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