Sorting std::vector instead of using std::set

main
Zhipeng Jia 9 years ago
parent 33e09c0e19
commit e0abec1580
  1. 32
      db/compaction_job.cc

@ -334,11 +334,6 @@ struct RangeWithSize {
: range(a, b), size(s) {}
};
bool SliceCompare(const Comparator* cmp, const Slice& a, const Slice& b) {
// Returns true if a < b
return cmp->Compare(ExtractUserKey(a), ExtractUserKey(b)) < 0;
}
// Generates a histogram representing potential divisions of key ranges from
// the input. It adds the starting and/or ending keys of certain input files
// to the working set and then finds the approximate size of data in between
@ -347,14 +342,13 @@ bool SliceCompare(const Comparator* cmp, const Slice& a, const Slice& b) {
void CompactionJob::GenSubcompactionBoundaries() {
auto* c = compact_->compaction;
auto* cfd = c->column_family_data();
std::set<Slice, std::function<bool(const Slice& a, const Slice& b)> > bounds(
std::bind(&SliceCompare, cfd->user_comparator(), std::placeholders::_1,
std::placeholders::_2));
const Comparator* cfd_comparator = cfd->user_comparator();
std::vector<Slice> bounds;
int start_lvl = c->start_level();
int out_lvl = c->output_level();
// Add the starting and/or ending key of certain input files as a potential
// boundary (because we're inserting into a set, it avoids duplicates)
// boundary
for (size_t lvl_idx = 0; lvl_idx < c->num_input_levels(); lvl_idx++) {
int lvl = c->level(lvl_idx);
if (lvl >= start_lvl && lvl <= out_lvl) {
@ -369,27 +363,37 @@ void CompactionJob::GenSubcompactionBoundaries() {
// For level 0 add the starting and ending key of each file since the
// files may have greatly differing key ranges (not range-partitioned)
for (size_t i = 0; i < num_files; i++) {
bounds.emplace(flevel->files[i].smallest_key);
bounds.emplace(flevel->files[i].largest_key);
bounds.emplace_back(flevel->files[i].smallest_key);
bounds.emplace_back(flevel->files[i].largest_key);
}
} else {
// For all other levels add the smallest/largest key in the level to
// encompass the range covered by that level
bounds.emplace(flevel->files[0].smallest_key);
bounds.emplace(flevel->files[num_files - 1].largest_key);
bounds.emplace_back(flevel->files[0].smallest_key);
bounds.emplace_back(flevel->files[num_files - 1].largest_key);
if (lvl == out_lvl) {
// For the last level include the starting keys of all files since
// the last level is the largest and probably has the widest key
// range. Since it's range partitioned, the ending key of one file
// and the starting key of the next are very close (or identical).
for (size_t i = 1; i < num_files; i++) {
bounds.emplace(flevel->files[i].smallest_key);
bounds.emplace_back(flevel->files[i].smallest_key);
}
}
}
}
}
std::sort(bounds.begin(), bounds.end(),
[cfd_comparator] (const Slice& a, const Slice& b) -> bool {
return cfd_comparator->Compare(ExtractUserKey(a), ExtractUserKey(b)) < 0;
});
// Remove duplicated entries from bounds
bounds.erase(std::unique(bounds.begin(), bounds.end(),
[cfd_comparator] (const Slice& a, const Slice& b) -> bool {
return cfd_comparator->Compare(ExtractUserKey(a), ExtractUserKey(b)) == 0;
}), bounds.end());
// Combine consecutive pairs of boundaries into ranges with an approximate
// size of data covered by keys in that range
uint64_t sum = 0;

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