From 6a90bb91ee72642241fdbeefa673f88370c7b245 Mon Sep 17 00:00:00 2001 From: neal-zhu <13126959424@163.com> Date: Tue, 11 Jun 2019 19:16:49 +0800 Subject: [PATCH] use ForEachOverlapping to impl Get --- db/version_set.cc | 115 +++++++++++++++++++++--------------------------------- 1 file changed, 45 insertions(+), 70 deletions(-) diff --git a/db/version_set.cc b/db/version_set.cc index b62a2d0..625598d 100644 --- a/db/version_set.cc +++ b/db/version_set.cc @@ -330,94 +330,69 @@ Status Version::Get(const ReadOptions& options, const LookupKey& k, const Comparator* ucmp = vset_->icmp_.user_comparator(); Status s; - stats->seek_file = nullptr; - stats->seek_file_level = -1; - FileMetaData* last_file_read = nullptr; - 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 a smaller level, later levels are irrelevant. - std::vector tmp; - FileMetaData* tmp2; - for (int level = 0; level < config::kNumLevels; level++) { - size_t num_files = files_[level].size(); - if (num_files == 0) continue; + struct State { + GetStats* stats; + const ReadOptions* options; + Slice ikey; + Slice user_key; + const Comparator* ucmp; + std::string* value; - // 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; + VersionSet *vset; + Status s; - 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 = nullptr; - 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 = nullptr; - num_files = 0; - } else { - files = &tmp2; - num_files = 1; - } - } - } + static bool Match(void* arg, int level, FileMetaData* f) { + State* state = reinterpret_cast(arg); - for (uint32_t i = 0; i < num_files; ++i) { - if (last_file_read != nullptr && stats->seek_file == nullptr) { + if (state->stats->seek_file == nullptr) { // 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; + state->stats->seek_file = f; + state->stats->seek_file_level = 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); + saver.ucmp = state->ucmp; + saver.user_key = state->user_key; + saver.value = state->value; + + Status s = state->vset->table_cache_->Get(*state->options, f->number, + f->file_size, state->ikey, + &saver, SaveValue); if (!s.ok()) { - return s; + state->s = s; + return false; } switch (saver.state) { case kNotFound: - break; // Keep searching in other files + return true; // Keep saerching in other files case kFound: - return s; + state->s = s; + return false; case kDeleted: - s = Status::NotFound(Slice()); // Use empty error message for speed - return s; + return false; case kCorrupt: - s = Status::Corruption("corrupted key for ", user_key); - return s; + state->s = Status::Corruption("corrupted key for ", state->user_key); + return false; } } - } + }; + + stats->seek_file = nullptr; + stats->seek_file_level = -1; + + State state; + state.s = Status::NotFound(Slice()); + state.stats = stats; + state.ikey = ikey; + state.user_key = user_key; + state.ucmp = ucmp; + state.value = value; + state.vset = vset_; + + ForEachOverlapping(user_key, ikey, &state, &State::Match); - return Status::NotFound(Slice()); // Use an empty error message for speed + return state.s; } bool Version::UpdateStats(const GetStats& stats) {