4f9c0fd083
Summary: Add a merge operator that allows users to register specific aggregation function so that they can does aggregation based per key using different aggregation types. See comments of function CreateAggMergeOperator() for actual usage. Pull Request resolved: https://github.com/facebook/rocksdb/pull/9780 Test Plan: Add a unit test to coverage various cases. Reviewed By: ltamasi Differential Revision: D35267444 fbshipit-source-id: 5b02f31c4f3e17e96dd4025cdc49fca8c2868628
50 lines
1.8 KiB
C++
50 lines
1.8 KiB
C++
// Copyright (c) 2017-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 <algorithm>
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#include <cstddef>
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#include <memory>
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#include <unordered_map>
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#include "rocksdb/merge_operator.h"
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#include "rocksdb/slice.h"
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#include "rocksdb/utilities/agg_merge.h"
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#include "utilities/cassandra/cassandra_options.h"
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namespace ROCKSDB_NAMESPACE {
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class AggMergeOperator : public MergeOperator {
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public:
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explicit AggMergeOperator();
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bool FullMergeV2(const MergeOperationInput& merge_in,
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MergeOperationOutput* merge_out) const override;
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bool PartialMergeMulti(const Slice& key,
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const std::deque<Slice>& operand_list,
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std::string* new_value, Logger* logger) const override;
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const char* Name() const override { return kClassName(); }
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static const char* kClassName() { return "AggMergeOperator.v1"; }
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bool AllowSingleOperand() const override { return true; }
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bool ShouldMerge(const std::vector<Slice>&) const override { return false; }
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private:
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class Accumulator;
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// Pack all merge operands into one value. This is called when aggregation
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// fails. The existing values are preserved and returned so that users can
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// debug the problem.
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static void PackAllMergeOperands(const MergeOperationInput& merge_in,
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MergeOperationOutput& merge_out);
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static Accumulator& GetTLSAccumulator();
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};
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extern std::string EncodeAggFuncAndPayloadNoCheck(const Slice& function_name,
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const Slice& value);
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} // namespace ROCKSDB_NAMESPACE
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