chore(search): Rax TreeMap #3909
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src/core/search/rax_tree.h
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| template <typename... Args> | ||
| std::pair<FindIterator, bool> try_emplace(std::string_view key, Args&&... args) { | ||
| if (auto it = find(key); it) | ||
| return {it, false}; | ||
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| void* ptr = mr_->allocate(sizeof(V), alignof(V)); | ||
| V* data = new (ptr) V(std::forward<Args>(args)...); | ||
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| V* old = nullptr; | ||
| raxInsert(tree_, to_key_ptr(key), key.size(), data, reinterpret_cast<void**>(&old)); | ||
| assert(old == nullptr); | ||
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| auto it = std::make_optional(std::make_pair(key, data)); | ||
| return std::make_pair(FindIterator{it}, true); | ||
| } |
Signed-off-by: Vladislav Oleshko <vlad@dragonflydb.io>
dranikpg
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I will replace the built-in absl::flat_hash_map with this data structure and we'll have prefix searches automatically, for suffix/infix searches we'll build a suffix tree on top of this struct |
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Forgot to mention, properly using polymorphic allocators is a pain because we use redis/zmalloc internally 😕 Not sure what to do about it 🤷🏻♂️ |
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Ah, I forgot our PMR_NS namespace 😅 Will fix it |
| std::optional<raxIterator> it; | ||
| }; | ||
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| struct FindIterator : public std::optional<std::pair<std::string_view, V&>> { |
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maybe add a comment that we use optional here to get "->" operators for free.
| } | ||
| } | ||
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| TEST_F(RaxTreeTest, LowerBound) { |
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check how it works with empty string_views, strings. Sometimes redis code has problems with zero length slices that have nullptr pointers
Signed-off-by: Vladislav Oleshko <vlad@dragonflydb.io>
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src/core/search/rax_tree_test.cc
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| // Test lower bound empty string | ||
| vector<string> keys2; | ||
| for (auto it = map.lower_bound(""); it != map.end(); ++it) |
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it's not enough.
"" actually is non-null string_view. I am talking about string_view{}.
Also the same with find and insert (empty string)
Signed-off-by: Vladislav Oleshko <vlad@dragonflydb.io>
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Self contained RaxTreeMap that hides rax functions + allocations