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/**
* Tests basic functionality of pushing $group into the find layer.
*/
(function() {
"use strict";
load("jstests/libs/analyze_plan.js");
const featureEnabled =
assert.commandWorked(db.adminCommand({getParameter: 1, featureFlagSBEGroupPushdown: 1}))
.featureFlagSBEGroupPushdown.value;
if (!featureEnabled) {
jsTestLog("Skipping test because the sbe group pushdown feature flag is disabled");
return;
}
const coll = db.group_pushdown;
coll.drop();
assert.commandWorked(coll.insert([
{"_id": 1, "item": "a", "price": 10, "quantity": 2, "date": ISODate("2014-01-01T08:00:00Z")},
{"_id": 2, "item": "b", "price": 20, "quantity": 1, "date": ISODate("2014-02-03T09:00:00Z")},
{"_id": 3, "item": "a", "price": 5, "quantity": 5, "date": ISODate("2014-02-03T09:05:00Z")},
{"_id": 4, "item": "b", "price": 10, "quantity": 10, "date": ISODate("2014-02-15T08:00:00Z")},
{"_id": 5, "item": "c", "price": 5, "quantity": 10, "date": ISODate("2014-02-15T09:05:00Z")},
]));
let assertGroupPushdown = function(coll, pipeline, expectedResults, expectedGroupCountInExplain) {
const explain = coll.explain().aggregate(pipeline);
// When $group isnever pushed down it be present as a stage in the 'winningPlan' of $cursor.
assert.eq(expectedGroupCountInExplain, getAggPlanStages(explain, "GROUP").length, explain);
let results = coll.aggregate(pipeline).toArray();
assert.sameMembers(results, expectedResults);
};
let assertNoGroupPushdown = function(coll, pipeline, expectedResults, options = {}) {
const explain = coll.explain().aggregate(pipeline, options);
assert.eq(null, getAggPlanStage(explain, "GROUP"), explain);
let resultNoGroupPushdown = coll.aggregate(pipeline, options).toArray();
assert.sameMembers(resultNoGroupPushdown, expectedResults);
};
let assertResultsMatchWithAndWithoutPushdown = function(
coll, pipeline, expectedResults, expectedGroupCountInExplain) {
// Make sure the provided pipeline is eligible for pushdown.
assertGroupPushdown(coll, pipeline, expectedResults, expectedGroupCountInExplain);
// Turn sbe off.
db.adminCommand({setParameter: 1, internalQueryEnableSlotBasedExecutionEngine: false});
// Sanity check the results when no pushdown happens.
let resultNoGroupPushdown = coll.aggregate(pipeline).toArray();
assert.sameMembers(resultNoGroupPushdown, expectedResults);
// Turn sbe on which will allow $group stages that contain supported accumulators to be pushed
// down under certain conditions.
db.adminCommand({setParameter: 1, internalQueryEnableSlotBasedExecutionEngine: true});
let resultWithGroupPushdown = coll.aggregate(pipeline).toArray();
assert.sameMembers(resultNoGroupPushdown, resultWithGroupPushdown);
};
// Baseline with SBE off.
assertNoGroupPushdown(coll,
[{$group: {_id: "$item", s: {$sum: "$price"}}}],
[{_id: "a", s: 15}, {_id: "b", s: 30}, {_id: "c", s: 5}]);
// Turn sbe on which will allow $group stages that contain supported accumulators to be pushed
// down under certain conditions.
db.adminCommand({setParameter: 1, internalQueryEnableSlotBasedExecutionEngine: true});
// Try a pipeline with no group stage.
assert.eq(
coll.aggregate([{$match: {item: "c"}}]).toArray(),
[{"_id": 5, "item": "c", "price": 5, "quantity": 10, "date": ISODate("2014-02-15T09:05:00Z")}]);
// Run a simple $group with supported $sum accumulator, and check if it gets pushed down.
assertResultsMatchWithAndWithoutPushdown(coll,
[{$group: {_id: "$item", s: {$sum: "$price"}}}],
[{_id: "a", s: 15}, {_id: "b", s: 30}, {_id: "c", s: 5}],
1);
// Two group stages both get pushed down.
assertResultsMatchWithAndWithoutPushdown(
coll,
[{$group: {_id: "$item", s: {$sum: "$price"}}}, {$group: {_id: "$quantity", c: {$count: {}}}}],
[{_id: null, c: 3}],
2);
// Run a group with an unsupported accumultor and check that it doesn't get pushed down.
assertNoGroupPushdown(coll, [{$group: {_id: "$item", s: {$stdDevSamp: "$quantity"}}}], [
{"_id": "a", "s": 2.1213203435596424},
{"_id": "b", "s": 6.363961030678928},
{"_id": "c", "s": null}
]);
// Run a simple group with $sum and object _id, check if it doesn't get pushed down.
assertNoGroupPushdown(coll,
[{$group: {_id: {"i": "$item"}, s: {$sum: "$price"}}}],
[{_id: {i: "a"}, s: 15}, {_id: {i: "b"}, s: 30}, {_id: {i: "c"}, s: 5}]);
// Spilling isn't supported yet so $group with 'allowDiskUse' true won't get pushed down.
assertNoGroupPushdown(coll,
[{$group: {_id: "$item", s: {$sum: "$price"}}}],
[{"_id": "b", "s": 30}, {"_id": "a", "s": 15}, {"_id": "c", "s": 5}],
{allowDiskUse: true, cursor: {batchSize: 1}});
// Run a pipeline with match, sort, group to check if the whole pipeline gets pushed down.
assertGroupPushdown(coll,
[{$match: {item: "a"}}, {$sort: {price: 1}}, {$group: {_id: "$item"}}],
[{"_id": "a"}],
1);
// Make sure the DISTINCT_SCAN case where the sort is proided by an index still works and is not
// executed in SBE.
assert.commandWorked(coll.createIndex({item: 1}));
let explain = coll.explain().aggregate([{$sort: {item: 1}}, {$group: {_id: "$item"}}]);
assert.neq(null, getAggPlanStage(explain, "DISTINCT_SCAN"), explain);
assert.eq(null, getAggPlanStage(explain, "SORT"), explain);
assert.commandWorked(coll.dropIndex({item: 1}));
// Time to see if indexes prevent pushdown. Add an index on item, and make sure we don't execute in
// sbe because we won't support $group pushdown until SERVER-58429.
assert.commandWorked(coll.createIndex({item: 1}));
assertNoGroupPushdown(coll,
[{$group: {_id: "$item", s: {$sum: "$price"}}}],
[{"_id": "b", "s": 30}, {"_id": "a", "s": 15}, {"_id": "c", "s": 5}]);
assert.commandWorked(coll.dropIndex({item: 1}));
// Supported group and then a group with no supported accumulators.
explain = coll.explain().aggregate([
{$group: {_id: "$item", s: {$sum: "$price"}}},
{$group: {_id: "$quantity", c: {$stdDevPop: "$price"}}}
]);
assert.neq(null, getAggPlanStage(explain, "GROUP"), explain);
assert(explain.stages[1].hasOwnProperty("$group"));
// A group with one supported and one unsupported accumulators.
explain = coll.explain().aggregate(
[{$group: {_id: "$item", s: {$sum: "$price"}, stdev: {$stdDevPop: "$price"}}}]);
assert.eq(null, getAggPlanStage(explain, "GROUP"), explain);
assert(explain.stages[1].hasOwnProperty("$group"));
// Leave sbe in the initial state.
db.adminCommand({setParameter: 1, internalQueryEnableSlotBasedExecutionEngine: false});
})();
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