132306fbf0
Summary: `PartialMergeMulti` implementation is enough for Cassandra, and `PartialMerge` is not required. Implementing both will just duplicate the code. As per https://github.com/facebook/rocksdb/blob/master/include/rocksdb/merge_operator.h#L130-L135 : ``` // The default implementation of PartialMergeMulti will use this function // as a helper, for backward compatibility. Any successor class of // MergeOperator should either implement PartialMerge or PartialMergeMulti, // although implementing PartialMergeMulti is suggested as it is in general // more effective to merge multiple operands at a time instead of two // operands at a time. ``` Closes https://github.com/facebook/rocksdb/pull/2737 Reviewed By: scv119 Differential Revision: D5633073 Pulled By: sagar0 fbshipit-source-id: ef4fa102c22fec6a0175ed12f5c44c15afe3c8ca
81 lines
2.3 KiB
C++
81 lines
2.3 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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#include "merge_operator.h"
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#include <memory>
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#include <assert.h>
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#include "rocksdb/slice.h"
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#include "rocksdb/merge_operator.h"
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#include "utilities/merge_operators.h"
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#include "utilities/cassandra/format.h"
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namespace rocksdb {
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namespace cassandra {
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// Implementation for the merge operation (merges two Cassandra values)
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bool CassandraValueMergeOperator::FullMergeV2(
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const MergeOperationInput& merge_in,
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MergeOperationOutput* merge_out) const {
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// Clear the *new_value for writing.
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merge_out->new_value.clear();
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if (merge_in.existing_value == nullptr && merge_in.operand_list.size() == 1) {
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// Only one operand
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merge_out->existing_operand = merge_in.operand_list.back();
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return true;
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}
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std::vector<RowValue> row_values;
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if (merge_in.existing_value) {
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row_values.push_back(
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RowValue::Deserialize(merge_in.existing_value->data(),
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merge_in.existing_value->size()));
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}
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for (auto& operand : merge_in.operand_list) {
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row_values.push_back(RowValue::Deserialize(operand.data(), operand.size()));
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}
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RowValue merged = RowValue::Merge(std::move(row_values));
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merge_out->new_value.reserve(merged.Size());
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merged.Serialize(&(merge_out->new_value));
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return true;
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}
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bool CassandraValueMergeOperator::PartialMergeMulti(
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const Slice& key,
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const std::deque<Slice>& operand_list,
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std::string* new_value,
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Logger* logger) const {
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// Clear the *new_value for writing.
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assert(new_value);
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new_value->clear();
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std::vector<RowValue> row_values;
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for (auto& operand : operand_list) {
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row_values.push_back(RowValue::Deserialize(operand.data(), operand.size()));
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}
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RowValue merged = RowValue::Merge(std::move(row_values));
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new_value->reserve(merged.Size());
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merged.Serialize(new_value);
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return true;
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}
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const char* CassandraValueMergeOperator::Name() const {
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return "CassandraValueMergeOperator";
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}
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} // namespace cassandra
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std::shared_ptr<MergeOperator>
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MergeOperators::CreateCassandraMergeOperator() {
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return std::make_shared<rocksdb::cassandra::CassandraValueMergeOperator>();
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}
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} // namespace rocksdb
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