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
|
// @tags: [
// assumes_balancer_off,
// assumes_unsharded_collection,
// # Asserts that some queries use a collection scan.
// assumes_no_implicit_index_creation,
// ]
(function() {
"use strict";
load("jstests/libs/fixture_helpers.js"); // For FixtureHelpers.
load("jstests/libs/analyze_plan.js"); // For planHasStage.
const coll = db.distinct_multikey_index;
coll.drop();
for (let i = 0; i < 10; i++) {
assert.commandWorked(coll.insert({a: 1, b: 1, geoField: [0, 0], text: "A"}));
assert.commandWorked(coll.insert({a: 1, b: 2, geoField: [1, 1], text: "B"}));
assert.commandWorked(coll.insert({a: 2, b: 1, geoField: [1, 2], text: "C"}));
assert.commandWorked(coll.insert({a: 2, b: 3, geoField: [1, 1], text: "D"}));
}
assert.commandWorked(coll.createIndex({a: 1, b: 1}));
const explain_distinct_with_query = coll.explain("executionStats").distinct('b', {a: 1});
assert.commandWorked(explain_distinct_with_query);
assert(planHasStage(db, getWinningPlan(explain_distinct_with_query.queryPlanner), "DISTINCT_SCAN"));
assert(planHasStage(
db, getWinningPlan(explain_distinct_with_query.queryPlanner), "PROJECTION_COVERED"));
// If the collection is sharded, we expect at most 2 distinct values per shard. If the
// collection is not sharded, we expect 2 returned.
assert.lte(explain_distinct_with_query.executionStats.nReturned,
2 * FixtureHelpers.numberOfShardsForCollection(coll));
const explain_distinct_without_query = coll.explain("executionStats").distinct('b');
assert.commandWorked(explain_distinct_without_query);
assert(planHasStage(db, getWinningPlan(explain_distinct_without_query.queryPlanner), "COLLSCAN"));
assert(!planHasStage(
db, getWinningPlan(explain_distinct_without_query.queryPlanner), "DISTINCT_SCAN"));
assert.eq(40, explain_distinct_without_query.executionStats.nReturned);
// Verify that compound special indexes such as '2dsphere' and 'text' can never use index to answer
// 'distinct' command.
const cmdObj = {
distinct: coll.getName(),
key: "a"
};
assert.commandWorked(coll.dropIndexes());
assert.commandWorked(coll.createIndex({a: 1, b: 1, geoField: "2dsphere"}));
assertStagesForExplainOfCommand({
coll: coll,
cmdObj: cmdObj,
expectedStages: ["COLLSCAN"],
stagesNotExpected: ["DISTINCT_SCAN"]
});
assert.commandWorked(coll.dropIndexes());
assert.commandWorked(coll.createIndex({a: 1, b: 1, text: "text"}));
assertStagesForExplainOfCommand({
coll: coll,
cmdObj: cmdObj,
expectedStages: ["COLLSCAN"],
stagesNotExpected: ["DISTINCT_SCAN"]
});
})();
|
