Kevacoin source tree
You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.

399 lines
14 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.
//
// The representation of a DBImpl consists of a set of Versions. The
// newest version is called "current". Older versions may be kept
// around to provide a consistent view to live iterators.
//
// Each Version keeps track of a set of Table files per level. The
// entire set of versions is maintained in a VersionSet.
//
// Version,VersionSet are thread-compatible, but require external
// synchronization on all accesses.
#ifndef STORAGE_LEVELDB_DB_VERSION_SET_H_
#define STORAGE_LEVELDB_DB_VERSION_SET_H_
#include <map>
#include <set>
#include <vector>
#include "db/dbformat.h"
#include "db/version_edit.h"
#include "port/port.h"
#include "port/thread_annotations.h"
namespace leveldb {
namespace log { class Writer; }
class Compaction;
class Iterator;
class MemTable;
class TableBuilder;
class TableCache;
class Version;
class VersionSet;
class WritableFile;
// Return the smallest index i such that files[i]->largest >= key.
// Return files.size() if there is no such file.
// REQUIRES: "files" contains a sorted list of non-overlapping files.
extern int FindFile(const InternalKeyComparator& icmp,
const std::vector<FileMetaData*>& files,
const Slice& key);
// Returns true iff some file in "files" overlaps the user key range
// [*smallest,*largest].
// smallest==NULL represents a key smaller than all keys in the DB.
// largest==NULL represents a key largest than all keys in the DB.
// REQUIRES: If disjoint_sorted_files, files[] contains disjoint ranges
// in sorted order.
extern bool SomeFileOverlapsRange(
const InternalKeyComparator& icmp,
bool disjoint_sorted_files,
const std::vector<FileMetaData*>& files,
const Slice* smallest_user_key,
const Slice* largest_user_key);
class Version {
public:
// Append to *iters a sequence of iterators that will
// yield the contents of this Version when merged together.
// REQUIRES: This version has been saved (see VersionSet::SaveTo)
void AddIterators(const ReadOptions&, std::vector<Iterator*>* iters);
// Lookup the value for key. If found, store it in *val and
// return OK. Else return a non-OK status. Fills *stats.
// REQUIRES: lock is not held
struct GetStats {
FileMetaData* seek_file;
int seek_file_level;
};
Status Get(const ReadOptions&, const LookupKey& key, std::string* val,
GetStats* stats);
// Adds "stats" into the current state. Returns true if a new
// compaction may need to be triggered, false otherwise.
// REQUIRES: lock is held
bool UpdateStats(const GetStats& stats);
// Record a sample of bytes read at the specified internal key.
// Samples are taken approximately once every config::kReadBytesPeriod
// bytes. Returns true if a new compaction may need to be triggered.
// REQUIRES: lock is held
bool RecordReadSample(Slice key);
// Reference count management (so Versions do not disappear out from
// under live iterators)
void Ref();
void Unref();
void GetOverlappingInputs(
int level,
const InternalKey* begin, // NULL means before all keys
const InternalKey* end, // NULL means after all keys
std::vector<FileMetaData*>* inputs);
// Returns true iff some file in the specified level overlaps
// some part of [*smallest_user_key,*largest_user_key].
// smallest_user_key==NULL represents a key smaller than all keys in the DB.
// largest_user_key==NULL represents a key largest than all keys in the DB.
bool OverlapInLevel(int level,
const Slice* smallest_user_key,
const Slice* largest_user_key);
// Return the level at which we should place a new memtable compaction
// result that covers the range [smallest_user_key,largest_user_key].
int PickLevelForMemTableOutput(const Slice& smallest_user_key,
const Slice& largest_user_key);
int NumFiles(int level) const { return files_[level].size(); }
// Return a human readable string that describes this version's contents.
std::string DebugString() const;
private:
friend class Compaction;
friend class VersionSet;
class LevelFileNumIterator;
Iterator* NewConcatenatingIterator(const ReadOptions&, int level) const;
// Call func(arg, level, f) for every file that overlaps user_key in
// order from newest to oldest. If an invocation of func returns
// false, makes no more calls.
//
// REQUIRES: user portion of internal_key == user_key.
void ForEachOverlapping(Slice user_key, Slice internal_key,
void* arg,
bool (*func)(void*, int, FileMetaData*));
VersionSet* vset_; // VersionSet to which this Version belongs
Version* next_; // Next version in linked list
Version* prev_; // Previous version in linked list
int refs_; // Number of live refs to this version
// List of files per level
std::vector<FileMetaData*> files_[config::kNumLevels];
// Next file to compact based on seek stats.
FileMetaData* file_to_compact_;
int file_to_compact_level_;
// Level that should be compacted next and its compaction score.
// Score < 1 means compaction is not strictly needed. These fields
// are initialized by Finalize().
double compaction_score_;
int compaction_level_;
explicit Version(VersionSet* vset)
: vset_(vset), next_(this), prev_(this), refs_(0),
file_to_compact_(NULL),
file_to_compact_level_(-1),
compaction_score_(-1),
compaction_level_(-1) {
}
~Version();
// No copying allowed
Version(const Version&);
void operator=(const Version&);
};
class VersionSet {
public:
VersionSet(const std::string& dbname,
const Options* options,
TableCache* table_cache,
const InternalKeyComparator*);
~VersionSet();
// Apply *edit to the current version to form a new descriptor that
// is both saved to persistent state and installed as the new
// current version. Will release *mu while actually writing to the file.
// REQUIRES: *mu is held on entry.
// REQUIRES: no other thread concurrently calls LogAndApply()
Status LogAndApply(VersionEdit* edit, port::Mutex* mu)
EXCLUSIVE_LOCKS_REQUIRED(mu);
// Recover the last saved descriptor from persistent storage.
Squashed 'src/leveldb/' changes from 20ca81f..a31c8aa a31c8aa Add NewAppendableFile for win32 environment 1913d71 Merge upstream LevelDB 1.19 3080a45 Increase leveldb version to 1.19. fa6dc01 A zippy change broke test assumptions about the size of compressed output. Fix the tests by allowing more slop in zippy's behavior. ------------- Created by MOE: https://github.com/google/moe MOE_MIGRATED_REVID=123432472 06a191b fix problems in LevelDB's caching code a7bff69 Fix LevelDB build when asserts are enabled in release builds. (#367) ea992b4 Change std::uint64_t to uint64_t (#354) e84b5bd This CL fixes a bug encountered when reading records from leveldb files that have been split, as in a [] input task split. 3211343 Deleted redundant null ptr check prior to delete. 7306ef8 Merge pull request #348 from randomascii/master 6b18316 Fix signed/unsigned mismatch on VC++ builds adbe3eb Putting build artifacts in subdirectory. 2d0320a Merge pull request #329 from ralphtheninja/travis-badge dd1c3c3 add travis build badge 43fcf23 Merge pull request #328 from cmumford/master 9fcae61 Added a Travis CI build file. dac40d2 Merge pull request #284 from ideawu/master 8ec241a Merge pull request #317 from falvojr/patch-1 5d36bed Merge pull request #272 from vapier/master 4753c9b Added a contributors section to README.md e2446d0 Merge pull request #275 from paulirish/patch-1 706b7f8 Resolve race when getting approximate-memory-usage property 3c9ff3c Only compiling TrimSpace on linux. f8d205c Including atomic_pointer.h in port_posix 889de31 Let LevelDB use xcrun to determine Xcode.app path instead of using a hardcoded path. 528c2bc Add "approximate-memory-usage" property to leveldb::DB::GetProperty 359b6bc Add leveldb::Cache::Prune 50e77a8 Fix size_t/int comparison/conversion issues in leveldb. 5208e79 Added leveldb::Status::IsInvalidArgument() method. ce45404 Suppress error reporting after seeking but before a valid First or Full record is encountered. b9afa1f include <assert> -> <cassert> edf2939 Update README.md 65190ac Will not reuse manifest if reuse_logs options is false. ac1d69d LevelDB now attempts to reuse the preceding MANIFEST and log file when re-opened. 76bba13 fix indent 8fcceb2 log compaction output file's level along with number 0e0f074 documentation. improved link c85addc readme: improved documentation link ceff6f1 Fix Android/MIPS build. 77948e7 Add benchmark that measures cost of repeatedly opening the database. 34ad72e Move header guard below copyright banner. a75d435 Clean up layering of storage/leveldb/... b234f65 Added a new fault injection test. c4c38f9 Add arm64 support to leveldb. cea9b10 Fixed incorrect comment wording for Iterator::Seek. c00c569 Deleted old README file. git-subtree-dir: src/leveldb git-subtree-split: a31c8aa408d5594830f7cb20ead1ef1dff51b79e
8 years ago
Status Recover(bool *save_manifest);
// Return the current version.
Version* current() const { return current_; }
// Return the current manifest file number
uint64_t ManifestFileNumber() const { return manifest_file_number_; }
// Allocate and return a new file number
uint64_t NewFileNumber() { return next_file_number_++; }
// Arrange to reuse "file_number" unless a newer file number has
// already been allocated.
// REQUIRES: "file_number" was returned by a call to NewFileNumber().
void ReuseFileNumber(uint64_t file_number) {
if (next_file_number_ == file_number + 1) {
next_file_number_ = file_number;
}
}
// Return the number of Table files at the specified level.
int NumLevelFiles(int level) const;
// Return the combined file size of all files at the specified level.
int64_t NumLevelBytes(int level) const;
// Return the last sequence number.
uint64_t LastSequence() const { return last_sequence_; }
// Set the last sequence number to s.
void SetLastSequence(uint64_t s) {
assert(s >= last_sequence_);
last_sequence_ = s;
}
// Mark the specified file number as used.
void MarkFileNumberUsed(uint64_t number);
// Return the current log file number.
uint64_t LogNumber() const { return log_number_; }
// Return the log file number for the log file that is currently
// being compacted, or zero if there is no such log file.
uint64_t PrevLogNumber() const { return prev_log_number_; }
// Pick level and inputs for a new compaction.
// Returns NULL if there is no compaction to be done.
// Otherwise returns a pointer to a heap-allocated object that
// describes the compaction. Caller should delete the result.
Compaction* PickCompaction();
// Return a compaction object for compacting the range [begin,end] in
// the specified level. Returns NULL if there is nothing in that
// level that overlaps the specified range. Caller should delete
// the result.
Compaction* CompactRange(
int level,
const InternalKey* begin,
const InternalKey* end);
// Return the maximum overlapping data (in bytes) at next level for any
// file at a level >= 1.
int64_t MaxNextLevelOverlappingBytes();
// Create an iterator that reads over the compaction inputs for "*c".
// The caller should delete the iterator when no longer needed.
Iterator* MakeInputIterator(Compaction* c);
// Returns true iff some level needs a compaction.
bool NeedsCompaction() const {
Version* v = current_;
return (v->compaction_score_ >= 1) || (v->file_to_compact_ != NULL);
}
// Add all files listed in any live version to *live.
// May also mutate some internal state.
void AddLiveFiles(std::set<uint64_t>* live);
// Return the approximate offset in the database of the data for
// "key" as of version "v".
uint64_t ApproximateOffsetOf(Version* v, const InternalKey& key);
// Return a human-readable short (single-line) summary of the number
// of files per level. Uses *scratch as backing store.
struct LevelSummaryStorage {
char buffer[100];
};
const char* LevelSummary(LevelSummaryStorage* scratch) const;
private:
class Builder;
friend class Compaction;
friend class Version;
Squashed 'src/leveldb/' changes from 20ca81f..a31c8aa a31c8aa Add NewAppendableFile for win32 environment 1913d71 Merge upstream LevelDB 1.19 3080a45 Increase leveldb version to 1.19. fa6dc01 A zippy change broke test assumptions about the size of compressed output. Fix the tests by allowing more slop in zippy's behavior. ------------- Created by MOE: https://github.com/google/moe MOE_MIGRATED_REVID=123432472 06a191b fix problems in LevelDB's caching code a7bff69 Fix LevelDB build when asserts are enabled in release builds. (#367) ea992b4 Change std::uint64_t to uint64_t (#354) e84b5bd This CL fixes a bug encountered when reading records from leveldb files that have been split, as in a [] input task split. 3211343 Deleted redundant null ptr check prior to delete. 7306ef8 Merge pull request #348 from randomascii/master 6b18316 Fix signed/unsigned mismatch on VC++ builds adbe3eb Putting build artifacts in subdirectory. 2d0320a Merge pull request #329 from ralphtheninja/travis-badge dd1c3c3 add travis build badge 43fcf23 Merge pull request #328 from cmumford/master 9fcae61 Added a Travis CI build file. dac40d2 Merge pull request #284 from ideawu/master 8ec241a Merge pull request #317 from falvojr/patch-1 5d36bed Merge pull request #272 from vapier/master 4753c9b Added a contributors section to README.md e2446d0 Merge pull request #275 from paulirish/patch-1 706b7f8 Resolve race when getting approximate-memory-usage property 3c9ff3c Only compiling TrimSpace on linux. f8d205c Including atomic_pointer.h in port_posix 889de31 Let LevelDB use xcrun to determine Xcode.app path instead of using a hardcoded path. 528c2bc Add "approximate-memory-usage" property to leveldb::DB::GetProperty 359b6bc Add leveldb::Cache::Prune 50e77a8 Fix size_t/int comparison/conversion issues in leveldb. 5208e79 Added leveldb::Status::IsInvalidArgument() method. ce45404 Suppress error reporting after seeking but before a valid First or Full record is encountered. b9afa1f include <assert> -> <cassert> edf2939 Update README.md 65190ac Will not reuse manifest if reuse_logs options is false. ac1d69d LevelDB now attempts to reuse the preceding MANIFEST and log file when re-opened. 76bba13 fix indent 8fcceb2 log compaction output file's level along with number 0e0f074 documentation. improved link c85addc readme: improved documentation link ceff6f1 Fix Android/MIPS build. 77948e7 Add benchmark that measures cost of repeatedly opening the database. 34ad72e Move header guard below copyright banner. a75d435 Clean up layering of storage/leveldb/... b234f65 Added a new fault injection test. c4c38f9 Add arm64 support to leveldb. cea9b10 Fixed incorrect comment wording for Iterator::Seek. c00c569 Deleted old README file. git-subtree-dir: src/leveldb git-subtree-split: a31c8aa408d5594830f7cb20ead1ef1dff51b79e
8 years ago
bool ReuseManifest(const std::string& dscname, const std::string& dscbase);
void Finalize(Version* v);
void GetRange(const std::vector<FileMetaData*>& inputs,
InternalKey* smallest,
InternalKey* largest);
void GetRange2(const std::vector<FileMetaData*>& inputs1,
const std::vector<FileMetaData*>& inputs2,
InternalKey* smallest,
InternalKey* largest);
void SetupOtherInputs(Compaction* c);
// Save current contents to *log
Status WriteSnapshot(log::Writer* log);
void AppendVersion(Version* v);
Env* const env_;
const std::string dbname_;
const Options* const options_;
TableCache* const table_cache_;
const InternalKeyComparator icmp_;
uint64_t next_file_number_;
uint64_t manifest_file_number_;
uint64_t last_sequence_;
uint64_t log_number_;
uint64_t prev_log_number_; // 0 or backing store for memtable being compacted
// Opened lazily
WritableFile* descriptor_file_;
log::Writer* descriptor_log_;
Version dummy_versions_; // Head of circular doubly-linked list of versions.
Version* current_; // == dummy_versions_.prev_
// Per-level key at which the next compaction at that level should start.
// Either an empty string, or a valid InternalKey.
std::string compact_pointer_[config::kNumLevels];
// No copying allowed
VersionSet(const VersionSet&);
void operator=(const VersionSet&);
};
// A Compaction encapsulates information about a compaction.
class Compaction {
public:
~Compaction();
// Return the level that is being compacted. Inputs from "level"
// and "level+1" will be merged to produce a set of "level+1" files.
int level() const { return level_; }
// Return the object that holds the edits to the descriptor done
// by this compaction.
VersionEdit* edit() { return &edit_; }
// "which" must be either 0 or 1
int num_input_files(int which) const { return inputs_[which].size(); }
// Return the ith input file at "level()+which" ("which" must be 0 or 1).
FileMetaData* input(int which, int i) const { return inputs_[which][i]; }
// Maximum size of files to build during this compaction.
uint64_t MaxOutputFileSize() const { return max_output_file_size_; }
// Is this a trivial compaction that can be implemented by just
// moving a single input file to the next level (no merging or splitting)
bool IsTrivialMove() const;
// Add all inputs to this compaction as delete operations to *edit.
void AddInputDeletions(VersionEdit* edit);
// Returns true if the information we have available guarantees that
// the compaction is producing data in "level+1" for which no data exists
// in levels greater than "level+1".
bool IsBaseLevelForKey(const Slice& user_key);
// Returns true iff we should stop building the current output
// before processing "internal_key".
bool ShouldStopBefore(const Slice& internal_key);
// Release the input version for the compaction, once the compaction
// is successful.
void ReleaseInputs();
private:
friend class Version;
friend class VersionSet;
Compaction(const Options* options, int level);
int level_;
uint64_t max_output_file_size_;
Version* input_version_;
VersionEdit edit_;
// Each compaction reads inputs from "level_" and "level_+1"
std::vector<FileMetaData*> inputs_[2]; // The two sets of inputs
// State used to check for number of overlapping grandparent files
// (parent == level_ + 1, grandparent == level_ + 2)
std::vector<FileMetaData*> grandparents_;
size_t grandparent_index_; // Index in grandparent_starts_
bool seen_key_; // Some output key has been seen
int64_t overlapped_bytes_; // Bytes of overlap between current output
// and grandparent files
// State for implementing IsBaseLevelForKey
// level_ptrs_ holds indices into input_version_->levels_: our state
// is that we are positioned at one of the file ranges for each
// higher level than the ones involved in this compaction (i.e. for
// all L >= level_ + 2).
size_t level_ptrs_[config::kNumLevels];
};
} // namespace leveldb
#endif // STORAGE_LEVELDB_DB_VERSION_SET_H_