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doris/be/src/exec/merge_join_node.h
chenhao7253886 37b4cafe87 Change variable and namespace name in BE (#268)
Change 'palo' to 'doris'
2018-11-02 10:22:32 +08:00

103 lines
3.7 KiB
C++

// 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 DORIS_BE_SRC_QUERY_EXEC_MERGE_JOIN_NODE_H
#define DORIS_BE_SRC_QUERY_EXEC_MERGE_JOIN_NODE_H
#include <boost/scoped_ptr.hpp>
#include <boost/unordered_set.hpp>
#include <boost/thread.hpp>
#include <string>
#include "exec/exec_node.h"
#include "runtime/row_batch.h"
#include "gen_cpp/PlanNodes_types.h" // for TJoinOp
namespace doris {
class MemPool;
class TupleRow;
// Node for in-memory merge joins:
// find the minimal tuple and output
class MergeJoinNode : public ExecNode {
public:
MergeJoinNode(ObjectPool* pool, const TPlanNode& tnode, const DescriptorTbl& descs);
~MergeJoinNode();
virtual Status init(const TPlanNode& tnode, RuntimeState* state = nullptr);
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);
static const char* LLVM_CLASS_NAME;
protected:
void debug_string(int indentation_level, std::stringstream* out) const;
private:
// our equi-join predicates "<lhs> = <rhs>" are separated into
// _left_exprs (over child(0)) and _right_exprs (over child(1))
// check which expr is min
std::vector<ExprContext*> _left_expr_ctxs;
std::vector<ExprContext*> _right_expr_ctxs;
// non-equi-join conjuncts from the JOIN clause
std::vector<ExprContext*> _other_join_conjunct_ctxs;
bool _eos; // if true, nothing left to return in get_next()
struct ChildReaderContext {
RowBatch batch;
int row_idx;
bool is_eos;
TupleRow* current_row;
ChildReaderContext(const RowDescriptor& desc, int batch_size, MemTracker* mem_tracker) :
batch(desc, batch_size, mem_tracker), row_idx(0), is_eos(false), current_row(NULL) {
}
};
// _left_batch must be cleared before calling get_next(). used cache child(0)'s data
// _rigth_batch must be cleared before calling get_next(). used cache child(1)'s data
// does not initialize all tuple ptrs in the row, only the ones that it
// is responsible for.
boost::scoped_ptr<ChildReaderContext> _left_child_ctx;
boost::scoped_ptr<ChildReaderContext> _right_child_ctx;
// _build_tuple_idx[i] is the tuple index of child(1)'s tuple[i] in the output row
std::vector<int> _right_tuple_idx;
int _right_tuple_size;
int _left_tuple_size;
RowBatch* _out_batch;
typedef int (*CompareFn)(const void*, const void*);
std::vector<CompareFn> _cmp_func;
// byte size of result tuple row (sum of the tuple ptrs, not the tuple data).
// This should be the same size as the probe tuple row.
int _result_tuple_row_size;
void create_output_row(TupleRow* out, TupleRow* left, TupleRow* right);
Status compare_row(TupleRow* left_row, TupleRow* right_row, bool* is_lt);
Status get_next_row(RuntimeState* state, TupleRow* out_row, bool* eos);
Status get_input_row(RuntimeState* state, int child_idx);
};
}
#endif