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
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
|
// Cannot implicitly shard accessed collections because of collection existing when none
// expected.
// @tags: [assumes_no_implicit_collection_creation_after_drop, does_not_support_stepdowns]
// Confirms correct behavior for hinted aggregation execution. This includes tests for scenarios
// where agg execution differs from query. It also includes confirmation that hint works for find
// command against views, which is converted to a hinted aggregation on execution.
(function() {
"use strict";
load("jstests/libs/analyze_plan.js"); // For getAggPlanStage.
const testDB = db.getSiblingDB("agg_hint");
assert.commandWorked(testDB.dropDatabase());
const coll = testDB.getCollection("test");
const view = testDB.getCollection("view");
function confirmWinningPlanUsesExpectedIndex(
explainResult, expectedKeyPattern, stageName, pipelineOptimizedAway) {
const planStage = pipelineOptimizedAway ? getPlanStage(explainResult, stageName)
: getAggPlanStage(explainResult, stageName);
assert.neq(null, planStage);
assert.eq(planStage.keyPattern, expectedKeyPattern, tojson(planStage));
}
// Runs explain on 'command', with the hint specified by 'hintKeyPattern' when not null.
// Confirms that the winning query plan uses the index specified by 'expectedKeyPattern'.
// If 'pipelineOptimizedAway' is set to true, then we expect the pipeline to be entirely
// optimized away from the plan and replaced with a query tier.
function confirmCommandUsesIndex({command = null,
hintKeyPattern = null,
expectedKeyPattern = null,
stageName = "IXSCAN",
pipelineOptimizedAway = false} = {}) {
if (hintKeyPattern) {
command["hint"] = hintKeyPattern;
}
const res =
assert.commandWorked(testDB.runCommand({explain: command, verbosity: "queryPlanner"}));
confirmWinningPlanUsesExpectedIndex(
res, expectedKeyPattern, stageName, pipelineOptimizedAway);
}
// Runs explain on an aggregation with a pipeline specified by 'aggPipeline' and a hint
// specified by 'hintKeyPattern' if not null. Confirms that the winning query plan uses the
// index specified by 'expectedKeyPattern'. If 'pipelineOptimizedAway' is set to true, then
// we expect the pipeline to be entirely optimized away from the plan and replaced with a
// query tier.
//
// This method exists because the explain command does not support the aggregation command.
function confirmAggUsesIndex({collName = null,
aggPipeline = [],
hintKeyPattern = null,
expectedKeyPattern = null,
stageName = "IXSCAN",
pipelineOptimizedAway = false} = {}) {
let options = {};
if (hintKeyPattern) {
options = {hint: hintKeyPattern};
}
const res = assert.commandWorked(
testDB.getCollection(collName).explain().aggregate(aggPipeline, options));
confirmWinningPlanUsesExpectedIndex(
res, expectedKeyPattern, stageName, pipelineOptimizedAway);
}
// Specify hint as a string, representing index name.
assert.commandWorked(coll.createIndex({x: 1}));
for (let i = 0; i < 5; ++i) {
assert.writeOK(coll.insert({x: i}));
}
confirmAggUsesIndex({
collName: "test",
aggPipeline: [{$match: {x: 3}}],
hintKeyPattern: "x_1",
expectedKeyPattern: {x: 1},
pipelineOptimizedAway: true
});
//
// For each of the following tests we confirm:
// * That the expected index is chosen by the query planner when no hint is provided.
// * That the expected index is chosen when hinted.
// * That an index other than the one expected is chosen when hinted.
//
// Hint on poor index choice should force use of the hinted index over one more optimal.
coll.drop();
assert.commandWorked(coll.createIndex({x: 1}));
for (let i = 0; i < 5; ++i) {
assert.writeOK(coll.insert({x: i}));
}
confirmAggUsesIndex({
collName: "test",
aggPipeline: [{$match: {x: 3}}],
expectedKeyPattern: {x: 1},
pipelineOptimizedAway: true
});
confirmAggUsesIndex({
collName: "test",
aggPipeline: [{$match: {x: 3}}],
hintKeyPattern: {x: 1},
expectedKeyPattern: {x: 1},
pipelineOptimizedAway: true
});
confirmAggUsesIndex({
collName: "test",
aggPipeline: [{$match: {x: 3}}],
hintKeyPattern: {_id: 1},
expectedKeyPattern: {_id: 1},
pipelineOptimizedAway: true
});
// With no hint specified, aggregation will always prefer an index that provides sort order over
// one that requires a blocking sort. A hinted aggregation should allow for choice of an index
// that provides blocking sort.
coll.drop();
assert.commandWorked(coll.createIndex({x: 1}));
assert.commandWorked(coll.createIndex({y: 1}));
for (let i = 0; i < 5; ++i) {
assert.writeOK(coll.insert({x: i, y: i}));
}
confirmAggUsesIndex({
collName: "test",
aggPipeline: [{$match: {x: {$gte: 0}}}, {$sort: {y: 1}}],
expectedKeyPattern: {y: 1},
pipelineOptimizedAway: true
});
confirmAggUsesIndex({
collName: "test",
aggPipeline: [{$match: {x: {$gte: 0}}}, {$sort: {y: 1}}],
hintKeyPattern: {y: 1},
expectedKeyPattern: {y: 1},
pipelineOptimizedAway: true
});
confirmAggUsesIndex({
collName: "test",
aggPipeline: [{$match: {x: {$gte: 0}}}, {$sort: {y: 1}}],
hintKeyPattern: {x: 1},
expectedKeyPattern: {x: 1}
});
// With no hint specified, aggregation will always prefer an index that provides a covered
// projection over one that does not. A hinted aggregation should allow for choice of an index
// that does not cover.
coll.drop();
assert.commandWorked(coll.createIndex({x: 1}));
assert.commandWorked(coll.createIndex({x: 1, y: 1}));
for (let i = 0; i < 5; ++i) {
assert.writeOK(coll.insert({x: i, y: i}));
}
confirmAggUsesIndex({
collName: "test",
aggPipeline: [{$match: {x: {$gte: 0}}}, {$project: {x: 1, y: 1, _id: 0}}],
expectedKeyPattern: {x: 1, y: 1},
pipelineOptimizedAway: true
});
confirmAggUsesIndex({
collName: "test",
aggPipeline: [{$match: {x: {$gte: 0}}}, {$project: {x: 1, y: 1, _id: 0}}],
hintKeyPattern: {x: 1, y: 1},
expectedKeyPattern: {x: 1, y: 1},
pipelineOptimizedAway: true
});
confirmAggUsesIndex({
collName: "test",
aggPipeline: [{$match: {x: {$gte: 0}}}, {$project: {x: 1, y: 1, _id: 0}}],
hintKeyPattern: {x: 1},
expectedKeyPattern: {x: 1}
});
// Confirm that a hinted agg can be executed against a view.
coll.drop();
view.drop();
assert.commandWorked(coll.createIndex({x: 1}));
for (let i = 0; i < 5; ++i) {
assert.writeOK(coll.insert({x: i}));
}
assert.commandWorked(testDB.createView("view", "test", [{$match: {x: {$gte: 0}}}]));
confirmAggUsesIndex({
collName: "view",
aggPipeline: [{$match: {x: 3}}],
expectedKeyPattern: {x: 1},
pipelineOptimizedAway: true
});
confirmAggUsesIndex({
collName: "view",
aggPipeline: [{$match: {x: 3}}],
hintKeyPattern: {x: 1},
expectedKeyPattern: {x: 1},
pipelineOptimizedAway: true
});
confirmAggUsesIndex({
collName: "view",
aggPipeline: [{$match: {x: 3}}],
hintKeyPattern: {_id: 1},
expectedKeyPattern: {_id: 1},
pipelineOptimizedAway: true
});
// Confirm that a hinted find can be executed against a view.
coll.drop();
view.drop();
assert.commandWorked(coll.createIndex({x: 1}));
for (let i = 0; i < 5; ++i) {
assert.writeOK(coll.insert({x: i}));
}
assert.commandWorked(testDB.createView("view", "test", []));
confirmCommandUsesIndex({
command: {find: "view", filter: {x: 3}},
expectedKeyPattern: {x: 1},
pipelineOptimizedAway: true
});
confirmCommandUsesIndex({
command: {find: "view", filter: {x: 3}},
hintKeyPattern: {x: 1},
expectedKeyPattern: {x: 1},
pipelineOptimizedAway: true
});
confirmCommandUsesIndex({
command: {find: "view", filter: {x: 3}},
hintKeyPattern: {_id: 1},
expectedKeyPattern: {_id: 1},
pipelineOptimizedAway: true
});
// Confirm that a hinted count can be executed against a view.
coll.drop();
view.drop();
assert.commandWorked(coll.createIndex({x: 1}));
for (let i = 0; i < 5; ++i) {
assert.writeOK(coll.insert({x: i}));
}
assert.commandWorked(testDB.createView("view", "test", []));
confirmCommandUsesIndex({
command: {count: "view", query: {x: 3}},
expectedKeyPattern: {x: 1},
stageName: "COUNT_SCAN"
});
confirmCommandUsesIndex({
command: {count: "view", query: {x: 3}},
hintKeyPattern: {x: 1},
expectedKeyPattern: {x: 1},
stageName: "COUNT_SCAN"
});
confirmCommandUsesIndex({
command: {count: "view", query: {x: 3}},
hintKeyPattern: {_id: 1},
expectedKeyPattern: {_id: 1}
});
})();
|