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
|
/**
* Test the $sampleRate match expression.
* @tags: [requires_fcv_46]
*/
(function() {
"use strict";
const coll = db.expression_sample_rate;
coll.drop();
print("Generating test collection...");
const N = 3000;
let i;
const bulk = coll.initializeUnorderedBulkOp();
for (i = 0; i < N; i++) {
bulk.insert({_id: i, v: 1});
}
assert.commandWorked(bulk.execute());
const p = 0.5;
const k = 1000;
// Average the number of docs sampled over k iterations.
const pipeline = [{$match: {$sampleRate: p}}, {$count: "n"}];
let nSampled = 0;
for (i = 0; i < k; i++) {
const resultArray = coll.aggregate(pipeline).toArray();
assert.eq(1, resultArray.length);
nSampled += resultArray[0]["n"];
}
const avg = nSampled / k;
print("Average docs sampled: ", avg);
// Test that the average number of sampled docs is within 10 standard deviations using the
// binomial distribution over k runs, 10 * sqrt(N * p * (1 - p) / k).
const mu = p * N;
const err = 10.0 * Math.sqrt(mu * (1 - p) / k);
assert.between(mu - err, avg, mu + err);
// Test that we accept 0.0 and 1.0.
let resultArray = coll.aggregate([{$match: {$sampleRate: 0.0}}]).toArray();
assert.eq(0, resultArray.length);
resultArray = coll.aggregate([{$match: {$sampleRate: 0}}]).toArray();
assert.eq(0, resultArray.length);
resultArray = coll.aggregate([{$match: {$sampleRate: 1.0}}, {$count: "n"}]).toArray();
assert.eq(1, resultArray.length);
assert.eq(resultArray[0]["n"], N);
resultArray = coll.aggregate([{$match: {$sampleRate: 1}}, {$count: "n"}]).toArray();
assert.eq(1, resultArray.length);
assert.eq(resultArray[0]["n"], N);
// Test parser failure cases.
assert.commandFailedWithCode(
db.runCommand({aggregate: coll.getName(), cursor: {}, pipeline: [{$match: {$sampleRate: -1}}]}),
ErrorCodes.BadValue);
assert.commandFailedWithCode(
db.runCommand(
{aggregate: coll.getName(), cursor: {}, pipeline: [{$match: {$sampleRate: -1.0}}]}),
ErrorCodes.BadValue);
assert.commandFailedWithCode(
db.runCommand(
{aggregate: coll.getName(), cursor: {}, pipeline: [{$match: {$sampleRate: 2.0}}]}),
ErrorCodes.BadValue);
assert.commandFailedWithCode(db.runCommand({
aggregate: coll.getName(),
cursor: {},
pipeline: [{$match: {$sampleRate: {$const: 0.25}}}]
}),
ErrorCodes.BadValue);
}());
|
