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
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
|
/**
* Copyright (C) 2019-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 "mongo/bson/ordering.h"
#include "mongo/db/db_raii.h"
#include "mongo/db/exec/sbe/stages/stages.h"
#include "mongo/db/exec/trial_run_progress_tracker.h"
#include "mongo/db/storage/record_store.h"
#include "mongo/db/storage/sorted_data_interface.h"
namespace mongo::sbe {
/**
* A stage that iterates the entries of a collection index, starting from a bound specified by the
* value in 'seekKeySlotLow' and ending (via IS_EOF) with the 'seekKeySlotHi' bound. (An unspecified
* 'seekKeySlowHi' scans to the end of the index. Leaving both bounds unspecified scans the index
* from beginning to end.)
*
* The input 'seekKeySlotLow' and 'seekKeySlotHi' slots get read as part of the open (or re-open)
* call. A common use case for an IndexScanStage is to place it as the inner child of LoopJoinStage.
* The outer side of the LoopJoinStage determines the bounds, and the inner IndexScanStage iterates
* through all the entries within those bounds.
*
* The "output" slots are
* - 'recordSlot': the "KeyString" representing the index entry,
* - 'recordIdSlot': a reference that can be used to fetch the entire document, and
* - 'vars': one slot for each value in the index key that should be "projected" out of the entry.
*
* The 'indexKeysToInclude' bitset determines which values are included in the projection based
* on their order in the index pattern. The number of bits set in 'indexKeysToInclude' must be
* the same as the number of slots in the 'vars' SlotVector.
*/
class IndexScanStage final : public PlanStage {
public:
IndexScanStage(const NamespaceStringOrUUID& name,
std::string_view indexName,
bool forward,
boost::optional<value::SlotId> recordSlot,
boost::optional<value::SlotId> recordIdSlot,
IndexKeysInclusionSet indexKeysToInclude,
value::SlotVector vars,
boost::optional<value::SlotId> seekKeySlotLow,
boost::optional<value::SlotId> seekKeySlotHi,
PlanYieldPolicy* yieldPolicy,
TrialRunProgressTracker* tracker);
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() const final;
const SpecificStats* getSpecificStats() const final;
std::vector<DebugPrinter::Block> debugPrint() const final;
protected:
void doSaveState() override;
void doRestoreState() override;
void doDetachFromOperationContext() override;
void doAttachFromOperationContext(OperationContext* opCtx) override;
private:
const NamespaceStringOrUUID _name;
const std::string _indexName;
const bool _forward;
const boost::optional<value::SlotId> _recordSlot;
const boost::optional<value::SlotId> _recordIdSlot;
const IndexKeysInclusionSet _indexKeysToInclude;
const value::SlotVector _vars;
const boost::optional<value::SlotId> _seekKeySlotLow;
const boost::optional<value::SlotId> _seekKeySlotHi;
std::unique_ptr<value::ViewOfValueAccessor> _recordAccessor;
std::unique_ptr<value::ViewOfValueAccessor> _recordIdAccessor;
// One accessor and slot for each key component that this stage will bind from an index entry's
// KeyString. The accessors are in the same order as the key components they bind to.
std::vector<value::ViewOfValueAccessor> _accessors;
value::SlotAccessorMap _accessorMap;
value::SlotAccessor* _seekKeyLowAccessor{nullptr};
value::SlotAccessor* _seekKeyHiAccessor{nullptr};
KeyString::Value _startPoint;
KeyString::Value* _seekKeyLow{nullptr};
KeyString::Value* _seekKeyHi{nullptr};
std::unique_ptr<SortedDataInterface::Cursor> _cursor;
std::weak_ptr<const IndexCatalogEntry> _weakIndexCatalogEntry;
boost::optional<Ordering> _ordering{boost::none};
boost::optional<AutoGetCollectionForRead> _coll;
boost::optional<KeyStringEntry> _nextRecord;
// This buffer stores values that are projected out of the index entry. Values in the
// '_accessors' list that are pointers point to data in this buffer.
BufBuilder _valuesBuffer;
bool _open{false};
bool _firstGetNext{true};
IndexScanStats _specificStats;
// If provided, used during a trial run to accumulate certain execution stats. Once the trial
// run is complete, this pointer is reset to nullptr.
TrialRunProgressTracker* _tracker{nullptr};
};
} // namespace mongo::sbe
|
