revert fractional cascading in farward iterator

Summary: As offline discussion with Siying, revert this since it has bug with seek.

Test Plan: make check -j64

Reviewers: yiwu, andrewkr, sdong

Reviewed By: sdong

Subscribers: andrewkr, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D65559
main
Aaron Gao 8 years ago
parent b9bc7a2aa4
commit bc429de490
  1. 46
      db/forward_iterator.cc

@ -359,61 +359,19 @@ void ForwardIterator::SeekInternal(const Slice& internal_key,
} }
} }
int32_t search_left_bound = 0;
int32_t search_right_bound = FileIndexer::kLevelMaxIndex;
for (int32_t level = 1; level < vstorage->num_levels(); ++level) { for (int32_t level = 1; level < vstorage->num_levels(); ++level) {
const std::vector<FileMetaData*>& level_files = const std::vector<FileMetaData*>& level_files =
vstorage->LevelFiles(level); vstorage->LevelFiles(level);
if (level_files.empty()) { if (level_files.empty()) {
search_left_bound = 0;
search_right_bound = FileIndexer::kLevelMaxIndex;
continue; continue;
} }
if (level_iters_[level - 1] == nullptr) { if (level_iters_[level - 1] == nullptr) {
continue; continue;
} }
uint32_t f_idx = 0; uint32_t f_idx = 0;
const auto& indexer = vstorage->file_indexer();
if (!seek_to_first) { if (!seek_to_first) {
if (search_left_bound == search_right_bound) { f_idx = FindFileInRange(level_files, internal_key, 0,
f_idx = search_left_bound; static_cast<uint32_t>(level_files.size()));
} else if (search_left_bound < search_right_bound) {
f_idx =
FindFileInRange(level_files, internal_key, search_left_bound,
search_right_bound == FileIndexer::kLevelMaxIndex
? static_cast<uint32_t>(level_files.size())
: search_right_bound);
} else {
// search_left_bound > search_right_bound
// There are only 2 cases this can happen:
// (1) target key is smaller than left most file
// (2) target key is larger than right most file
assert(search_left_bound == (int32_t)level_files.size() ||
search_right_bound == -1);
if (search_right_bound == -1) {
assert(search_left_bound == 0);
f_idx = 0;
} else {
indexer.GetNextLevelIndex(
level, level_files.size() - 1,
1, 1, &search_left_bound, &search_right_bound);
continue;
}
}
// Prepare hints for the next level
if (f_idx < level_files.size()) {
int cmp_smallest = user_comparator_->Compare(
user_key, level_files[f_idx]->smallest.user_key());
assert(user_comparator_->Compare(
user_key, level_files[f_idx]->largest.user_key()) <= 0);
indexer.GetNextLevelIndex(level, f_idx, cmp_smallest, -1,
&search_left_bound, &search_right_bound);
} else {
indexer.GetNextLevelIndex(
level, level_files.size() - 1,
1, 1, &search_left_bound, &search_right_bound);
}
} }
// Seek // Seek

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