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// Cannot implicitly shard accessed collections because of collection existing when none
// expected.
// @tags: [assumes_no_implicit_collection_creation_after_drop]
/**
* This test ensures that explain on the distinct command works.
*/
(function() {
'use strict';
load("jstests/libs/analyze_plan.js");
var collName = "jstests_explain_distinct";
var coll = db[collName];
function runDistinctExplain(collection, keyString, query) {
var distinctCmd = {distinct: collection.getName(), key: keyString};
if (typeof query !== 'undefined') {
distinctCmd.query = query;
}
return coll.runCommand({explain: distinctCmd, verbosity: 'executionStats'});
}
coll.drop();
// Collection doesn't exist.
var explain = runDistinctExplain(coll, 'a', {});
assert.commandWorked(explain);
assert(planHasStage(db, explain.queryPlanner.winningPlan, "EOF"));
// Insert the data to perform distinct() on.
for (var i = 0; i < 10; i++) {
assert.writeOK(coll.insert({a: 1, b: 1}));
assert.writeOK(coll.insert({a: 2, c: 1}));
}
assert.commandFailed(runDistinctExplain(coll, {}, {})); // Bad keyString.
assert.commandFailed(runDistinctExplain(coll, 'a', 'a')); // Bad query.
assert.commandFailed(runDistinctExplain(coll, 'b', {$not: 1})); // Bad query.
assert.commandFailed(runDistinctExplain(coll, 'a', {$not: 1})); // Bad query.
assert.commandFailed(runDistinctExplain(coll, '_id', {$not: 1})); // Bad query.
// Ensure that server accepts a distinct command with no 'query' field.
assert.commandWorked(runDistinctExplain(coll, '', null));
assert.commandWorked(runDistinctExplain(coll, ''));
assert.eq([1], coll.distinct('b'));
var explain = runDistinctExplain(coll, 'b', {});
assert.commandWorked(explain);
assert.eq(20, explain.executionStats.nReturned);
assert(isCollscan(db, explain.queryPlanner.winningPlan));
assert.commandWorked(coll.createIndex({a: 1}));
assert.eq([1, 2], coll.distinct('a'));
var explain = runDistinctExplain(coll, 'a', {});
assert.commandWorked(explain);
assert.eq(2, explain.executionStats.nReturned);
assert(planHasStage(db, explain.queryPlanner.winningPlan, "PROJECTION_COVERED"));
assert(planHasStage(db, explain.queryPlanner.winningPlan, "DISTINCT_SCAN"));
// Check that the DISTINCT_SCAN stage has the correct stats.
var stage = getPlanStage(explain.queryPlanner.winningPlan, "DISTINCT_SCAN");
assert.eq({a: 1}, stage.keyPattern);
assert.eq("a_1", stage.indexName);
assert.eq(false, stage.isMultiKey);
assert.eq(false, stage.isUnique);
assert.eq(false, stage.isSparse);
assert.eq(false, stage.isPartial);
assert.lte(1, stage.indexVersion);
assert("indexBounds" in stage);
assert.commandWorked(coll.createIndex({a: 1, b: 1}));
assert.eq([1], coll.distinct('a', {a: 1}));
var explain = runDistinctExplain(coll, 'a', {a: 1});
assert.commandWorked(explain);
assert.eq(1, explain.executionStats.nReturned);
assert(planHasStage(db, explain.queryPlanner.winningPlan, "PROJECTION_COVERED"));
assert(planHasStage(db, explain.queryPlanner.winningPlan, "DISTINCT_SCAN"));
assert.eq([1], coll.distinct('b', {a: 1}));
var explain = runDistinctExplain(coll, 'b', {a: 1});
assert.commandWorked(explain);
assert.eq(1, explain.executionStats.nReturned);
assert(!planHasStage(db, explain.queryPlanner.winningPlan, "FETCH"));
assert(planHasStage(db, explain.queryPlanner.winningPlan, "PROJECTION_COVERED"));
assert(planHasStage(db, explain.queryPlanner.winningPlan, "DISTINCT_SCAN"));
})();
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