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Merge pull request #698 from neal-zhu:master

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PiperOrigin-RevId: 266001777
This commit is contained in:
Victor Costan 2019-08-28 15:05:07 -07:00
commit 21304d41f7
1 changed files with 52 additions and 76 deletions
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152
db/version_set.cc
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@ -281,7 +281,6 @@ static bool NewestFirst(FileMetaData* a, FileMetaData* b) {
void Version::ForEachOverlapping(Slice user_key, Slice internal_key, void* arg,
bool (*func)(void*, int, FileMetaData*)) {
// TODO(sanjay): Change Version::Get() to use this function.
const Comparator* ucmp = vset_->icmp_.user_comparator();
// Search level-0 in order from newest to oldest.
@ -325,99 +324,76 @@ void Version::ForEachOverlapping(Slice user_key, Slice internal_key, void* arg,
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 = 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<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 = 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;
}
}
}
for (uint32_t i = 0; i < num_files; ++i) {
if (last_file_read != nullptr && 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;
}
FileMetaData* f = files[i];
last_file_read = f;
last_file_read_level = level;
struct State {
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;
}
}
GetStats* stats;
const ReadOptions* options;
Slice ikey;
FileMetaData* last_file_read;
int last_file_read_level;
VersionSet* vset;
Status s;
bool found;
static bool Match(void* arg, int level, FileMetaData* f) {
State* state = reinterpret_cast<State*>(arg);
if (state->stats->seek_file == nullptr &&
state->last_file_read != nullptr) {
// We have had more than one seek for this read. Charge the 1st file.
state->stats->seek_file = state->last_file_read;
state->stats->seek_file_level = state->last_file_read_level;
}
return Status::NotFound(Slice()); // Use an empty error message for speed
state->last_file_read = f;
state->last_file_read_level = level;
state->s = state->vset->table_cache_->Get(*state->options, f->number,
f->file_size, state->ikey,
&state->saver, SaveValue);
if (!state->s.ok()) {
state->found = true;
return false;
}
switch (state->saver.state) {
case kNotFound:
return true; // Keep searching in other files
case kFound:
state->found = true;
return false;
case kDeleted:
return false;
case kCorrupt:
state->s =
Status::Corruption("corrupted key for ", state->saver.user_key);
state->found = true;
return false;
}
}
};
State state;
state.found = false;
state.stats = stats;
state.last_file_read = nullptr;
state.last_file_read_level = -1;
state.options = &options;
state.ikey = k.internal_key();
state.vset = vset_;
state.saver.state = kNotFound;
state.saver.ucmp = vset_->icmp_.user_comparator();
state.saver.user_key = k.user_key();
state.saver.value = value;
ForEachOverlapping(state.saver.user_key, state.ikey, &state, &State::Match);
return state.found ? state.s : Status::NotFound(Slice());
}
bool Version::UpdateStats(const GetStats& stats) {