1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
|
/**
* Copyright (C) 2020-present MongoDB, Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the Server Side Public License, version 1,
* as published by MongoDB, Inc.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* Server Side Public License for more details.
*
* You should have received a copy of the Server Side Public License
* along with this program. If not, see
* <http://www.mongodb.com/licensing/server-side-public-license>.
*
* As a special exception, the copyright holders give permission to link the
* code of portions of this program with the OpenSSL library under certain
* conditions as described in each individual source file and distribute
* linked combinations including the program with the OpenSSL library. You
* must comply with the Server Side Public License in all respects for
* all of the code used other than as permitted herein. If you modify file(s)
* with this exception, you may extend this exception to your version of the
* file(s), but you are not obligated to do so. If you do not wish to do so,
* delete this exception statement from your version. If you delete this
* exception statement from all source files in the program, then also delete
* it in the license file.
*/
#pragma once
#include <queue>
#include "mongo/db/exec/sbe/stages/stages.h"
namespace mongo::sbe {
/**
* Combines values from multiple streams into one stream. The union has n 'inputStages', each of
* which provides m slots, specified as a vector of slot vectors 'inputVals'. (This vector has n * m
* total slots.) The union stage itself also returns m slots, specified as 'outputVals'. Each of the
* n branches is executed in turn until reaching EOF, and the values from its m slots are remapped
* to the m output slots.
*
* This is a binding reflector, meaning that only the 'outputVals' slots are visible to stages
* higher in the tree.
*
* Debug string repsentation:
*
* union [<output slots>] [[<input slots 1>] childStage_1, ..., [<input slots n>] childStage_n]
*/
class UnionStage final : public PlanStage {
public:
UnionStage(PlanStage::Vector inputStages,
std::vector<value::SlotVector> inputVals,
value::SlotVector outputVals,
PlanNodeId planNodeId);
std::unique_ptr<PlanStage> clone() const final;
void prepare(CompileCtx& ctx) final;
value::SlotAccessor* getAccessor(CompileCtx& ctx, value::SlotId slot) final;
void open(bool reOpen) final;
PlanState getNext() final;
void close() final;
std::unique_ptr<PlanStageStats> getStats(bool includeDebugInfo) const final;
const SpecificStats* getSpecificStats() const final;
std::vector<DebugPrinter::Block> debugPrint() const final;
size_t estimateCompileTimeSize() const final;
private:
struct UnionBranch {
PlanStage* stage{nullptr};
const bool reOpen{false};
bool isOpen{false};
void open() {
if (!isOpen) {
stage->open(reOpen);
isOpen = true;
}
}
void close() {
if (isOpen) {
stage->close();
isOpen = false;
}
}
};
void clearBranches();
const std::vector<value::SlotVector> _inputVals;
const value::SlotVector _outputVals;
std::vector<value::SwitchAccessor> _outValueAccessors;
std::queue<UnionBranch> _remainingBranchesToDrain;
PlanStage* _currentStage{nullptr};
size_t _currentStageIndex{0};
};
} // namespace mongo::sbe
|
