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
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
|
/**
* Copyright (C) 2018-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 <vector>
#include "mongo/db/catalog/clustered_collection_options_gen.h"
#include "mongo/db/jsobj.h"
#include "mongo/db/query/collation/collator_interface.h"
#include "mongo/db/query/index_entry.h"
#include "mongo/db/query/query_knobs_gen.h"
namespace mongo {
/**
* Struct containing basic stats about a collection useful for query planning.
*/
struct CollectionStats {
// The number of records in the collection.
long long noOfRecords{0};
// The approximate size of the collection in bytes.
long long approximateDataSizeBytes{0};
// The allocated storage size in bytes.
long long storageSizeBytes{0};
};
/**
* Struct containing information about secondary collections (such as the 'from' collection in
* $lookup) useful for query planning.
*/
struct SecondaryCollectionInfo {
std::vector<IndexEntry> indexes{};
std::vector<ColumnIndexEntry> columnIndexes{};
bool exists{true};
CollectionStats stats{};
};
// This holds information about the internal traversal preference used for time series. If we choose
// an index that involves fields we're interested in, we prefer a specific direction to avoid a
// blocking sort.
struct TraversalPreference {
// If we end up with an index that provides {sortPattern}, we prefer to scan it in direction
// {direction}.
BSONObj sortPattern;
int direction;
// Cluster key for the collection this query accesses (for time-series it's control.min.time).
// If a collection scan is chosen, this will be compared against the sortPattern to see if we
// can satisfy the traversal preference.
std::string clusterField;
};
struct QueryPlannerParams {
QueryPlannerParams(size_t options = DEFAULT)
: options(options),
indexFiltersApplied(false),
maxIndexedSolutions(internalQueryPlannerMaxIndexedSolutions.load()),
clusteredCollectionCollator(nullptr),
availableMemoryBytes(0) {}
enum Options {
// You probably want to set this.
DEFAULT = 0,
// Set this if you don't want a table scan.
// See http://docs.mongodb.org/manual/reference/parameters/
NO_TABLE_SCAN = 1,
// Set this if you *always* want a collscan outputted, even if there's an ixscan. This
// makes ranking less accurate, especially in the presence of blocking stages.
INCLUDE_COLLSCAN = 1 << 1,
// Set this if you're running on a sharded cluster. We'll add a "drop all docs that
// shouldn't be on this shard" stage before projection.
//
// In order to set this, you must check OperationShardingState::isComingFromRouter() in the
// same lock that you use to build the query executor. You must also wrap the PlanExecutor
// in a ClientCursor within the same lock.
//
// See the comment on ShardFilterStage for details.
INCLUDE_SHARD_FILTER = 1 << 2,
// Set this if you want to turn on index intersection.
INDEX_INTERSECTION = 1 << 3,
// Set this to generate covered whole IXSCAN plans.
GENERATE_COVERED_IXSCANS = 1 << 4,
// Set this to track the most recent timestamp seen by this cursor while scanning the
// oplog or change collection.
TRACK_LATEST_OPLOG_TS = 1 << 5,
// Set this so that collection scans on the oplog wait for visibility before reading.
OPLOG_SCAN_WAIT_FOR_VISIBLE = 1 << 6,
// Set this so that getExecutorDistinct() will only use a plan that _guarantees_ it will
// return exactly one document per value of the distinct field. See the comments above the
// declaration of getExecutorDistinct() for more detail.
STRICT_DISTINCT_ONLY = 1 << 7,
// Set this on an oplog scan to uassert that the oplog has not already rolled over the
// minimum 'ts' timestamp specified in the query.
ASSERT_MIN_TS_HAS_NOT_FALLEN_OFF_OPLOG = 1 << 8,
// Instruct the plan enumerator to enumerate contained $ors in a special order. $or
// enumeration can generate an exponential number of plans, and is therefore limited at some
// arbitrary cutoff controlled by a parameter. When this limit is hit, the order of
// enumeration is important. For example, a query like the following has a "contained $or"
// (within an $and):
// {a: 1, $or: [{b: 1, c: 1}, {b: 2, c: 2}]}
// For this query if there are indexes a_b={a: 1, b: 1} and a_c={a: 1, c: 1}, the normal
// enumeration order would output assignments [a_b, a_b], [a_c, a_b], [a_b, a_c], then [a_c,
// a_c]. This flag will instruct the enumerator to instead prefer a different order. It's
// hard to summarize, but perhaps the phrases "lockstep enumeration", "simultaneous
// advancement", or "parallel iteration" will help the reader. The effect is to give earlier
// enumeration to plans which use the same index of alternative across all branches. In this
// order, we would get assignments [a_b, a_b], [a_c, a_c], [a_c, a_b], then [a_b, a_c]. This
// is thought to be helpful in general, but particularly in cases where all children of the
// $or use the same fields and have the same indexes available, as in this example.
ENUMERATE_OR_CHILDREN_LOCKSTEP = 1 << 9,
// Ensure that any plan generated returns data that is "owned." That is, all BSONObjs are
// in an "owned" state and are not pointing to data that belongs to the storage engine.
RETURN_OWNED_DATA = 1 << 10,
// When generating column scan queries, splits match expressions so that the filters can be
// applied per-column. This is off by default, since the execution side doesn't support it
// yet.
GENERATE_PER_COLUMN_FILTERS = 1 << 11,
};
// See Options enum above.
size_t options;
// What indices are available for planning?
std::vector<IndexEntry> indices;
// Columnar indexes available.
std::vector<ColumnIndexEntry> columnStoreIndexes;
// Basic collection stats for the main collection.
CollectionStats collectionStats;
// What's our shard key? If INCLUDE_SHARD_FILTER is set we will create a shard filtering
// stage. If we know the shard key, we can perform covering analysis instead of always
// forcing a fetch.
BSONObj shardKey;
// Were index filters applied to indices?
bool indexFiltersApplied;
// What's the max number of indexed solutions we want to output? It's expensive to compare
// plans via the MultiPlanStage, and the set of possible plans is very large for certain
// index+query combinations.
size_t maxIndexedSolutions;
// Specifies the clusteredIndex information necessary to utilize the cluster key in bounded
// collection scans and other query operations.
boost::optional<ClusteredCollectionInfo> clusteredInfo;
// Specifies the collator information necessary to utilize the cluster key in bounded
// collection scans and other query operations.
const CollatorInterface* clusteredCollectionCollator;
// List of information about any secondary collections that can be executed against.
std::map<NamespaceString, SecondaryCollectionInfo> secondaryCollectionsInfo;
boost::optional<TraversalPreference> traversalPreference = boost::none;
// Size of available memory in bytes.
long long availableMemoryBytes;
};
} // namespace mongo
|
