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// @tags: [assumes_balancer_off]
(function() {
"use strict";
load("jstests/libs/fixture_helpers.js"); // For FixtureHelpers.
load("jstests/libs/analyze_plan.js"); // For planHasStage.
var coll = db.distinct_multikey_index;
coll.drop();
for (var i = 0; i < 10; i++) {
assert.writeOK(coll.save({a: 1, b: 1}));
assert.writeOK(coll.save({a: 1, b: 2}));
assert.writeOK(coll.save({a: 2, b: 1}));
assert.writeOK(coll.save({a: 2, b: 3}));
}
coll.createIndex({a: 1, b: 1});
var explain_distinct_with_query = coll.explain("executionStats").distinct('b', {a: 1});
assert.commandWorked(explain_distinct_with_query);
assert(planHasStage(db, explain_distinct_with_query.queryPlanner.winningPlan, "DISTINCT_SCAN"));
assert(
planHasStage(db, explain_distinct_with_query.queryPlanner.winningPlan, "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));
var explain_distinct_without_query = coll.explain("executionStats").distinct('b');
assert.commandWorked(explain_distinct_without_query);
assert(planHasStage(db, explain_distinct_without_query.queryPlanner.winningPlan, "COLLSCAN"));
assert(!planHasStage(db, explain_distinct_without_query.queryPlanner.winningPlan, "DISTINCT_SCAN"));
assert.eq(40, explain_distinct_without_query.executionStats.nReturned);
})();
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