rocksdb/util/duplicate_detector.h
Maysam Yabandeh 62277e15c3 WritePrepared Txn: Move DuplicateDetector to util
Summary:
Move DuplicateDetector and SetComparator to its own header file in util. It would also address a complaint in the unity test.
Closes https://github.com/facebook/rocksdb/pull/3567

Differential Revision: D7163268

Pulled By: maysamyabandeh

fbshipit-source-id: 6ddf82773473646dbbc1284ae601a78c4907c778
2018-03-05 23:57:12 -08:00

49 lines
1.5 KiB
C++

// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
// This source code is licensed under both the GPLv2 (found in the
// COPYING file in the root directory) and Apache 2.0 License
// (found in the LICENSE.Apache file in the root directory).
#pragma once
#include "util/set_comparator.h"
namespace rocksdb {
// During recovery if the memtable is flushed we cannot rely on its help on
// duplicate key detection and as key insert will not be attempted. This class
// will be used as a emulator of memtable to tell if insertion of a key/seq
// would have resulted in duplication.
class DuplicateDetector {
public:
explicit DuplicateDetector(DBImpl* db) : db_(db) {}
bool IsDuplicateKeySeq(uint32_t cf, const Slice& key, SequenceNumber seq) {
assert(seq >= batch_seq_);
if (batch_seq_ != seq) { // it is a new batch
keys_.clear();
}
batch_seq_ = seq;
CFKeys& cf_keys = keys_[cf];
if (cf_keys.size() == 0) { // just inserted
InitWithComp(cf);
}
auto it = cf_keys.insert(key);
if (it.second == false) { // second is false if a element already existed.
keys_.clear();
InitWithComp(cf);
keys_[cf].insert(key);
return true;
}
return false;
}
private:
SequenceNumber batch_seq_ = 0;
DBImpl* db_;
using CFKeys = std::set<Slice, SetComparator>;
std::map<uint32_t, CFKeys> keys_;
void InitWithComp(const uint32_t cf) {
auto cmp = db_->GetColumnFamilyHandle(cf)->GetComparator();
keys_[cf] = CFKeys(SetComparator(cmp));
}
};
} // namespace rocksdb