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Summary: Continuing from the previous MultiCfIterator Implementations - (https://github.com/facebook/rocksdb/issues/12422, https://github.com/facebook/rocksdb/issues/12480 #12465), this PR completes the `AttributeGroupIterator` by implementing `AttributeGroupIteratorImpl::AddToAttributeGroups()`. While implementing the `AttributeGroupIterator`, we had to make some changes in `MultiCfIteratorImpl` and found an opportunity to improve `Coalesce()` in `CoalescingIterator`. Lifting `UNDER CONSTRUCTION - DO NOT USE` comment by replacing it with `EXPERIMENTAL` Here are some implementation details: - `IteratorAttributeGroups` is introduced to avoid having to copy all `WideColumn` objects during iteration. - `PopulateIterator()` no longer advances non-top iterators that have the same key as the top iterator in the heap. - `AdvanceIterator()` needs to advance the non-top iterators when they have the same key as the top iterator in the heap. - Instead of populating one by one, `PopulateIterator()` now collects all items with the same key and calls `populate_func(items)` at once. - This allowed optimization in `Coalesce()` such that we no longer do K-1 rounds of 2-way merge, but do one K-way merge instead. Pull Request resolved: https://github.com/facebook/rocksdb/pull/12534 Test Plan: Uncommented the assertions in `verifyAttributeGroupIterator()` ``` ./multi_cf_iterator_test ``` Reviewed By: ltamasi Differential Revision: D56089019 Pulled By: jaykorean fbshipit-source-id: 6b0b4247e221f69b40b147d41492008cc9b15054
21 lines
684 B
C++
21 lines
684 B
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/attribute_group_iterator_impl.h"
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namespace ROCKSDB_NAMESPACE {
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const AttributeGroups kNoAttributeGroups;
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const IteratorAttributeGroups kNoIteratorAttributeGroups;
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void AttributeGroupIteratorImpl::AddToAttributeGroups(
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const autovector<MultiCfIteratorInfo>& items) {
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for (const auto& item : items) {
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attribute_groups_.emplace_back(item.cfh, &item.iterator->columns());
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}
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}
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} // namespace ROCKSDB_NAMESPACE
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