be queued if true. This is used to prevent new
// background jobs from being queued after WaitForCompact() completes waiting
// all background jobs then attempts to close when close_db_ option is true.
bool reject_new_background_jobs_;
// RecoveryContext struct stores the context about version edits along
// with corresponding column_family_data and column_family_options.
class RecoveryContext {
public:
~RecoveryContext() {
for (auto& edit_list : edit_lists_) {
for (auto* edit : edit_list) {
delete edit;
}
}
}
void UpdateVersionEdits(ColumnFamilyData* cfd, const VersionEdit& edit) {
assert(cfd != nullptr);
if (map_.find(cfd->GetID()) == map_.end()) {
uint32_t size = static_cast<uint32_t>(map_.size());
map_.emplace(cfd->GetID(), size);
cfds_.emplace_back(cfd);
mutable_cf_opts_.emplace_back(cfd->GetLatestMutableCFOptions());
edit_lists_.emplace_back(autovector<VersionEdit*>());
}
uint32_t i = map_[cfd->GetID()];
edit_lists_[i].emplace_back(new VersionEdit(edit));
}
std::unordered_map<uint32_t, uint32_t> map_; // cf_id to index;
autovector<ColumnFamilyData*> cfds_;
autovector<const MutableCFOptions*> mutable_cf_opts_;
autovector<autovector<VersionEdit*>> edit_lists_;
// Stale SST files to delete found upon recovery. This stores a mapping from
// such a file's absolute path to its parent directory.
std::unordered_map<std::string, std::string> files_to_delete_;
bool is_new_db_ = false;
};
// Persist options to options file. Must be holding options_mutex_.
// Will lock DB mutex if !db_mutex_already_held.
Status WriteOptionsFile(const WriteOptions& write_options,
bool db_mutex_already_held);
Status CompactRangeInternal(const CompactRangeOptions& options,
ColumnFamilyHandle* column_family,
const Slice* begin, const Slice* end,
const std::string& trim_ts);
// 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, FlushReason flush_reason);
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);
void NotifyOnExternalFileIngested(
ColumnFamilyData* cfd, const ExternalSstFileIngestionJob& ingestion_job);
Status FlushAllColumnFamilies(const FlushOptions& flush_options,
FlushReason flush_reason);
virtual Status FlushForGetLiveFiles();
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,
PostMemTableCallback* post_memtable_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.
// recovery_ctx stores the context about version edits and all those
// edits are persisted to new Manifest after successfully syncing the new WAL.
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,
RecoveryContext* recovery_ctx = nullptr);
virtual bool OwnTablesAndLogs() const { return true; }
// Setup DB identity file, and write DB ID to manifest if necessary.
Status SetupDBId(const WriteOptions& write_options, bool read_only,
RecoveryContext* recovery_ctx);
// Assign db_id_ and write DB ID to manifest if necessary.
void SetDBId(std::string&& id, bool read_only, RecoveryContext* recovery_ctx);
// 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
// RecoveryContext, DB crashes when syncing the MANIFEST, the VersionEdits are
// still not synced to MANIFEST during recovery.)
// It stores the SST files to be deleted in RecoveryContext. 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.
// recovery_ctx stores the context about version edits and files to be
// deleted. All those edits are persisted to new Manifest after successfully
// syncing the new WAL.
Status DeleteUnreferencedSstFiles(RecoveryContext* recovery_ctx);
// SetDbSessionId() should be called in the constuctor DBImpl()
// to ensure that db_session_id_ gets updated every time the DB is opened
void SetDbSessionId();
Status FailIfCfHasTs(const ColumnFamilyHandle* column_family) const;
Status FailIfTsMismatchCf(ColumnFamilyHandle* column_family,
const Slice& ts) const;
// Check that the read timestamp `ts` is at or above the `full_history_ts_low`
// timestamp in a `SuperVersion`. It's necessary to do this check after
// grabbing the SuperVersion. If the check passed, the referenced SuperVersion
// this read holds on to can ensure the read won't be affected if
// `full_history_ts_low` is increased concurrently, and this achieves that
// without explicitly locking by piggybacking the SuperVersion.
Status FailIfReadCollapsedHistory(const ColumnFamilyData* cfd,
const SuperVersion* sv,
const Slice& ts) const;
// recovery_ctx stores the context about version edits and
// LogAndApplyForRecovery persist all those edits to new Manifest after
// successfully syncing new WAL.
// LogAndApplyForRecovery should be called only once during recovery and it
// should be called when RocksDB writes to a first new MANIFEST since this
// recovery.
Status LogAndApplyForRecovery(const RecoveryContext& recovery_ctx);
void InvokeWalFilterIfNeededOnColumnFamilyToWalNumberMap();
// Return true to proceed with current WAL record whose content is stored in
// `batch`. Return false to skip current WAL record.
bool InvokeWalFilterIfNeededOnWalRecord(uint64_t wal_number,
const std::string& wal_fname,
log::Reader::Reporter& reporter,
Status& status, bool& stop_replay,
WriteBatch& batch);
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;
friend class ForwardIterator;
friend struct SuperVersion;
friend class CompactedDBImpl;
#ifndef NDEBUG
friend class DBTest_ConcurrentFlushWAL_Test;
friend class DBTest_MixedSlowdownOptionsStop_Test;
friend class DBCompactionTest_CompactBottomLevelFilesWithDeletions_Test;
friend class DBCompactionTest_CompactionDuringShutdown_Test;
friend class DBCompactionTest_DelayCompactBottomLevelFilesWithDeletions_Test;
friend class DBCompactionTest_DisableCompactBottomLevelFiles_Test;
friend class StatsHistoryTest_PersistentStatsCreateColumnFamilies_Test;
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() {
// TODO: plumb Env::IOActivity, Env::IOPriority
Status s = writer->WriteBuffer(WriteOptions());
delete writer;
writer = nullptr;
return s;
}
bool IsSyncing() { return getting_synced; }
uint64_t GetPreSyncSize() {
assert(getting_synced);
return pre_sync_size;
}
void PrepareForSync() {
assert(!getting_synced);
// Size is expected to be monotonically increasing.
assert(writer->file()->GetFlushedSize() >= pre_sync_size);
getting_synced = true;
pre_sync_size = writer->file()->GetFlushedSize();
}
void FinishSync() {
assert(getting_synced);
getting_synced = false;
}
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
private:
// true for some prefix of logs_
bool getting_synced = false;
// The size of the file before the sync happens. This amount is guaranteed
// to be persisted even if appends happen during sync so it can be used for
// tracking the synced size in MANIFEST.
uint64_t pre_sync_size = 0;
};
struct LogContext {
explicit LogContext(bool need_sync = false)
: need_log_sync(need_sync), need_log_dir_sync(need_sync) {}
bool need_log_sync = false;
bool need_log_dir_sync = false;
log::Writer* writer = nullptr;
LogFileNumberSize* log_file_number_size = nullptr;
};
// 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),
flush_reason_(FlushReason::kOthers) {}
BGFlushArg(ColumnFamilyData* cfd, uint64_t max_memtable_id,
SuperVersionContext* superversion_context,
FlushReason flush_reason)
: cfd_(cfd),
max_memtable_id_(max_memtable_id),
superversion_context_(superversion_context),
flush_reason_(flush_reason) {}
// 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_;
FlushReason flush_reason_;
};
// Argument passed to flush thread.
struct FlushThreadArg {
DBImpl* db_;
Env::Priority thread_pri_;
};
// Information for a manual compaction
struct ManualCompactionState {
ManualCompactionState(ColumnFamilyData* _cfd, int _input_level,
int _output_level, uint32_t _output_path_id,
bool _exclusive, bool _disallow_trivial_move,
std::atomic<bool>* _canceled)
: cfd(_cfd),
input_level(_input_level),
output_level(_output_level),
output_path_id(_output_path_id),
exclusive(_exclusive),
disallow_trivial_move(_disallow_trivial_move),
canceled(_canceled ? *_canceled : canceled_internal_storage) {}
// When _canceled is not provided by ther user, we assign the reference of
// canceled_internal_storage to it to consolidate canceled and
// manual_compaction_paused since DisableManualCompaction() might be
// called
ColumnFamilyData* cfd;
int input_level;
int output_level;
uint32_t output_path_id;
Status status;
bool done = false;
bool in_progress = false; // compaction request being processed?
bool incomplete = false; // 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; // nullptr means beginning of key range
const InternalKey* end = nullptr; // nullptr means end of key range
InternalKey* manual_end = nullptr; // 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
// When the user provides a canceled pointer in CompactRangeOptions, the
// above varaibe is the reference of the user-provided
// `canceled`, otherwise, it is the reference of canceled_internal_storage
std::atomic<bool> canceled_internal_storage = false;
std::atomic<bool>& canceled; // Compaction canceled pointer reference
};
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();
// Create a column family, without some of the follow-up work yet
Status CreateColumnFamilyImpl(const ReadOptions& read_options,
const WriteOptions& write_options,
const ColumnFamilyOptions& cf_options,
const std::string& cf_name,
ColumnFamilyHandle** handle);
// Follow-up work to user creating a column family or (families)
Status WrapUpCreateColumnFamilies(
const ReadOptions& read_options, const WriteOptions& write_options,
const std::vector<const ColumnFamilyOptions*>& cf_options);
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(const WriteOptions& write_options,
JobContext* job_context, VersionEdit* synced_wals,
bool error_recovery_in_prog);
// 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, FlushReason flush_reason,
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,
RecoveryContext* recovery_ctx);
// 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, WriteThread& write_thread,
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);
// Select and output column families qualified for atomic flush in
// `selected_cfds`. If `provided_candidate_cfds` is non-empty, it will be used
// as candidate CFs to select qualified ones from. Otherwise, all column
// families are used as candidate to select from.
//
// REQUIRES: mutex held
void SelectColumnFamiliesForAtomicFlush(
autovector<ColumnFamilyData*>* selected_cfds,
const autovector<ColumnFamilyData*>& provided_candidate_cfds = {});
// Force current memtable contents to be flushed.
Status FlushMemTable(ColumnFamilyData* cfd, const FlushOptions& options,
FlushReason flush_reason,
bool entered_write_thread = false);
// Atomic-flush memtables from quanlified CFs among `provided_candidate_cfds`
// (if non-empty) or amomg all column families and atomically record the
// result to the MANIFEST.
Status AtomicFlushMemTables(
const FlushOptions& options, FlushReason flush_reason,
const autovector<ColumnFamilyData*>& provided_candidate_cfds = {},
bool entered_write_thread = false);
Status RetryFlushesForErrorRecovery(FlushReason flush_reason, bool wait);
// 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; });
}
}
// TaskType is used to identify tasks in thread-pool, currently only
// differentiate manual compaction, which could be unscheduled from the
// thread-pool.
enum class TaskType : uint8_t {
kDefault = 0,
kManualCompaction = 1,
kCount = 2,
};
// Task tag is used to identity tasks in thread-pool, which is
// dbImpl obj address + type
inline void* GetTaskTag(TaskType type) {
return GetTaskTag(static_cast<uint8_t>(type));
}
inline void* GetTaskTag(uint8_t type) {
return static_cast<uint8_t*>(static_cast<void*>(this)) + type;
}
// 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,
LogContext* log_context, WriteContext* write_context);
// Merge write batches in the write group into merged_batch.
// Returns OK if merge is successful.
// Returns Corruption if corruption in write batch is detected.
Status MergeBatch(const WriteThread::WriteGroup& write_group,
WriteBatch* tmp_batch, WriteBatch** merged_batch,
size_t* write_with_wal, WriteBatch** to_be_cached_state);
IOStatus WriteToWAL(const WriteBatch& merged_batch,
const WriteOptions& write_options,
log::Writer* log_writer, uint64_t* log_used,
uint64_t* log_size,
LogFileNumberSize& log_file_number_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,
LogFileNumberSize& log_file_number_size);
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);
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);
ColumnFamilyData* GetColumnFamilyDataByName(const std::string& cf_name);
void MaybeScheduleFlushOrCompaction();
struct FlushRequest {
FlushReason flush_reason;
// A map from column family to flush to 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.
std::unordered_map<ColumnFamilyData*, uint64_t>
cfd_to_max_mem_id_to_persist;
#ifndef NDEBUG
int reschedule_count = 1;
#endif /* !NDEBUG */
};
// In case of atomic flush, generates a `FlushRequest` for the latest atomic
// cuts for these `cfds`. Atomic cuts are recorded in
// `AssignAtomicFlushSeq()`. For each entry in `cfds`, all CFDs sharing the
// same latest atomic cut must also be present.
//
// REQUIRES: mutex held
void GenerateFlushRequest(const autovector<ColumnFamilyData*>& cfds,
FlushReason flush_reason, FlushRequest* req);
void SchedulePendingFlush(const FlushRequest& req);
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,
bool* flush_rescheduled_to_retain_udt,
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);
// Return true if the `FlushRequest` can be rescheduled to retain the UDT.
// Only true if there are user-defined timestamps in the involved MemTables
// with newer than cutoff timestamp `full_history_ts_low` and not flushing
// immediately will not cause entering write stall mode.
bool ShouldRescheduleFlushRequestToRetainUDT(const FlushRequest& flush_req);
// Schedule background tasks
Status StartPeriodicTaskScheduler();
// Cancel scheduled periodic tasks
Status CancelPeriodicTaskScheduler();
Status RegisterRecordSeqnoTimeWorker(const ReadOptions& read_options,
const WriteOptions& write_options,
bool is_new_db);
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
void MarkLogsSynced(uint64_t up_to, bool synced_dir, VersionEdit* edit);
Status ApplyWALToManifest(const ReadOptions& read_options,
const WriteOptions& write_options,
VersionEdit* edit);
// 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);
// If snapshot_seq != kMaxSequenceNumber, then this function can only be
// called from the write thread that publishes sequence numbers to readers.
// For 1) write-committed, or 2) write-prepared + one-write-queue, this will
// be the write thread performing memtable writes. For write-prepared with
// two write queues, this will be the write thread writing commit marker to
// the WAL.
// If snapshot_seq == kMaxSequenceNumber, this function is called by a caller
// ensuring no writes to the database.
std::pair<Status, std::shared_ptr<const SnapshotImpl>>
CreateTimestampedSnapshotImpl(SequenceNumber snapshot_seq, uint64_t ts,
bool lock = true);
uint64_t GetMaxTotalWalSize() const;
FSDirectory* GetDataDir(ColumnFamilyData* cfd, size_t path_id) const;
Status MaybeReleaseTimestampedSnapshotsAndCheck();
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);
void UpdateDeletionCompactionStats(const std::unique_ptr<Compaction>& c);
void BuildCompactionJobInfo(const ColumnFamilyData* cfd, Compaction* c,
const Status& st,
const CompactionJobStats& compaction_job_stats,
const int job_id,
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);
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(const WriteOptions& write_options, 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);
void MultiGetCommon(const ReadOptions& options,
ColumnFamilyHandle* column_family, const size_t num_keys,
const Slice* keys, PinnableSlice* values,
PinnableWideColumns* columns, std::string* timestamps,
Status* statuses, bool sorted_input);
void MultiGetCommon(const ReadOptions& options, const size_t num_keys,
ColumnFamilyHandle** column_families, const Slice* keys,
PinnableSlice* values, PinnableWideColumns* columns,
std::string* timestamps, Status* statuses,
bool sorted_input);
// 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
//
// `sv_from_thread_local` being set to false indicates that the SuperVersion
// obtained from the ColumnFamilyData, whereas true indicates they are thread
// local.
// A non-OK status will be returned if for a column family that enables
// user-defined timestamp feature, the specified `ReadOptions.timestamp`
// attemps to read collapsed history.
template <class T>
Status MultiCFSnapshot(
const ReadOptions& read_options, ReadCallback* callback,
std::function<MultiGetColumnFamilyData*(typename T::iterator&)>&
iter_deref_func,
T* cf_list, SequenceNumber* snapshot, bool* sv_from_thread_local);
// 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);
void MultiGetWithCallbackImpl(
const ReadOptions& read_options, ColumnFamilyHandle* column_family,
ReadCallback* callback,
autovector<KeyContext*, MultiGetContext::MAX_BATCH_SIZE>* sorted_keys);
Status DisableFileDeletionsWithLock();
Status IncreaseFullHistoryTsLowImpl(ColumnFamilyData* cfd,
std::string ts_low);
bool ShouldReferenceSuperVersion(const MergeContext& merge_context);
template <typename IterType, typename ImplType,
typename ErrorIteratorFuncType>
std::unique_ptr<IterType> NewMultiCfIterator(
const ReadOptions& _read_options,
const std::vector<ColumnFamilyHandle*>& column_families,
ErrorIteratorFuncType error_iterator_func);
// Lock over the persistent DB state. Non-nullptr iff successfully acquired.
FileLock* db_lock_;
// Guards changes to DB and CF options to ensure consistency between
// * In-memory options objects
// * Settings in effect
// * Options file contents
// while allowing the DB mutex to be released during slow operations like
// persisting options file or modifying global periodic task timer.
// Always acquired *before* DB mutex when this one is applicable.
InstrumentedMutex options_mutex_;
// Guards reads and writes to in-memory stats_history_.
InstrumentedMutex stats_history_mutex_;
// In addition to mutex_, log_write_mutex_ protects 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 deadlock, 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_;
// Log files that we can recycle. Must be protected by db mutex_.
std::deque<uint64_t> log_recycle_files_;
// Protected by log_write_mutex_.
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
// expensive mutex_ lock during WAL write, which update log_empty_.
bool log_empty_;
ColumnFamilyHandleImpl* persist_stats_cf_handle_;
bool persistent_stats_cfd_exists_ = true;
// alive_log_files_ is protected by mutex_ and log_write_mutex_ with details
// as follows:
// 1. read by FindObsoleteFiles() which can be called in either application
// thread or RocksDB bg threads, both mutex_ and log_write_mutex_ are
// held.
// 2. pop_front() by FindObsoleteFiles(), both mutex_ and log_write_mutex_
// are held.
// 3. push_back() by DBImpl::Open() and DBImpl::RestoreAliveLogFiles()
// (actually called by Open()), only mutex_ is held because at this point,
// the DB::Open() call has not returned success to application, and the
// only other thread(s) that can conflict are bg threads calling
// FindObsoleteFiles() which ensure that both mutex_ and log_write_mutex_
// are held when accessing alive_log_files_.
// 4. read by DBImpl::Open() is protected by mutex_.
// 5. push_back() by SwitchMemtable(). Both mutex_ and log_write_mutex_ are
// held. This is done by the write group leader. Note that in the case of
// two-write-queues, another WAL-only write thread can be writing to the
// WAL concurrently. See 9.
// 6. read by SwitchWAL() with both mutex_ and log_write_mutex_ held. This is
// done by write group leader.
// 7. read by ConcurrentWriteToWAL() by the write group leader in the case of
// two-write-queues. Only log_write_mutex_ is held to protect concurrent
// pop_front() by FindObsoleteFiles().
// 8. read by PreprocessWrite() by the write group leader. log_write_mutex_
// is held to protect the data structure from concurrent pop_front() by
// FindObsoleteFiles().
// 9. read by ConcurrentWriteToWAL() by a WAL-only write thread in the case
// of two-write-queues. Only log_write_mutex_ is held. This suffices to
// protect the data structure from concurrent push_back() by current
// write group leader as well as pop_front() by FindObsoleteFiles().
std::deque<LogFileNumberSize> alive_log_files_;
// Log files that aren't fully synced, and the current log file.
// Synchronization:
// 1. read by FindObsoleteFiles() which can be called either in application
// thread or RocksDB bg threads. log_write_mutex_ is always held, while
// some reads are performed without mutex_.
// 2. pop_front() by FindObsoleteFiles() with only log_write_mutex_ held.
// 3. read by DBImpl::Open() with both mutex_ and log_write_mutex_.
// 4. emplace_back() by DBImpl::Open() with both mutex_ and log_write_mutex.
// Note that at this point, DB::Open() has not returned success to
// application, thus the only other thread(s) that can conflict are bg
// threads calling FindObsoleteFiles(). See 1.
// 5. iteration and clear() from CloseHelper() always hold log_write_mutex
// and mutex_.
// 6. back() called by APIs FlushWAL() and LockWAL() are protected by only
// log_write_mutex_. These two can be called by application threads after
// DB::Open() returns success to applications.
// 7. read by SyncWAL(), another API, protected by only log_write_mutex_.
// 8. read by MarkLogsNotSynced() and MarkLogsSynced() are protected by
// log_write_mutex_.
// 9. erase() by MarkLogsSynced() protected by log_write_mutex_.
// 10. read by SyncClosedLogs() protected by only log_write_mutex_. This can
// happen in bg flush threads after DB::Open() returns success to
// applications.
// 11. reads, e.g. front(), iteration, and back() called by PreprocessWrite()
// holds only the log_write_mutex_. This is done by the write group
// leader. A bg thread calling FindObsoleteFiles() or MarkLogsSynced()
// can happen concurrently. This is fine because log_write_mutex_ is used
// by all parties. See 2, 5, 9.
// 12. reads, empty(), back() called by SwitchMemtable() hold both mutex_ and
// log_write_mutex_. This happens in the write group leader.
// 13. emplace_back() by SwitchMemtable() hold both mutex_ and
// log_write_mutex_. This happens in the write group leader. Can conflict
// with bg threads calling FindObsoleteFiles(), MarkLogsSynced(),
// SyncClosedLogs(), etc. as well as application threads calling
// FlushWAL(), SyncWAL(), LockWAL(). This is fine because all parties
// require at least log_write_mutex_.
// 14. iteration called in WriteToWAL(write_group) protected by
// log_write_mutex_. This is done by write group leader when
// two-write-queues is disabled and write needs to sync logs.
// 15. back() called in ConcurrentWriteToWAL() protected by log_write_mutex_.
// This can be done by the write group leader if two-write-queues is
// enabled. It can also be done by another WAL-only write thread.
//
// Other observations:
// - 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. Note that calling back() without
// mutex may be unsafe because different implementations of deque::back() may
// access other member variables of deque, causing undefined behaviors.
// Generally, do not access stl containers without proper synchronization.
// - 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 consecutive 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 log_write_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_;
TimestampedSnapshotList timestamped_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. Protected by db mutex_.
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_;
// 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_;
// Number of running IngestExternalFile() or CreateColumnFamilyWithImport()
// calls.
// REQUIRES: mutex held
int num_running_ingest_file_;
WalManager wal_manager_;
// 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_;
// Scheduler to run DumpStats(), PersistStats(), and FlushInfoLog().
// Currently, internally it has a global timer instance for running the tasks.
PeriodicTaskScheduler periodic_task_scheduler_;
// It contains the implementations for each periodic task.
std::map<PeriodicTaskType, const PeriodicTaskFunc> periodic_task_functions_;
// 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_;
// Flag to check whether Close() has been called on this DB
bool closed_;
// save the closing status, for re-calling the close()
Status closing_status_;
// mutex for DB::Close()
InstrumentedMutex closing_mutex_;
// 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_;
std::atomic<uint64_t> max_total_wal_size_;
BlobFileCompletionCallback blob_callback_;
// Pointer to WriteBufferManager stalling interface.
std::unique_ptr<StallInterface> wbm_stall_;
// seqno_to_time_mapping_ stores the sequence number to time mapping, it's not
// thread safe, both read and write need db mutex hold.
SeqnoToTimeMapping seqno_to_time_mapping_;
// Stop write token that is acquired when first LockWAL() is called.
// Destroyed when last UnlockWAL() is called. Controlled by DB mutex.
// See lock_wal_count_
std::unique_ptr<WriteControllerToken> lock_wal_write_token_;
// The number of LockWAL called without matching UnlockWAL call.
// See also lock_wal_write_token_
uint32_t lock_wal_count_;
};
class GetWithTimestampReadCallback : public ReadCallback {
public:
explicit GetWithTimestampReadCallback(SequenceNumber seq)
: ReadCallback(seq) {}
bool IsVisibleFullCheck(SequenceNumber seq) override {
return seq <= max_visible_seq_;
}
};
Options SanitizeOptions(const std::string& db, const Options& src,
bool read_only = false,
Status* logger_creation_s = nullptr);
DBOptions SanitizeOptions(const std::string& db, const DBOptions& src,
bool read_only = false,
Status* logger_creation_s = nullptr);
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.
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.
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.
uint64_t PrecomputeMinLogNumberToKeepNon2PC(
VersionSet* vset, const ColumnFamilyData& cfd_to_flush,
const autovector<VersionEdit*>& edit_list);
// For atomic flush.
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.
uint64_t FindMinPrepLogReferencedByMemTable(
VersionSet* vset, const autovector<MemTable*>& memtables_to_flush);
// For atomic flush.
uint64_t FindMinPrepLogReferencedByMemTable(
VersionSet* vset,
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;
}
inline Status DBImpl::FailIfCfHasTs(
const ColumnFamilyHandle* column_family) const {
if (!column_family) {
return Status::InvalidArgument("column family handle cannot be null");
}
assert(column_family);
const Comparator* const ucmp = column_family->GetComparator();
assert(ucmp);
if (ucmp->timestamp_size() > 0) {
std::ostringstream oss;
oss << "cannot call this method on column family "
<< column_family->GetName() << " that enables timestamp";
return Status::InvalidArgument(oss.str());
}
return Status::OK();
}
inline Status DBImpl::FailIfTsMismatchCf(ColumnFamilyHandle* column_family,
const Slice& ts) const {
if (!column_family) {
return Status::InvalidArgument("column family handle cannot be null");
}
assert(column_family);
const Comparator* const ucmp = column_family->GetComparator();
assert(ucmp);
if (0 == ucmp->timestamp_size()) {
std::stringstream oss;
oss << "cannot call this method on column family "
<< column_family->GetName() << " that does not enable timestamp";
return Status::InvalidArgument(oss.str());
}
const size_t ts_sz = ts.size();
if (ts_sz != ucmp->timestamp_size()) {
std::stringstream oss;
oss << "Timestamp sizes mismatch: expect " << ucmp->timestamp_size() << ", "
<< ts_sz << " given";
return Status::InvalidArgument(oss.str());
}
return Status::OK();
}
inline Status DBImpl::FailIfReadCollapsedHistory(const ColumnFamilyData* cfd,
const SuperVersion* sv,
const Slice& ts) const {
// Reaching to this point means the timestamp size matching sanity check in
// `DBImpl::FailIfTsMismatchCf` already passed. So we skip that and assume
// column family has the same user-defined timestamp format as `ts`.
const Comparator* const ucmp = cfd->user_comparator();
assert(ucmp);
const std::string& full_history_ts_low = sv->full_history_ts_low;
assert(full_history_ts_low.empty() ||
full_history_ts_low.size() == ts.size());
if (!full_history_ts_low.empty() &&
ucmp->CompareTimestamp(ts, full_history_ts_low) < 0) {
std::stringstream oss;
oss << "Read timestamp: " << ts.ToString(true)
<< " is smaller than full_history_ts_low: "
<< Slice(full_history_ts_low).ToString(true) << std::endl;
return Status::InvalidArgument(oss.str());
}
return Status::OK();
}
} // namespace ROCKSDB_NAMESPACE
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