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rocksdb/db/db_impl.h

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6.6 KiB

// 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.
#ifndef STORAGE_LEVELDB_DB_DB_IMPL_H_
#define STORAGE_LEVELDB_DB_DB_IMPL_H_
#include <set>
#include "db/dbformat.h"
#include "db/log_writer.h"
#include "db/snapshot.h"
#include "include/db.h"
#include "include/env.h"
#include "port/port.h"
namespace leveldb {
class MemTable;
class TableCache;
class Version;
class VersionEdit;
class VersionSet;
class DBImpl : public DB {
public:
DBImpl(const Options& options, const std::string& dbname);
virtual ~DBImpl();
// Implementations of the DB interface
virtual Status Put(const WriteOptions&, const Slice& key, const Slice& value);
virtual Status Delete(const WriteOptions&, const Slice& key);
virtual Status Write(const WriteOptions& options, WriteBatch* updates);
virtual Status Get(const ReadOptions& options,
const Slice& key,
std::string* value);
virtual Iterator* NewIterator(const ReadOptions&);
virtual const Snapshot* GetSnapshot();
virtual void ReleaseSnapshot(const Snapshot* snapshot);
virtual bool GetProperty(const Slice& property, uint64_t* value);
virtual void GetApproximateSizes(const Range* range, int n, uint64_t* sizes);
// Extra methods (for testing) that are not in the public DB interface
// Compact any files in the named level that overlap [begin,end]
void TEST_CompactRange(
int level,
const std::string& begin,
const std::string& end);
// Force current memtable contents to be compacted.
Status TEST_CompactMemTable();
// 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.
Iterator* TEST_NewInternalIterator();
// Return the maximum overlapping data (in bytes) at next level for any
// file at a level >= 1.
int64 TEST_MaxNextLevelOverlappingBytes();
private:
friend class DB;
Iterator* NewInternalIterator(const ReadOptions&,
SequenceNumber* latest_snapshot);
Status NewDB();
// 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.
Status Recover(VersionEdit* edit);
// Apply the specified updates and save the resulting descriptor to
// persistent storage. If cleanup_mem is non-NULL, arrange to
// delete it when all existing snapshots have gone away iff Install()
// returns OK.
Status Install(VersionEdit* edit,
uint64_t new_log_number,
MemTable* cleanup_mem);
void MaybeIgnoreError(Status* s) const;
// Delete any unneeded files and stale in-memory entries.
void DeleteObsoleteFiles();
// Called when an iterator over a particular version of the
// descriptor goes away.
static void Unref(void* arg1, void* arg2);
// Compact the in-memory write buffer to disk. Switches to a new
// log-file/memtable and writes a new descriptor iff successful.
Status CompactMemTable();
Status RecoverLogFile(uint64_t log_number,
VersionEdit* edit,
SequenceNumber* max_sequence);
Status WriteLevel0Table(MemTable* mem, VersionEdit* edit);
bool HasLargeValues(const WriteBatch& batch) const;
// Process data in "*updates" and return a status. "assigned_seq"
// is the sequence number assigned to the first mod in "*updates".
// If no large values are encountered, "*final" is set to "updates".
// If large values were encountered, registers the references of the
// large values with the VersionSet, writes the large values to
// files (if appropriate), and allocates a new WriteBatch with the
// large values replaced with indirect references and stores a
// pointer to the new WriteBatch in *final. If *final != updates on
// return, then the client should delete *final when no longer
// needed. Returns OK on success, and an appropriate error
// otherwise.
Status HandleLargeValues(SequenceNumber assigned_seq,
WriteBatch* updates,
WriteBatch** final);
// Helper routine for HandleLargeValues
void MaybeCompressLargeValue(
const Slice& raw_value,
Slice* file_bytes,
std::string* scratch,
LargeValueRef* ref);
struct CompactionState;
void MaybeScheduleCompaction();
static void BGWork(void* db);
void BackgroundCall();
void BackgroundCompaction();
void CleanupCompaction(CompactionState* compact);
Status DoCompactionWork(CompactionState* compact);
Status OpenCompactionOutputFile(CompactionState* compact);
Status FinishCompactionOutputFile(CompactionState* compact, Iterator* input);
Status InstallCompactionResults(CompactionState* compact);
// Constant after construction
Env* const env_;
const InternalKeyComparator internal_comparator_;
const Options options_; // options_.comparator == &internal_comparator_
bool owns_info_log_;
const std::string dbname_;
// table_cache_ provides its own synchronization
TableCache* table_cache_;
// Lock over the persistent DB state. Non-NULL iff successfully acquired.
FileLock* db_lock_;
// State below is protected by mutex_
port::Mutex mutex_;
port::AtomicPointer shutting_down_;
port::CondVar bg_cv_; // Signalled when !bg_compaction_scheduled_
port::CondVar compacting_cv_; // Signalled when !compacting_
SequenceNumber last_sequence_;
MemTable* mem_;
WritableFile* logfile_;
log::Writer* log_;
uint64_t log_number_;
SnapshotList snapshots_;
// Set of table files to protect from deletion because they are
// part of ongoing compactions.
std::set<uint64_t> pending_outputs_;
// Has a background compaction been scheduled or is running?
bool bg_compaction_scheduled_;
// Is there a compaction running?
bool compacting_;
VersionSet* versions_;
// Have we encountered a background error in paranoid mode?
Status bg_error_;
// No copying allowed
DBImpl(const DBImpl&);
void operator=(const DBImpl&);
const Comparator* user_comparator() const {
return internal_comparator_.user_comparator();
}
};
// Sanitize db options. The caller should delete result.info_log if
// it is not equal to src.info_log.
extern Options SanitizeOptions(const std::string& db,
const InternalKeyComparator* icmp,
const Options& src);
}
#endif // STORAGE_LEVELDB_DB_DB_IMPL_H_