mirror of https://github.com/facebook/rocksdb.git
48 lines
1.4 KiB
C++
48 lines
1.4 KiB
C++
// Copyright (c) Meta Platforms, Inc. and affiliates.
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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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#include "db/coalescing_iterator.h"
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#include "db/wide/wide_columns_helper.h"
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namespace ROCKSDB_NAMESPACE {
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void CoalescingIterator::Coalesce(
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const autovector<MultiCfIteratorInfo>& items) {
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assert(wide_columns_.empty());
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MinHeap heap;
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for (const auto& item : items) {
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assert(item.iterator);
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for (auto& column : item.iterator->columns()) {
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heap.push(WideColumnWithOrder{&column, item.order});
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}
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}
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if (heap.empty()) {
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return;
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}
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wide_columns_.reserve(heap.size());
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auto current = heap.top();
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heap.pop();
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while (!heap.empty()) {
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int comparison = current.column->name().compare(heap.top().column->name());
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if (comparison < 0) {
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wide_columns_.push_back(*current.column);
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} else if (comparison > 0) {
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// Shouldn't reach here.
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// Current item in the heap is greater than the top item in the min heap
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assert(false);
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}
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current = heap.top();
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heap.pop();
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}
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wide_columns_.push_back(*current.column);
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if (WideColumnsHelper::HasDefaultColumn(wide_columns_)) {
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value_ = WideColumnsHelper::GetDefaultColumn(wide_columns_);
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}
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}
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} // namespace ROCKSDB_NAMESPACE
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