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doris/be/src/exec/sort_node.h
2019-06-14 23:38:31 +08:00

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// 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 INF_DORIS_QE_SRC_BE_EXEC_SORT_NODE_H
#define INF_DORIS_QE_SRC_BE_EXEC_SORT_NODE_H
#include "exec/exec_node.h"
#include "exec/sort_exec_exprs.h"
#include "runtime/merge_sorter.h"
#include "runtime/buffered_block_mgr.h"
namespace doris {
// Node that implements a full sort of its input with a fixed memory budget, spilling
// to disk if the input is larger than available memory.
// Uses Sorter and BufferedBlockMgr for the external sort implementation.
// Input rows to SortNode are materialized by the Sorter into a single tuple
// using the expressions specified in sort_exec_exprs_.
// In GetNext(), SortNode passes in the output batch to the sorter instance created
// in Open() to fill it with sorted rows.
// If a merge phase was performed in the sort, sorted rows are deep copied into
// the output batch. Otherwise, the sorter instance owns the sorted data.
class SortNode : public ExecNode {
public:
SortNode(ObjectPool* pool, const TPlanNode& tnode, const DescriptorTbl& descs);
~SortNode();
virtual Status prepare(RuntimeState* state);
virtual Status open(RuntimeState* state);
virtual Status get_next(RuntimeState* state, RowBatch* row_batch, bool* eos);
virtual Status close(RuntimeState* state);
protected:
virtual void debug_string(int indentation_level, std::stringstream* out) const;
private:
Status init(const TPlanNode& tnode, RuntimeState* state = nullptr);
// Fetch input rows and feed them to the sorter until the input is exhausted.
Status sort_input(RuntimeState* state);
// Create a block manager object and set it in block_mgr_.
// Returns and sets the query status to Status::MemoryLimitExceeded("Memory limit exceeded") if there is not
// enough memory for the sort.
Status create_block_mgr(RuntimeState* state);
// Number of rows to skip.
int64_t _offset;
int64_t _num_rows_skipped;
// Object used for external sorting.
boost::scoped_ptr<MergeSorter> _sorter;
// Expressions and parameters used for tuple materialization and tuple comparison.
SortExecExprs _sort_exec_exprs;
std::vector<bool> _is_asc_order;
std::vector<bool> _nulls_first;
boost::scoped_ptr<MemPool> _tuple_pool;
};
}
#endif