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
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
|
/**
* 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/collection_helpers.h"
#include "mongo/db/exec/sbe/stages/stages.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 'seekKeySlotHigh' bound. (An
* unspecified 'seekKeySlotHigh' scans to the end of the index. Leaving both bounds unspecified
* scans the index from beginning to end.)
*
* The input 'seekKeySlotLow' and 'seekKeySlotHigh' 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,
* - 'snapshotIdSlot': the storage snapshot that this index scan is reading from, 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.
*
* The 'forward' flag indicates the direction of the index scan, which can be either forwards or
* backwards.
*
* Debug string representation:
*
* ixscan recordSlot? recordIdSlot? snapshotIdSlot? [slot_1 = fieldNo_1, ..., slot2 = fieldNo_n]
* collectionUuid indexName forward
*
* ixseek lowKey highKey recordSlot? recordIdSlot? snapshotIdSlot?
* [slot_1 = fieldNo_1, ..., slot2 = fieldNo_n]
* collectionUuid indexName forward
*/
class IndexScanStage final : public PlanStage {
public:
IndexScanStage(CollectionUUID collUuid,
StringData indexName,
bool forward,
boost::optional<value::SlotId> recordSlot,
boost::optional<value::SlotId> recordIdSlot,
boost::optional<value::SlotId> snapshotIdSlot,
IndexKeysInclusionSet indexKeysToInclude,
value::SlotVector vars,
boost::optional<value::SlotId> seekKeySlotLow,
boost::optional<value::SlotId> seekKeySlotHigh,
PlanYieldPolicy* yieldPolicy,
PlanNodeId nodeId);
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;
protected:
void doSaveState() override;
void doRestoreState() override;
void doDetachFromOperationContext() override;
void doAttachToOperationContext(OperationContext* opCtx) override;
void doDetachFromTrialRunTracker() override;
void doAttachToTrialRunTracker(TrialRunTracker* tracker) override;
private:
/**
* When this stage is re-opened after being closed, or during yield recovery, called to verify
* that the index (and the index's collection) remain valid. If any validity check fails, throws
* a UserException that terminates execution of the query.
*/
void restoreCollectionAndIndex();
const KeyString::Value& getSeekKeyLow() const;
const KeyString::Value* getSeekKeyHigh() const;
const CollectionUUID _collUuid;
const std::string _indexName;
const bool _forward;
const boost::optional<value::SlotId> _recordSlot;
const boost::optional<value::SlotId> _recordIdSlot;
const boost::optional<value::SlotId> _snapshotIdSlot;
const IndexKeysInclusionSet _indexKeysToInclude;
const value::SlotVector _vars;
const boost::optional<value::SlotId> _seekKeySlotLow;
const boost::optional<value::SlotId> _seekKeySlotHigh;
// These members are default constructed to boost::none and are initialized when 'prepare()'
// is called. Once they are set, they are never modified again.
boost::optional<NamespaceString> _collName;
boost::optional<uint64_t> _catalogEpoch;
CollectionPtr _coll;
std::unique_ptr<value::OwnedValueAccessor> _recordAccessor;
std::unique_ptr<value::OwnedValueAccessor> _recordIdAccessor;
std::unique_ptr<value::OwnedValueAccessor> _snapshotIdAccessor;
// 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::OwnedValueAccessor> _accessors;
value::SlotAccessorMap _accessorMap;
value::SlotAccessor* _seekKeyLowAccessor{nullptr};
value::SlotAccessor* _seekKeyHiAccessor{nullptr};
std::unique_ptr<value::OwnedValueAccessor> _seekKeyLowHolder;
std::unique_ptr<value::OwnedValueAccessor> _seekKeyHighHolder;
std::unique_ptr<SortedDataInterface::Cursor> _cursor;
std::weak_ptr<const IndexCatalogEntry> _weakIndexCatalogEntry;
boost::optional<Ordering> _ordering{boost::none};
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.
TrialRunTracker* _tracker{nullptr};
};
} // namespace mongo::sbe
|
