3f7af03a2d
Summary: Use a std::priority_queue in merger.cc instead of doing a o(n) search every time. Currently only the ForwardIteration uses a Priority Queue. Test Plan: make all check Reviewers: dhruba Reviewed By: dhruba CC: emayanke, zshao Differential Revision: https://reviews.facebook.net/D7629
64 lines
1.7 KiB
C++
64 lines
1.7 KiB
C++
// Copyright 2008-present Facebook. All Rights Reserved.
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#ifndef STORAGE_LEVELDB_ITER_HEAP_H_
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#define STORAGE_LEVELDB_ITER_HEAP_H_
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#include <queue>
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#include "leveldb/comparator.h"
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#include "table/iterator_wrapper.h"
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namespace leveldb {
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// Return the max of two keys.
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class MaxIteratorComparator {
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public:
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MaxIteratorComparator(const Comparator* comparator) :
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comparator_(comparator) {}
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bool operator()(IteratorWrapper* a, IteratorWrapper* b) {
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return comparator_->Compare(a->key(), b->key()) <= 0;
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}
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private:
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const Comparator* comparator_;
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};
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// Return the max of two keys.
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class MinIteratorComparator {
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public:
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// if maxHeap is set comparator returns the max value.
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// else returns the min Value.
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// Can use to create a minHeap or a maxHeap.
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MinIteratorComparator(const Comparator* comparator) :
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comparator_(comparator) {}
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bool operator()(IteratorWrapper* a, IteratorWrapper* b) {
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return comparator_->Compare(a->key(), b->key()) > 0;
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}
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private:
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const Comparator* comparator_;
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};
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typedef std::priority_queue<
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IteratorWrapper*,
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std::vector<IteratorWrapper*>,
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MaxIteratorComparator> MaxIterHeap;
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typedef std::priority_queue<
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IteratorWrapper*,
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std::vector<IteratorWrapper*>,
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MinIteratorComparator> MinIterHeap;
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// Return's a new MaxHeap of IteratorWrapper's using the provided Comparator.
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MaxIterHeap NewMaxIterHeap(const Comparator* comparator) {
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return MaxIterHeap(MaxIteratorComparator(comparator));
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}
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// Return's a new MinHeap of IteratorWrapper's using the provided Comparator.
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MinIterHeap NewMinIterHeap(const Comparator* comparator) {
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return MinIterHeap(MinIteratorComparator(comparator));
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}
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} // namespace leveldb
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#endif // STORAGE_LEVELDB_ITER_HEAP_H_
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