aboutsummaryrefslogtreecommitdiff
path: root/db/version_set.cc
diff options
context:
space:
mode:
Diffstat (limited to 'db/version_set.cc')
-rw-r--r--db/version_set.cc1443
1 files changed, 1443 insertions, 0 deletions
diff --git a/db/version_set.cc b/db/version_set.cc
new file mode 100644
index 0000000..4fd1dde
--- /dev/null
+++ b/db/version_set.cc
@@ -0,0 +1,1443 @@
+// 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.
+
+#include "db/version_set.h"
+
+#include <algorithm>
+#include <stdio.h>
+#include "db/filename.h"
+#include "db/log_reader.h"
+#include "db/log_writer.h"
+#include "db/memtable.h"
+#include "db/table_cache.h"
+#include "leveldb/env.h"
+#include "leveldb/table_builder.h"
+#include "table/merger.h"
+#include "table/two_level_iterator.h"
+#include "util/coding.h"
+#include "util/logging.h"
+
+namespace leveldb {
+
+static const int kTargetFileSize = 2 * 1048576;
+
+// Maximum bytes of overlaps in grandparent (i.e., level+2) before we
+// stop building a single file in a level->level+1 compaction.
+static const int64_t kMaxGrandParentOverlapBytes = 10 * kTargetFileSize;
+
+// Maximum number of bytes in all compacted files. We avoid expanding
+// the lower level file set of a compaction if it would make the
+// total compaction cover more than this many bytes.
+static const int64_t kExpandedCompactionByteSizeLimit = 25 * kTargetFileSize;
+
+static double MaxBytesForLevel(int level) {
+ // Note: the result for level zero is not really used since we set
+ // the level-0 compaction threshold based on number of files.
+ double result = 10 * 1048576.0; // Result for both level-0 and level-1
+ while (level > 1) {
+ result *= 10;
+ level--;
+ }
+ return result;
+}
+
+static uint64_t MaxFileSizeForLevel(int level) {
+ return kTargetFileSize; // We could vary per level to reduce number of files?
+}
+
+static int64_t TotalFileSize(const std::vector<FileMetaData*>& files) {
+ int64_t sum = 0;
+ for (size_t i = 0; i < files.size(); i++) {
+ sum += files[i]->file_size;
+ }
+ return sum;
+}
+
+namespace {
+std::string IntSetToString(const std::set<uint64_t>& s) {
+ std::string result = "{";
+ for (std::set<uint64_t>::const_iterator it = s.begin();
+ it != s.end();
+ ++it) {
+ result += (result.size() > 1) ? "," : "";
+ result += NumberToString(*it);
+ }
+ result += "}";
+ return result;
+}
+} // namespace
+
+Version::~Version() {
+ assert(refs_ == 0);
+
+ // Remove from linked list
+ prev_->next_ = next_;
+ next_->prev_ = prev_;
+
+ // Drop references to files
+ for (int level = 0; level < config::kNumLevels; level++) {
+ for (size_t i = 0; i < files_[level].size(); i++) {
+ FileMetaData* f = files_[level][i];
+ assert(f->refs > 0);
+ f->refs--;
+ if (f->refs <= 0) {
+ delete f;
+ }
+ }
+ }
+}
+
+int FindFile(const InternalKeyComparator& icmp,
+ const std::vector<FileMetaData*>& files,
+ const Slice& key) {
+ uint32_t left = 0;
+ uint32_t right = files.size();
+ while (left < right) {
+ uint32_t mid = (left + right) / 2;
+ const FileMetaData* f = files[mid];
+ if (icmp.InternalKeyComparator::Compare(f->largest.Encode(), key) < 0) {
+ // Key at "mid.largest" is < "target". Therefore all
+ // files at or before "mid" are uninteresting.
+ left = mid + 1;
+ } else {
+ // Key at "mid.largest" is >= "target". Therefore all files
+ // after "mid" are uninteresting.
+ right = mid;
+ }
+ }
+ return right;
+}
+
+static bool AfterFile(const Comparator* ucmp,
+ const Slice* user_key, const FileMetaData* f) {
+ // NULL user_key occurs before all keys and is therefore never after *f
+ return (user_key != NULL &&
+ ucmp->Compare(*user_key, f->largest.user_key()) > 0);
+}
+
+static bool BeforeFile(const Comparator* ucmp,
+ const Slice* user_key, const FileMetaData* f) {
+ // NULL user_key occurs after all keys and is therefore never before *f
+ return (user_key != NULL &&
+ ucmp->Compare(*user_key, f->smallest.user_key()) < 0);
+}
+
+bool SomeFileOverlapsRange(
+ const InternalKeyComparator& icmp,
+ bool disjoint_sorted_files,
+ const std::vector<FileMetaData*>& files,
+ const Slice* smallest_user_key,
+ const Slice* largest_user_key) {
+ const Comparator* ucmp = icmp.user_comparator();
+ if (!disjoint_sorted_files) {
+ // Need to check against all files
+ for (size_t i = 0; i < files.size(); i++) {
+ const FileMetaData* f = files[i];
+ if (AfterFile(ucmp, smallest_user_key, f) ||
+ BeforeFile(ucmp, largest_user_key, f)) {
+ // No overlap
+ } else {
+ return true; // Overlap
+ }
+ }
+ return false;
+ }
+
+ // Binary search over file list
+ uint32_t index = 0;
+ if (smallest_user_key != NULL) {
+ // Find the earliest possible internal key for smallest_user_key
+ InternalKey small(*smallest_user_key, kMaxSequenceNumber,kValueTypeForSeek);
+ index = FindFile(icmp, files, small.Encode());
+ }
+
+ if (index >= files.size()) {
+ // beginning of range is after all files, so no overlap.
+ return false;
+ }
+
+ return !BeforeFile(ucmp, largest_user_key, files[index]);
+}
+
+// An internal iterator. For a given version/level pair, yields
+// information about the files in the level. For a given entry, key()
+// is the largest key that occurs in the file, and value() is an
+// 16-byte value containing the file number and file size, both
+// encoded using EncodeFixed64.
+class Version::LevelFileNumIterator : public Iterator {
+ public:
+ LevelFileNumIterator(const InternalKeyComparator& icmp,
+ const std::vector<FileMetaData*>* flist)
+ : icmp_(icmp),
+ flist_(flist),
+ index_(flist->size()) { // Marks as invalid
+ }
+ virtual bool Valid() const {
+ return index_ < flist_->size();
+ }
+ virtual void Seek(const Slice& target) {
+ index_ = FindFile(icmp_, *flist_, target);
+ }
+ virtual void SeekToFirst() { index_ = 0; }
+ virtual void SeekToLast() {
+ index_ = flist_->empty() ? 0 : flist_->size() - 1;
+ }
+ virtual void Next() {
+ assert(Valid());
+ index_++;
+ }
+ virtual void Prev() {
+ assert(Valid());
+ if (index_ == 0) {
+ index_ = flist_->size(); // Marks as invalid
+ } else {
+ index_--;
+ }
+ }
+ Slice key() const {
+ assert(Valid());
+ return (*flist_)[index_]->largest.Encode();
+ }
+ Slice value() const {
+ assert(Valid());
+ EncodeFixed64(value_buf_, (*flist_)[index_]->number);
+ EncodeFixed64(value_buf_+8, (*flist_)[index_]->file_size);
+ return Slice(value_buf_, sizeof(value_buf_));
+ }
+ virtual Status status() const { return Status::OK(); }
+ private:
+ const InternalKeyComparator icmp_;
+ const std::vector<FileMetaData*>* const flist_;
+ uint32_t index_;
+
+ // Backing store for value(). Holds the file number and size.
+ mutable char value_buf_[16];
+};
+
+static Iterator* GetFileIterator(void* arg,
+ const ReadOptions& options,
+ const Slice& file_value) {
+ TableCache* cache = reinterpret_cast<TableCache*>(arg);
+ if (file_value.size() != 16) {
+ return NewErrorIterator(
+ Status::Corruption("FileReader invoked with unexpected value"));
+ } else {
+ return cache->NewIterator(options,
+ DecodeFixed64(file_value.data()),
+ DecodeFixed64(file_value.data() + 8));
+ }
+}
+
+Iterator* Version::NewConcatenatingIterator(const ReadOptions& options,
+ int level) const {
+ return NewTwoLevelIterator(
+ new LevelFileNumIterator(vset_->icmp_, &files_[level]),
+ &GetFileIterator, vset_->table_cache_, options);
+}
+
+void Version::AddIterators(const ReadOptions& options,
+ std::vector<Iterator*>* iters) {
+ // Merge all level zero files together since they may overlap
+ for (size_t i = 0; i < files_[0].size(); i++) {
+ iters->push_back(
+ vset_->table_cache_->NewIterator(
+ options, files_[0][i]->number, files_[0][i]->file_size));
+ }
+
+ // For levels > 0, we can use a concatenating iterator that sequentially
+ // walks through the non-overlapping files in the level, opening them
+ // lazily.
+ for (int level = 1; level < config::kNumLevels; level++) {
+ if (!files_[level].empty()) {
+ iters->push_back(NewConcatenatingIterator(options, level));
+ }
+ }
+}
+
+// Callback from TableCache::Get()
+namespace {
+enum SaverState {
+ kNotFound,
+ kFound,
+ kDeleted,
+ kCorrupt,
+};
+struct Saver {
+ SaverState state;
+ const Comparator* ucmp;
+ Slice user_key;
+ std::string* value;
+};
+}
+static void SaveValue(void* arg, const Slice& ikey, const Slice& v) {
+ Saver* s = reinterpret_cast<Saver*>(arg);
+ ParsedInternalKey parsed_key;
+ if (!ParseInternalKey(ikey, &parsed_key)) {
+ s->state = kCorrupt;
+ } else {
+ if (s->ucmp->Compare(parsed_key.user_key, s->user_key) == 0) {
+ s->state = (parsed_key.type == kTypeValue) ? kFound : kDeleted;
+ if (s->state == kFound) {
+ s->value->assign(v.data(), v.size());
+ }
+ }
+ }
+}
+
+static bool NewestFirst(FileMetaData* a, FileMetaData* b) {
+ return a->number > b->number;
+}
+
+Status Version::Get(const ReadOptions& options,
+ const LookupKey& k,
+ std::string* value,
+ GetStats* stats) {
+ Slice ikey = k.internal_key();
+ Slice user_key = k.user_key();
+ const Comparator* ucmp = vset_->icmp_.user_comparator();
+ Status s;
+
+ stats->seek_file = NULL;
+ stats->seek_file_level = -1;
+ FileMetaData* last_file_read = NULL;
+ int last_file_read_level = -1;
+
+ // We can search level-by-level since entries never hop across
+ // levels. Therefore we are guaranteed that if we find data
+ // in an smaller level, later levels are irrelevant.
+ std::vector<FileMetaData*> tmp;
+ FileMetaData* tmp2;
+ for (int level = 0; level < config::kNumLevels; level++) {
+ size_t num_files = files_[level].size();
+ if (num_files == 0) continue;
+
+ // Get the list of files to search in this level
+ FileMetaData* const* files = &files_[level][0];
+ if (level == 0) {
+ // Level-0 files may overlap each other. Find all files that
+ // overlap user_key and process them in order from newest to oldest.
+ tmp.reserve(num_files);
+ for (uint32_t i = 0; i < num_files; i++) {
+ FileMetaData* f = files[i];
+ if (ucmp->Compare(user_key, f->smallest.user_key()) >= 0 &&
+ ucmp->Compare(user_key, f->largest.user_key()) <= 0) {
+ tmp.push_back(f);
+ }
+ }
+ if (tmp.empty()) continue;
+
+ std::sort(tmp.begin(), tmp.end(), NewestFirst);
+ files = &tmp[0];
+ num_files = tmp.size();
+ } else {
+ // Binary search to find earliest index whose largest key >= ikey.
+ uint32_t index = FindFile(vset_->icmp_, files_[level], ikey);
+ if (index >= num_files) {
+ files = NULL;
+ num_files = 0;
+ } else {
+ tmp2 = files[index];
+ if (ucmp->Compare(user_key, tmp2->smallest.user_key()) < 0) {
+ // All of "tmp2" is past any data for user_key
+ files = NULL;
+ num_files = 0;
+ } else {
+ files = &tmp2;
+ num_files = 1;
+ }
+ }
+ }
+
+ for (uint32_t i = 0; i < num_files; ++i) {
+ if (last_file_read != NULL && stats->seek_file == NULL) {
+ // We have had more than one seek for this read. Charge the 1st file.
+ stats->seek_file = last_file_read;
+ stats->seek_file_level = last_file_read_level;
+ }
+
+ FileMetaData* f = files[i];
+ last_file_read = f;
+ last_file_read_level = level;
+
+ Saver saver;
+ saver.state = kNotFound;
+ saver.ucmp = ucmp;
+ saver.user_key = user_key;
+ saver.value = value;
+ s = vset_->table_cache_->Get(options, f->number, f->file_size,
+ ikey, &saver, SaveValue);
+ if (!s.ok()) {
+ return s;
+ }
+ switch (saver.state) {
+ case kNotFound:
+ break; // Keep searching in other files
+ case kFound:
+ return s;
+ case kDeleted:
+ s = Status::NotFound(Slice()); // Use empty error message for speed
+ return s;
+ case kCorrupt:
+ s = Status::Corruption("corrupted key for ", user_key);
+ return s;
+ }
+ }
+ }
+
+ return Status::NotFound(Slice()); // Use an empty error message for speed
+}
+
+bool Version::UpdateStats(const GetStats& stats) {
+ FileMetaData* f = stats.seek_file;
+ if (f != NULL) {
+ f->allowed_seeks--;
+ if (f->allowed_seeks <= 0 && file_to_compact_ == NULL) {
+ file_to_compact_ = f;
+ file_to_compact_level_ = stats.seek_file_level;
+ return true;
+ }
+ }
+ return false;
+}
+
+void Version::Ref() {
+ ++refs_;
+}
+
+void Version::Unref() {
+ assert(this != &vset_->dummy_versions_);
+ assert(refs_ >= 1);
+ --refs_;
+ if (refs_ == 0) {
+ delete this;
+ }
+}
+
+bool Version::OverlapInLevel(int level,
+ const Slice* smallest_user_key,
+ const Slice* largest_user_key) {
+ return SomeFileOverlapsRange(vset_->icmp_, (level > 0), files_[level],
+ smallest_user_key, largest_user_key);
+}
+
+int Version::PickLevelForMemTableOutput(
+ const Slice& smallest_user_key,
+ const Slice& largest_user_key) {
+ int level = 0;
+ if (!OverlapInLevel(0, &smallest_user_key, &largest_user_key)) {
+ // Push to next level if there is no overlap in next level,
+ // and the #bytes overlapping in the level after that are limited.
+ InternalKey start(smallest_user_key, kMaxSequenceNumber, kValueTypeForSeek);
+ InternalKey limit(largest_user_key, 0, static_cast<ValueType>(0));
+ std::vector<FileMetaData*> overlaps;
+ while (level < config::kMaxMemCompactLevel) {
+ if (OverlapInLevel(level + 1, &smallest_user_key, &largest_user_key)) {
+ break;
+ }
+ GetOverlappingInputs(level + 2, &start, &limit, &overlaps);
+ const int64_t sum = TotalFileSize(overlaps);
+ if (sum > kMaxGrandParentOverlapBytes) {
+ break;
+ }
+ level++;
+ }
+ }
+ return level;
+}
+
+// Store in "*inputs" all files in "level" that overlap [begin,end]
+void Version::GetOverlappingInputs(
+ int level,
+ const InternalKey* begin,
+ const InternalKey* end,
+ std::vector<FileMetaData*>* inputs) {
+ inputs->clear();
+ Slice user_begin, user_end;
+ if (begin != NULL) {
+ user_begin = begin->user_key();
+ }
+ if (end != NULL) {
+ user_end = end->user_key();
+ }
+ const Comparator* user_cmp = vset_->icmp_.user_comparator();
+ for (size_t i = 0; i < files_[level].size(); ) {
+ FileMetaData* f = files_[level][i++];
+ const Slice file_start = f->smallest.user_key();
+ const Slice file_limit = f->largest.user_key();
+ if (begin != NULL && user_cmp->Compare(file_limit, user_begin) < 0) {
+ // "f" is completely before specified range; skip it
+ } else if (end != NULL && user_cmp->Compare(file_start, user_end) > 0) {
+ // "f" is completely after specified range; skip it
+ } else {
+ inputs->push_back(f);
+ if (level == 0) {
+ // Level-0 files may overlap each other. So check if the newly
+ // added file has expanded the range. If so, restart search.
+ if (begin != NULL && user_cmp->Compare(file_start, user_begin) < 0) {
+ user_begin = file_start;
+ inputs->clear();
+ i = 0;
+ } else if (end != NULL && user_cmp->Compare(file_limit, user_end) > 0) {
+ user_end = file_limit;
+ inputs->clear();
+ i = 0;
+ }
+ }
+ }
+ }
+}
+
+std::string Version::DebugString() const {
+ std::string r;
+ for (int level = 0; level < config::kNumLevels; level++) {
+ // E.g.,
+ // --- level 1 ---
+ // 17:123['a' .. 'd']
+ // 20:43['e' .. 'g']
+ r.append("--- level ");
+ AppendNumberTo(&r, level);
+ r.append(" ---\n");
+ const std::vector<FileMetaData*>& files = files_[level];
+ for (size_t i = 0; i < files.size(); i++) {
+ r.push_back(' ');
+ AppendNumberTo(&r, files[i]->number);
+ r.push_back(':');
+ AppendNumberTo(&r, files[i]->file_size);
+ r.append("[");
+ r.append(files[i]->smallest.DebugString());
+ r.append(" .. ");
+ r.append(files[i]->largest.DebugString());
+ r.append("]\n");
+ }
+ }
+ return r;
+}
+
+// A helper class so we can efficiently apply a whole sequence
+// of edits to a particular state without creating intermediate
+// Versions that contain full copies of the intermediate state.
+class VersionSet::Builder {
+ private:
+ // Helper to sort by v->files_[file_number].smallest
+ struct BySmallestKey {
+ const InternalKeyComparator* internal_comparator;
+
+ bool operator()(FileMetaData* f1, FileMetaData* f2) const {
+ int r = internal_comparator->Compare(f1->smallest, f2->smallest);
+ if (r != 0) {
+ return (r < 0);
+ } else {
+ // Break ties by file number
+ return (f1->number < f2->number);
+ }
+ }
+ };
+
+ typedef std::set<FileMetaData*, BySmallestKey> FileSet;
+ struct LevelState {
+ std::set<uint64_t> deleted_files;
+ FileSet* added_files;
+ };
+
+ VersionSet* vset_;
+ Version* base_;
+ LevelState levels_[config::kNumLevels];
+
+ public:
+ // Initialize a builder with the files from *base and other info from *vset
+ Builder(VersionSet* vset, Version* base)
+ : vset_(vset),
+ base_(base) {
+ base_->Ref();
+ BySmallestKey cmp;
+ cmp.internal_comparator = &vset_->icmp_;
+ for (int level = 0; level < config::kNumLevels; level++) {
+ levels_[level].added_files = new FileSet(cmp);
+ }
+ }
+
+ ~Builder() {
+ for (int level = 0; level < config::kNumLevels; level++) {
+ const FileSet* added = levels_[level].added_files;
+ std::vector<FileMetaData*> to_unref;
+ to_unref.reserve(added->size());
+ for (FileSet::const_iterator it = added->begin();
+ it != added->end(); ++it) {
+ to_unref.push_back(*it);
+ }
+ delete added;
+ for (uint32_t i = 0; i < to_unref.size(); i++) {
+ FileMetaData* f = to_unref[i];
+ f->refs--;
+ if (f->refs <= 0) {
+ delete f;
+ }
+ }
+ }
+ base_->Unref();
+ }
+
+ // Apply all of the edits in *edit to the current state.
+ void Apply(VersionEdit* edit) {
+ // Update compaction pointers
+ for (size_t i = 0; i < edit->compact_pointers_.size(); i++) {
+ const int level = edit->compact_pointers_[i].first;
+ vset_->compact_pointer_[level] =
+ edit->compact_pointers_[i].second.Encode().ToString();
+ }
+
+ // Delete files
+ const VersionEdit::DeletedFileSet& del = edit->deleted_files_;
+ for (VersionEdit::DeletedFileSet::const_iterator iter = del.begin();
+ iter != del.end();
+ ++iter) {
+ const int level = iter->first;
+ const uint64_t number = iter->second;
+ levels_[level].deleted_files.insert(number);
+ }
+
+ // Add new files
+ for (size_t i = 0; i < edit->new_files_.size(); i++) {
+ const int level = edit->new_files_[i].first;
+ FileMetaData* f = new FileMetaData(edit->new_files_[i].second);
+ f->refs = 1;
+
+ // We arrange to automatically compact this file after
+ // a certain number of seeks. Let's assume:
+ // (1) One seek costs 10ms
+ // (2) Writing or reading 1MB costs 10ms (100MB/s)
+ // (3) A compaction of 1MB does 25MB of IO:
+ // 1MB read from this level
+ // 10-12MB read from next level (boundaries may be misaligned)
+ // 10-12MB written to next level
+ // This implies that 25 seeks cost the same as the compaction
+ // of 1MB of data. I.e., one seek costs approximately the
+ // same as the compaction of 40KB of data. We are a little
+ // conservative and allow approximately one seek for every 16KB
+ // of data before triggering a compaction.
+ f->allowed_seeks = (f->file_size / 16384);
+ if (f->allowed_seeks < 100) f->allowed_seeks = 100;
+
+ levels_[level].deleted_files.erase(f->number);
+ levels_[level].added_files->insert(f);
+ }
+ }
+
+ // Save the current state in *v.
+ void SaveTo(Version* v) {
+ BySmallestKey cmp;
+ cmp.internal_comparator = &vset_->icmp_;
+ for (int level = 0; level < config::kNumLevels; level++) {
+ // Merge the set of added files with the set of pre-existing files.
+ // Drop any deleted files. Store the result in *v.
+ const std::vector<FileMetaData*>& base_files = base_->files_[level];
+ std::vector<FileMetaData*>::const_iterator base_iter = base_files.begin();
+ std::vector<FileMetaData*>::const_iterator base_end = base_files.end();
+ const FileSet* added = levels_[level].added_files;
+ v->files_[level].reserve(base_files.size() + added->size());
+ for (FileSet::const_iterator added_iter = added->begin();
+ added_iter != added->end();
+ ++added_iter) {
+ // Add all smaller files listed in base_
+ for (std::vector<FileMetaData*>::const_iterator bpos
+ = std::upper_bound(base_iter, base_end, *added_iter, cmp);
+ base_iter != bpos;
+ ++base_iter) {
+ MaybeAddFile(v, level, *base_iter);
+ }
+
+ MaybeAddFile(v, level, *added_iter);
+ }
+
+ // Add remaining base files
+ for (; base_iter != base_end; ++base_iter) {
+ MaybeAddFile(v, level, *base_iter);
+ }
+
+#ifndef NDEBUG
+ // Make sure there is no overlap in levels > 0
+ if (level > 0) {
+ for (uint32_t i = 1; i < v->files_[level].size(); i++) {
+ const InternalKey& prev_end = v->files_[level][i-1]->largest;
+ const InternalKey& this_begin = v->files_[level][i]->smallest;
+ if (vset_->icmp_.Compare(prev_end, this_begin) >= 0) {
+ fprintf(stderr, "overlapping ranges in same level %s vs. %s\n",
+ prev_end.DebugString().c_str(),
+ this_begin.DebugString().c_str());
+ abort();
+ }
+ }
+ }
+#endif
+ }
+ }
+
+ void MaybeAddFile(Version* v, int level, FileMetaData* f) {
+ if (levels_[level].deleted_files.count(f->number) > 0) {
+ // File is deleted: do nothing
+ } else {
+ std::vector<FileMetaData*>* files = &v->files_[level];
+ if (level > 0 && !files->empty()) {
+ // Must not overlap
+ assert(vset_->icmp_.Compare((*files)[files->size()-1]->largest,
+ f->smallest) < 0);
+ }
+ f->refs++;
+ files->push_back(f);
+ }
+ }
+};
+
+VersionSet::VersionSet(const std::string& dbname,
+ const Options* options,
+ TableCache* table_cache,
+ const InternalKeyComparator* cmp)
+ : env_(options->env),
+ dbname_(dbname),
+ options_(options),
+ table_cache_(table_cache),
+ icmp_(*cmp),
+ next_file_number_(2),
+ manifest_file_number_(0), // Filled by Recover()
+ last_sequence_(0),
+ log_number_(0),
+ prev_log_number_(0),
+ descriptor_file_(NULL),
+ descriptor_log_(NULL),
+ dummy_versions_(this),
+ current_(NULL) {
+ AppendVersion(new Version(this));
+}
+
+VersionSet::~VersionSet() {
+ current_->Unref();
+ assert(dummy_versions_.next_ == &dummy_versions_); // List must be empty
+ delete descriptor_log_;
+ delete descriptor_file_;
+}
+
+void VersionSet::AppendVersion(Version* v) {
+ // Make "v" current
+ assert(v->refs_ == 0);
+ assert(v != current_);
+ if (current_ != NULL) {
+ current_->Unref();
+ }
+ current_ = v;
+ v->Ref();
+
+ // Append to linked list
+ v->prev_ = dummy_versions_.prev_;
+ v->next_ = &dummy_versions_;
+ v->prev_->next_ = v;
+ v->next_->prev_ = v;
+}
+
+Status VersionSet::LogAndApply(VersionEdit* edit, port::Mutex* mu) {
+ if (edit->has_log_number_) {
+ assert(edit->log_number_ >= log_number_);
+ assert(edit->log_number_ < next_file_number_);
+ } else {
+ edit->SetLogNumber(log_number_);
+ }
+
+ if (!edit->has_prev_log_number_) {
+ edit->SetPrevLogNumber(prev_log_number_);
+ }
+
+ edit->SetNextFile(next_file_number_);
+ edit->SetLastSequence(last_sequence_);
+
+ Version* v = new Version(this);
+ {
+ Builder builder(this, current_);
+ builder.Apply(edit);
+ builder.SaveTo(v);
+ }
+ Finalize(v);
+
+ // Initialize new descriptor log file if necessary by creating
+ // a temporary file that contains a snapshot of the current version.
+ std::string new_manifest_file;
+ Status s;
+ if (descriptor_log_ == NULL) {
+ // No reason to unlock *mu here since we only hit this path in the
+ // first call to LogAndApply (when opening the database).
+ assert(descriptor_file_ == NULL);
+ new_manifest_file = DescriptorFileName(dbname_, manifest_file_number_);
+ edit->SetNextFile(next_file_number_);
+ s = env_->NewWritableFile(new_manifest_file, &descriptor_file_);
+ if (s.ok()) {
+ descriptor_log_ = new log::Writer(descriptor_file_);
+ s = WriteSnapshot(descriptor_log_);
+ }
+ }
+
+ // Unlock during expensive MANIFEST log write
+ {
+ mu->Unlock();
+
+ // Write new record to MANIFEST log
+ if (s.ok()) {
+ std::string record;
+ edit->EncodeTo(&record);
+ s = descriptor_log_->AddRecord(record);
+ if (s.ok()) {
+ s = descriptor_file_->Sync();
+ }
+ if (!s.ok()) {
+ Log(options_->info_log, "MANIFEST write: %s\n", s.ToString().c_str());
+ if (ManifestContains(record)) {
+ Log(options_->info_log,
+ "MANIFEST contains log record despite error; advancing to new "
+ "version to prevent mismatch between in-memory and logged state");
+ s = Status::OK();
+ }
+ }
+ }
+
+ // If we just created a new descriptor file, install it by writing a
+ // new CURRENT file that points to it.
+ if (s.ok() && !new_manifest_file.empty()) {
+ s = SetCurrentFile(env_, dbname_, manifest_file_number_);
+ // No need to double-check MANIFEST in case of error since it
+ // will be discarded below.
+ }
+
+ mu->Lock();
+ }
+
+ // Install the new version
+ if (s.ok()) {
+ AppendVersion(v);
+ log_number_ = edit->log_number_;
+ prev_log_number_ = edit->prev_log_number_;
+ } else {
+ delete v;
+ if (!new_manifest_file.empty()) {
+ delete descriptor_log_;
+ delete descriptor_file_;
+ descriptor_log_ = NULL;
+ descriptor_file_ = NULL;
+ env_->DeleteFile(new_manifest_file);
+ }
+ }
+
+ return s;
+}
+
+Status VersionSet::Recover() {
+ struct LogReporter : public log::Reader::Reporter {
+ Status* status;
+ virtual void Corruption(size_t bytes, const Status& s) {
+ if (this->status->ok()) *this->status = s;
+ }
+ };
+
+ // Read "CURRENT" file, which contains a pointer to the current manifest file
+ std::string current;
+ Status s = ReadFileToString(env_, CurrentFileName(dbname_), &current);
+ if (!s.ok()) {
+ return s;
+ }
+ if (current.empty() || current[current.size()-1] != '\n') {
+ return Status::Corruption("CURRENT file does not end with newline");
+ }
+ current.resize(current.size() - 1);
+
+ std::string dscname = dbname_ + "/" + current;
+ SequentialFile* file;
+ s = env_->NewSequentialFile(dscname, &file);
+ if (!s.ok()) {
+ return s;
+ }
+
+ bool have_log_number = false;
+ bool have_prev_log_number = false;
+ bool have_next_file = false;
+ bool have_last_sequence = false;
+ uint64_t next_file = 0;
+ uint64_t last_sequence = 0;
+ uint64_t log_number = 0;
+ uint64_t prev_log_number = 0;
+ Builder builder(this, current_);
+
+ {
+ LogReporter reporter;
+ reporter.status = &s;
+ log::Reader reader(file, &reporter, true/*checksum*/, 0/*initial_offset*/);
+ Slice record;
+ std::string scratch;
+ while (reader.ReadRecord(&record, &scratch) && s.ok()) {
+ VersionEdit edit;
+ s = edit.DecodeFrom(record);
+ if (s.ok()) {
+ if (edit.has_comparator_ &&
+ edit.comparator_ != icmp_.user_comparator()->Name()) {
+ s = Status::InvalidArgument(
+ edit.comparator_ + " does not match existing comparator ",
+ icmp_.user_comparator()->Name());
+ }
+ }
+
+ if (s.ok()) {
+ builder.Apply(&edit);
+ }
+
+ if (edit.has_log_number_) {
+ log_number = edit.log_number_;
+ have_log_number = true;
+ }
+
+ if (edit.has_prev_log_number_) {
+ prev_log_number = edit.prev_log_number_;
+ have_prev_log_number = true;
+ }
+
+ if (edit.has_next_file_number_) {
+ next_file = edit.next_file_number_;
+ have_next_file = true;
+ }
+
+ if (edit.has_last_sequence_) {
+ last_sequence = edit.last_sequence_;
+ have_last_sequence = true;
+ }
+ }
+ }
+ delete file;
+ file = NULL;
+
+ if (s.ok()) {
+ if (!have_next_file) {
+ s = Status::Corruption("no meta-nextfile entry in descriptor");
+ } else if (!have_log_number) {
+ s = Status::Corruption("no meta-lognumber entry in descriptor");
+ } else if (!have_last_sequence) {
+ s = Status::Corruption("no last-sequence-number entry in descriptor");
+ }
+
+ if (!have_prev_log_number) {
+ prev_log_number = 0;
+ }
+
+ MarkFileNumberUsed(prev_log_number);
+ MarkFileNumberUsed(log_number);
+ }
+
+ if (s.ok()) {
+ Version* v = new Version(this);
+ builder.SaveTo(v);
+ // Install recovered version
+ Finalize(v);
+ AppendVersion(v);
+ manifest_file_number_ = next_file;
+ next_file_number_ = next_file + 1;
+ last_sequence_ = last_sequence;
+ log_number_ = log_number;
+ prev_log_number_ = prev_log_number;
+ }
+
+ return s;
+}
+
+void VersionSet::MarkFileNumberUsed(uint64_t number) {
+ if (next_file_number_ <= number) {
+ next_file_number_ = number + 1;
+ }
+}
+
+void VersionSet::Finalize(Version* v) {
+ // Precomputed best level for next compaction
+ int best_level = -1;
+ double best_score = -1;
+
+ for (int level = 0; level < config::kNumLevels-1; level++) {
+ double score;
+ if (level == 0) {
+ // We treat level-0 specially by bounding the number of files
+ // instead of number of bytes for two reasons:
+ //
+ // (1) With larger write-buffer sizes, it is nice not to do too
+ // many level-0 compactions.
+ //
+ // (2) The files in level-0 are merged on every read and
+ // therefore we wish to avoid too many files when the individual
+ // file size is small (perhaps because of a small write-buffer
+ // setting, or very high compression ratios, or lots of
+ // overwrites/deletions).
+ score = v->files_[level].size() /
+ static_cast<double>(config::kL0_CompactionTrigger);
+ } else {
+ // Compute the ratio of current size to size limit.
+ const uint64_t level_bytes = TotalFileSize(v->files_[level]);
+ score = static_cast<double>(level_bytes) / MaxBytesForLevel(level);
+ }
+
+ if (score > best_score) {
+ best_level = level;
+ best_score = score;
+ }
+ }
+
+ v->compaction_level_ = best_level;
+ v->compaction_score_ = best_score;
+}
+
+Status VersionSet::WriteSnapshot(log::Writer* log) {
+ // TODO: Break up into multiple records to reduce memory usage on recovery?
+
+ // Save metadata
+ VersionEdit edit;
+ edit.SetComparatorName(icmp_.user_comparator()->Name());
+
+ // Save compaction pointers
+ for (int level = 0; level < config::kNumLevels; level++) {
+ if (!compact_pointer_[level].empty()) {
+ InternalKey key;
+ key.DecodeFrom(compact_pointer_[level]);
+ edit.SetCompactPointer(level, key);
+ }
+ }
+
+ // Save files
+ for (int level = 0; level < config::kNumLevels; level++) {
+ const std::vector<FileMetaData*>& files = current_->files_[level];
+ for (size_t i = 0; i < files.size(); i++) {
+ const FileMetaData* f = files[i];
+ edit.AddFile(level, f->number, f->file_size, f->smallest, f->largest);
+ }
+ }
+
+ std::string record;
+ edit.EncodeTo(&record);
+ return log->AddRecord(record);
+}
+
+int VersionSet::NumLevelFiles(int level) const {
+ assert(level >= 0);
+ assert(level < config::kNumLevels);
+ return current_->files_[level].size();
+}
+
+const char* VersionSet::LevelSummary(LevelSummaryStorage* scratch) const {
+ // Update code if kNumLevels changes
+ assert(config::kNumLevels == 7);
+ snprintf(scratch->buffer, sizeof(scratch->buffer),
+ "files[ %d %d %d %d %d %d %d ]",
+ int(current_->files_[0].size()),
+ int(current_->files_[1].size()),
+ int(current_->files_[2].size()),
+ int(current_->files_[3].size()),
+ int(current_->files_[4].size()),
+ int(current_->files_[5].size()),
+ int(current_->files_[6].size()));
+ return scratch->buffer;
+}
+
+// Return true iff the manifest contains the specified record.
+bool VersionSet::ManifestContains(const std::string& record) const {
+ std::string fname = DescriptorFileName(dbname_, manifest_file_number_);
+ Log(options_->info_log, "ManifestContains: checking %s\n", fname.c_str());
+ SequentialFile* file = NULL;
+ Status s = env_->NewSequentialFile(fname, &file);
+ if (!s.ok()) {
+ Log(options_->info_log, "ManifestContains: %s\n", s.ToString().c_str());
+ return false;
+ }
+ log::Reader reader(file, NULL, true/*checksum*/, 0);
+ Slice r;
+ std::string scratch;
+ bool result = false;
+ while (reader.ReadRecord(&r, &scratch)) {
+ if (r == Slice(record)) {
+ result = true;
+ break;
+ }
+ }
+ delete file;
+ Log(options_->info_log, "ManifestContains: result = %d\n", result ? 1 : 0);
+ return result;
+}
+
+uint64_t VersionSet::ApproximateOffsetOf(Version* v, const InternalKey& ikey) {
+ uint64_t result = 0;
+ for (int level = 0; level < config::kNumLevels; level++) {
+ const std::vector<FileMetaData*>& files = v->files_[level];
+ for (size_t i = 0; i < files.size(); i++) {
+ if (icmp_.Compare(files[i]->largest, ikey) <= 0) {
+ // Entire file is before "ikey", so just add the file size
+ result += files[i]->file_size;
+ } else if (icmp_.Compare(files[i]->smallest, ikey) > 0) {
+ // Entire file is after "ikey", so ignore
+ if (level > 0) {
+ // Files other than level 0 are sorted by meta->smallest, so
+ // no further files in this level will contain data for
+ // "ikey".
+ break;
+ }
+ } else {
+ // "ikey" falls in the range for this table. Add the
+ // approximate offset of "ikey" within the table.
+ Table* tableptr;
+ Iterator* iter = table_cache_->NewIterator(
+ ReadOptions(), files[i]->number, files[i]->file_size, &tableptr);
+ if (tableptr != NULL) {
+ result += tableptr->ApproximateOffsetOf(ikey.Encode());
+ }
+ delete iter;
+ }
+ }
+ }
+ return result;
+}
+
+void VersionSet::AddLiveFiles(std::set<uint64_t>* live) {
+ for (Version* v = dummy_versions_.next_;
+ v != &dummy_versions_;
+ v = v->next_) {
+ for (int level = 0; level < config::kNumLevels; level++) {
+ const std::vector<FileMetaData*>& files = v->files_[level];
+ for (size_t i = 0; i < files.size(); i++) {
+ live->insert(files[i]->number);
+ }
+ }
+ }
+}
+
+int64_t VersionSet::NumLevelBytes(int level) const {
+ assert(level >= 0);
+ assert(level < config::kNumLevels);
+ return TotalFileSize(current_->files_[level]);
+}
+
+int64_t VersionSet::MaxNextLevelOverlappingBytes() {
+ int64_t result = 0;
+ std::vector<FileMetaData*> overlaps;
+ for (int level = 1; level < config::kNumLevels - 1; level++) {
+ for (size_t i = 0; i < current_->files_[level].size(); i++) {
+ const FileMetaData* f = current_->files_[level][i];
+ current_->GetOverlappingInputs(level+1, &f->smallest, &f->largest,
+ &overlaps);
+ const int64_t sum = TotalFileSize(overlaps);
+ if (sum > result) {
+ result = sum;
+ }
+ }
+ }
+ return result;
+}
+
+// Stores the minimal range that covers all entries in inputs in
+// *smallest, *largest.
+// REQUIRES: inputs is not empty
+void VersionSet::GetRange(const std::vector<FileMetaData*>& inputs,
+ InternalKey* smallest,
+ InternalKey* largest) {
+ assert(!inputs.empty());
+ smallest->Clear();
+ largest->Clear();
+ for (size_t i = 0; i < inputs.size(); i++) {
+ FileMetaData* f = inputs[i];
+ if (i == 0) {
+ *smallest = f->smallest;
+ *largest = f->largest;
+ } else {
+ if (icmp_.Compare(f->smallest, *smallest) < 0) {
+ *smallest = f->smallest;
+ }
+ if (icmp_.Compare(f->largest, *largest) > 0) {
+ *largest = f->largest;
+ }
+ }
+ }
+}
+
+// Stores the minimal range that covers all entries in inputs1 and inputs2
+// in *smallest, *largest.
+// REQUIRES: inputs is not empty
+void VersionSet::GetRange2(const std::vector<FileMetaData*>& inputs1,
+ const std::vector<FileMetaData*>& inputs2,
+ InternalKey* smallest,
+ InternalKey* largest) {
+ std::vector<FileMetaData*> all = inputs1;
+ all.insert(all.end(), inputs2.begin(), inputs2.end());
+ GetRange(all, smallest, largest);
+}
+
+Iterator* VersionSet::MakeInputIterator(Compaction* c) {
+ ReadOptions options;
+ options.verify_checksums = options_->paranoid_checks;
+ options.fill_cache = false;
+
+ // Level-0 files have to be merged together. For other levels,
+ // we will make a concatenating iterator per level.
+ // TODO(opt): use concatenating iterator for level-0 if there is no overlap
+ const int space = (c->level() == 0 ? c->inputs_[0].size() + 1 : 2);
+ Iterator** list = new Iterator*[space];
+ int num = 0;
+ for (int which = 0; which < 2; which++) {
+ if (!c->inputs_[which].empty()) {
+ if (c->level() + which == 0) {
+ const std::vector<FileMetaData*>& files = c->inputs_[which];
+ for (size_t i = 0; i < files.size(); i++) {
+ list[num++] = table_cache_->NewIterator(
+ options, files[i]->number, files[i]->file_size);
+ }
+ } else {
+ // Create concatenating iterator for the files from this level
+ list[num++] = NewTwoLevelIterator(
+ new Version::LevelFileNumIterator(icmp_, &c->inputs_[which]),
+ &GetFileIterator, table_cache_, options);
+ }
+ }
+ }
+ assert(num <= space);
+ Iterator* result = NewMergingIterator(&icmp_, list, num);
+ delete[] list;
+ return result;
+}
+
+Compaction* VersionSet::PickCompaction() {
+ Compaction* c;
+ int level;
+
+ // We prefer compactions triggered by too much data in a level over
+ // the compactions triggered by seeks.
+ const bool size_compaction = (current_->compaction_score_ >= 1);
+ const bool seek_compaction = (current_->file_to_compact_ != NULL);
+ if (size_compaction) {
+ level = current_->compaction_level_;
+ assert(level >= 0);
+ assert(level+1 < config::kNumLevels);
+ c = new Compaction(level);
+
+ // Pick the first file that comes after compact_pointer_[level]
+ for (size_t i = 0; i < current_->files_[level].size(); i++) {
+ FileMetaData* f = current_->files_[level][i];
+ if (compact_pointer_[level].empty() ||
+ icmp_.Compare(f->largest.Encode(), compact_pointer_[level]) > 0) {
+ c->inputs_[0].push_back(f);
+ break;
+ }
+ }
+ if (c->inputs_[0].empty()) {
+ // Wrap-around to the beginning of the key space
+ c->inputs_[0].push_back(current_->files_[level][0]);
+ }
+ } else if (seek_compaction) {
+ level = current_->file_to_compact_level_;
+ c = new Compaction(level);
+ c->inputs_[0].push_back(current_->file_to_compact_);
+ } else {
+ return NULL;
+ }
+
+ c->input_version_ = current_;
+ c->input_version_->Ref();
+
+ // Files in level 0 may overlap each other, so pick up all overlapping ones
+ if (level == 0) {
+ InternalKey smallest, largest;
+ GetRange(c->inputs_[0], &smallest, &largest);
+ // Note that the next call will discard the file we placed in
+ // c->inputs_[0] earlier and replace it with an overlapping set
+ // which will include the picked file.
+ current_->GetOverlappingInputs(0, &smallest, &largest, &c->inputs_[0]);
+ assert(!c->inputs_[0].empty());
+ }
+
+ SetupOtherInputs(c);
+
+ return c;
+}
+
+void VersionSet::SetupOtherInputs(Compaction* c) {
+ const int level = c->level();
+ InternalKey smallest, largest;
+ GetRange(c->inputs_[0], &smallest, &largest);
+
+ current_->GetOverlappingInputs(level+1, &smallest, &largest, &c->inputs_[1]);
+
+ // Get entire range covered by compaction
+ InternalKey all_start, all_limit;
+ GetRange2(c->inputs_[0], c->inputs_[1], &all_start, &all_limit);
+
+ // See if we can grow the number of inputs in "level" without
+ // changing the number of "level+1" files we pick up.
+ if (!c->inputs_[1].empty()) {
+ std::vector<FileMetaData*> expanded0;
+ current_->GetOverlappingInputs(level, &all_start, &all_limit, &expanded0);
+ const int64_t inputs0_size = TotalFileSize(c->inputs_[0]);
+ const int64_t inputs1_size = TotalFileSize(c->inputs_[1]);
+ const int64_t expanded0_size = TotalFileSize(expanded0);
+ if (expanded0.size() > c->inputs_[0].size() &&
+ inputs1_size + expanded0_size < kExpandedCompactionByteSizeLimit) {
+ InternalKey new_start, new_limit;
+ GetRange(expanded0, &new_start, &new_limit);
+ std::vector<FileMetaData*> expanded1;
+ current_->GetOverlappingInputs(level+1, &new_start, &new_limit,
+ &expanded1);
+ if (expanded1.size() == c->inputs_[1].size()) {
+ Log(options_->info_log,
+ "Expanding@%d %d+%d (%ld+%ld bytes) to %d+%d (%ld+%ld bytes)\n",
+ level,
+ int(c->inputs_[0].size()),
+ int(c->inputs_[1].size()),
+ long(inputs0_size), long(inputs1_size),
+ int(expanded0.size()),
+ int(expanded1.size()),
+ long(expanded0_size), long(inputs1_size));
+ smallest = new_start;
+ largest = new_limit;
+ c->inputs_[0] = expanded0;
+ c->inputs_[1] = expanded1;
+ GetRange2(c->inputs_[0], c->inputs_[1], &all_start, &all_limit);
+ }
+ }
+ }
+
+ // Compute the set of grandparent files that overlap this compaction
+ // (parent == level+1; grandparent == level+2)
+ if (level + 2 < config::kNumLevels) {
+ current_->GetOverlappingInputs(level + 2, &all_start, &all_limit,
+ &c->grandparents_);
+ }
+
+ if (false) {
+ Log(options_->info_log, "Compacting %d '%s' .. '%s'",
+ level,
+ smallest.DebugString().c_str(),
+ largest.DebugString().c_str());
+ }
+
+ // Update the place where we will do the next compaction for this level.
+ // We update this immediately instead of waiting for the VersionEdit
+ // to be applied so that if the compaction fails, we will try a different
+ // key range next time.
+ compact_pointer_[level] = largest.Encode().ToString();
+ c->edit_.SetCompactPointer(level, largest);
+}
+
+Compaction* VersionSet::CompactRange(
+ int level,
+ const InternalKey* begin,
+ const InternalKey* end) {
+ std::vector<FileMetaData*> inputs;
+ current_->GetOverlappingInputs(level, begin, end, &inputs);
+ if (inputs.empty()) {
+ return NULL;
+ }
+
+ // Avoid compacting too much in one shot in case the range is large.
+ // But we cannot do this for level-0 since level-0 files can overlap
+ // and we must not pick one file and drop another older file if the
+ // two files overlap.
+ if (level > 0) {
+ const uint64_t limit = MaxFileSizeForLevel(level);
+ uint64_t total = 0;
+ for (size_t i = 0; i < inputs.size(); i++) {
+ uint64_t s = inputs[i]->file_size;
+ total += s;
+ if (total >= limit) {
+ inputs.resize(i + 1);
+ break;
+ }
+ }
+ }
+
+ Compaction* c = new Compaction(level);
+ c->input_version_ = current_;
+ c->input_version_->Ref();
+ c->inputs_[0] = inputs;
+ SetupOtherInputs(c);
+ return c;
+}
+
+Compaction::Compaction(int level)
+ : level_(level),
+ max_output_file_size_(MaxFileSizeForLevel(level)),
+ input_version_(NULL),
+ grandparent_index_(0),
+ seen_key_(false),
+ overlapped_bytes_(0) {
+ for (int i = 0; i < config::kNumLevels; i++) {
+ level_ptrs_[i] = 0;
+ }
+}
+
+Compaction::~Compaction() {
+ if (input_version_ != NULL) {
+ input_version_->Unref();
+ }
+}
+
+bool Compaction::IsTrivialMove() const {
+ // Avoid a move if there is lots of overlapping grandparent data.
+ // Otherwise, the move could create a parent file that will require
+ // a very expensive merge later on.
+ return (num_input_files(0) == 1 &&
+ num_input_files(1) == 0 &&
+ TotalFileSize(grandparents_) <= kMaxGrandParentOverlapBytes);
+}
+
+void Compaction::AddInputDeletions(VersionEdit* edit) {
+ for (int which = 0; which < 2; which++) {
+ for (size_t i = 0; i < inputs_[which].size(); i++) {
+ edit->DeleteFile(level_ + which, inputs_[which][i]->number);
+ }
+ }
+}
+
+bool Compaction::IsBaseLevelForKey(const Slice& user_key) {
+ // Maybe use binary search to find right entry instead of linear search?
+ const Comparator* user_cmp = input_version_->vset_->icmp_.user_comparator();
+ for (int lvl = level_ + 2; lvl < config::kNumLevels; lvl++) {
+ const std::vector<FileMetaData*>& files = input_version_->files_[lvl];
+ for (; level_ptrs_[lvl] < files.size(); ) {
+ FileMetaData* f = files[level_ptrs_[lvl]];
+ if (user_cmp->Compare(user_key, f->largest.user_key()) <= 0) {
+ // We've advanced far enough
+ if (user_cmp->Compare(user_key, f->smallest.user_key()) >= 0) {
+ // Key falls in this file's range, so definitely not base level
+ return false;
+ }
+ break;
+ }
+ level_ptrs_[lvl]++;
+ }
+ }
+ return true;
+}
+
+bool Compaction::ShouldStopBefore(const Slice& internal_key) {
+ // Scan to find earliest grandparent file that contains key.
+ const InternalKeyComparator* icmp = &input_version_->vset_->icmp_;
+ while (grandparent_index_ < grandparents_.size() &&
+ icmp->Compare(internal_key,
+ grandparents_[grandparent_index_]->largest.Encode()) > 0) {
+ if (seen_key_) {
+ overlapped_bytes_ += grandparents_[grandparent_index_]->file_size;
+ }
+ grandparent_index_++;
+ }
+ seen_key_ = true;
+
+ if (overlapped_bytes_ > kMaxGrandParentOverlapBytes) {
+ // Too much overlap for current output; start new output
+ overlapped_bytes_ = 0;
+ return true;
+ } else {
+ return false;
+ }
+}
+
+void Compaction::ReleaseInputs() {
+ if (input_version_ != NULL) {
+ input_version_->Unref();
+ input_version_ = NULL;
+ }
+}
+
+} // namespace leveldb
generated by cgit v1.2.3 (git 2.25.1) at 2024-06-12 18:42:29 +0000