Merge commit 'b3cd242c6a0c1ef3e7dc63c870604f4ccc92c7a8' as 'Subtrees/hyperleveldb'

Subtrees/hyperleveldb/db/db_impl.h

@@ -0,0 +1,223 @@
+// 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 <deque>
+#include <set>
+#include "db/dbformat.h"
+#include "db/log_writer.h"
+#include "db/snapshot.h"
+#include "hyperleveldb/db.h"
+#include "hyperleveldb/env.h"
+#include "port/port.h"
+#include "port/thread_annotations.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, std::string* value);
+  virtual void GetApproximateSizes(const Range* range, int n, uint64_t* sizes);
+  virtual void CompactRange(const Slice* begin, const Slice* end);
+
+  // 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 Slice* begin, const Slice* 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_t TEST_MaxNextLevelOverlappingBytes();
+
+ private:
+  friend class DB;
+  struct CompactionState;
+  struct Writer;
+
+  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) EXCLUSIVE_LOCKS_REQUIRED(mutex_);
+
+  void MaybeIgnoreError(Status* s) const;
+
+  // Delete any unneeded files and stale in-memory entries.
+  void DeleteObsoleteFiles();
+
+  // A background thread to compact the in-memory write buffer to disk.
+  // Switches to a new log-file/memtable and writes a new descriptor iff
+  // successful.
+  static void CompactMemTableWrapper(void* db)
+  { reinterpret_cast<DBImpl*>(db)->CompactMemTableThread(); }
+  void CompactMemTableThread();
+
+  Status RecoverLogFile(uint64_t log_number,
+                        VersionEdit* edit,
+                        SequenceNumber* max_sequence)
+      EXCLUSIVE_LOCKS_REQUIRED(mutex_);
+
+  Status WriteLevel0Table(MemTable* mem, VersionEdit* edit, Version* base, uint64_t* number)
+      EXCLUSIVE_LOCKS_REQUIRED(mutex_);
+
+  Status SequenceWriteBegin(Writer* w, WriteBatch* updates)
+      EXCLUSIVE_LOCKS_REQUIRED(mutex_);
+  void SequenceWriteEnd(Writer* w)
+      EXCLUSIVE_LOCKS_REQUIRED(mutex_);
+
+  static void CompactLevelWrapper(void* db)
+  { reinterpret_cast<DBImpl*>(db)->CompactLevelThread(); }
+  void CompactLevelThread();
+  Status BackgroundCompaction() EXCLUSIVE_LOCKS_REQUIRED(mutex_);
+
+  static void CompactOptimisticWrapper(void* db)
+  { reinterpret_cast<DBImpl*>(db)->CompactOptimisticThread(); }
+  void CompactOptimisticThread();
+  Status OptimisticCompaction() EXCLUSIVE_LOCKS_REQUIRED(mutex_);
+
+  void CleanupCompaction(CompactionState* compact)
+      EXCLUSIVE_LOCKS_REQUIRED(mutex_);
+  Status DoCompactionWork(CompactionState* compact)
+      EXCLUSIVE_LOCKS_REQUIRED(mutex_);
+  Status OpenCompactionOutputFile(CompactionState* compact);
+  Status FinishCompactionOutputFile(CompactionState* compact, Iterator* input);
+  Status InstallCompactionResults(CompactionState* compact)
+      EXCLUSIVE_LOCKS_REQUIRED(mutex_);
+
+  // Constant after construction
+  Env* const env_;
+  const InternalKeyComparator internal_comparator_;
+  const InternalFilterPolicy internal_filter_policy_;
+  const Options options_;  // options_.comparator == &internal_comparator_
+  bool owns_info_log_;
+  bool owns_cache_;
+  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_;
+  MemTable* mem_;
+  MemTable* imm_;                // Memtable being compacted
+  port::AtomicPointer has_imm_;  // So bg thread can detect non-NULL imm_
+  WritableFile* logfile_;
+  uint64_t logfile_number_;
+  log::Writer* log_;
+
+  // Synchronize writers
+  uint64_t __attribute__ ((aligned (8))) writers_lower_;
+  uint64_t __attribute__ ((aligned (8))) writers_upper_;
+
+  SnapshotList snapshots_;
+
+  // Set of table files to protect from deletion because they are
+  // part of ongoing compactions.
+  std::set<uint64_t> pending_outputs_;
+
+  bool allow_background_activity_;
+  bool levels_locked_[leveldb::config::kNumLevels];
+  int num_bg_threads_;
+  // Tell the foreground that background has done something of note
+  port::CondVar bg_fg_cv_;
+  // Communicate with compaction background thread
+  port::CondVar bg_compaction_cv_;
+  // Communicate with memtable->L0 background thread
+  port::CondVar bg_memtable_cv_;
+  // Communicate with the optimistic background thread
+  bool bg_optimistic_trip_;
+  port::CondVar bg_optimistic_cv_;
+  // Mutual exlusion protecting the LogAndApply func
+  port::CondVar bg_log_cv_;
+  bool bg_log_occupied_;
+
+  // Information for a manual compaction
+  struct ManualCompaction {
+    int level;
+    bool done;
+    const InternalKey* begin;   // NULL means beginning of key range
+    const InternalKey* end;     // NULL means end of key range
+    InternalKey tmp_storage;    // Used to keep track of compaction progress
+  };
+  ManualCompaction* manual_compaction_;
+
+  VersionSet* versions_;
+
+  // Have we encountered a background error in paranoid mode?
+  Status bg_error_;
+  int consecutive_compaction_errors_;
+
+  // Per level compaction stats.  stats_[level] stores the stats for
+  // compactions that produced data for the specified "level".
+  struct CompactionStats {
+    int64_t micros;
+    int64_t bytes_read;
+    int64_t bytes_written;
+
+    CompactionStats() : micros(0), bytes_read(0), bytes_written(0) { }
+
+    void Add(const CompactionStats& c) {
+      this->micros += c.micros;
+      this->bytes_read += c.bytes_read;
+      this->bytes_written += c.bytes_written;
+    }
+  };
+  CompactionStats stats_[config::kNumLevels];
+
+  // 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 InternalFilterPolicy* ipolicy,
+                               const Options& src);
+
+}  // namespace leveldb
+
+#endif  // STORAGE_LEVELDB_DB_DB_IMPL_H_