| /** |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, |
| * software distributed under the License is distributed on an |
| * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| * KIND, either express or implied. See the License for the |
| * specific language governing permissions and limitations |
| * under the License. |
| **/ |
| |
| #ifndef QUICKSTEP_EXPRESSIONS_WINDOW_AGGREGATION_WINDOW_AGGREGATION_HANDLE_HPP_ |
| #define QUICKSTEP_EXPRESSIONS_WINDOW_AGGREGATION_WINDOW_AGGREGATION_HANDLE_HPP_ |
| |
| #include <cstddef> |
| #include <memory> |
| #include <vector> |
| |
| #include "catalog/CatalogRelationSchema.hpp" |
| #include "catalog/CatalogTypedefs.hpp" |
| #include "storage/StorageBlockInfo.hpp" |
| #include "types/Type.hpp" |
| #include "types/TypeFactory.hpp" |
| #include "types/TypeID.hpp" |
| #include "types/TypedValue.hpp" |
| #include "types/containers/ColumnVector.hpp" |
| #include "types/containers/ColumnVectorsValueAccessor.hpp" |
| #include "types/operations/comparisons/Comparison.hpp" |
| #include "types/operations/comparisons/ComparisonFactory.hpp" |
| #include "types/operations/comparisons/ComparisonID.hpp" |
| #include "types/operations/binary_operations/BinaryOperation.hpp" |
| #include "types/operations/binary_operations/BinaryOperationFactory.hpp" |
| #include "types/operations/binary_operations/BinaryOperationID.hpp" |
| #include "utility/Macros.hpp" |
| |
| namespace quickstep { |
| |
| class Scalar; |
| class Type; |
| class ValueAccessor; |
| |
| /** \addtogroup Expressions |
| * @{ |
| */ |
| |
| /** |
| * @brief WindowAggregationHandle encapsulates logic for actually computing |
| * window aggregates with particular argument(s). |
| * @note See also WindowAggregateFunction, which represents a SQL aggregate |
| * function in the abstract sense. |
| * |
| * A WindowAggregationHandle is created by calling |
| * WindowAggregateFunction::createHandle(). The WindowAggregationHandle object |
| * provides methods that are used to actually compute the window aggregate. |
| * |
| * The work flow for computing a window aggregate is: |
| * 1. One thread will handle all the computation, iterating from the first |
| * tuple to the last tuple. Note there will be two modes that could be |
| * used upon different situations: |
| * a. If the window aggregate is defined as accumulative, which are: |
| * i. Functions applied to whole partition, such as rank(), ntile() |
| * and dense_rank(). (Not implemented yet). |
| * ii. The window frame is defined as "BETWEEN UNBOUNDED PRECEDING |
| * AND CURRENT ROW" or "BETWEEN CURRENT ROW AND UNBOUNDED |
| * FOLLOWING". |
| * Then, for functions except median, we could store some global |
| * values without keeping all the tuple values around. For simplicity, |
| * in avg(), count() and sum(), we treat the accumulative one as |
| * sliding window since the time complexity does not vary. |
| * b. If the window frame is sliding, such as "BETWEEN 3 PRECEDING AND |
| * 3 FOLLOWING", we have to store all the tuples in the state (at |
| * least two pointers to the start tuple and end tuple), so that |
| * we could know which values should be dropped as the window slides. |
| * For each computed value, generate a TypedValue and store it into a |
| * ColumnVector for window aggregate values. |
| * 2. Return the result ColumnVector. |
| * |
| * TODO(Shixuan): Currently we don't support parallelization. The basic idea for |
| * parallelization is to calculate the partial result inside each block. Each |
| * block could visit the following blocks as long as the block's last partition |
| * is not finished. WindowAggregationOperationState will be used for handling |
| * the global state of the calculation. |
| **/ |
| |
| class WindowAggregationHandle { |
| public: |
| /** |
| * @brief Destructor. |
| **/ |
| virtual ~WindowAggregationHandle() {} |
| |
| /** |
| * @brief Calculate the window aggregate result. |
| * |
| * @param block_accessors A pointer to the value accessor of block attributes. |
| * @param arguments The ColumnVectors of arguments |
| * |
| * @return A ColumnVector of the calculated window aggregates. |
| **/ |
| virtual ColumnVector* calculate(ColumnVectorsValueAccessor* block_accessors, |
| const std::vector<ColumnVector*> &arguments) const = 0; |
| |
| protected: |
| /** |
| * @brief Constructor. |
| * |
| * @param partition_by_attributes A list of attributes used as partition key. |
| * @param order_by_attributes A list of attributes used as order key. |
| * @param is_row True if the frame mode is ROWS, false if RANGE. |
| * @param num_preceding The number of rows/range that precedes the current row. |
| * @param num_following The number of rows/range that follows the current row. |
| **/ |
| WindowAggregationHandle( |
| const std::vector<std::unique_ptr<const Scalar>> &partition_by_attributes, |
| const std::vector<std::unique_ptr<const Scalar>> &order_by_attributes, |
| const bool is_row, |
| const std::int64_t num_preceding, |
| const std::int64_t num_following); |
| |
| /** |
| * @brief Check if test tuple is in the same partition as the current |
| * tuple in the accessor. |
| * |
| * @param tuple_accessor The ValueAccessor for tuples. |
| * @param test_tuple_id The id of the test tuple. |
| * |
| * @return True if test tuple is in the same partition as the current tuple in |
| * the accessor, false if not. |
| **/ |
| bool samePartition(const ColumnVectorsValueAccessor *tuple_accessor, |
| const tuple_id test_tuple_id) const; |
| |
| /** |
| * @brief Check if test tuple is in the defined range. |
| * |
| * @param tuple_accessor The ValueAccessor for tuples. |
| * @param test_tuple_id The id of the test tuple. |
| * |
| * @return True if test tuple is in the defined window, false if not. |
| **/ |
| bool inWindow(const ColumnVectorsValueAccessor *tuple_accessor, |
| const tuple_id test_tuple_id) const; |
| |
| // IDs and comparators for partition keys. |
| std::vector<attribute_id> partition_key_ids_; |
| std::vector<std::unique_ptr<UncheckedComparator>> partition_equal_comparators_; |
| |
| // IDs, type, Comparator and operator for frame boundary check in RANGE mode. |
| std::vector<attribute_id> order_key_ids_; |
| std::unique_ptr<UncheckedBinaryOperator> range_add_operator_; |
| std::unique_ptr<UncheckedComparator> range_comparator_; // Less than or Equal |
| const Type* range_compare_type_; |
| |
| // Window frame information. |
| const bool is_row_; |
| const std::int64_t num_preceding_; |
| const std::int64_t num_following_; |
| |
| private: |
| DISALLOW_COPY_AND_ASSIGN(WindowAggregationHandle); |
| }; |
| |
| } // namespace quickstep |
| |
| #endif // QUICKSTEP_EXPRESSIONS_WINDOW_AGGREGATION_WINDOW_AGGREGATION_HANDLE_HPP_ |